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INITIAL ENVIRONMENTAL EVALUATION (IEE) FOR

SCOTT BASE

WASTEWATER TREATMENT

JUNE 2001

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TABLE OF CONTENTS

TABLE OF CONTENTS ....................................................................................................................... 2

LIST OF TABLES ................................................................................................................................. 3

LIST OF FIGURES ............................................................................................................................... 3

LIST OF ACRONYMS .......................................................................................................................... 4

CONTACT DETAILS ........................................................................................................................... 5

NONTECHNICAL SUMMARY .......................................................................................................... 6

1. INTRODUCTION ....................................................................................................................... 7

1.1 BACKGROUND ............................................................................................................................ 7 1.2 SCOTT BASE AND EXISTING WASTEWATER DISPOSAL. .............................................................. 7

2. PROPOSED ACTIVITY .......................................................................................................... 11

2.1 THE PURPOSE OF AND THE NEED FOR THE ACTIVITY ............................................................... 11 2.2 DESCRIPTION OF THE ACTIVITY ............................................................................................... 13 2.3 CONSTRUCTION REQUIREMENTS ............................................................................................. 16 2.4 OPERATIONAL REQUIREMENTS ............................................................................................... 17

3. ALTERNATIVES ..................................................................................................................... 19

3.1 DO NOTHING ............................................................................................................................ 19 3.2 ALTERNATIVE SYSTEMS .......................................................................................................... 20 3.3 ALTERNATIVE SITES ................................................................................................................ 22 3.4 ALTERNATIVE PIPELINES AND OUTFALL ................................................................................. 22

4. POTENTIAL ENVIRONMENTAL IMPACTS OF PROPOSED ACTIVITY ................... 24

4.1 TERRESTRIAL ENVIRONMENT .................................................................................................. 24 4.2 MARINE ENVIRONMENT ........................................................................................................... 25 4.3 AIR ENVIRONMENT .................................................................................................................. 29 4.4 VISUAL AND AESTHETIC VALUES ............................................................................................ 30 4.5 INDIRECT IMPACTS ................................................................................................................... 30 4.6 CUMULATIVE IMPACTS ............................................................................................................ 31 4.7 EVALUATION OF POTENTIAL IMPACTS .................................................................................... 31

5. MONITORING ......................................................................................................................... 33

6. CONCLUSION .......................................................................................................................... 33

7. REFERENCES .......................................................................................................................... 34

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LIST OF TABLES

TABLE 1. Description of the Wastewater Systems Under Consideration for Scott Base. TABLE 2. Timeline of procuring the wastewater system for Scott Base. TABLE 3. Construction Requirements for Each of the Wastewater Systems Under

Consideration. TABLE 4. Major Equipment and Vehicle Needs. TABLE 5. Operational requirements of the Four Wastewater Systems Under

Consideration. TABLE 6. Alternative Wastewater Systems for Scott Base. TABLE 7. Composition of Effluent Quality for the Various Systems TABLE 8. Evaluation of Common Potential Impacts on the Environment of the Four

Systems Under Consideration for Scott Base.

LIST OF FIGURES

FIGURE 1. Location of Scott Base, Ross Island, Antarctica

FIGURE 2. Scott Base. Top: Aerial Photo, October 2000. Bottom: Map of Existing Scott Base Buildings and Existing Wastewater Outlet.

FIGURE 3. Photo of Recently Upgraded Scott Base Outfall Line.

FIGURE 4. Scott Base layout with outlines of possible wastewater systems at the two site

options.

FIGURE 5. (Top): Contours of BOD5 concentration at 1m depth measured by Redvers with an outgoing tide and discharge of untreated wastewater from Scott Base. (Lower) Predicted contours of BOD5 concentration at 1m depth under the same tide conditions but with wastewater treated to contain 30mg/L BOD5.

FIGURE 6. Bathymetry immediately offshore from Scott Base.

APPENDIX

APPENDIX A: Proposed piping between tanks, STP and new wastewater lines.

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LIST OF ACRONYMS

BOD Biochemical oxygen demand. This is a measure of the amount of oxygen that would be absorbed if the organic matter or chemicals such as nitrogen was oxidised to a stable form. It therefore indicates how much oxygen (from air) that a treatment plant must provide to break down organic matter mainly to water, carbon dioxide, nitrate and new bacteria cells. Such a BOD can be exerted on a river or in the ocean, and may result in low dissolved oxygen concentrations and consequent suffocation of fish and other biota.

BOD5 Biochemical oxygen demand is usually measured over a 5-day period.

Historically, this is because rivers in England take about five days to reach the ocean, and a measure was required of the effect of wastewater and other discharges on the oxygen content of the rivers over this period.

COD Chemical oxygen demand. This is a measure of the total amount of oxygen

that would be required to oxidise the organic matter and chemicals in wastewater. It is determined by a chemical test rather then a bio-chemical test.

FC Faecal coliform bacteria. Faecal coliform are used as an indicator of the

presence of material of faecal origin, which may also indicate the presence of other pathogenic (disease causing) bacteria and viruses.

IEE Initial Environmental Evaluation SS Suspended solids. Suspended solid matter that may exist in wastewater. The

solids may include organic matter, bacