East Central Solid Waste Commission SLF Expansion ...

East Central Solid Waste Commission Sanitary Landfill (SW-17) Expansion Environmental Assessment Worksheet

Table of Contents

Page 1. Project Title ......................................................................................................................................................... 1 2. Proposer ............................................................................................................................................................... 1 3. RGU ..................................................................................................................................................................... 1 4. Reason for EAW Preparation .............................................................................................................................. 1 5. Project Location ................................................................................................................................................... 1 List of Tables, Figures, and Appendices attached to the EAW .................................................................................. 2 6. Project Description .............................................................................................................................................. 2 7. Project Magnitude Data ..................................................................................................................................... 17 8. Permits and approvals required ......................................................................................................................... 18 9. Land Use ............................................................................................................................................................ 18 10. Cover Types ....................................................................................................................................................... 19 11. Fish, Wildlife, and Ecologically Sensitive Resources ....................................................................................... 20 12. Physical Impacts on Water Resources ............................................................................................................... 22 13. Water Use .......................................................................................................................................................... 22 14. Water-related land use management districts .................................................................................................... 24 15. Water Surface Use ............................................................................................................................................. 24 16. Erosion and Sedimentation ................................................................................................................................ 24 17. Water Quality – Surface-water Run-off ............................................................................................................ 25 18. Water Quality – Wastewater .............................................................................................................................. 27 19. Geologic hazards and soil conditions ................................................................................................................ 29 20. Solid Wastes, Hazardous Wastes, Storage Tanks .............................................................................................. 33 21. Traffic/Parking spaces ....................................................................................................................................... 34 22. Vehicle-related Air Emissions ........................................................................................................................... 35 23. Stationary Source Air Emissions ....................................................................................................................... 35 24. Odors, noise and dust ......................................................................................................................................... 38 25. Nearby resources ............................................................................................................................................... 40 26. Visual impacts ................................................................................................................................................... 40 27. Compatibility with plans and land use regulations ............................................................................................ 41 28. Impact on infrastructure and public services ..................................................................................................... 41 29. Cumulative potential effects .............................................................................................................................. 41 30. Other Potential Environmental Impacts ............................................................................................................. 45 31. Summary of issues ............................................................................................................................................. 46 RGU Certification .................................................................................................................................................... 46

ENVIRONMENTAL ASSESSMENT WORKSHEET

Note to reviewers: The Environmental Assessment Worksheet (EAW) provides information about a project that may have the potential for significant environmental effects. This EAW was prepared by the Minnesota Pollution Control Agency (MPCA), acting as the Responsible Governmental Unit (RGU), to determine whether an Environmental Impact Statement (EIS) should be prepared. The project proposer supplied reasonably accessible data for, but did not complete the final worksheet. Comments on the EAW must be submitted to the MPCA during the 30-day comment period which begins with notice of the availability of the EAW in the Minnesota Environmental Quality Board (EQB) Monitor. Comments on the EAW should address the accuracy and completeness of information, potential impacts that are reasonably expected to occur that warrant further investigation, and the need for an EIS. A copy of the EAW may be obtained from the MPCA by calling 651-757-2101. An electronic version of the completed EAW is available at the MPCA Web site http://www.pca.state.mn.us/news/eaw/index.html#open-eaw. 1. Project Title: East Central Solid Waste Commission Sanitary Landfill (SW-17) Expansion 2.

Proposer:

East Central Solid Waste Commission (ECSWC)

3.

RGU:

Minnesota Pollution Control Agency

Contact Person Janelle Troupe Contact Person William Lynott and Title Executive Director and Title Planner Principal Address PO Box 29 Address 520 Lafayette Road North Mora, Minnesota 55051 St. Paul, Minnesota 55155-4194 Phone 320-679-4930 Phone 651-757-2542 Fax Fax 651-297-2343 E-mail E-mail [email protected] 4. Reason for EAW Preparation:

EIS Scoping

Mandatory EAW

X

Citizen Petition

RGU Discretion

Proposer Volunteered

If EAW or EIS is mandatory give EQB rule

category subpart number and name: Minn. R. 4410.4300, subp. 17

5. Project Location: County Kanabec City/Twp Arthur Township

ECSWC owns approximately 226.5 acres located off State Highway 23, approximately four miles southwest of Mora, Minnesota (Attachment 1). The Landfill disposal area and operation facilities are located on approximately 160 acres, with the remaining area currently used as buffer property. The facility is located centrally within the ECSWC’s five-county service area, and is bounded on the south and east by County Road 60 and Imperial Street, respectively. The general site location coordinates are as follows:

SE ¼ of Section 20, SW ¼ of Section 21, NE ¼ of Section 29, Township 39N, Range 24W

GPS Coordinates: N W

Tax Parcel Number

p-ear1-04 TDD (for hearing and speech impaired only): 651-282-5332

Printed on recycled paper containing 30% fibers from paper recycled by consumers

http://www.pca.state.mn.us/news/eaw/index.html#open-eaw

East Central Solid Waste Commission Sanitary Landfill (SW-17) Expansion Environmental Assessment Arthur Township, Minnesota 2 Worksheet

Tables, Figures, and Appendices attached to the EAW:

• Attachment 1 Site Location Map • Attachment 2 U.S. Geological Survey (USGS) Topographic Map • Attachment 3 Land Use Map • Attachment 4 • Attachment 4a

Existing Conditions and Facilities Site Map Environmental Monitoring System

• Attachment 5 Site Schematic • Attachment 6 Proposed SW-17 Expansion Permit Development • Attachment 7 Expansion Construction Details • Attachment 8 Ultimate Development Plan • Attachment 9 Correspondence from Minnesota State Historical Preservation Office • Attachment 10 Correspondence from the U.S. Army of Engineers confirming No Jurisdiction for onsite

wetlands • Attachment 11 Correspondence from Minnesota Department of Natural Resources (DNR) Natural

Heritage and Nongame Program • Attachment 12 Air Emission Risk Assessment (AERA) • Attachment 13 Cumulative Effects Map

6. Description:

a. Provide a project summary of 50 words or less to be published in the EQB Monitor. The ECSWC is proposing to expand its existing municipal sanitary landfill (Landfill). More or less simultaneously, the Southern Minnesota Municipal Power Agency proposes to install an internal combustion engine/generator set on the site to burn landfill gas (LFG) and produce electricity for the power grid.

b. Give a complete description of the proposed project and related new construction. Attach additional sheets as necessary. Emphasize construction, operation methods and features that will cause physical manipulation of the environment or will produce wastes. Include modifications to existing equipment or industrial processes and significant demolition, removal or remodeling of existing structures. Indicate the timing and duration of construction activities. 1. Existing Landfill

ECSWC Sanitary Landfill (permit SW-17) is located on 226.5 acres in Sections 20, 21, and 29 of Arthur Township (Township 39 North, Range 24 West) in Kanabec County. The facility currently occupies approximately 160 acres within this parcel. The site is located approximately four miles southwest of Mora, Minnesota on the north side of State Highway 23 (Attachments 1 and 2). A Land Use Map, showing significant project and natural features, property owners within a one-mile vicinity of the Landfill, and residential wells, is included as Attachment 3. The site includes a closed unlined mixed municipal solid waste (MSW) landfill, a currently operated lined MSW landfill, a former demolition debris landfill, and a new demolition debris landfill. Prior to 1991, waste was deposited in the unlined landfill. The unlined landfill, located at the southern end of the facility, was closed in 1991 (Attachments 4 and 5). The approximate area of the closed portion of the landfill is 10 acres, and it holds approximately 629,200 cubic yards of waste. As detailed in Items 6.B.3 and 19, groundwater impacts emanating from the closed unlined portion of the Landfill have been identified in past monitoring events. This is discussed further elsewhere in this EAW, along with remediation efforts associated with the identified groundwater impacts.


Facilities currently located at the site, as indicated on Attachment 4 include: • Scalehouse and residential customer waste drop-off area • Operation maintenance building • ECSWC administrative office • Materials Recovery and Compost building and infrastructure, currently used for equipment and

material storage Attachments 4 and 5 also illustrate other site features and the currently permitted development phases. The property is bounded on the south by Kanabec County Road 60 (180th Avenue) and on the east by Imperial Road (formerly Rittenouer Road), maintained by Arthur Township. ECSWC owns additional parcels east and south of these boundaries. The surrounding owned areas (totaling approximately 66.5 acres) are used currently as buffer properties. Property surrounding the Landfill is generally zoned for agricultural and rural residential use. Access to the Landfill is restricted by fencing along County Road 60 and Imperial Road, as well as along the northern and western property boundary. A 158-acre parcel located north of the ECSWC property is owned by Knife River Corporation for the purpose of sand and gravel mining. The main gate to the Landfill is located on County Road 60 and is marked by signs identifying the facilities located on the site. The main gate remains open during business hours and is otherwise locked. A secondary entrance to the Landfill is located along Imperial Road on the eastern boundary. This entrance is used primarily for access to the soil borrow operations north of the MSW Landfill and for facility contractors, and generally remains locked. A third gate is located along County Road 60, west of the main gate, near the stormwater detention basin for the former compost facility. This gate is rarely used and remains locked. Former owners of the Landfill originally applied for and obtained an MPCA permit (SW-17) to operate a Pre-Subtitle D, unlined sanitary landfill in October 1970. In 1979, the MPCA issued a modified permit for the filling of an additional ten acres at the site. Though the additional ten acres was approved, the entire expansion area was not utilized. The ECSWC, established in 1988 as is a consortium of Kanabec, Chisago, Isanti, Pine, and Mille Lacs Counties, was formed for the purpose of managing residential and commercial solid waste. In 1988, the MPCA issued a five-year permit to the ECSWC for continued operation of the facility. In June 1991, the MPCA issued a modified permit to the ECSWC to construct and operate a lined expansion of the existing sanitary landfill. The subsequent permit amendment authorized an expansion of capacity for the disposal of 477,000 cubic yards (CY) of MSW and cover soils in the lined expansion. A permit renewal issued in May 1999 increased the total capacity for lined Phases 1 through 5 to an estimated 1,429,700 CY of airspace. The permit authorized the Landfill to utilize up to 950,890 CY of airspace as long as the Certificate of Need capacity was available. This includes compacted, in-place MSW and all daily, intermediate and final cover soil to be deposited in Phases 3A through 5.


Another permit renewal in September 2004, which included a vertical expansion within the previously identified MSW footprint, granted approval for 355,000 CY of additional disposal capacity. The locations of Phases 1 through 5 are shown on Attachments 4 and 5. The current permitted Landfill volume totals 1,784,700 CY (inclusive of all cover soils), providing MSW and demolition debris disposal capacity to ECSWC customers through 2010. The September 2004, permit reissuance also allowed ECSWC to begin a pilot leachate recirculation study. The purpose of leachate recirculation is to stabilize the waste, reduce its volume, and maximize LFG production to be burned in the flare and genset for greenhouse gas reduction (see Item 23 below). Leachate recirculation operations are limited to Phases 4 and 5. The leachate recirculation system was constructed in 2004 and recirculation began in October 2004. The permit modification approval included additional facility monitoring parameters, and operation and monitoring reports to be submitted to the MPCA on a quarterly basis. The ECSWC Materials Recovery and Compost Facility (SW-360) was permitted by the MPCA in 1990 (Attachments 4 and 5). Regionalized planning and cooperation were necessary to finance and construct a facility of this type that was undertaken by the ECSWC in an effort to comply with the goals and objectives of the Waste Management Act. The Materials Recovery and Compost Facility was designed with a capacity of 250 tons per day. The facility operated until the summer of 1994, when it was damaged during a fire. The facility has not operated since. In 1995, ECSWC entered into an operations agreement with a composting and recycling company to operate this component of facility operations. However, the contracted facility operators were not able to produce a useful compost product, and could not operate the system in an economical manner. The operations agreement was, therefore, terminated in 1999. ECSWC currently has no plans to resume the MSW processing operations. The ECSWC and its serviced counties developed a Solid Waste Management Plan in 2006 that identifies the Landfill as a means of disposal for waste not reused or recycled. A three-acre construction and demolition (C&D) debris landfill (SW-415) on the 160-acre ECSWC site was permitted in 1992 (Attachments 4 and 5). The demolition debris landfill was operated until 2004, when ECSWC transferred the existing C&D waste in-place to the MSW footprint as part of the 2003 SW-17 permit reissuance. C&D waste was disposed of in the MSW landfill until 2008. In 2007, the MPCA approved a new C&D material landfill to the north of the existing MSW landfill, beneath the subgrade of the proposed MSW expansion area. The new C&D Landfill is incorporated into the facility’s current MSW permit, SW-17 and has been utilized exclusively for C&D material disposal since September 2008. The C&D expansion area is excavated and graded prior to demolition fill placement. The Landfill currently places demolition material in both the MSW Landfill and the C&D expansion area, depending on the quantity of demolition materials received and weather conditions allowing access to the C&D expansion area. MSW collection within the ECSWC service area is supported by transfer stations located near Cambridge (SW-400) and Hinckley (SW-401). Both transfer stations are owned and operated by the ECSWC. A portion of waste generated in Aitkin County is transported through a transfer station owned by Garrison Disposal before being hauled to the Landfill. A portion of waste generated in Chisago County is transported through a privately-owned transfer station before being transported to the ECSWC transfer station in Cambridge.


2. Proposed Expansion

The current MPCA permit divides the Landfill into five MSW phases, identified as Phase 1 through 5, and four C&D phases identified as Phase 1 through 4 (Attachments 4 and 5). The current permitted capacity of the MSW Landfill is 1,784,700 CY. The current permitted capacity of the C&D Landfill is 126,500 CY. The current solid waste permit renewal application seeks MPCA approval for the construction of additional MSW landfill cells Phase 6A and 6B, north of MSW Landfill Phase 5 and construction of additional C&D landfill Phases 5 and 6, west of C&D Landfill Phase 4 (Attachment 6). Associated construction details with this proposed expansion are included as Attachment 7. An ultimate development plan has been developed for the MSW Landfill, consisting of expansion through Phase 9, and is presented as Attachment 8. The total additional volume of MSW ultimate disposal capacity, if developed as planned and approved by MPCA, would be 9,035,823 CY, representing approximately 88 years of operating life based on current and projected disposal rates. The current permit application and this EAW address disposal for a ten-year time period. Future developments will be subject to new permit renewals and environmental review under rules and policies then in effect. As described in Item 6.B.A, the proposed expansion included with the November 2009 solid waste operations permit application includes two additional MSW waste cells, providing an additional MSW disposal capacity of 968,022 CY, and two additional C&D waste cells, providing additional C&D disposal capacity of 116,121 CY. Annual MSW volumes received at the Landfill have remained relatively flat, at around 75,000 tons per year for the past four years. A slight increase in tonnage was gained from 2006 to 2008 due to a new hauler from Aitkin County. The ECSWC submitted a waste designation plan to the MPCA Policy, Local Government Assistance and Solid Waste Section in 2008. Should the waste designation plan be approved at both state and local levels, it is projected the waste received by the Landfill would be approximately 92,000 tons per year. Either way, annual volumes are expected to remain relatively consistent throughout the life of the Landfill, with any slight increase in tonnage due to population growth offset with increased recycling and waste reduction efforts. The table below presents the recent annual waste flows as well as for future waste flows assuming the project is permitted.

Annual Waste Flow Summary

Year Annual MSW Disposed (Tons)

Annual Airspace Consumed(1) (CY)

End of Year Remaining Airspace (CY)

2008 80,966 91,229 255,193 Continue Phase 5 Fill 2009 80,000 90,141 125,659 2010 80,000 90,141 514,821 Build Phase 6A 2011 92,000 103,662 411,159 2012 92,000 103,662 307,497 2013 92,000 103,662 203,835 2014 92,000 103,662 577,506 Build Phase 6B 2015 92,000 103,662 473,844 2016 92,000 103,662 370,182

-continued-


Year Annual MSW

Disposed (Tons) Annual Airspace

Consumed(1) (CY) End of Year Remaining

Airspace (CY)

2017 92,000 103,662 266,520 2018 92,000 103,662 162,858 2019 92,000 103,662 898,004 Build Phase 6C3 (1) Based on AUF of 1,775 lbs per CY (2) Prorated waste to be placed after April 22, 2008 (3) Expansion of the Landfill through Phase 6C will be included in the subsequent solid

waste operation permit application and environmental review

Previous C&D disposal records, along with hauler’s proposals, indicate the annual gate C&D disposal volumes are expected to range anywhere from 1,000 CY to 20,000 CY. At 20,000 CY, and a 50 percent expected compaction volume, a ten-year volume disposal would require approximately 116,500 CY. This volume represents the C&D Landfill expansion of Phases 5 and 6, included in the solid waste operation permit renewal application.

3. Environmental Protection Features Several features have been incorporated into existing portions of the Landfill to mitigate environmental impacts. These features have been designed to comply with permit requirements and MPCA regulations. The proposed expansion cells will be equipped with these features as well. Key environmental protection features are described below: WASTE SCREENING Wastes accepted at the Landfill include primarily commercial, municipal, and residential waste material. Small amounts of non-hazardous industrial material are allowed under special acceptance requirements of the ECSWC Industrial Solid Waste Management Plan. These materials are documented and tracked separately from other MSW. As mentioned in Item 6.B.1 above, demolition debris is currently disposed of either within the existing MSW Landfill or in the C&D expansion area. Screening of incoming demolition debris is conducted prior to placement to remove unacceptable materials from the C&D expansion area. The C&D disposal area is located beneath what will eventually be the sideslopes of the proposed MSW Landfill expansion area. There will be a minimum ten-foot buffer between the top of demolition debris and the side slope subgrade for Phases 6 through 9. Special wastes and common recyclable materials such as white goods (mainly waste appliances), tires, and scrap metal are not accepted in the disposal area, but are directed to a specific area for consolidation and recovery. The Landfill does not accept hazardous waste, untreated sewage sludge, septic tank pumpings, infectious wastes, radioactive wastes, or waste containing free liquids, which are prohibited by law. Landfill personnel identifying waste not acceptable for disposal will, or request the customer to, divert or transfer the material to the proper disposal or recycling facility.


PHASED DEVELOPMENT AND CLOSURE In general, operations will be performed in a manner that provides a logical sequence of filling that will bring the area to final grade as soon as possible, minimize problems associated with access to the working face, and provide adequate surface water drainage during the filling process. The currently permitted portion of the Landfill has been designed to be constructed and closed in a total of five phases, identified as Phases 1 through 5. As the Phase 5 disposal area approaches fill capacity, Phase 6 will be constructed and intermediate cover will be placed on Phase 5. Areas reaching final grade with no remaining capacity will be scheduled for final closure. This phasing method will be continued for the remainder of the Landfill ultimate development, to Phases 7, 8, and 9, if approved by future permitting processes. The following table summarizes the area, volume, and life expectancies of existing and proposed lined Landfill development phases.

Summary

Phase Surface Area

(acres)

Waste/Daily Intermediate Cover

Airspace Volume (cubic yards)

Estimated Remaining

Life (years)

Status of Disposal Area

1-5 19.2 1,707,217 <1 Active 6A & 6B 8.6 917,242 10 Proposed

6C 5.4 838,807 7 Ultimate Development 7 11.5 1,926,543 19 Ultimate Development 8 10.8 2,096,279 20 Ultimate Development 9 13.0 3,256,951 32 Ultimate Development

Total Phases 6-9 49.3 9,035,823 88 Total 68.5 10,743,040 88

Note: Total surface area for expansion phases include existing landfill areas planned for vertical expansion. Waste/Daily Cover Airspace Volume does not include Final Cover

LANDFILL LINER SYSTEM Landfill liners are hydraulic barriers designed to minimize the migration of leachate beyond the landfill's boundaries. In addition, landfill liners help minimize LFG migration. Composite liners are composed of a primary liner (a high-density polyethylene geomembrane) underlain by a secondary liner (a layer of low-permeable soil, such as clay) (Attachment 7). Composite liner are now regarded as the state-of-the-art proven technology for MSW landfills because of their low permeability and inherently redundant design. A continuous composite liner (two feet of low-permeability clay soil plus a 60-mil thick high density polyethylene [HDPE] geomembrane) is currently in place in Phases 1 through 5. The proposed composite liner system will be installed in a similar manner for proposed expansion areas and will be tied into existing portions of the Landfill to form a continuous barrier. A technical description and engineering design specifications are included in the October 2009 Permit Reissuance Application report for the Landfill. This report may be reviewed at the Landfill office (on site), or at the MPCA offices in St. Paul or Brainerd, Minnesota. Prior to installation of the liner in the proposed expansion area, demolition debris may be placed below the side slope liner of each expansion area. To ensure the liner is not damaged, a minimum ten-foot compacted on-site soil buffer will be placed between any demolition debris and the new liner. Lining is not required for demolition debris since only stable materials (e.g., concrete) are accepted at the facility.


The proposed composite liner system consists of (described from finished grade downward): • Drainage Layer. A one-foot thick drainage layer will be constructed of permeable sand. This

drainage material will protect the liner system from MSW fill and allow for movement of leachate to the collection sumps

• Geomembrane (primary liner). A 60-mil thick HDPE geomembrane is proposed because of its superior resistance to puncture, weathering, and chemical attack The geomembrane may be textured for slope stability purposes if leachate recirculation is incorporated into the expansion area.

• Barrier Layer (secondary liner). Two feet of compacted low-permeability material (clay) with an in-place compacted permeability less than 1 x 10-7 cm/sec, pursuant to MPCA requirements.

• Subgrade. In-place compacted material graded to minimum two percent to five percent bottom slopes (toward the leachate collection pipes) and 3:1 side slopes. The subgrade will be either native, acceptable soils or a minimum of ten feet of earthen cover if demolition debris is placed beneath the sideslopes.

• Demolition Debris Layer. Ten feet below the liner, a demolition debris fill area will be placed along the northern, eastern, and western side slopes of the MSW fill area (see Attachment 8).

FREEZE PROTECTION In accordance with Minn. R. 7035.2815, subp. 13, Item U, a minimum of six feet of waste will be placed within open cells in order to provide frost protection. As part of the cell construction procedure, two feet of straw will be placed over the composite liner footprint in the event there is not enough waste available to be placed in a timely manner. The straw will be removed prior to waste placement to prevent bio-fouling of the sand drainage layer. LEACHATE COLLECTION, LEAK DETECTION, AND TRANSMISSION Leachate is created from water percolating through or coming in contact with the MSW. The leachate collection system consists of drain material and perforated pipe above the liner system to collect any leachate that is produced in the Landfill and move it to the leachate treatment and storage areas. The design of the Landfill includes a stormwater system to prevent surface water run-on during active operations and a low-permeability final cover to reduce precipitation infiltration after closure. Together, these systems are intended to substantially reduce the amount of leachate that is produced after landfill closure. The proposed leachate management system will expand on the existing system installed for Phases 1 through 5 to include: • Drainage layer to efficiently transmit leachate toward the leachate collection pipes • Leachate collection pipes within a gravel drain • Leachate collection pipe cleanouts • A transducer to measure the leachate head above the low point in the liner system • Leachate collection sumps, side slope risers (SSRs), and vaults • Leachate transmission main around the northern and eastern Landfill boundary to the leachate

treatment ponds or the above ground storage tanks (ASTs) The Landfill bottom is graded so that the drainage layer slopes toward the low point of the liner and collects within a gravel sump.


The proposed leachate collection system includes perforated pipe positioned within each sump and within the gravel backfill. Each of these pipes, termed an SSR, angles toward the perimeter of the Landfill into a leachate collection vault. Access to the SSR is provided within the vault located at the berm. A submersible pump will be set at the base of each SSR to transfer leachate from the sump to the vault. Each pump discharge line will enter a lateral to a leachate transmission main, which will convey the leachate to the leachate storage and treatment system. A sample port will be provided for leachate monitoring of each phase, if necessary. The proposed liner system will also be equipped with leak detection as another means of environmental protection. At the low point in each phase, adjacent to the leachate collection sump, an underlying leak detection lysimeter sump will be constructed so as to collect any leakage through the liner. A pipe will be installed at the base of the lysimeter sump within the gravel backfill. This pipe will transition to a solid leak detection riser pipe, as the base of which will be installed to transfer liquid collected within the lysimeter into the leachate collection system. A sample port will be provided for monitoring of each leak detection riser pipe. Leak detection results are reported to the MPCA as required under the solid waste operations permit. The leachate transmission main has been sized for expected maximum leachate volumes without increasing hydraulic head on the liner system to more than one foot. The inner pipe carries leachate from each of the vaults to the ponds or the ASTs; the outer pipe acts to contain leaks, should they occur, from the inner pipe. STORMWATER CONTROLS Minn. R. 7035.2815, subp. 5 (D-F) require the installation of stormwater controls at MSW landfills to divert surface water drainage around and away from the site operating area; to design and maintain slopes and drainage ways to prevent stormwater erosion; and to provide sediment settling ponds if run-off would otherwise carry excessive sediment off the facility property. The ECSWC has a National Pollutant Discharge Elimination System/State Disposal System General Stormwater Permit MNG611000 for Industrial Activity (Permit ID #SWIS00017-SW). As part of the permit approval, a Stormwater Pollution Prevention Plan (SWPPP) was prepared to identify and monitor best management practices for stormwater control at the facility. The SWPPP is available for review at the Landfill office (on site), or at the MPCA offices in St. Paul and Brainerd, Minnesota. Stormwater controls are necessary to limit leachate generation and surface water ponding during active filling and prevent it after closure. These controls will: 1) intercept precipitation falling on or near the active fill area and route it away from the waste; 2) control run-off/run-on near support facilities such as the storage and treatment ponds; and 3) divert run-off from the low-permeability cover system after final closure. Run-off from active areas of the Landfill will be directed back into the working face as much as reasonably practicable. Any run-off or precipitation that comes in contact with waste is collected and managed as leachate. Drainage ditches have been constructed around the perimeter of the existing Landfill to divert stormwater run-off to sedimentation basins for precipitation of fines and infiltration to groundwater. Overland discharges from the sedimentation basins go to wetlands located on adjacent ECSWC property east of the Landfill. The topography of the site in addition to the drainage berms minimizes stormwater run-on. There are currently three sedimentation basins used to control stormwater drainage from the Landfill; a basin located near the maintenance building, a basin located near the leachate loadout on the southeast portion of the property, and a temporary basin located north of Phase 5, within the proposed Phases 6A and 6B expansion area (Attachment 6). An additional sedimentation basin is located on the property, near the former


Materials Recovery and Composting Facility, though it does not accept stormwater run-off from the Landfill. The Southeast Basin (near the leachate loadout) will be enlarged as part of the Landfill expansion to accept run-off from Phase 6A. This basin will continue to discharge to the wetland at the southeast corner of the Landfill property. The sedimentation basin currently located north of Phase 5 will be filled in during the construction of Phase 6A, and in its place, a temporary sedimentation basin north of Phase 6A (within the proposed Phase 6B expansion area) will be constructed. Similarly, during the construction of Phase 6B, a temporary sedimentation basin will be constructed in Phase 6C, north of Phase 6B. High intensity storms are characteristic of the area. For the Kanabec County area, the 25-year, 24-hour precipitation is 4.55 inches. Stormwater controls are designed for the 25-year, 24-hour stormwater event. In accordance with the Minnesota Stormwater Manual, sedimentation basins are designed as wet basins to temporarily store and control the discharge of the 1-year, 10-year and 100-year stormwater event, while maintaining a permanent pool volume. COVER SYSTEMS Minn. R. 7035.2815, subp. 6 (D, C, and E) requires daily, intermediate, and final cover systems to control LFG movement; to prevent surface water ponding; to reduce erosion, litter and dust; to retain slope stability; to reduce the effects of freeze-thaw; to maintain vegetative growth; and to control vectors. The cover systems at the Landfill will include the following elements (Attachment 7): Daily Cover During active landfill operations, placement of clean soil or alternate material over compacted refuse will reduce odors, litter, and vermin and limit the amount of precipitation percolating through the refuse. Daily cover material will consist of on-site soils, or an approved alternative daily cover. Intermediate Cover System Whenever a waste cell is not expected to receive additional overlying waste for at least 30 days, it will be covered with an intermediate, rather than daily, cover system. Intermediate cover will be placed at a minimum depth of 12 inches over the underlying compacted refuse. The intermediate cover will be graded to prevent surface water ponding and to further promote run-off and evaporation of any precipitation falling on the cell. Once a cell is filled to final elevation, intermediate cover will be placed over the waste for a period of time to allow settling. Areas of settlement will be filled with waste, if airspace is available, and then additional intermediate cover material to attain uniform sloping prior to final cover construction. Existing intermediate cover will be removed prior to placement of additional waste. Final Cover System Once a portion of the Landfill reaches final grade with minimal settlement, construction of a low-permeability final cover is the most effective way to minimize the production of leachate. The main functions of the final cover are to reduce moisture infiltration, to enhance evapotranspiration and run-off, and to minimize LFG emissions. As per Minn. R. 7035.2815, subps. 6 and 7, the final cover system must be designed and constructed to contain or reject at least 90 percent of the precipitation falling on the system; and the liner system in combination with the cover system must achieve an overall site efficiency of 98.5 percent collection or rejection and minimize the amount of leachate leaving the fill site to the


soil and groundwater system below the site. The proposed combined cover/liner system performance was analyzed using the HELP (Hydrologic Evaluation Landfill Performance) Model version 3.07 and efficiency was determined to be greater than 98.5 percent, in accordance with Minn. R. 7035.2815, subp. 7. The final cover system will have minimum slopes, for the crown, of 5 percent and maximum side slopes of 33 percent. Stormwater terraces, or benches, will be constructed every 40 vertical feet for all slopes greater than 20 percent to control stormwater drainage and reduce the potential for erosion. The final cover system will consist of: • Soil Layer: A 24-inch soil layer that includes 6 inches of topsoil to promote vegetative growth.

The lower 12 inches act to minimize root penetration into the drainage layer and to maximize the evapotranspiration potential, thus adding stability to the topsoil layer. An additional six inches of cover soil will be placed on 3:1 side slopes. The topsoil will be tested to determine its nutrient mixture requirements. The seed mix selected will produce a hardy but shallow-rooted grass cover.

• Drainage Layer: Different drainage layers are proposed for the Landfill side slopes and crown.

A. Side Slopes – Geocomposite: A geonet encased on both sides by geotextile fabric will be installed above the geomembrane on side slopes greater than 20 percent to protect the barrier layer and to promote lateral drainage of surface water above the geomembrane cover.

B. Crown – Sand: A 12-inch layer of sand will be placed on the crown for lateral drainage of surface water above the geomembrane cover.

• Geomembrane Barrier Layer: A 40-mil linear low density polyethylene geomembrane will be placed above the soil buffer layer. It is recommended because of its tear resistance when sustaining waste differential settlement. The geomembrane is anchored into the perimeter trench with the liner HDPE. The quality assurance/quality control program for geomembrane installation will include both destructive and non-destructive seam testing and strict criteria for geomembrane manufacturing, storage, handling, and placement. For slopes greater than 5:1, a textured (both sides) geomembrane will be specified.

• Buffer Layer: The six-inch soil buffer layer will be graded in one minimum six-inch lift. Stones and sharp objects will be removed and the material will be free of organics and have less than five percent fines. The buffer layer provides a smooth, stable base for the geomembrane.

• Intermediate Cover Layer: A 12-inch intermediate cover foundation layer will allow for gas transmission upward to vent points and movement of leachate down the landfill side slopes to the drainage layer of the liner system. This layer will be graded to a smooth, uniform foundation that is free of depressions. Large rocks greater than three inches in diameter, and other extraneous materials, such as sharp objects, will be removed.

LEACHATE MANAGEMENT Leachate from MSW landfills has a variable composition that depends upon waste characteristics, rate of moisture infiltration, and landfill age. Generally, for a given layer of waste, the strength, or parameter concentrations, of the leachate will be related to the biological degradation of the waste. Typically, the leachate will increase in strength over the first few years, and then gradually decrease in strength.


Leachate generated from the lined phases of the Landfill currently discharges into either an on-site 550,000-gallon leachate storage and treatment pond, or to a 28,000-gallon AST. Leachate can be transferred from the AST to the pond vault, and pumped from the pond or AST into a tanker truck for transportation to the Metropolitan Council Environmental Services (MCES) wastewater treatment facility in St. Paul for treatment and disposal. The ECSWC is proposing an additional, one million-gallon leachate storage pond north of the existing 550,000-gallon pond. The proposed pond will be used for additional leachate storage and treatment. The pond liner profile for both ponds is as follows in descending order: • 60-mil textured HDPE geomembrane (primary) • Bentonite geosynthetic clay liner (GCL) • Geocomposite drainage layer (geonet with geotextile on each side) • 60-mil smooth HDPE geomembrane (secondary) • Geotextile cushion A perforated leak detection collection pipe is located at the sloped low area of the pond, between the GCL and the secondary geomembrane, and is backfilled with drainage stone. The pipe transitions to a solid wall pipe, and extends up the sideslope between the GCL and secondary liner, daylighting as a leak detection standpipe (LDSP) located beyond the perimeter of the pond. Each LDSP has a dedicated pump that discharges any liquid back into the pond. The perimeter berm of the pond will be raised a minimum of one foot above the surrounding ground surface to prevent run-on of surface water into the pond. The existing pond valve vault will be retrofitted to allow transfer to the proposed pond from the existing leachate management system. Per MPCA approval, a pilot leachate recirculation system is currently in operation at Phases 4 and 5. This system pumps leachate back into the Landfill through recirculation laterals (RL) and a granular bed (GB) located within the waste. Benefits associated with leachate recirculation include: • Reduction in volume of leachate sent to MCES for treatment and disposal • Reduction in the leachate concentration of volatile organic and metal compounds • Increased compaction and settlement, thereby optimizing airspace utilization • More rapid production of methane gas Areas that are monitored to reduce potential risks associated with leachate recirculation include leachate head buildup on the liner, metals concentrations, waste moisture content, LFG production, and perimeter air quality. Each of these parameters has been monitored since leachate recirculation began. Results are presented in the Leachate Recirculation Pilot Study Quarterly and Annual Reports submitted to the MPCA. System adjustments have been implemented as necessary. Implementing a full-scale leachate recirculation program within the proposed Landfill development is conditional upon MPCA approval. Following completion of the current pilot study, a final report providing results and recommendations for long-term leachate recirculation will be submitted to the MPCA for review. Upon MPCA approval of the proposed long-term leachate recirculation system, the current system would be extended into the proposed expansion area. The current leachate management system (LMS) consists of the following elements: leachate collection and treatment, leak detection, a pilot leachate recirculation project, and ultimate disposal. Proposed modifications to the existing LMS include land application of treated leachate and full-scale leachate recirculation operations. Leachate will be collected through the leachate collection system and transferred via double containment mains to either the leachate storage and treatment


ponds or the ASTs. The existing and proposed storage and treatment pond will be used during active filling of Phases 6A and 6B. This pond will be designed to complete recirculation, land application, and treatment. Currently, no treatment is required prior to disposal at the MCES facility. However, the existing and proposed storage and treatment ponds will be aerated to reduce concentrations of 5-day Biochemical Oxygen Demand, Chemical Oxygen Demand (COD), and nitrogen. The MCES Special Discharge Permit that allows the disposal of the leachate has specific monitoring and reporting requirements. Samples are collected monthly for analysis of COD, pH, and Total Suspended Solids concentrations and quarterly for analysis of an extensive list of inorganic, volatile organic, and semi-volatile organic constituents. Leachate volumes and laboratory analytical data are submitted within quarterly special discharge reports. Leachate quality data have been provided in past Landfill Quarterly and Annual Reports. Approximately 2,200,031 gallons of leachate were generated in 2007 from Phases 1 to 5, and 2,166,908 gallons were hauled from the Landfill for disposal at the MCES in St. Paul. As part of the MPCA-approved leachate recirculation system pilot project, 2,864,897 gallons were recirculated into the Landfill in 2007. Recirculation allows the ECSWC to take advantage of such benefits as operational flexibility when the pond and ASTs are at capacity, increased rate of waste stabilization, leachate storage and volume reduction within the waste, accelerated Landfill settlement prior to final closure, and reduced leachate disposal costs. The proposed leachate land application would initially be conducted using the seven acres immediately west of the former demolition debris landfill. This area is depicted on Attachment 6. This application area will provide a minimum 100-foot buffer distance from the property boundary. A second phase of the leachate land application is also proposed for the approximately 18 acres of land north of the initial seven-acre parcel. This second phase will likely be constructed within the next three years. A construction schedule for the second phase of the leachate land application program has not yet been proposed, and construction will occur as financial considerations allow. The second phase will be constructed in a similar manner to the first phase of the leachate land application system presented in this document and in the October 2009 solid waste operation permit renewal application. Proposed design details for the second phase will be submitted to the MPCA for approval prior to construction. The proposed leachate land application area (Attachment 6) was previously vegetated with oak trees, some poplar trees, and other deciduous vegetation. The trees were logged because the area had previously been considered for use as a demolition fill area, which ultimately was permitted in a different location. The area, currently undisturbed land, will be cleared, grubbed, leveled with additional site soil, and planted with reed canary grass prior to application. Reed canary grass is a vigorous species, a good sod building grass that is opportunistic and will spread to open areas. It also provides for a large uptake of nitrogen. The land application site is not within 600 feet of any downgradient, private water supply wells or 1,000 feet of any public water supply wells. The surrounding properties of the land application site are primarily wooded, rural residential, and commercial (i.e., aggregate mining). The proposed application system is a fixed sprinkler head system that would be supplied by a forcemain connecting to a valve at Recirculation Manhole 5 (RM-5), located on the east side of Phase 5. The treated leachate designated for land application will come from the secondary (one million-gallon) leachate treatment pond, which will be routed to RM 5. Treatment standards for the leachate designated for land application are described in the October 2009 solid waste operations


permit reissuance application report. The sprinkler system would consist of approximately 27 stationary sprinklers with the capability of spraying a radius of approximately 70 feet each. The proposed system will provide total coverage of the initial seven-acre proposed land application area. The pumping system delivering the treated leachate from the manhole will be set on an electronic timer, to run on a one-hour duration per zone, per event. The system is designed with five zones of four to six sprinkler heads per zone, per event. Each zone will operate for approximately one hour, and the entire spray field will be irrigated in approximately five hours. The intended sprinkler (Rainbird 70H sprinkler head) is rated at 21.4 gallons per minute, which will deliver 1,284 gallons per hour over an area of 14,095 square feet. This converts to an application rate of 0.15 inches per hour, and which is less than the maximum application rate for site specific conditions outlined in Table 1 of the MPCA “Land Treatment of Landfill Leachate” guidance document (0.2 to 0.4 inches per hour for silty clay loam and clay, for less than a three percent slope). GAS CONTROL, ELECTRICAL GENERATOR, AND MONITORING SYSTEMS Decomposition of organic wastes in a landfill will produce various gases - principally methane and carbon dioxide. LFG usually contains between 40 percent and 50 percent methane and 50 percent to 60 percent carbon dioxide in. Gas production is a concern because of the combustibility (e.g., the lower and upper explosive limits of methane are 5 percent and 15 percent by volume), the potential release of odorous and/or noxious emissions to the atmosphere, and greenhouse gas emissions. If not restricted, the gas produced by refuse decomposition within a landfill may escape either by vertical or lateral movement. The liner system is designed to reduce/prevent lateral migration of LFG, while the cover system is used to limit vertical gas emissions. As required under Minn. R. 7035.2815, subp. 11, ECSWC implements a plan that includes gas probe, building, and confined space LFG monitoring. The existing gas probes are indicated on Attachment 4. The probes are monitored quarterly for methane and oxygen concentrations. Site structures are monitored monthly. The monitoring program also records a temperature, weather conditions, precipitation, evidence of frost, and barometric pressure at the time of sampling. The MPCA will be notified if methane concentrations exceed the lower explosive limit (LEL) at the property boundary or 25 percent of the LEL within site structures. During each monthly gas monitoring event, the LFG wells and recirculation lateral cleanouts are measured for percent methane and oxygen, as required by the recirculation pilot demonstration program. Gas monitoring results are forwarded to the MPCA quarterly. ECSWC voluntarily installed a gas collection and control system (GCCS) in 2005 within the MSW Landfill to actively collect LFG produced by the Landfill that otherwise would be passively emitted to the atmosphere. The GCCS currently consists of 16 vertical LFG wells installed to a depth of approximately 80 percent of the waste thickness, one dual phase extraction well (DPW-1) installed above the Phase 3 leachate collection sump, tie-in connections to the leachate collection cleanouts, leachate recirculation lateral cleanouts and leachate collection sump SSRs, lateral and header piping to route the collected LFG, and a blower/candlestick flare system to collect and combust the LFG. The GCCS began operation in October 2005 and has continued to operate without significant adverse incidents. This system is monitored weekly for LFG flow, and the content of methane and oxygen. ECSWC signed a LFG purchase agreement with the Southern Minnesota Municipal Power Agency (SMMPA) in June 2008. The agreement includes diverting a portion of the LFG collected within the GCCS to fuel an electric generator. All equipment associated with the electric generation will be situated on the Landfill property, near the former materials recovery and compost buildings. The


location of the proposed engine and generator is included on Attachment 6. The proposed engine is a Caterpillar G3520C rated for low energy fuel, such as LFG. The engine provides a continuous energy output of approximately 1,600 kilowatts. The generated electricity will be introduced into the city of Mora, Minnesota utility grid. A discussion of potential air emissions from the engine is presented in Item 23. The generator set will be housed on a concrete pad within a sealed enclosure, to protect the equipment from outdoor elements. The engine area will be fenced off for security. The housing unit will be prefabricated and no site building structures will be required. The engine will be connected into the existing GCCS at the vacuum blower equipment pad, and piping and associated valves will route the collected LFG into the engine. Additional piping will be required to route condensate liquid generated from engine operations into the existing GCCS condensate collection system. It is anticipated that the engine will be operated using separate controls and monitors, although safety devices may be incorporated for emergency shutdown procedures for the flare and engine. The existing LFG flare will remain in place as a backup destruction device during engine maintenance downtime or repair work. A significant amount of downtime or maintenance work for the engine is not expected. Therefore, once the engine is installed and operating, it will be the primary destruction device for the collected LFG. Construction is anticipated to begin within approximately two to three months after MPCA approval of the facility air permit, with electricity production from the LFG to begin after completion of construction.

Commencement of construction of the proposed expansion will trigger applicability of the federal New Source Performance Standard (NSPS) for Municipal Solid Waste Landfills (Subpart WWW). This standard requires annual determination of non-methane organic compound (NMOC) emissions. When annual NMOC emissions (calculated or measured using a three-tier approach as prescribed in NSPS Subpart WWW) exceed 50 megagrams (Mg), NSPS Subpart WWW requires installation of a GCCS. Until the calculated or measured NMOC emissions exceed 50 Mg, the existing GCCS is considered “voluntary” with respect to NSPS Subpart WWW. However, ECSWC is not proposing to discontinue operation of the GCCS. ECSWC proposes to expand the existing GCCS by installing horizontal LFG extraction collectors in development areas. The LFG horizontal wells will be installed during active filling at intervals of 200 feet horizontal spacing and 40 feet vertical spacing, and will alternate vertically between RLs or GBs. Since they are installed during waste filling rather than when final grades are attained, horizontal collectors will more efficiently maximize LFG collection and odor control. The existing gas transmission and flare infrastructure will be expanded as necessary to accommodate the additional gas collection, including connections to the future cell recirculating laterals and granular beds, leachate collection pipe cleanouts and SSR pipes. Perforated six-inch diameter casing pipe will be installed in a trench within the waste layer. The perforated section of casing will terminate at least 50 feet from the liner or cover geomembrane, while the remaining pipe will be solid. The trench will be backfilled with washed stone or other permitted media. The vertical pipe penetration through the cover geomembrane will be sealed and the annular space will be capped with a clay/bentonite seal. The casing will extend above final grade and will be fitted with a horizontal gas well head and gas control system for connection into the GCCS.


ENVIRONMENTAL MONITORING NETWORK The Landfill has in-place an environmental monitoring system that provides for early detection of potential leachate releases from the facility, including the closed unlined area, the existing permitted lined phases, the proposed phases of the Landfill, and the leachate storage and treatment ponds. The system incorporates both groundwater and surface water monitoring points selected in association with the hydrogeologic conditions that have been defined for the Landfill. As discussed in Item 19, hydrogeologic evaluations were most recently completed in 2005 for the North Development Area (NDA) and 2006 for the Northwest Development Area (NWDA). The NDA coincides with proposed Phase 6, and the NWDA includes proposed ultimate development Phases 7, 8, and 9. These investigations, combined with previous work, have included 74 soil borings, and 44 monitoring wells installed at 32 different locations. All monitoring wells were installed in accordance with MPCA approved work plans, permits, and the Minnesota Department of Health (MDH) Well Construction Code. During the operating history of the facility, minor modifications to the monitoring system have been necessary in response to phased development and groundwater quality data. A summary table of the site groundwater monitoring wells is available upon request. Shallower wells (water table wells) are designated with an “A” suffix and the deeper wells with a “B” or “C” suffix. Monitoring well locations are shown on the site map included as Attachment 4. Based on the predominant southeasterly groundwater flow direction, monitoring wells west of waste disposal areas can generally provide upgradient or background water quality, and wells to the east monitor for potential releases from the facility. It is noted that groundwater quality impacts have historically been identified at the Landfill and specifically associated with the old unlined portion of the Landfill. Over time, and as reported in Annual Reports, the impacts have diminished. There have been no confirmed groundwater impacts attributed to leakage from the lined landfill cells. Water quality from the monitoring system is addressed further in Item 19.a. The Landfill compliance boundary was originally approved by the MPCA in October 1991 at the conclusion of the initial phased hydrogeologic investigation. In mid-1995, the compliance boundary was revised per discussions with the MPCA to accommodate additional lined landfill phases. Compliance boundary monitoring points have subsequently been added to account for Phase 5 and the newly permitted Demolition Landfill cell. The current compliance boundary monitoring locations effectively monitor the current Landfill operations with monitoring points generally in place for future phases. The compliance boundary is illustrated on the site map included as Attachment 4. The monitoring program also incorporates two surface water monitoring stations and a number of nearby residential water supply wells. The surface water locations include the sedimentation basin and wetland in the southeastern corner of the site. Residential water supply well testing has been conducted at selected wells required by the MPCA since 1990 and the testing results are provided to the individual residents and the MPCA. Wells routinely tested are situated downgradient (east-southeast) of the facility. Since 2003, there have been no confirmed volatile organic compound (VOC) detections in any of the residential well samples. Prior to that time, a few intermittent detections were associated with the original supply well associated with the former Fluegge residence, located across County Road 60 and immediately south of the old unlined portion of the Landfill. A deeper replacement supply well was installed in 1991 by ECSWC and was used for water supply by the residents until the Fluegge property was acquired by the ECSWC in the mid-1990s. Both the original and replacement wells remain in place and have been used strictly as monitoring wells since that time. Residential well testing is further discussed in Item 19.a.


Sample collection and analyses are completed by the contract laboratory in accordance with the Landfill permit utilizing established field and laboratory protocols that have been reviewed and approved by the MPCA. Some minor modifications to the monitoring schedule may occur in response to review of analytical data or minor changes to reissued MPCA permits.

c. Explain the project purpose; if the project will be carried out by a governmental unit, explain the

need for the project and identify its beneficiaries. The purpose of this project is to extend the permitted disposal capacity of the ECSWC Sanitary Landfill. The Landfill will continue to serve five nearby counties, including Kanabec, Chisago, Isanti, Pine, and Mille Lacs, to provide a long-term viable solid waste disposal option for the region. The beneficiaries will include the residents and businesses of the counties using the Landfill for solid waste disposal.

d. Are future stages of this development including development on any other property planned or likely

to happen? Yes No If yes, briefly describe future stages, relationship to present project, timeline and plans for environmental review. The ECSWC Sanitary Landfill has been operated as a MSW landfill since 1970 under the MPCA Solid Waste Permit SW-17. The current 2004 permit limits the volume of MSW disposed within the limits shown on Attachments 4 and 5. The proposed expansion would extend those limits both areally and vertically to provide additional solid waste disposal capacity. An ultimate development plan has been prepared for the facility and is included as Attachment 8.

e. Is this project a subsequent stage of an earlier project? Yes No

If yes, briefly describe the past development, timeline and any past environmental review. See above. An EAW was prepared on this facility in 1991.

7. Project Magnitude Data Total Project Area (acres) 160 or Length (miles) N/A

Number of Residential Units:

Unattached

0

Attached

0

Maximum Units Per Building:

Commercial/Industrial/Institutional Building Area (gross floor space):

total square feet

111,673

Indicate area of specific uses (in square feet):

Office 2,805 Manufacturing 0

Retail

0 Other Industrial (vacant buildings)

96,820

Warehouse 0 Institutional 0 Light Industrial 0 Agricultural 0 Other Commercial (specify) 12,048 Building height 2 stories If over 2 stories, compare to heights of nearby buildings


With the exception of a small modular enclosure to house the generator, there are no proposed new building structures or modifications to the existing structures on site.

8. Permits and approvals required. List all known local, state and federal permits, approvals and financial assistance for the project. Include modifications of any existing permits, governmental review of plans, and all direct and indirect forms of public financial assistance including bond guarantees, Tax Increment Financing and infrastructure. All of these final decisions are prohibited until all appropriate environmental review has been completed. See Minn. R. 4410.3100.

Unit of Government Type of Permit/Approval Status MPCA Solid Waste Disposal Facility Permit Approved SW-17; modification

required for expansion. MPCA Facility Industrial Storm Water Permit Existing SWIS00017-SW,

modification required for expansion. MPCA Construction Storm Water Permit Required MPCA Landfill Expansion Certificate of Need

(CON) Required prior to construction

MPCA Title V Air Permit – Methane Engine Facility

Submitted

MPCA Operating Air Permit – Landfill Submitted MCES Industrial Discharge Permit Approved Arthur Township Conditional Use Permit Approved Kanabec County Wetland Mitigation Approved

9. Land use. Describe current and recent past land use and development on the site and on adjacent

lands. Discuss project compatibility with adjacent and nearby land uses. Indicate whether any potential conflicts involve environmental matters. Identify any potential environmental hazards due to past site uses, such as soil contamination or abandoned storage tanks, or proximity to nearby hazardous liquid or gas pipelines. The Landfill is located on 226.5 acres of permitted solid waste property located approximately four miles southwest of Mora, Minnesota on the north side of State Highway 23. Landfill operations occur over approximately 160 acres within the 226.5 ECSWC owned property. The Landfill has a Conditional Use Permit issued by Arthur Township for solid waste activities. The Landfill was originally a privately owned and operated facility that was first permitted in 1970. Prior to use of the site for waste disposal, portions were mined for sand and gravel. The western and northern portions of the site were forested with some isolated wetland areas (Attachment 5). The original unlined and now closed portion of the Landfill occupies a mined area. In 1991, the unlined area was closed, and the new lined Landfill areas were permitted immediately adjacent to, and north of the original unlined waste deposit. The first lined Landfill cell, Phase 1, piggybacks onto a portion of the original unlined waste deposit. Subsequent development of the facility into lined Landfill cells has been preceded by mining of sand and gravel. As mentioned in Item 6.b., groundwater impacts have been attributed to the closed unlined portion of the facility. Mitigation of these impacts has included construction of a landfill cover, deep passive gas vent well installation, and more recently, active gas collection. The extent and magnitude of groundwater impacts has greatly diminished over the past decade through implementation of these actions. There have been no impacts associated with leachate leakage from the lined Landfill cells, and there is no anticipated effect of the closed unlined portion of the Landfill on the operation and continued development into the proposed phases of the facility. Water quality monitoring data is further discussed in Item 19.a.


Sand and gravel mining also occurs on adjacent property north and south of the Landfill. Mining to the north is currently conducted by Knife River Corporation, and the mining operation to the south is conducted by Bjorklund Companies. Each of these mining operations maintains a water appropriations permit for sand and gravel washing operations. The appropriations permit for the Bjorklund operation was issued in 2008 by the DNR following review of the proposed groundwater use in consideration of its proximity to the waste footprint of the Landfill. Water use at these facilities is intermittent (seasonal) and the wash water is returned and recycled to on-site infiltration basins, such that the effect of water use at these sites on groundwater flow is relatively localized and temporary. Neither of these mining operations is anticipated to affect the lined Landfill design or operation of existing or proposed phases. Other land use at the Landfill site has included the construction and operation of a material recovery and compositing facility. These operations were terminated in the 1999, although the facility structures remain near the Landfill office. Neither their past operation, nor the existing structures, pose an environmental hazard that would affect the operation or continued development of the Landfill. Portions of the current Landfill property were previously occupied by private residences. These include the Chandler, Johnson, and Templin properties on the east side of the Landfill operations site. Of these, the Templin residence was located within the current fenced in portion of the site near the leachate tank. The other two properties were located on the east side of the Township Road. These three properties were acquired by the ECSWC in 1990 and 1991. The dwellings were demolished, and the well and septic systems decommissioned. In the mid-1990’s the ECSWC acquired the Fluegge property that is located south of the closed portion of the Landfill across County Road 60. The Fluegge buildings were removed and the water supply wells converted to use strictly as monitoring wells as previously noted in Item 6.b. None of these former residential properties pose an environmental hazard that would affect the operation or continued development of the Landfill. The operation of the Landfill has generally been compatible with the neighboring sites and nearby land uses, and this is not anticipated to change with the proposed expansion. Potential environmental impacts, such as groundwater contamination, odors, noise, dust, and litter, resulting from the proposed development are discussed in previous or subsequent sections of this EAW. The future Landfill expansion will require removal of various wetlands currently located on ECSWC Solid Waste Management property. Kanabec County has approved a mitigation plan to replace these wetlands. ECSWC has purchased equivalent wetland acreage credits from a wetland bank to gain approval for the wetland removal needed for Landfill expansion. These wetlands are described in greater detail in Item 11.

10. Cover Types. Estimate the acreage of the site with each of the following cover types before and after development:

Before After Before After

Types 2-8 wetlands(1)

2.1

2.1 Urban/Suburban Lawn Landscaping (2)

49.0

50.7

Wooded/forest 27.9 10.1 Impervious Surfaces(3) 16.5 19.0 Brush/grassland Landfill Final Cover(4) 29.2 37.8 Cropland Other (describe) Type 1 Wetlands(5) 4.5 1.0 Landfill Operations(6) 30.8 39.3 TOTAL 160.0 160.0


(1) Includes 0.1 acres for Wetland G (Type 2) and 2.0 acres for Wetlands A and B (Type 3). (2) Includes sedimentation basins for stormwater. (3) Includes lined leachate storage and treatment ponds, proposed engine generator pad and paved surfaces. (4) Includes proposed final cover for Phases 1 through 5 and the Unlined Landfill. (5) Includes Wetlands I, J, Q, R, S, T, and U (Type 1 – Seasonally flooded isolated basins) (6) Includes gravel roads, shoulders, stormwater ditch, treated leachate land application area and soil borrow/stockpile. 11. Fish, Wildlife, and Ecologically Sensitive Resources. a. Identify fish and wildlife resources and habitats on or near the site and describe how they would

be affected by the project. Describe any measures to be taken to minimize or avoid impacts. Of the 226.5 acres operated as ECSWC Solid Waste Management property, approximately 160 acres are currently being used for Landfill operations including access roads, soil borrow, and stockpile. Phases 6A and 6B would be expanded into areas that are currently being used for Landfill operations. No significant wildlife populations have been observed permanently residing within these areas, as they are used for Landfill operations. A sedimentation basin is currently located within the proposed Phase 6A footprint. This sedimentation basin may provide seasonal habitat to waterfowl and other birds. As described in Item 6.B.3., a replacement sedimentation basin will be constructed north of the existing sedimentation basin. Landfill operations occur within and around the proposed Phase 6A and 6B area six days a week and, therefore, there is little habitat for wildlife. Although a fence is located around the facility to provide security, deer are occasionally observed within the vicinity of the proposed expansion area. The deer are typically observed as they are traveling across the site. The deer likely reside in or near the Tosher Creek Wildlife Management Area (WMA), located approximately 0.3 miles southeast of the Landfill footprint. The WMA is immediately south of the gravel mining property to the south of the Landfill property. The WMA is a 323-acre site that provides habitat to deer, bear, small game, forest game birds, upland field birds, and wetland and forest wildlife. A records search provided by the DNR Natural Heritage and Nongame Program (included as Attachment 11) identified rare species or other significant natural features known to occur within an approximate one-mile radius of the proposed project. This is further discussed in Item 11b. Additional rare, non-threatened species identified in the vicinity of the project by the records search include: • Occupied bald eagle nest near Kent Lake (approximately 0.8 miles northeast of the Landfill

footprint boundary) in 2005. • Creek Heelsplitter (mussel species) within/near Ann River (approximately 0.6 miles northeast of

Landfill footprint boundary) in 1999. • Fluted shell (mussel species) within/near Knife River, Snake River and Ann River in 2000. • Black sandshell (mussel species) within/near Knife River, Snake River, Ann River, and

Groundhouse River in 2006. A search of the DNR County Biological Survey records for common/non-rare wildlife species indicated no survey data were available for the Landfill property vicinity.


A Wetland Replacement Plan and a Wetland Mitigation Plan have been adopted for the site by ECSWC. The Mitigation Plan identified portions of ten different wetland basins located on the Landfill property. Two of the wetlands, identified as A and B, were classified as Type 3 and two of the wetlands, identified as G and H, were classified as Type 2. These wetlands, representing 2.2 acres, are defined as predominantly emergent and scrub-shrub wetlands, generally dominated by reed canary grass, sedges, dogwood, and willows. Sedimentation basins currently used by the Landfill were identified as a portion of the designated wetland. The 0.1-acre Wetland H has been removed as part of previous site development. Kanabec County approval for the wetland filling was dated April 21, 2006, for the ultimate development of the facility (depicted on Attachment 8). Wetland H was filled in June 2005 by aggregate mining activities under the authorization of a Wetland Conservation Act exemption and a U.S. Army of Engineers “no jurisdiction” determination. Wetlands A and B are located along State Highway 23 and County Highway 60, and Wetland G is located between the northern, adjacent gravel mine and the existing Landfill. These wetlands have not historically been significantly utilized by fish and wildlife populations. The existing wetlands located on ECSWC property to the east, across Imperial Street, are considered to be more valuable as fish and wildlife habitat as they are located in a relatively undisturbed area that has a direct and hydrologic connection to Ann River. There are six other Type 1 wetlands, identified as I, J, R, S, T, and U, present within the proposed expansion area. These wetlands, representing 4.5 acres, are defined as seasonally flooded isolated basins, generally dominated by green ash, American elm, and red maple trees, as well as sedges, marsh marigold, and sensitive fern. These basins appear to be supported by surface water as opposed to shallow groundwater. The Wetland Replacement Plan addresses the proposed Landfill ultimate development expansion impacts into 4.98 acres of wetland at the site property. However, the construction of the treated leachate land application Phase 2 area will require mitigation of these wetlands to provide the designed grade surface and removal of trees, shrubs, or other vegetation that may inhibit the sprayer system. A total of 4.98 acres of New Wetland Credits has been purchased by ECSWC from Meadowlark Preserve, LLC to mitigate the wetlands impact from expansion. The plan also describes alternative proposed expansion efforts and construction phasing within the impacted wetlands. The plan is available for review at the Landfill office (on site) or at the MPCA offices in St. Paul and Brainerd, Minnesota. Following final closure of the entire Landfill, depicted in Attachment 8 as the ultimate facility development, the site will be converted to open space, which will encourage wildlife habitat.

b. Are any state (endangered or threatened) species, rare plant communities or other sensitive

ecological resources on or near the site? Yes No

If yes, describe the resource and how it would be affected by the project.

The DNR Natural Heritage Program has identified six rare features near the Ann River in the vicinity of the existing and proposed Landfill. Of the rare species, the mucket and round pigtoe mussels are both state listed as threatened. The DNR states that, provided the project will not negatively impact the water quality of Ann River, the project will not affect any known occurrences of rare features. As discussed further in Item 12, surface water run-off will be collected in ditches/basins and diverted to sedimentation basins for settling of suspended solids; the project is not expected to impact the water quality of Ann River. See Attachment 9 for Minnesota Historical Society index of records and correspondence.


Describe any measures that will be taken to minimize or avoid adverse impacts. Provide the license agreement number (LA-___________) and/or Division of Ecological Resources contact number (ERDB_20070290-0003_) from which the data were obtained and attach the response letter from the DNR Division of Ecological Resources. Indicate if any additional survey work has been conducted within the site and describe the results.

12. Physical Impacts on Water Resources. Will the project involve the physical or hydrologic alteration

(dredging, filling, stream diversion, outfall structure, diking, and impoundment) of any surface waters such as a lake, pond, wetland, stream or drainage ditch? Yes No If yes, identify water resource affected and give the DNR Public Waters Inventory (PWI) number(s) if the water resources affected are on the PWI. Describe alternatives considered and proposed mitigation measures to minimize impacts. As previously detailed in Item 11, there are approximately 6.7 acres of Type 1/2/3 wetlands currently located within the 160-acre Landfill operations area. The proposed Landfill expansion of Phases 6A and 6B will not impinge on any of the identified wetlands. The proposed treated leachate land application area will impinge on approximately 3.5 acres of existing Type 1 wetlands. The U.S. Army Corp of Engineers has acknowledged no jurisdiction over the wetlands on the property, referenced in correspondence provided as Attachment 10. Kanabec County has approved mitigation of these wetlands by allowing ECSWC to purchase wetland credits, in accordance with DNR Wetlands Programs guidelines. Perimeter drainage ditches will be extended around the proposed Landfill development phases to collect and transfer stormwater run-off to sedimentation basins. The perimeter drainage ditches, as well as other stormwater controls, have been designed to manage the 24-hour, 25-year storm event. The Landfill final cover construction was designed to replicate pre-development run-off patterns and final discharge locations to the extent possible. There is no indication that stormwater run-off from the Landfill currently causes negative impacts to groundwater or the surrounding wetlands, such as excessive sedimentation. Sedimentation controls are described in further detail in Item 16.

13. Water Use. Will the project involve installation or abandonment of any water wells, connection to or

changes in any public water supply or appropriation of any ground or surface water (including dewatering)? Yes No If yes, as applicable, give location and purpose of any new wells; public supply affected, changes to be made, and water quantities to be used; the source, duration, quantity and purpose of any appropriations; and unique well numbers and DNR appropriation permit numbers, if known. Identify any existing and new wells on the site map. If there are no wells known on site, explain methodology used to determine. No public water supply wells will be installed or affected as part of the proposed expansion, nor will appropriation of surface water or groundwater be required for this project. Water for general clean up and employee use is obtained from an on-site water supply well located near the Landfill office. All other wells at the site are groundwater monitoring wells.


As discussed in Item 6.b., the environmental monitoring network includes numerous wells that have defined the hydrogeologic conditions at the site. Selected wells are incorporated into a compliance monitoring program to provide for the early detection of potential releases from the facility. The current monitoring network is situated to provide for compliance monitoring for the existing facility and future phases. Wells not utilized for water quality monitoring provide groundwater elevation data. Some modification of the monitoring network is anticipated as development progresses into Phase 6A and beyond. Consistent with past work at the Landfill, all well sealing and construction work will be completed with the concurrence of the MPCA and by licensed well contractors in accordance with the MDH Well Code. The monitoring wells associated with the Landfill are shown on the site map included as Attachment 4 and are summarized in Table 1.

Table 1: East Central Sanitary Landfill Monitoring Well Network

Well No. Unique Well ID Longitude Latitude Depth from Ground

MW-3A 433194 -93.3518 45.84629 26 MW-3C 433195 -93.3518 45.84629 46 MW-4A 433196 -93.3494 45.84636 28 MW-4B 433197 -93.3494 45.84636 53 MW-4C 462456 -93.3494 45.84636 79 MW-5 433198 -93.3496 45.84782 21 MW-6 433123 -93.3486 45.84719 17

MW-8A 508665 -93.3491 45.8484 27 MW-8B 508664 -93.3491 45.8484 50 MW-12 508670 -93.3491 45.84964 44 MW-13 472106 -93.3537 45.8474 50 TW-1 511523 -93.3484 45.84703 70 OSB-1 511521 -93.3489 458.847 68 OSB-2 511522 -93.3485 45.84757 72

MW-14A 577144 -93.3505 45.84588 27 MW-15A 577146 -93.3494 45.84539 13 MW-16A 577147 -93.3494 45.84539 18 MW-16B 577148 -93.3489 45.85031 48 MW-17A 661511 -93.3489 45.85089 38 MW-18A 682740 -93.3463 45.84722 40 MW-20A 717932 -93.3503 45.85324 56 MW-21A 717933 -93.3536 45.85237 82 MW-22A 717927 -93.3492 45.85314 45 MW-23A 740980 -93.3582 45.8535 70 MW-23B 740981 -93.3582 45.8535 100 MW-24A 740982 -93.3543 45.8532 70 MW-25A 740983 -93.3569 45.8517 90 MW-26A 740984 -93.3584 45.85 80 MW-27A 740985 -93.3543 45.8532 92 MW-27B 740986 -93.3544 45.85 110

A number of residential, privately-owned off-site wells have been incorporated into the landfill’s routine water quality monitoring program. The results of that monitoring have not identified any Landfill impacts in the residential well samples. Additional discussion regarding the residential well sampling program is provided in Item 19.


Water appropriations permits exist for the Knife River Corporation and Bjorklund Companies gravel mining operations located immediately north and south of the Landfill respectively. As mentioned in Item 9, neither of these operations is anticipated to affect existing or proposed Landfill operation or development. Water use at these facilities is intermittent and seasonal, and wash water is returned and recycled to on-site infiltration basins, such that their effect on groundwater flow is localized and temporary. Other high capacity water supply wells are approximately five miles or more from the Landfill and include the city of Mora municipal wells and Spring Brook Golf Course. Their distance and downgradient location are such that there would be no influence on groundwater flow at the Landfill. One additional monitoring well is proposed for the Landfill expansion. The proposed location for the monitoring well will be near the northeast corner of Pond 2. A work plan will be submitted to the MPCA for review and approval, outlining the proposed well location and construction specifications. At this time, it is believed no monitoring wells listed in Table 1 will require abandonment for the proposed project.

14. Water-related land use management districts. Does any part of the project involve a shoreland

zoning district, a delineated 100-year flood plain, or a state or federally designated wild or scenic river land use district? Yes No If yes, identify the district and discuss project compatibility with district land use restrictions.

15. Water Surface Use. Will the project change the number or type of watercraft on any water body? Yes No

If yes, indicate the current and projected watercraft usage and discuss any potential overcrowding or conflicts with other uses.

16. Erosion and Sedimentation. Give the acreage to be graded or excavated and the cubic yards of soil to be moved: 9 acres; 350,000 cubic yards. Describe any steep slopes or highly erodible soils and identify them on the site map. Describe any erosion and sedimentation control

measures to be used during and after project construction. Acreage identified only includes newly developed areas. A majority of the existing slopes at the facility are approximately 20 to 33 percent. Maximum final cover slopes of the proposed expansion zones will be designed at 33 percent. Final cover slopes exceeding 20 percent will be designed with permanent benches and other controls to minimize erosion and provide stability, in accordance with MPCA guidance. The benches will be designed so that drainage lengths on steep slopes do not exceed 40 vertical feet. This series of benches with drainage diversion ditches is expected to reduce the potential for erosion of the side slopes. Surface water is directed into perimeter ditches or a riprap downdrain on the west Landfill slope. In the interim, intermediate and daily cover material, consisting of either on-site soils, or alternate daily cover materials are used to cover the waste. Efforts are made by the operators to place soil material with lower erosion properties on the sideslopes. Erosion washouts that may occur due to heavy storms are repaired and mitigated as necessary. The stormwater management system is discussed in greater detail in Item 17. The surface water management plan for the Landfill is intended to minimize erosion and sedimentation impacts. Conditions conductive to significant soil erosion and sedimentation typically exist during the construction and active operation of waste cells. Removal of natural ground cover creates potential erosion conditions from the movement of water and wind. During the construction phases of the project, erosion will be minimized by the following techniques. Water Erosion. Areas required for facility construction will be cleared and grubbed. Topsoil will be stripped and stockpiled for future restoration activities. Run-off that does occur will be directed to open ditches, which will then direct water to the existing or newly constructed Landfill sedimentation basins.


To reduce the erosion impact from run-off prior to establishing vegetative growth, silt fences, hay bales, netting, and mulch will be used in areas susceptible to erosion. During project operation, ditches and berms will control run-off resulting from at least the 24-hour, 25-year storm in a manner to reduce erosion. Potential run-on resulting from the 24-hour, 25-year storm will be diverted to prevent flow onto the active portion of the Landfill. Erosion of the drainage layers placed above the Landfill liner will be reduced by immediate placement of waste following liner construction. Straw will be used for temporary erosion control if waste filling is not anticipated to begin immediately. This measure will also provide freeze protection and protection from wind erosion. Any straw placed on the liner will be removed prior to waste placement to avoid potential biofouling of the drainage layer. All culverts and open channels will be constructed in a manner that will minimize erosion both during and after construction. Ditches generally will be grass lined. Where high run-off velocities are expected, ditches will be rock lined to provide further erosion protection. Standard erosion control measures will be used to protect temporary stockpiles of soil as well. Other possible temporary and/or permanent erosion control measures include the use of riprap, straw bales, silt fences, swales and berms, surface roughening, seeding, and matting and mulching. Final restoration of disturbed areas is intended to enhance the appearance of the site and make it compatible with the surrounding region. The land disturbed temporarily by construction activities will be graded and seeded. The reseeding method used at the site will be in accordance with those identified in the permit documents approved by the MPCA. Wind Erosion. The site is generally surrounded by mature trees, which provide a wind break. During construction, dust control measures will continue to involve spraying of traffic areas with water as necessary or treated leachate if this is approved in the permit. Permanent wind erosion control will be accomplished by planting hardy perennial grasses, legumes, or other ground covers selected for their ability to establish themselves quickly and promote soil stabilization.

17. Water Quality – Surface-water Run-off. a. Compare the quantity and quality of site run-off before and after the project. Describe

permanent controls to manage or treat run-off. Describe any storm-water pollution prevention plans. SWPPPs will be prepared for construction with the permit application to the MPCA. Currently, approximately 13.1 acres representing the eastern portions of Phases 1 through 5 drain to the existing southeast basin. Surface water from the southeast basin discharges to the existing wetland in the southeast corner of the property. Internal access roads and facilities, as well as the western portion of Phases 1 through 5 (representing approximately 8.4 acres), currently drains to the existing southwest basin, which discharges to the southern boundary drainage ditch along County Highway 60. The majority of surface water run-off from the proposed Phases 6A and 6B development areas, totaling approximately 8.6 acres, currently drains to the existing sedimentation basin north of Phase 5. Surface water run-off from the proposed treated leachate land application area representing approximately 25 acres, currently drains to wetlands located on the western portion of the property and adjacent to the northwest portion of the site.


The proposed Landfill final cover construction was designed to replicate pre-development run-off quantities and patterns as well as final discharge locations to the extent possible. The northern sedimentation basin will be displaced during development of Phase 6, and Wetland U will be displaced during development of Phase 2 of the treated leachate land application system. Following placement of final cover, 8.3 acres, primarily from the western portions of Phases 1 through 5 will continue to drain to the southwest basin. The southeast basin will be expanded to receive run-off from 27.9 acres in the eastern portions of Phases 1 through 6. Sedimentation discharge routes are further discussed in Part b. of this Item. The proposed stormwater management system at the Landfill will expand on currently existing controls including the construction of permanent benches and downdrains to route run-off from the final cover to a perimeter collection ditch around the Landfill and sedimentation basins located to the west and southeast. As previously mentioned, these stormwater controls will be designed to minimize potential water-quality impacts by limiting flow velocities, temporarily storing and treating run-off, and controlling discharges to downstream stormwater receptors. Stormwater run-off from the active fill areas is and will continue to be collected in the active cell leachate collection system and treated as leachate. Minn. R. 7050.0222, subp. 6 requires that discharges to wetlands maintain natural background standards of dissolved oxygen, pH, and temperature in order to avoid significant adverse impacts. Since run-off directed towards sedimentation basins never contacts the waste material within the Landfill, elevated levels of pollutants or changes in pH are not expected. Run-off temperature is usually dependent upon atmospheric conditions, and it is not anticipated that post-Landfill stormwater run-off temperatures will be significantly different than pre-Landfill run-off temperatures. Slightly lower dissolved oxygen may result from increased levels of sediment as run-off from vegetated final cover areas may collect a minor amount of sediment. Sedimentation basins at the Landfill have been designed to achieve 80 percent sediment removal efficiency, in accordance with MPCA General Stormwater Permit requirements. Soils to be used for the drainage layer above final cover will not contain high levels of nutrients so as to minimize possible nutrient loading in run-off.

b. Identify routes and receiving water bodies for run-off from the site; include major downstream water bodies as well as the immediate receiving waters. Estimate impact run-off on the quality of receiving waters. The entire property and surrounding area is within the Ann River watershed and flows to the Snake River, then to the Lower St. Croix River. As the Landfill expansion is developed in phases, run-off from areas that reach permitted elevations will be directed toward sedimentation basins, as described in Part a. of this Item. A combination of terraces, channels and downdrains will direct flows efficiently to the new and existing sedimentation basins (redesigned as wet basins to conform to the MPCA’s General Stormwater Permit requirements) that will be utilized for stormwater management purposes. Stormwater run-off from the southeast and southwest basins will continue their current method of discharge. The southeast basin discharges directly to Wetland A. Overflow from Wetland A travels east through a culvert across Imperial Street, eventually discharging to Tosher Creek to the southeast of the property. Tosher Creek travels south and outlets to Fish Lake.


18. Water Quality – Wastewater. a. Describe sources, composition and quantities of all sanitary, municipal and industrial

wastewater produced or treated at the site.

b. Describe waste treatment methods or pollution prevention efforts and give estimates of composition after treatment. Identify receiving waters, including major downstream water bodies (identifying any impaired waters), and estimate the discharge impact on the quality of receiving waters. If the project involves on-site sewage systems, discuss the suitability of site conditions for such systems.

c. If wastes will be discharged into a publicly owned treatment facility, identify the facility, describe any pretreatment provisions and discuss the facility’s ability to handle the volume and composition of wastes, identifying any improvements necessary. The Landfill will generate MSW leachate. Leachate is generated in MSW landfills from the small amount of liquid found in household waste, when precipitation falls onto the waste during filling activities, or minimal percolation through the final cover system. The Landfill is designed with lined waste containment cells and a leachate collection system. Leachate will continue to be routed to the ASTs or the leachate storage and treatment ponds for temporary storage and aeration. An estimate of the amount of leachate generated by the expansion was calculated for both the active and closed phases of the Landfill. During the active phase of operation, approximately 208,201 gallons per acre per year of leachate will be generated, while approximately 6,100 gallons per acre per year will be generated after closure and installation of the final cover of the Landfill. In 2008, the Landfill produced approximately 3,868,995 gallons, or 200,466 gallons per acre. The peak daily leachate generation during active fill is calculated as 4,853 gallons per acre per day. As described in Item 6, the design of the leachate collection, storage and treatment/disposal system is based on these leachate generation rates. Currently, leachate is being recirculated from the pond into Phases 4 and 5 of the Landfill as part of a pilot study. Upon completion of the pilot study, results and recommendations will be submitted to the MPCA for review. If approved by the MPCA, the proposed development would utilize full-scale leachate recirculation. With the proposed design and construction of a second leachate treatment and storage pond at the Landfill, there will be two ponds, Pond 1 (500,000 gallon capacity) and Pond 2 (one million-gallon capacity) to operate in series for leachate treatment. The ponds are designed to reduce biochemical oxygen demand (BOD), COD, VOCs, and metals in the leachate by mechanical aeration. The ponds also provide additional leachate storage capacity and leachate load-out operations for off-site treatment. Aeration equipment was installed during Pond 1 construction to provide treatment and control potential odors associated with the stored leachate. An aspirating aerator housing unit with a hollow drive shaft is mounted to a galvanized tri-float assembly frame, installed to float above the Pond 1 surface. This same aeration equipment (two units) will be installed in Pond 2.


The ponds will operate in series. Leachate collected in Lift Station LS-1, Phases 6A and 6B, and possibly MH-4 and MH-5, will be routed through the pond transfer vault and will discharge into Pond 1 for primary treatment. Leachate may be pumped into Pond 1 from these sources until maximum operating capacity is attained. During primary treatment, organic concentrations are reduced via biological conversion or volatilization, ammonia is converted to nitrate, and metals precipitated. After primary treatment, leachate will be transferred to Pond 2 for long-term storage, settling, and additional aerobic or anoxic treatment. Aeration may be turned off to promote denitrification of nitrate. By October or November of each year, the ponds are typically reduced to the minimum operating level. This provides the storage required to manage winter snow melt and spring rain. During the winter and spring months, leachate may be transferred into the ponds until maximum elevation is reached. Pond transfers, loadout for off-site treatment, and leachate recirculation may occur during winter if warranted by liquid levels and if the temperature allows. Leachate quality is monitored on a quarterly basis as part of the MPCA Permit (SW-17) and leachate disposal agreement between the ECSWC and the MCES Treatment Facility in St. Paul, Minnesota. The MCES treatment facility has been accepting leachate since 1991 and the increase in leachate due to the expansion should not cause adverse impacts to the plant. The priority of leachate management options will depend on the time of year. As a starting point for discussion, assume that the sequencing begins on November 1. The operation is divided into three sequences. The time frames are approximate but are based on operating experience at other landfill sites in Minnesota, and may vary with weather conditions. Sequence 1 - November 1 to April 1: At this point, land application would cease due to freezing temperatures. Raw leachate flow will be directed to the ASTs, the leachate storage and treatment ponds or into the recirculation system. Due to the winterization of the leachate recirculation system, and waste temperature within the Landfill, the recirculation system should operate without freezing problems. Leachate hauling will occur as necessary based on pond storage and treatment capacity and the ability to recirculate. Sequence 2 - April 1 to July 1: Following the spring snowmelt and during spring rains, raw leachate will continue to be pumped into the leachate storage and treatment ponds, the ASTs, or the recirculation system at Landfill personnel's discretion. Recirculation from the ponds can begin, including working face spray (if approved in the facility’s operating permit). Leachate stored within the ponds would be treated and aerated for the period of November 1 to July 1, which should maintain or increase the current treatment efficiencies. Land application of treated leachate will not take place unless weather, leachate treatment, and cover crop conditions allow in May or June. Leachate hauling will occur as necessary based on pond storage and treatment capacity. Sequence 3 - July 1 to November 1: July 1 is the date when land application of leachate should become feasible, depending on rainfall. Once land application of treated leachate begins and the leachate storage and treatment ponds have capacity, raw leachate will be discharged to the ponds or the recirculation system, at Landfill personnel's discretion. If the ponds and ASTs approach their maximum levels during this sequence and conditions are too wet to land apply, the discharge from the leachate collection system will be switched back to the recirculation forcemain full-time until the ponds and/or ASTs regain capacity. Leachate hauling will also occur as needed. Recirculation from the ponds into the leachate recirculation system or working face spray can occur at any time (if approved by the facility’s operating permit).


The leachate treatment and disposal processes described above are anticipated to proceed through the duration of the time frame included with the solid waste operations permit renewal application. The quantity of treated leachate to be land applied will follow the MPCA Guidance Document for Land Treatment of Landfill Leachate and the solid waste operations permit application document.

19. Geologic hazards and soil conditions. a. Approximate depth (in feet) to Ground water: 5 minimum; 50 average. Bedrock: 100 minimum; 100 average.

Describe any of the following geologic site hazards to ground water and also identify them on the site map: sinkholes, shallow limestone formations or karst conditions. Describe measures to avoid or minimize environmental problems due to any of these hazards. There are no sinkholes, karst conditions, or shallow limestone formations at, or in the immediate vicinity of the Landfill. Portions of the site are characterized by sand and gravel deposits that have relatively high infiltration rates. Higher infiltration rates, coupled with mining of sand and gravel that reduces the distance to the water table, increases the susceptibility of the shallow groundwater to potential releases. However, state of the art landfill design with engineered controls that include composite liners and leachate collection systems effectively minimizes potential impacts from the Landfill. Other facility design and operating procedures that are also protective of surface and groundwater resources, include secondary containment for ASTs, leak detection monitoring, routine maintenance of equipment, storage of fuels and supplies in designated areas, development of SWPPPs, and controlled access to the site to protect against such things as vandalism and illegal dumping. The GCCS at the Landfill also works to minimize potential impact to groundwater by capturing and destroying volatile organics that may otherwise impact groundwater through adsorption at the gas-water interface. The following paragraphs provide additional detail regarding the hydrogeologic characteristics of the site followed by an overview of water quality monitoring results. Hydrogeologic Conditions As discussed in Item 6.b., the Landfill site has been thoroughly evaluated through a number of hydrogeologic investigations that have been completed for various phases of Landfill permitting. The most recent investigations were for the NDA (2005) and NWDA (2006) that include the proposed phases of Landfill development addressed by this EAW. Each of the investigations was initiated following MPCA review and approval of work plans. The primary documents that summarize the investigation results are listed below, and are on file with the MPCA. In addition, Annual Reports are prepared and submitted to the MPCA each year to summarize environmental monitoring results and any modifications made or proposed to the monitoring network. • Site Assessment and Analysis Report for East Central Sanitary Landfill (Kanabec County, Mora,

Minnesota). Prepared for the East Central Sanitary Landfill. E. A. Hickok and Associates, March 1988.

• Phase II – Hydrogeologic Evaluation Report and Phase III – Water Monitoring System Work Plan. Prepared for the East Central Solid Waste Commission. Liesch Associates, Inc. May 1990.

• Supplemental Phase I Report and Phase II Hydrogeologic Evaluation Workplan for the East Central Sanitary Landfill; North Development Area (NDA). Liesch Associates, Inc. November 2004.


• East Central Sanitary Landfill: North Development Area (NDA) Hydrogeologic Evaluation Report for the East Central Solid Waste Commission. Liesch Associates, Inc. February 2006.

• East Central Sanitary Landfill: Northwest Development Area (NWDA) Hydrogeologic Evaluation Report for the East Central Solid Waste Commission. Liesch Associates, Inc. January 2007.

The regional bedrock geology consists of four formations, the Warman Quartz Monzonite, Hinckley Sandstone, Fond du Lac Formation, and the Mount Simon Sandstone. The Hinckley and Fond du Lac Formations are undifferentiated in this area and underlie a greater portion of the Snake River Watershed, including the Landfill site. The Hinckley formation is the uppermost unit in the vicinity of the Landfill and typically consists of a medium to coarse grained, poorly sorted gray sandstone. The Fond du Lac Formation typically contains coarse-grained arkosic sandstones and conglomerates. Both units have interbedded shales present throughout which may act as limited confining layers. These formations contain bedrock valleys that glacial deposits have filled. The nearest bedrock valley is located approximately two miles southeast of the Landfill (HA-488, Lindholm et al., 1974).

Surficial geology in the region consists of quaternary deposits of glacial outwash and reddish brown undifferentiated drift. The outwash deposits consist of brown sand and gravel and some finer alluvium. The undifferentiated drift material is mainly sandy clay till. The red sandy till deposits are typically associated with the advance and retreat of the Superior lobe during the St. Croix and Automba phases of the Wisconsin Age glaciation (H.E. Wright Jr., Quaternary History of Minnesota, in Geology of Minnesota; a Centennial Volume, eds. Sims P.K. and Morey, G.B. Minnesota Geological Survey, 1972). Most water supply wells in the watershed are completed at depths between 50 and 150 feet within the undifferentiated drift and outwash deposits. In less common cases, municipal water supplies may be obtained from the Hinckley sandstone when capacities needed cannot be obtained from the undifferentiated drift. Regional groundwater flow is towards the Snake River located southeast of the Landfill. The thickness of the glacial drift in the watershed ranges from zero where bedrock outcrops, to over 200 feet. The thickest areas of glacial drift deposits occur along narrow bands where bedrock valleys exist. At the Landfill site, the predominant soil type is sand intermixed with varying amounts of gravel, clay, and silt. Greater percentages of silt and clay appear to occur in the east and southeast portions of the Landfill site. Investigations of the Landfill have identified the unconsolidated glacial deposits to be approximately 100 feet thick and associated with the advance and retreat of the Superior lobe. The recent hydrogeologic investigations for the NDA and NWDA indicate that the conditions at the proposed future phases of the Landfill are generally consistent with those identified for existing permitted areas. For the NDA and NWDA, there is a predominance of sand and gravel from approximately 15 to 60 feet below the natural land surface; these sand and gravel deposit appear to represent a continuation of the materials that have been mined at the site for earlier phases, including a large portion of the NDA that represents proposed Phase 6. Below the sand and gravel deposits, the percentage of silt and clay increases. Horizontal hydraulic conductivities, as determined from slug tests of wells, range from approximately 5 x 10-5 cm/sec for silty sands to 1.1 x 10-2 cm/sec for sand with gravel. The vertical hydraulic conductivities range from 1 x 10-7 cm/s for sandy silt and clay to 1.2 x 10-1 cm/s for fine to coarse sand. Average linear velocities across the Landfill property range from 0.40 feet/day to 0.425 feet/day, or approximately 146 to 155 feet/year.


Depth to the water table ranges at the site ranges from less than a few feet in the lowland areas in the southeastern most corner of the Landfill site to over 70 feet in the upland central portions of the property that coincide with proposed Phases 7 through 9. The water table at most locations that have not been altered by mining is encountered below 60 feet. The wetland areas adjacent to the Landfill to the east are expressions of the water table. The primary difference between the existing permitted area and the proposed development areas is a smaller (flatter) horizontal groundwater gradient. Groundwater elevation data from the Landfill monitoring network has identified consistent groundwater movement toward the southeast in both the shallow and deeper unconsolidated deposits. Along the north-eastern portion of the site, there appears to be a slight northeasterly component of groundwater flow for the shallow (water table) horizon. Deeper groundwater flow as determined from “B” horizon wells is also toward the east-southeast. Groundwater contour maps and a tabulation of water elevation data are provided with each Annual Water Quality Monitoring Report. Vertical groundwater flow potentials have been evaluated from water level data from nested wells. At the MW-4A/B/C and MW-8A/B nests, upward flow potentials are observed. A very slight upward gradient has been measured in piezometers PZ-1A/B in the North Development Area. The vertical gradients in the Northwest Development Area exhibit varying but slight vertical gradients. A slight downward flow potential was historically identified at well nest MW-9A/B (wells sealed in 1998) and has also been observed at MW-19A/B. Data from nested wells MW-3A/3C and MW-16A/16B are very similar for most monitoring dates, suggesting horizontal groundwater movement with no consistent trend for an upward or downward flow potential. Water Quality Monitoring The groundwater quality monitoring program for the Landfill incorporates selected monitoring wells and residential wells with the sampling frequency occurring on a quarterly basis that excludes the winter quarter. Surface water monitoring includes both the wetland in the very southeastern corner of the site and the sedimentation basin located south of the leachate tank. Results of the monitoring program are submitted to the MPCA following each event, culminating with the Annual Report. As mentioned previously, the monitoring program has identified groundwater impacts emanating from the closed unlined portion of the Landfill and the adjacent wells, namely the MW-4A/B/C well nest, MW-5A, MW-6A/B nest, and Obs-2 (see the site map included as Attachment 4). There have been no confirmed groundwater impacts attributed to leakage from the lined Landfill cells. The impacts emanating from the closed unlined portion of the Landfill are primarily associated with VOCs, some of which have exceeded drinking water standards (Health Risk Limits, or HRLs) as developed by the MDH for private water supplies. Other VOCs have been below the HRLs but above the intervention limits (ILs) as listed in the Landfill operating permit (ILs are a fraction of the HRL). In some instances, a few inorganic parameters have also been detected at or slightly above their respective IL. It is noted that in some of the cases, such as manganese, naturally occurring inorganic parameter concentrations may occur above the both ILs and HRLs. A comprehensive tabulation of the IL exceedances from the Landfill monitoring program since 1992 is available upon request. Monitoring data identify the improvement in water quality that has occurred over time, which is attributed to the construction of a landfill cover, installation of deep gas vent wells in the mid-1990’s, and the recent implementation of active gas collection. The decrease in VOCs detected occurs in both the number of individual VOCs detected, their concentrations, and the number of locations where detected. Residential well monitoring has been a requirement of the MPCA permit for VOCs since 1990. Since 1990, only a few intermittent and low-level detections have occurred, and these were typically not confirmed (detected in subsequent confirmation testing) and attributed to contamination of


collected samples during transit by some outside interference; thus they were not indicative of actual water quality from the sampled wells. No VOC detections have been recorded since 2003. In 2008, the ECSWC voluntarily performed a one-time sampling event that included 20 residential wells and two surface-water monitoring points to assess downgradient water-quality conditions. Two independent analytical laboratories were retained to collect samples from the residential wells May 21-23, 2008. There were no detectable VOCs in any of the samples collected and analyzed. A July 10, 2008, memorandum that lists the wells sampled and summarizes the results is available upon request. ECSWC provided the results to the residents and provided a copy of the memorandum to the MPCA.

b. Describe the soils on the site, giving Natural Resources Conservation Service (NRCS) classifications, if known. Discuss soil texture and potential for ground-water contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. The geology at the Landfill consists of glacial drift deposits that are approximately 100 feet thick, which are, in turn, underlain by the Hinckley and Fond Du Lac bedrock units. The glacial drift deposits at the Landfill vary and consist of outwash and gravel deposits, clay, and silt. The predominant soil type observed at most drilling locations is sand intermixed with varying amounts of gravel, clay, and silt. Soils with a greater clay and silt content appear to exist in the eastern and southeastern portions of the Landfill. Coarser grained sand and gravel deposits may be more prominent in the northern and western portions of the existing Landfill, near the abandoned Demolition Landfill site. At depths below approximately 45 feet, the clay content is noted to increase; however, sand is still the predominant soil type. The geologic logs indicate the predominance of sand and gravel to depths of 115 and 97 feet respectively, corresponding to elevations of 944 and 969 feet above sea level. The uppermost bedrock unit beneath the Landfill is the Hinckley Formation, which is a medium to coarse-grained, poorly sorted sandstone. Underlying the Hinckley Formation are coarse-grained arkosic sandstone and conglomerates of the Fond Du Lac Formation. Interbedded shales may occur in each of these units. A listing of the NRCS soil classifications for the Landfill property is provided below: Map Symbol

Soil Unit

Acres*

Notes

1007 Udorthents, shallow (sanitary landfill) 86.6 C1B Milaca-Brennvielle Complex 11.7 3 to 8%, stony C6A Cebana Silt Loam 66.1 0 to 2% slopes, stony C10B Brennyville Complex 48.5 1 to 6% slopes, stony

C11B Mora-Brennyville 29.6 Wet, complex, 1 to 6% slopes, stony

C12A Brennyville, wet-Cebana Complex 272.5 0 to 4% slopes, stony C17C Rosholt-Chetek Complex 8.4 8 to 15% slopes C17E Rosholt-Chetek Complex 2.6 15 to 40% slopes C23B Antigo-Chetek Complex 3.2 2 to 8% slopes C49A Antigo Silt Loam 4.2 0 to 2% slopes C75A Seelyville and Cathro, Milaca Catena Soils 17.9 Depressional, 0 to 1% slopes

C89A Cathro (Grasston Cantena) and Seelyeville Soils 0.2 Depressional, 0 to 1% slopes

-continued-


Map Symbol

Soil Unit

Acres*

Notes

C91B Milaca, stony-Chetek Complex 29.8 3 to 8% slopes C91C Milaca, stony-Chetek Complex 21.3 8 to 15% C91E Milaca, stony-Chetek Complex 4.4 15 to 30% slopes C96A Cathro, Twig, and Giese, stony, soils, slopes 7.6 Depressional, 0 to 1%

C97A Cathro, sandy substratum, and Seelyeville soils 2.1 Depressional, 0 to 1% slopes

C105A Dalbo, wet-Brickton Complex 6.2 0 to 2% slopes C106B Dalbo Complex 7.0 2 to 6% slopes

C111C2 Dalbo Silt Loam 2.7 6 to 12% slopes, moderately eroded

GP Pits, gravel-Udipsamments Complex 0.1 * Acres on Landfill property per NRCS.

The NRCS Soil Survey for the Landfill identifies 22 soils series, with a large portion of the site mapped as Udorthents, which are disturbed soils associated with the Landfill operations and sand and gravel mining activities. Other soil types include some hydric soils, indicating the potential presence of wetlands. As discussed in Items 9 and 11, the wetlands associated with the site have been delineated, and wetland acreage credits will be purchased to account for the wetland areas that will be affected by the proposed expansion of the landfill. Measures to mitigate releases that could potentially impact groundwater and surface water resources were noted in Item 19.a., and more thoroughly discussed with respect to the overall design, engineering and operation of the landfill, as described in Item 6.b.

20. Solid Wastes, Hazardous Wastes, Storage Tanks. a. Describe types, amounts and compositions of solid or hazardous wastes, including solid animal

manure, sludge and ash, produced during construction and operation. Identify method and location of disposal. For projects generating municipal solid waste, indicate if there is a source separation plan; describe how the project will be modified for recycling. If hazardous waste is generated, indicate if there is a hazardous waste minimization plan and routine hazardous waste reduction assessments. Sludge will continue to be generated in the existing leachate storage and treatment pond, and will be generated in the proposed leachate storage and treatment pond as well. The sludge material will be analyzed and screened for hazardous concentrations of various constituents. Although it is not expected, if the sludge is found to be hazardous, it will be disposed of in accordance with state and federal regulations. If concentrations of the constituents do not exceed hazardous waste criteria, the sludge will be periodically dewatered and disposed of within the Landfill.


b. Identify any toxic or hazardous materials to be used or present at the site and identify measures

to be used to prevent them from contaminating ground water. If the use of toxic or hazardous materials will lead to a regulated waste, discharge or emission, discuss any alternatives considered to minimize or eliminate the waste, discharge or emission. Leachate generated at the Landfill may have elevated concentrations of various constituents. Methane generated as LFG may be hazardous. LFG is controlled at the site through the GCCS. Please refer to the response to Item 6.B.3 for a discussion of leachate quality and LFG management.

c. Indicate the number, location, size and use of any above or below ground tanks to store petroleum products or other materials, except water. Describe any emergency response containment plans. In 2003, the underground 8,000-gallon leachate tank was abandoned in-place and replaced by a 28,000-gallon AST, in accordance with state and local regulations. It is located adjacent to Phase 1 of the lined Landfill, on the southeast side of the property. There is a portable 1,000-gallon diesel fuel tank for Landfill equipment refueling currently parked near the working face within the Landfill footprint.

21. Traffic. Parking spaces added: 0 Existing spaces (if project involves expansion): 25 Estimated total average daily traffic generated: Estimated maximum peak hour traffic generated and time of occurrence:

No additional parking spaces are planned or required with the development of the proposed Landfill. Established parking areas are located in close proximity to the existing Landfill office and scale house. These areas have been established to serve users and employees of the Landfill and may accommodate 20 vehicles. For each affected road, indicate the ADT and the directional distribution of traffic with and without the project. Provide an estimate of the impact on traffic congestion on the affected roads and describe any traffic improvements which will be necessary. Traffic resulting from Landfill operations typically comes from State Highway 23 and turns west on County Highway 60. The proposed Landfill expansion will increase the solid waste disposal capacity, but is not expected to increase the amount of waste deliveries. The current estimated Average Daily Traffic (ADT) is 45 vehicles delivering waste per day including public vehicles. Another 400 tanker trucks per year are utilized for leachate transportation for disposal. According to the 2008 Trunk Highway Volume Analysis, prepared by the Minnesota Department of Transportation, the 2008 average annual daily traffic (AADT) count for the Highway 23 segment from County Road 14 to County Road 12 is 5,200. AADT data was unavailable for County Road 60 and Imperial Street. Based on information provided by the Landfill operations staff, traffic is relatively steady throughout the day. To date, no traffic congestion issues have been identified on roads in the nearby area, including adjacent State Highway 23 and County Highway 60. Since the daily traffic will not change significantly, there will be no significant increases in site related traffic. An estimated 10-30 additional vehicles per day are expected during periodic construction activities associated with construction of the Landfill expansion.


22. Vehicle-related Air Emissions. Estimate the effect of the project’s traffic generation on air quality,

including carbon monoxide levels. Discuss the effect of traffic improvements or other mitigation measures on air quality impacts. Vehicle-related exhaust emissions during construction phases will be temporarily greater due to an increase in trucks and heavy equipment operations. However, these activities will not be sustained and are similar to previous construction activities. Normal operations during the active phase of the expansion are expected to be unchanged; therefore, overall vehicle-related air emissions are not expected to change due to the proposed expansion.

23. Stationary Source Air Emissions. Describe the type, sources, quantities and compositions of any

emissions from stationary sources of air emissions such as boilers, exhaust stacks or fugitive dust sources. Include any hazardous air pollutants (consult EAW Guidelines for a listing), any greenhouse gases (such as carbon dioxide, methane, and nitrous oxides), and ozone-depleting chemicals (chlorofluorocarbons, hydrofluorocarbons, perfluorocarbons or sulfur hexafluoride). Also describe any proposed pollution prevention techniques and proposed air pollution control devices. Describe the impacts on air quality. GREENHOUSE GASES LFG, which primarily consists of carbon dioxide and methane, is generated as a result of the biological decomposition of waste material within the Landfill. Methane may pose a safety problem if it is mixed with air at concentrations of greater than 5 percent and less than 15 percent. Typically, LFG also contains minor amounts of NMOCs. Carbon dioxide and methane happen to be two of the primary greenhouse gases, which trap heat near the earth’s surface, causing the earth’s climate to warm. Volume for volume, methane is much more potent in this regard than is carbon dioxide. ECSWC employs the GCCS flare to convert methane to carbon dioxide, thus reducing the facility’s level of greenhouse impact. The main source of worldwide greenhouse gas emissions is the combustion of fossil fuels to run vehicles, heat buildings, and produce electricity. While landfills are a source of greenhouse gases, they do not represent a significant percentage of statewide greenhouse gas emissions. In Minnesota, landfills contribute approximately one to four percent towards total inventoried Minnesota greenhouse gas emission sources. CRITERIA POLLUTANTS Other emissions produced by the flare and proposed engine include carbon monoxide, nitrogen oxides, and particulate matter (PM). When LFG is produced in excess of what can be used for the generator, or during periods where a generator is down for maintenance, the LFG will be routed through the flare. ECSWC has submitted an air emissions permit application for the flare and facility operations to the MPCA. SMMPA, the owner and operator of the proposed engine, has submitted a corresponding air emissions permit application for the engine. The operations of ECSWC and SMMPA together comprise a single stationary source subject to the requirement to obtain a Part 70 permit under Minn. R. 7007.0200, subp. 2.B. Potential to emit (PTE) calculations were completed for the “worst-case” scenario of both the engine and flare operating at maximum equipment capacity, 25 percent of LFG remaining uncollected, and peak truck/hauler traffic. During actual operations, it is likely that there will not be enough LFG generated to operate both the engine and the flare at maximum capacity. PTE calculations for the “worst-case” scenario are presented in Table 2.


PTE Calculations Summary (tons per year) NOx CO PM PM2.5 PM10 VOC Total

HAPs Dioxin/ Furan

SO2 HCl HF

ECSWC – flare 5.9 7.0 2.3 2.3 2.3 0.4 3.2 6.35x10-8 1.9 1.7 0.5 ECSWC - Truck Traffic

N/A N/A 17.3 0.5 4.9 N/A N/A N/A N/A N/A N/A

ECSWC - Fugitive LFG

N/A N/A N/A N/A N/A 3.8 2.5 N/A N/A N/A N/A

ECSWC - Waste Handling & Compaction

N/A N/A 6.8 0.2 3.0 N/A N/A N/A N/A N/A N/A

SMMPA – engine 21.6 101.3 1.0 1.0 1.0 14.0 1.1 4.19x10-7 0.8 0.7 0.2 Total Stationary Source PTE

27.5 108.3 27.3 4.0 2.7 18.1 6.8 4.7 x 10-7 2.7 2.4 0.7

Part 70 PTE thresholdA 100 100 100 100 100 100 25 N/A 100 N/A N/A NOx – Nitrogen Oxides PM2.5 – Particulate Matter less than 2.5 micrometers PM10 – Particulate matter less than 10 µm (micrograms) in size HAPs – Hazardous Air Pollutants SO2 – Sulfur Dioxide HCl – Hydrochloric Acid HF – Hydrofluoric Acid N/A - Not Applicable A Threshold limits in table indicate the need for the facility to obtain a federal Part 70 air permit.

AIR EMISSION RISK ASSESSMENT The MPCA has developed an AERA process to provide for: (1) a standardized health review of facility air emissions; and (2) a consistent format for presenting the quantitative risk estimates, along with qualitative information to provide context to these risk estimates. An AERA estimates cancer and non-cancer risks to human health from a proposed project and/or an existing facility. In general, facility risk guidelines have been developed by the MPCA, in consultation with the MDH, that are consistent with U.S. Environmental Protection Agency (EPA) guidance. The cancer risk guidelines were established such that if the increased risk of additional cancer cases in a population of 100,000 exceeds 1 (the scientific shorthand for this is 1E-5), a more refined analysis is called for that more precisely defines the risks and the potential countereffects of mitigation. The guideline for non-carcinogenic chemicals is that the sum of the risks (called“hazard indices”) should be less than 1. If emissions from a facility result in estimated risks in excess of these levels, MPCA staff evaluates whether further refinement of the analysis, or modifications to the facility, or stricter air emissions limits, are warranted. Interested readers can find more detailed information on the air risk analysis process at http://www.pca.state.mn.us/air/aera.html. ECSWC/SMMPA characterized potential health risks from the existing landfill and the landfill after the proposed modifications (engine addition and MSW expansion Phases 6A and 6B), using the AERA screening process, for over 80 pollutants, including those which were expected to be emitted on the MDH Risk Value Charts. The analysis is presented in the AERA document (Attachment 12). Potential risk estimates for the current facility, included emissions from the flare (at maximum capacity), idling trucks, and fugitives from the current landfill. In addition to the sources included in the current facility analysis, potential risk estimates for the landfill after the modifications also included emissions

http://www.pca.state.mn.us/air/aera.html


from the proposed engine (at maximum capacity) and fugitives from the expanded MSW landfill. Since neither SMMPA nor ECSWC can legally control each other’s operations, the analysis includes both the flare and the engine operating simultaneously at full capacity, which is a worst-case scenario. This is an overestimate of emissions due to the fact that there will not be enough LFG to power both at capacity at the same time. As noted in the table below, screening level potential risk estimates for the post-modifications landfill are at or below facility risk guidelines, with the exception of the farmer cancer risk estimates, which include screening exposure assumptions that are unlikely (i.e., milk production at the potentially maximum impacted location contributing to the farmer cancer risk). The farmer screening scenario includes worst-case assumptions that, in addition to risks from inhalation and vegetable consumption, that the farmer raises and eats beef, pork, and chicken and consumes milk and eggs produced from animals raised on forage grown at the location of the maximum predicted impact. The area where the maximum impacts are expected to occur for the farmer scenario is along the southern fence line of the landfill. The majority of the potential cancer risks for this farmer scenario are due to ingesting dairy products produced by animals that are assumed to live at this location and consume hay and feed grown in this same area that have been impacted by the dioxins/furans emitted from the engine. Since dairy farming does not occur at the maximally impacted location and risk estimates dissipate quickly with distance, MPCA conducted additional, more refined risk modeling and estimated that the farmer cancer risks are at or below facility risk guidelines at current farming locations (in a field south of the landfill entrance) or at the maximum impacted area without dairy consumption. These refinements were done using IRAP-h View modeling, which is based on the Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities. MPCA staff also used IRAP-h View to estimate potential health risk impacts from non-mercury pollutants emitted from the modified landfill, from ingesting fish from Fish Lake (the potentially most impacted fishing lake in the area from the landfill). These potential health risk estimates were at or below facility risk guidelines for both a subsistence fisher pathway (fish ingestion alone < 0.01 HQ and 0.4E-5 cancer) and recreational fisher pathway (fish ingestion alone < 0.01 HQ and < 0.1E-5 cancer). Since the proposed facility is estimated to emit around one tenth of a pound of mercury per year, as for other facilities with similar emissions, MPCA staff concluded that only a very small amount would deposit locally and the increment of what does deposit relative to background concentrations would be extremely small. A cumulative effects analysis of potential air emissions from the landfill in combination with potential background risk estimates was conducted and is explained in Section 29 of this EAW.

Air Toxics Screening Results

Total Inhalation Screening Hazard Indices and Cancer Risks

Acute Subchronic Noncancer

Chronic Noncancer Cancer

Current landfill 0.1 < 0.01 0.07 0.5E-5 Post Modifications 0.2 0.01 0.08 0.6E-5 Guidelines* 1 1 1 1E-5 Total Indirect Pathway Screening Hazard Indices and Cancer Risks

Farmer Noncancer Farmer Cancer

Resident Noncancer

Resident Cancer

Current landfill < 0.01 0.5E-5 < 0.01 < 0.1E-5 Post Modifications < 0.01

6E-5 (0.4E-5 IRAP no milk) < 0.01 0.1E-5

Guidelines* 1 1E-5 1 1E-5 -continued-


Total Multipathway Screening Hazard Indices and Cancer Risks

Farmer Noncancer Farmer Cancer

Resident Noncancer

Resident Cancer

Current landfill 0.07 0.9E-5 0.07 0.5E-5

Post Modifications 0.09

7E-5 (1E-5 IRAP

no milk) 0.08 0.8E-5 Guidelines* 1 1E-5 1 1E-5

*Note: The hazard index (HI) against which facility risks are compared for acute, sub-chronic, and chronic non-cancer risks is 1. The cancer risk against which facility risks are compared is 1 E-5 (or 1 chance in 100,000). These facility risk guidelines are risk management-based. They are not a discrete indicator of observed adverse effect. If a risk estimate falls below facility risk guidelines, the MPCA may, without further investigation, conclude that a proposed action does not present an unacceptable risk. A risk estimate that exceeds these guidelines, however, would not, in and of itself, necessarily indicate that the proposed action is not safe or that it presents an unacceptable risk. Rather, a risk estimate that exceeds a guideline triggers a more refined analysis that includes likely actual exposures, distances from source to receptors, types of sources and receptors, and others.

As shown in the table, the installation of the engine does not significantly increase the calculated HI. The calculated inhalation risks at the combination of maximum impact for both modeled scenarios indicate an overall hazard quotient that is less than the target value of 1.0 for acute, subchronic non-cancer, and chronic noncancer risks. The lifetime cancer risk of 6.27E-06 is a very slight increase to the background value of 2.5E-05. Additionally, the Total Indirect Pathway Risks and the Total Multi-pathway Risks indicate acceptable levels of risk for the “Existing Conditions” scenario. For the “After Engine Installation” scenario, the Farmer Cancer Risk for both Total Indirect Pathway (5.9E-05) and Total Multi-pathway (6.5E-05) are greater than the 1.0E-05 target value. However, further refined analysis of the Farmer Cancer Risk results in values that are less than the 1.0E-05 target value. This is explained further in the AERA document (Attachment 12).

24. Odors, noise and dust. Will the project generate odors, noise or dust during construction or during

operation? Yes No

If yes, describe sources, characteristics, duration, quantities or intensity and any proposed measures to mitigate adverse impacts. Also identify locations of nearby sensitive receptors and estimate impacts on them. Discuss potential impacts on human health or quality of life. (Note: fugitive dust generated by operations may be discussed at item 23 instead of here.) The proposed expansion is a continuation of current landfilling activities. Existing odor, noise, and dust conditions at the site are not expected to change substantially with expansion, as only portions of the Landfill will be active at any given time. Existing controls to minimize the quantities and intensity of noise and dust will be continued throughout the extended service life of the Landfill. The existing Landfill GCCS was expanded during the summer of 2008, to provide further control to minimize odor and LFG emissions at the site. There have been no recorded noise or dust complaints in the past. Nearby gravel mining operations north of the Landfill generate significant amounts of noise and dust.


ODORS Even with the proposed expansion, a restricted working face will still be enforced to ensure odors from exposed waste are minimized. Per the Odor Control Plan, daily cover soils, or an alternate ConCover material, are used to cover waste disposed each day and prevent odor migration. All recent odor complaints, which are mostly limited to during cell construction activities, have been managed through the Odor Control Plan, which describes guidelines for additional soil cover and continued expansion of the GCCS as waste levels and operations permit. The GCCS that currently collects odorous gases generated within the Landfill will be expanded. Therefore, the existing odor conditions and odor generation are expected to improve. NOISE The proposed expansion may alter the existing noise generation at the site during the construction phases. Construction activities will be temporary in duration and contractors will comply with local noise ordinances. Construction will take place primarily during the daylight hours. The installation of the engine may increase noise levels within the immediate vicinity of the engine installation area. However, the engine will be housed within an enclosure, which will significantly lessen these potential noise impacts. Also, because the engine will be placed almost 500 feet from the property boundary, noise impacts to neighboring properties due to the engine installation are not anticipated. Ongoing noise presently generated at the site from daily operations is the result of equipment used for hauling, compacting and covering refuse. The vacuum blower located near the southwest corner of the Landfill also contributes to noise levels at the facility. However, because the noise occurs over 226.5 acres, impacts to neighboring properties are greatly diminished. Since the level of daily activity will not change, these noise conditions should not increase significantly with the proposed expansion. The proposed engine-generator set is designed to meet the Daytime and Nighttime standards for a Class 3 noise area established in Minn. R. 7030.0040. Noise controls include limiting heavy equipment and construction equipment hours of operation and maintaining the vegetation shelter of trees and shrubs along the property boundary. OPERATING HOURS The Landfill operates between 7:00 a.m. and 5:00 p.m, Monday through Friday and 8:00 a.m. to 12:00 noon on Saturdays. No ECSWC heavy equipment operates outside of these times. NEARBY SENSITIVE RECEPTORS The closest property to the proposed expansion is the gravel mine to the north of the Landfill. The closest residential property to the ECSWC Solid Waste Management Property is adjacent to the west of the former compost area. Since daily activity at the landfill will not change, odor, noise, and dust impacts to the nearby sensitive receptors are not expected to significantly increase with the expansion. Visual screening of the Landfill expansion will be provided by existing trees between the residences and the Landfill. FUGITIVE DUST Fugitive dust emissions at the Landfill are caused by refuse trucks and earth moving equipment during operation and cell construction. Fugitive dust emission modeling was completed as part of the facility operations air permit application. Based on the model results, the estimated tonnage per year for fugitive emission of PM2.5 is 1.21, for PM10 is 12.8, and for total PM, 43.62. Fugitive dust emissions are controlled by the following practices:


• Proper maintenance and repair of facility gravel access roads • An on-site water truck to apply water to areas subject to creating dust, when necessary • Cover and revegetation of inactive areas If approved by the MPCA, treated leachate may be used for dust control on haul roads within the extent of the Landfill property.

25. Nearby resources. Are any of the following resources on or in proximity to the site?

If yes, describe the resource and identify any project-related impacts on the resources. Describe any measures to minimize or avoid adverse impacts.

a. Archaeological, historical, or architectural resources? Yes No

The Minnesota Historical Society has provided information about an archaeological site, as well as a historical/architectural site near the Landfill property. Further information about these locations can be found in Attachment 9. These sites are not expected to be affected by the continuation and expansion of Landfill operations.

b. Prime or unique farmlands or land within an agricultural preserve? Yes No

c. Designated parks, recreation areas, or trails? Yes No The Tosher Creek WMA runs along Ann River, southeast of the property, approximately 0.8 miles from the Landfill. In addition, the Fish Lake and Ann River Game Refuge is located approximately 1.8 miles southeast of the Landfill. The proposed Landfill expansion to the north and west will extend in the opposing direction. These resources are not expected be impacted by a continuation and expansion of the current Landfill.

d. Scenic views and vistas? Yes No

e. Other unique resources? Yes No 26. Visual impacts. Will the project create adverse visual impacts during construction or operation?

Such as glare from intense lights, lights visible in wilderness areas and large visible plumes from cooling towers or exhaust stacks? Yes No If yes, explain. Currently, trees are used for visual screening on all sides of the Landfill. The construction of the treated leachate land application area may require the removal of trees within the Landfill footprint, but existing trees within the 100-foot buffer to the north and 200-foot buffer to the west of the expansion area will be maintained to provide continued visual screening from neighboring properties. The proposed solid waste operations permit reissuance report engineering design for the expansion of Phases 6A and 6B includes a final cover height of 22 feet higher than the current permitted waste height. This expansion is proposed on the northeast corner of the property. The nearest residents on the east side are approximately 0.3 miles southeast of the proposed high point of the expansion. The northwest corner of the Tosher Creek WMA is approximately 0.6 miles south to southeast of the proposed high point of the expansion. Though there may be some visual impacts associated with the increase in height, due to the distance from residences and the WMA, it is not anticipated to be significant to these receptors.


There is a cumulative visual impact if future landfill development is approved. While the visual impact from this current expansion will result in a 22-foot increase in the landfill height, the ultimate expansion plans bring the height to nearly 100 feet higher than currently approved. The future expansions would make the landfill 150 feet higher than any surrounding natural features for miles around. These expansions are not a part of the currently proposed project, however, and, thus, are not a part of the impact potential for the currently proposed project.

27. Compatibility with plans and land use regulations. Is the project subject to an adopted local

comprehensive plan, land use plan or regulation, or other applicable land use, water, or resource management plan of a local, regional, state or federal agency? Yes No

If yes, describe the plan, discuss its compatibility with the project and explain how any conflicts will be resolved. If no, explain. Landfill operations occur within a 226.5-acre parcel that is zoned general commercial. The Landfill is currently operating and will continue to operate under a Conditional Use Permit issued by Arthur Township for solid waste activities. The ECSWC Solid Waste Management Plan was recently updated to review and evaluate solid waste generation, recovery, and disposal options within the member counties. ECSWC also has an Industrial Solid Waste Management Plan to serve as a guideline for handling industrial waste within the counties. This Plan is available at the landfill.

28. Impact on infrastructure and public services. Will new or expanded utilities, roads, other infrastructure or public services be required to serve the project? Yes No If yes, describe the new or additional infrastructure or services needed With the installation of the LFG-fueled generator set, a power line will be installed to provide electricity generated by the engine into the local utility grid.

29. Cumulative potential effects. Minn. R. 4410.1700, subp. 7, item B requires that the RGU consider the “cumulative potential effects of related or anticipated future projects” when determining the need for an environmental impact statement. Identify any past, present or reasonably foreseeable future projects that may interact with the project described in this EAW in such a way as to cause cumulative potential effects. (Such future projects would be those that are actually planned or for which a basis of expectation has been laid.) Describe the nature of the cumulative potential effects and summarize any other available information relevant to determining whether there is potential for significant environmental effects due to these cumulative effects (or discuss each cumulative effect under appropriate item(s) elsewhere on this form). The Landfill has been operating as a lined MSW landfill since 1991. The environmental impacts known to exist from past or present activities and the mitigative measures employed or proposed to prevent or minimize these impacts have been identified in this EAW. There is no evidence that the proposed expansion and the generator installation will affect any reasonably foreseeable future projects near the Landfill. A key issue for an EAW is whether a proposed project, which may not individually have the potential to cause significant environmental effects, could have a significant effect when considered along with other projects. This type of impact is known as a cumulative potential effect. In order to assess the proposed project’s “cumulative potential effects of related or anticipated future projects” as required by the rules, the MPCA conducted an analysis that addressed other projects or operations that: (1) are already in existence or planned for the future; (2) are located in the surrounding area; and (3) might reasonably be expected to affect the same natural resources. The following is a review of this analysis.


Surface Waters The proposed project is located entirely within an unnamed subwatershed of the Ann River/Snake River/St Croix River watershed (Attachment 16). Land use in the vicinity is a mix of forested and agricultural, which can contribute to nonpoint source pollution of surface waters. The bulk of noncontact run-off from the landfill will be directed to sedimentation basins that are designed to remove 80 percent of the sediment from the run-off. Soils are quite sandy in the area and infiltration is likely to be a significant factor. Any treated run-off that does discharge from the sediment basins would move to Wetland A in the southeast corner of the site. Overflow from this wetland moves to additional wetlands and then to Tosher Creek, which is not an impaired water, and which, in turn, empties into Fish Lake, which is impaired. Since most run-off from the site is expected to infiltrate before reaching Fish Lake, this runoff is not expected not exacerbate the impairment. Available data shows no other known regulated projects, including feedlots, within the unnamed subwatershed, although there are farms within the unnamed subwatershed. Feedlots in Minnesota are regulated at the state and/or county level and are required to store manure in a safe manner, land apply manure at agronomic rates, and observe application setbacks from sensitive resources. These requirements minimize the potential for surplus nutrients to impact water resources, and any feedlots within this area that do not show up on MPCA databases would, thus, be expected to add little to any impact from the landfill. Based on the above, significant cumulative effects on surface waters in the area of the project are not expected to occur. Groundwater Quality Groundwater beneath the landfill has been impacted by leachate produced in the old unlined portion of the landfill, shown on Attachment 5, which was the first portion of the landfill to be filled in the 1970s and 1980s. This area was unlined, but it has been capped with impermeable materials. Subsequent filling has been done in lined areas, and there is no evidence that additional groundwater contamination has resulted from these areas. The only known groundwater contamination is a plume extending easterly of the landfill site in the area of Wetland A. Remediation of this plume has included capping the old unlined landfill with impermeable materials and lining and properly closing subsequent disposal areas. The result has been a reduction in the impact level of the plume. Monitoring is ongoing. See Item 19 for additional details. The plume and its remediation represent an ongoing condition of the old unlined landfill, and are not to be thought of as an impact related to this project. The project itself, consisting of lined disposal cells whose impacts are managed via leachate collection and proper disposal, would not add to the plume or its impacts. No cumulative effects on groundwater are expected. Air Quality Impacts The potential impacts to air quality associated with this project are generally limited to greenhouse gas emissions, odors, air toxics, and criteria pollutants. Air Toxics (Non-criteria air pollutants) To form a more complete picture of potential cumulative health risks from inhaling outside air pollution in the vicinity of the landfill, monitoring data from a rural monitoring station with similar population density was considered along with potential risks from the landfill (see table below). This rural


monitoring based risk estimates reflect emissions from industrial facilities, traffic, gas stations, wood-burning stoves, etc. and distant emissions sources that contribute to a regional level of pollutants that have been detected at similar levels across Minnesota. Cumulative inhalation risks estimates were below facility risk guidelines except for cancer risks, which are above facility risk guidelines throughout the state. The percent contribution of the cumulative potential inhalation cancer risk estimates from the project modification is six percent.

Potential Cumulative Inhalation Health Risk Estimates

Max Acute Inhalation

Hazard Index

Max Chronic Non-Cancer Inhalation

Hazard Index

Max Cancer Inhalation

Risk Risk estimates from rural population monitoring data 0.2 0.6 2E-5 Total current landfill risk estimates 0.1 < 0.1 0.5E-5 Total landfill risk estimates after modifications at the site of maximum impact 0.2 < 0.1 0.6E-5 Total Cumulative Sum at the site of maximum impact 0.4 0.7 3E-5 % contribution from modifications 21% < 2% 6%

Criteria pollutants Cumulative impacts were analyzed via computer modeling of the dispersion of criteria pollutant emissions to demonstrate compliance with the National Ambient Air Quality Standards and the Minnesota Ambient Air Quality Standards (MAAQS) for PM10, PM2.5, NOx, and SO2 and CO. Lead was not modeled as it is not emitted from any of the facility sources. The following table summarizes the results of the cumulative modeling analysis. The table shows that modeled facility concentrations are below NAAQS and MAAQS for all pollutants. When MPCA background concentrations are added to the facility modeled concentrations, impacts remain below both the NAAQS and MAAQS. In anticipation of the EPA’s new one-hour NOx standard, the facility conducted a one-hour NOx modeling analysis. The facility’s modeled impact is 18 ug/m3. The MPCA estimated a conservative background concentration of 71 ug/m3, based on data from the EPA Monitor Values Report-Criteria Air Pollutants website (http://www.epa.gov/air/data/monvals.html?st~MN~Minnesota), and added this background value to the facility concentration. The estimated total 1-hr NOx impact is 89 ug/m3, which is 72 percent of the standard.

http://www.epa.gov/air/data/monvals.html?st%7EMN%7EMinnesota

PollutantAve raging

Time Facility Background Total

% of N AAQS/M AAQS

N AAQS/M AAQS Standard

PM10 24-Hour 89.80 33 122.80 82 150Annual 14.60 15 29.60 59 50

PM2.5 24-Hour 3.70 24 27.70 79 35Annual 1.10 8 9.10 15 61

SO2 1-Hour 0.94 26 26.94 2 13003-Hour 0.87 13 13.87 1/2 1300/91524-Hour 0.56 5 5.56 15 365Annual 0.08 3 3.08 4/5 80/60

NOx *1-Hour 18 71 89.00 72 123Annual 1.30 7 8.30 8 100

CO 1-Hour 83.40 5520 5603 14 40,0008-Hour 61.60 2875 2937 29 10,000

*EPA has not published the new one-hour NOx standard.

Greenhouse gas emissions Greenhouse gas emissions at the landfill are in the process of being reduced by the installation of an active gas collection system. Part of this system is already in place, and the collected gas burned in a fare. This has the effect of greatly reducing landfill methane emissions and producing carbon dioxide emissions instead. Methane is a much more potent greenhouse gas than carbon dioxide, and the collection system greatly reduces the greenhouse effect that can be attributed to the landfill. In addition, the addition of the SMMPA generator set to burn LFG for electricity production will accomplish the same goal, with the added benefit of energy production, . The only other known regulated projects in the vicinity of the landfill are feedlots. While animal agriculture as a whole is a significant contributor to the worldwide greenhouse effect, there is no evidence that individual feedlots in the area produce measurable contributions. Based on the above, no significant cumulative greenhouse effects are expected. Odors Odors at a landfill are a function of the disposal area that is open at any one time and the effectiveness of LFG control. The project is a continuation of landfilling activities that have been ongoing for some time, so there is no reason to expect a significant increase in odorous emissions from the project. Also, odors will be minimized by the expanded gas collection system and combustion of LFG in the flare and generator set, so that odor impacts are likely to be lower than historically. Feedlots create odorous emissions as well. However, there are few in the vicinity, and the nearest one found in MPCA files is over one mile southwest of the proposed disposal area. Since the winds that carry odors also eventually dissipate them, it is not likely that there would be significant cumulative odorous effects associated with the project.



Dust To date, dust emissions have not been a significant issue at the landfill, and this is not expected to change. Other than agricultural fields and County Highway 12, there are no other known sources of measurable dust in the vicinity. No significant cumulative effects are expected. Noise To date, noise emissions have not been a significant issue at the landfill, and this is not expected to change. There are no other significant sources of noise in the vicinity. No cumulative effects are expected. Land Use The land occupied by this project has been defined for many years as the SE¼ of Section 20, SW¼ of Section 21, NE¼ of Section 29, Township 39 North, Range 24 West. The project would be implemented within this land parcel and would not involve the occupation of additional land. Three issues have been identified as potentially posing cumulative effects issues with respect to land resources – wildlife habitat, row crop agriculture, and traffic. Wildlife Habitat As noted, the project would not involve disturbance of additional land beyond what has been dedicated to the landfill for many years. The proposed project will not displace or disrupt any wildlife habitat and, as a result, would not contribute to an adverse cumulative potential effect related to habitat fragmentation and loss. As noted elsewhere, groundwater contamination plume movement is to the east of Wetland A. The contamination parameter is vinyl chloride, which appears to be volatilizing into the atmosphere at that point. There is no evidence that this would cause environmental effects on habitat values in the wetland. There are no other known contributors to groundwater contamination in the area. Therefore, no cumulative effects on habitat are expected.

Traffic Implementation of the project would be expected to continue the current levels of landfill operations, so traffic volumes to and from the landfill are not expected to change significantly. Periodic increases due to construction activities would be similar to what has gone on in the past. Leachate traffic from the landfill to wastewater treatment plants will likely decrease with the implementation of leachate recirculation, so this traffic is likely to decrease as well. The project would, thus, not be expected to contribute to any significant cumulative effects with respect to traffic.

30. Other Potential Environmental Impacts. If the project may cause any adverse environmental impacts

not addressed by items 1 to 28, identify and discuss them here, along with any proposed mitigation.

No additional adverse environmental impacts are anticipated that have not been addressed in this EAW.

PROJECT LOCATION

ECSWCSANITARYLANDFILL

SITE LOCATION MAP

VICINITY MAP

2

345

6

7

17

89

12

1315

19

18

20

21

2223

24

25

26

27

28

29

33

32

31

30

14

16

33

3435

36

37

39

38

40

STATE

7

4

5

6

24

23

2221

20

19 16

12

263

17

10 1411

21

18

9 27

1/4-MILE RADIUS

1-MILE RADIUS

30

31

3229

28

37

36

38

34

35

25

39

1 33

HWY 23IMPE

RIAL

STR

EET

COUNTY HWY 6013

15

8

11

10

BA

B CA

APPROXIMATEECSWC PROPERTYBOUNDARY

VICINITY MAP

PROPERTY AND WELL OWNERSHIP MAP

LEGEND

NOTES:

LEGEND

MINNESOTA POLLUTION CONTROL AGENCYAIR QUALITY520 LAFAYETTE ROADST. PAUL, MN 55155-4194

AERA INTERNAL FORM-02IMPACT ANALYSIS SUMMARY

Page 1 of 12

1. AQ Facility ID No.: 06500032 and 065000332. AQ File No.: 3. Facility Name: Southern Minnesota Power Agency (SMMPA) and East Central Solid Waste Commission

(ECSWC) 4. Date of Initial Submittal (and major revisions): 11/19/09; Emissions updated 1/5/10; 2/4/105. Date of Risk Manager Meeting: 2/22/106. Project Team Members: Heather Magee-Hill, Toni Volkmeier, Ruth Roberson, William Lynott.7. Assigned Section Manager: Don Smith8. Standard Industrial Classification (SIC):

9. Summary: a. Facility and Project Description Southern Minnesota Power Agency (SMMPA) is proposing to install an engine generator set (engine) to

combust the municipal waste landfill gas currently being collected and flared by the East Central Solid Waste Commission (ECSWC) in order to generate 1.6 MW of electricity. SMMPA submitted a permit application for the engine in January of 2008. The MPCA public noticed a permit for the engine in August 2008 and received some public comments questioning the health and safety of residents living within one mile (1.6 km) of the facility. Due to these comments the MPCA requested an Air Emission Risk Analysis (AERA) be performed and submitted.

Meanwhile, the ECSWC is proposing an expansion of the existing landfill footprint to the north, to provide an additional 10 years of service life. The total municipal solid waste facility capacity through the end of the expansion is estimated to be 2,872,845 tons. The facility includes leachate recirculation in a portion of the landfill and a gas collection and control system, which consists of a flare. The landfill expansion triggered an EAW under Minn. R. 4410.4300 Subp. 17.

b. Site Setting The landfill is located in a rural area approximately 2 and ¾ miles (4.4 km) southwest of Mora, MN in

Kanabec County. Within 1.5 kilometers of the landfill there are multiple residences and farms but no schools, hospitals, daycare centers or similar receptors. The nearest residents are approximately 400m from the proposed engine, west and south of the facility (See Map 2). The nearest agricultural operation is a commercial beef ranch to the northeast, McVay Farms, which has a feedlot permit. The McVay farm is not permitted for dairy operations. There is no dairy farming done within 1.5km of the facility. There are about 10 acres of hay fields across the street from the landfill entrance in the area modeled to have the greatest impact from the engine. Within 3km there are several potentially fishable lakes the largest being Fish Lake (DNR# 33003600), which is in the watershed potentially most impacted by this facility, has public access, has fish consumption advisories for mercury, and according to the DNR Lake Finder website “By all accounts the northern pike fishery in Fish Lake is presently healthy with good numbers and showing great signs of quality angling.” (See Map 1).

c. Emissions Summary Emission estimates were calculated for over 80 pollutants, including those listed in the Minnesota

Department of Health Risk Values Charts, which were expected to be emitted. Emission estimates were based on draft EPA AP-42 values (updated 10/08), California Air Toxics Emission Factor Database, stack test results (including 5/2008 dioxin/furan results from the Spruce Ridge Resource Management Facility in Glenco, MN), LandGEM, or Mobil 6.2.

Emission calculations are based on PTE. For the current facility, risk estimates included emissions from the flare (at maximum capacity), idling trucks, and fugitive air toxics from the current landfill. In addition to

ATTACHMENT 12

MINNESOTA POLLUTION CONTROL AGENCY AIR QUALITY 520 LAFAYETTE ROAD ST. PAUL, MN 55155-4194

AERA INTERNAL FORM-02 IMPACT ANALYSIS SUMMARY

Page 2 of 12

the sources included in the current facility, the facility after modification emission estimates also included the engine (at maximum capacity) and fugitive air toxics from the expanded landfill. Since neither SMMPA nor ECSWC can legally control each other’s operations the analysis includes both the flare and the engine operating simultaneously at full capacity, which is a worst-case scenario. The AERA submittal explained that this is an over estimate of emissions due to the fact that there will not be enough landfill gas to power both at capacity at the same time. d. Dispersion Summary The project proposer chose to use AERMOD to refine dispersion factors used in the Screening RASS’s.

The approach increases the accuracy of the results and makes them more site specific. MPCA staff did additional modeling refinements for the farmer and fisher exposure pathways using AERMOD and following the Human Health Risk Assessment Protocol (HHRAP) for Hazardous Waste Combustion Facilities using IRAP-h View.

e. Risk Summary Screening level potential risk estimates for the entire landfill, after the modifications, are at or below

facility risk guidelines, with the exception of conditions where the exposure assumptions are unlikely (i.e. milk production at the potential maximum impacted locations). The farmer scenario assumes, in addition to risks from inhalation and vegetable consumption, that the farmer raises and eats beef, pork, chicken and consumes milk and eggs produced from animals raised on forage grown at the location of maximum predicted impact. The majority of the farmer cancer risks come from dioxins/furans emitted from the engine and consumed through milk ingestion. Since farming does not occur at the potentially maximally impacted location and risk estimates dissipate with distance, MPCA staff looked at further refinements to the farmer cancer risks estimates. Risk estimates from the more refined analysis are at or below facility risk guidelines at current farming locations (see Map 2) or under current practices (no milk ingestion) at the site of maximum impact for the engine.

No fish ingestion analysis was submitted but given the distances to the fishable water bodies and emissions, it is likely that persistent, bioaccumulative and toxic chemicals (PBTs) from the landfill and engine do not pose a risk above MPCA guidelines. MPCA staff used IRAP and estimated that risks from fish ingestion from Fish Lake from non-mercury pollutants are below facility risk guidelines for both the subsistence (<0.01 HQ and 0.4E-5 cancer) and recreational fishing (<0.01 HQ and <0.1E-5 cancer) pathways. Since the facility is estimated to emit around one tenth of a pound of mercury per year, like other facilities with similar emissions, MPCA staff concluded that only a very small amount would deposit locally and the increment of what does deposit relative to background concentrations would be extremely small and likely immeasurable.

Risks from idling trucks were not estimated to be above risk driver levels. As is consistent with other projects, risks from moving vehicles were not estimated.

f. Cumulative Risk Summary Rural ambient monitoring data was used to characterize potential background risks for the area. The

MPCA staff did additional analysis of possible risks from Engineering Polymers Corp. in Mora and found that the rural monitoring data would sufficiently characterize estimated risks from Engineering Polymers based on actual emission estimates and conservative modeling assumptions.

Cumulative inhalation risks estimates were below facility risk guidelines except for cancer risks, which are above facility risk guidelines throughout the state. The percent contribution to the cumulative potential inhalation cancer risk estimates from the project modification is 6%.

Quantitative Summary



Page 3 of 12

10. What is the source of the following summaries? From an MPCA RASS based on the RASS e-mailed

2/4/2010 but MPCA used detection limits instead of ½ of the detection limits

Air Toxics Screen Before Modifications Total Inhalation Screening Hazard Indices and Cancer

Risks

Total Indirect Pathway Screening Hazard Indices and

Cancer Risks Total Multipathway Screening

Hazard Indices and Cancer Risks

Acute

Subchronic Noncancer

Chronic Noncanc

er

Cancer Farme

r Noncancer

Farmer Cancer

Resident

Noncancer

Resident Cancer

Farmer

Noncancer

Farmer Cancer

Resident Noncancer

Resident Cancer

0.1 <0.01 0.07 0.5E-5 <0.01 0.5 E-05 <0.01 <0.1 E-5 0.07 0.9E-05 0.07 0.5E-05

1 1 1 1E-05 1 1E-05 1 1E-05 1 1 E-05 1 1E-05

a. Risks after modification including the engine (at maximum capacity), fugitives from the current and

expanded landfill, the flare (at maximum capacity), and risks from idling trucks.

Air Toxics Screen After Modifications Total Inhalation Screening Hazard Indices and Cancer

Risks

Total Indirect Pathway Screening Hazard Indices and

Cancer Risks Total Multipathway Screening

Hazard Indices and Cancer Risks

Acute

Subchronic Noncancer

Chronic Noncan

cer

Cancer

Farmer Noncan

cer

Farmer Cancer

Resident

Noncancer

Resident Cancer

Farmer

Noncancer

Farmer Cancer

Resident

Noncancer

Resident Cancer

0.2 0.01 0.08 0.6 E-05 <0.01

6E-05 (0.4E-5

IRAP no milk,

0.7E-5 IRAP in

field with milk,

0.2E-5 IRAP in field no

milk)

<0.01

0.1E-05 0.09

7E-05 (1E-5 IRAP

with no milk,

1.3E-5 IRAP in

field with milk,

0.8E-5 IRAP in field no

milk)

0.08 0.8 E-05

1 1 1 1E-05 1 1E-05 1 1E-05 1 1 E-05 1 1E-05



Page 4 of 12

Note: The hazard index (HI) against which facility risks are compared for acute, sub-chronic and chronic non-cancer risks is 1. The cancer risk against which facility risks are compared is 1 E-5 (or 1 chance in 100,000). These facility risk guidelines are risk management-based. They are not a discrete indicator of observed adverse effect. If a risk estimate falls below facility risk guidelines, the MPCA may, without further investigation, conclude that a proposed action does not present an unacceptable risk. A risk estimate that exceeds these guidelines, however, would not, in and of itself, necessarily indicate that the proposed action is not safe or that it presents an unacceptable risk. Rather, a risk estimate that exceeds a guideline triggers further careful consideration. 11. Mass and Percent Mass Assessed in each RASS Analysis

Scenario Description

Mass HAPS (tons per year)

% HAPS Mass VOC (tons per year)

% VOC

Screening RASS 6.8 100% 18.5 23% 12. For each exposure pathway below, list the risk drivers and their percent contribution to the hazard

indices or cancer risks.

a. Inhalation Exposure Pathway Chemical HQ/cancer

risk % contribution

Exposure Duration Comments (endpoints)

Acrylonitrile 2.8E-6 44% Cancer Tetrachloroethane, 1,1,2,2-

1.3E-6 21% Cancer

Nitrogen dioxide (NO2)

0.2 78% Acute (Respiratory)

b. Indirect Exposure Pathway

Chemical HQ/cancer risk

% contribution

Exposure Comments

Dioxins/furans 5.6E-5 93% Farmer Cancer Benzo(a)pyrene 0.2E-5 3% Farmer Cancer Dibenz(a,h)antrhacene 0.2E-5 3% Farmer Cancer

c. Were surrogate inhalation health benchmarks used for risk drivers? Which ones and what further analysis might better inform the risks? No.

13. Are the criteria pollutants compared to the AAQS using “high first high” modeled concentrations (rather than the regulatory standard)? If not, what was used? Additional criteria pollutant modeling was done for the EAW, which included more fugitive sources of criteria pollutants. Summary from HG 2003 14. Mercury Analysis: Around one tenth of a pound of mercury per year is estimated to be emitted from this facility. Like other AERAs with less than one pound of mercury per year, a Hg fish consumption pathway analysis using the MPCA Mercury Risk Estimation Method (MMREM) was not required as part of this AERA. This decision was based on the relatively small amount of mercury emitted. Based on the source of the emissions, only a very small amount would deposit locally and the increment of what does deposit relative to background concentrations would be extremely small.



Page 5 of 12

Qualitative Evaluation Exposure Setting 15. Describe multimedia issues that may be relevant to this facility. The facility has the potential to emit persistent, bioaccumulative and toxic chemicals (PBTs) such as dioxin/furans and polycyclic aromatic hydrocarbons (PAH’s). There is a commercial cattle farm near the facility but no dairy farms within 1.5 km. There are several water bodies within 3km of the facility. 16. Describe current or future exposure based on zoning and land use information. Arthur Township does not have a zoning map but the majority of the township is zoned ”agriculture-open” or industrial. 17. Describe the types of sensitive receptors within 1.5 kilometers from the facility. Within 1.5 kilometers of the landfill there are multiple residences and farms but no schools, hospitals daycare centers or similar receptors. 18. Summarize evidence that land in the area of impact will or will not be used for agriculture. Describe agricultural setting. The nearest agricultural operation is a commercial beef ranch, McVay Farms. McVay farms do not have dairy cows and are not permitted to operate a dairy. There is no dairy farming within 1.5km. There are about 10 acres of hay fields across the street from the landfill entrance in the potentially most impacted area. The IRAP analysis included a receptor in this field (See Map 2). 19. If PBTs are emitted, list and describe fishable water bodies within appropriate radius from facility/property boundary. Ann River is within 1 km of the landfill. The river runs through the McVay land and people access the river by climbing over the railing of a bridge on highway 23. The Ann River widens into Fish Lake (DNR# 33003600) about 2.4 km from the landfill. The following information is known about Fish Lake: it is in the watershed potentially most impacted by this project, has public access, has fish consumption advisories for mercury and according to the DNR Lake Finder website “By all accounts the northern pike fishery in Fish Lake is presently healthy with good numbers and showing great signs of quality angling.” Other smaller lakes or wetland areas, which would be expected to be less of a source of potential risks from fish ingestion than Fish Lake include: Kent Lake (DNR#33003500) which is about 1.7 km from the facility, the Tosher Creek State Wildlife management area which is about 2 km from the facility and Devil Lake which is about 2.5 km from the landfill. Cumulative Analysis 20. What other permitted facilities that have air emissions are located within a 1.5 kilometer radius of the facility? No other facilities are located within a 1.5 km radius of the facility. While there are facilities located in Mora, MPCA staff concluded that rural background risk estimates sufficiently characterized the background risks surrounding the landfill. Using the MPCA Risk Screening tool (MNRiskS) and refined emission estimates from Engineered Polymers Corp. and conservative RASS dispersion assumptions. MPCA staff estimated potential risks from Engineered Polymers Corp. contributing about 0.01 to the acute inhalation hazard index and 0.3 to the subchronic inhalation non-cancer HI at the landfill.



Page 6 of 12

21. Describe general statewide monitoring data and how it relates to the chemicals emitted at this facility. If monitor is within vicinity, provide data. Since the zip code population density of the facility is estimated to be in the rural range (46 people per square mile), data from the MPCA rural Holloway monitoring site are included below to be representative of the area near the facility. Total Risks by pollutant families for zip code population densities of less than 500 people per square mile

Pollutant Group Name Acute non-cancer

Chronic non-cancer

Cancer risk in 100,000

Metals 0.1 0.05

VOCs 0.01 0.06 1.43

Carbonyls 0.1 0.41 0.66

NO2 0.12

Sum 0.24 0.57 2.14

Risks by target health endpoints for zip code population densities of less than 500 people per square mile

Respiratory Nervous System

Eyes Reproductive Developmental Hematopoietic

Chronic 0.41 0.32

Acute 0.22 0.1

Risks for risk driver pollutants (non-cancer hazard quotient of >0.1 or cancer risk >0.1 in 100,000) for zip code population densities of less than 500 people per square mile

Pollutant Acute non-cancer HQs

Chronic non-cancer HQs

Cancer risk in 100,000

Carbon tetrachloride 0.83

Ethylene chloride 0.10

Benzene 0.40

Formaldehyde 0.1 0.32 0.48

Acetaldehyde 0.09 0.18

NO2 0.12 Potential Cumulative Inhalation Health Risk Estimates (Facility and monitored data)

Max Acute Inhalation Hazard Index

Max Chronic Non-Cancer Inhalation Hazard Index

Max Cancer Inhalation Risk

Risk estimates from rural population monitoring data 0.2 0.6 2E-5 Total current landfill risk estimates 0.1 <0.1 0.5E-5 Total landfill screening risk estimates after modification 0.2 <0.1 0.6E-5 Total Cumulative Sum 0.4 0.7 3E-5 % contribution from modifications 21% <2% 6%



Page 7 of 12

ADDITIONAL INFORMATION 22. Missing chemicals or sources: We assume a reasonable effort was made to find chemicals and sources. We are not claiming that

we know what all of the chemicals or sources are at the facility. a. Are there any potentially missing sources from the emission list not included in the RASS or

Q/CHI workbook? Insignificant sources (by regulatory definition) were not included, such as propane fired heaters for building heat and a small portable generator used to power tools for emergency repairs.

b. Is there information suggesting additional chemicals are emitted (e.g., based on experience at

similar facilities)? No. 23. List chemicals emitted but lacking inhalation health benchmarks. From AP-42. 1,2,3-Trimethylbenzene 1,2,4-Trimethylbenzene 1,2-Dichloro-1,1,2,2-tetrafluoroethane (Freon 114) 1,2-Dichloroethene 1,2-Diethylbenzene 1,3,5-Trimethylbenzene 1,3-Diethylbenzene 1,4-Diethylbenzene 1-Butene / 2-Methylbutene 1-Butene / 2-Methylpropene 1-Ethyl-4-methylbenzene (4-Ethyl toluene) 1-Ethyl-4-methylbenzene (4-Ethyl toluene) + 1,3,5-Trimethylbenzene 1-Heptene 1-Hexene / 2-Methyl-1-pentene 1-Methylcyclohexene 1-Methylcyclopentene 1-Pentene 1-Propanethiol (n-Propyl mercaptan) 2,2,3-Trimethylbutane 2,2,5-Trimethylhexane 2,2-Dimethylbutane 2,2-Dimethylpentane 2,2-Dimethylpropane 2,3,4-Trimethylpentane 2,3-Dimethylbutane 2,3-Dimethylpentane 2,4-Dimethylhexane 2,4-Dimethylpentane 2,5-Dimethylhexane

2,5-Dimethylthiophene 2-Ethyl-1-butene 2-Ethylthiophene 2-Ethyltoluene 2-Hexanone (Methyl butyl ketone) 2-Methyl-1-butene 2-Methyl-1-propanethiol (Isobutyl mercaptan) 2-Methyl-2-butene 2-Methyl-2-propanethiol (tert-Butylmercaptan) 2-Methylbutane 2-Methylheptane 2-Methylhexane 2-Methylpentane 3,6-Dimethyloctane 3-Ethyltoluene 3-Methyl-1-pentene 3-Methylheptane 3-Methylhexane 3-Methylpentane 3-Methylthiophene 4-Methyl-1-pentene 4-Methylheptane Acetone Bromodichloromethane Butane Carbon tetrafluoride (Freon 14) cis-1,2-Dichloroethene cis-1,2-Dimethylcyclohexane cis-1,3-Dimethylcyclohexane cis-1,4-Dimethylcyclohexane / trans-1,3-Dimethylcyclohexane

cis-2-Butene cis-2-Heptene cis-2-Hexene cis-2-Octene cis-2-Pentene cis-3-Methyl-2-pentene Cyclohexene Cyclopentane Cyclopentene Decane Dibromochloromethane Dibromomethane (Methylene dibromide) Dichlorofluoromethane Diethyl sulfide Dimethyl disulfide Dimethyl sulfide Dodecane (n-Dodecane) Ethane Ethanol Ethyl acetate Ethyl mercaptan (Ethanediol) Ethyl methyl sulfide Heptane Indane (2,3-Dihydroindene) Isobutane (2-Methylpropane) Isobutylbenzene Isoprene (2-Methyl-1,3-butadiene) Isopropyl mercaptan Mercury (monomethyl) Mercury (dimethyl) Methanethiol (Methyl mercaptan)



Page 8 of 12

Methyl tert-butyl ether (MTBE)c Methylcyclopentane n-Butylbenzene Nonane n-Propylbenzene (Propylbenzene) Octane p-Cymene (1-Methyl-4-lsopropylbenzene) Pentane

Propane Propyne sec-Butylbenzene Tetrahydrofuran (Diethylene oxide) trans-1,2-Dichloroethene Thiophene trans-1,2-Dimethylcyclohexane trans-1,4-Dimethylcyclohexane trans-2-Butene

trans-2-Heptene trans-2-Hexene trans-2-Octene trans-2-Pentene trans-3-Methyl-2-pentene Undecane Trimethylpentane, 2,2,4- Carbonyl sulfide

24. List known respiratory sensitizers emitted. Formaldehyde, Nickel.

25. List developmental toxicants emitted. Benzene, carbon disulfide, carbon tetrachloride, chloroform, ethyl benzene, ethyl chloride, mercury, and trichloroethylene. No developmental toxicants are above ceiling values. 26. Where is the maximum modeled concentration (risk) for acute? Chronic? The maximum impacts, both chronic and acute, from the engine and flare, which are the sources of most of the potential risk estimates, are modeled to be south of the facility along the fence line (See Map 2). For the trucks and fugitives from the landfill area, the estimated maximum impacts, both chronic and acute, are east of the facility on the fenceline.

27. Accidental Release information (Incident Management System data on facility reports of SSM events

from the last 5 years). Additional information as relevant. The Incident Management System contains a 2004 report from the facility about a leachate spill and a 2005 call reporting odors from the landfill. 28. Internal Combustion Engines. (AERA-04 Certification for Emergency Internal Combustion Engines) From the submittal, “There is a small portable generator used by maintenance as needed. It is small enough to be lifted into the back of a pickup truck by one person and is also insignificant [by regulatory definition] based on emissions.” 29. Describe known community concerns as they relate to health risks associated with this facility. Around Aug 21, 2008 the MPCA received several petitions for a public informational hearing about the previous draft of the permit for the proposed engine questioning the health and safety of residents living within one mile (1.6 km) of the facility. The petitions noted that there was no information about health risks especially from pollutants that are noted in the Minnesota Department of Health Risk Values Charts and possible risks from pollutants created through the chemical reaction of the site-specific gas components during the combustion cycle. They also question whether there would be health effects from a significant increase in diesel truck traffic. 30. Additional Considerations: An increase in truck traffic is not expected with this expansion. Idling trucks were modeled as a point source on the landfill and contributed 0.1 to the acute hazard index mostly from NO2 and below risk driver levels for other risk estimates. According to the submittal “At the scale house trucks are required to be shut off. On the landfill – it typically takes five minutes for regular garbage trucks- walking floor trailers takes fifteen minutes to



Page 9 of 12

unload. About 14 walking floors per day April- Oct. and about 7 smaller trucks. During the winter months – East Central Landfill gests about 8 walking floor loads and still around 7 smaller trucks.” Moving truck traffic was not modeled for this project because 1) an increase in truck traffic is not expected with this expansion, and 2) it is not standard MPCA practice to estimate risks from moving vehicles for projects of this type.

31. Should a risk recalculation requirement be included in the permit? Summary of rational.

Risk estimates are below facility risk guidance levels except for the farmer scenario, which is dominated by potential risks from dioxins/furans from the engine. Risk estimates would not be expected to increase greatly unless the flare or engine analyzed in this AERA were relocated, or additional engines or flares were added. Since additional modifications would likely trigger a permit amendment no risk recalculation clause is recommend with the understanding that at permit reissuance the team would consider the need for updated risk estimates.

Impact Analysis Summary 32. How close are the emission estimates to what the facility will actually emit? What are the factors that

impact this? From the AERA submittal, “Worst-case was operating the engine at maximum capacity as well as operating the flare at its designed capacity. In reality there will not be enough gas to operate the engine and the flare at maximum capacity.” Thus the emission estimates used are expected to overestimate what will actually be emitted. Emission estimates, especially for dioxin/furans, are from a limited number of test results and thus could contribute to over or underestimating risks. There may be other pollutants emitted from the facility which have not been tested for (such as other carcinogenic PAHs) which may contribute to an underestimating of risk. 33. How accurate is the dispersion model to the actual site dispersion? What are the factors impacting

the accuracy? Screening risk estimates are probably slightly conservative since potential maximum dispersion factors for each source were added together regardless of location. More refined air dispersion modeling may alter the concentrations and risks by a factor of 2. 34. What is the impact of the toxicity values on the risk analysis? What are the factors impacting the

analysis? The toxicity values could contribute to an over or under prediction of risk.

RASS multimedia factors are not clearly over or under protective. A lack of health benchmarks for numerous chemicals potentially emitted could result in an under-prediction of risks. For example Dioxins/furans are known to have non-cancer effects, yet health benchmarks are not yet available with which to assess these endpoints. Not including age adjusted cancer potency factors for non-dioxin/furan carcinogens would probably have increased the cancer risk estimates, the MPCA and MDH are currently working on guidance for doing so.

35. What is the impact of the exposure assumptions on the risk analysis? What are the factors impacting

the analysis?



Page 10 of 12

The exposure assumptions may over or under predict actual exposures (e.g., this depends on the applicability of the scenario assumptions and whether individuals are actually exposed at maximum impact locations). 36. What is the impact of other factors on underestimating and/or overestimating risks in the analysis? The use of averaged risks from ambient monitoring data may contribute to over or under estimating the risks in this analysis. Staff Conclusions and Recommendations MDH Coordination: Did MDH provide comments? None were asked for. Staff team recommendations:

MPCA staff recommends that the permitting and environmental review processes can proceed without additional input from the AERA. Screening level potential risk estimates for the entire facility, after the modifications, are at or below facility risk guidelines, with the exception of conditions where the exposure assumptions are unlikely (i.e. milk production at the potential maximum impacted location). MPCA staff confirmed with additional refined modeling (IRAP) that either without milk production at the potentially maximum impacted area or further way from the potentially maximally impacted area, that estimated facility risk estimates are at or below facility risk guidelines. Cumulative inhalation risks estimates were below facility risk guidelines except for cancer risks, which are above facility risk guidelines throughout the state. The percent contribution of the cumulative potential inhalation cancer risk estimates from the project expansion is 6%. Since additional modifications would likely trigger a permit amendment no risk recalculation clause is recommend with the understanding that at permit reissuance the team would consider the need for updated risk estimates. Since dioxins/furans emission estimates were based on only one stack test and were a major contribution to potential risk estimates, additional dioxin/furan stack testing is recommended.



Page 11 of 12

Appendix Map 1: ~1.5 and ~3 km radius showing water bodies and watersheds (purple outline).



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Map 2: Close up map of facility showing the maximum Engine dispersion factors and risk receptors (surrounding residences and farming areas) used in the IRAP refinement.

Unitized dispersion factors for 1988 (Max year) for Engine Blue 0.10-0.65 Green 0.65-1.20 Yellow 1.20-1.75 Red 1.75-2.30 Black are risk receptors in IRAP analysis

Residence receptor

Residence receptor

Residence receptor

McVay Farm receptor

Receptor in potentially most impacted agricultural field

Flare and Engine

Receptor most impacted by the engine

Cumulative Effects Map--East Central Landfill Expansion/

0 850 1,700 2,550 3,400425Meters

Attachment 13

East Central Landfill

Ann River

Fish Lake

Tosher

Creek

WMA

LegendFeedlots

tmdl06_final_streams

tmdl06_final_lakes

East Central Solid Waste Commission SLF Expansion ...

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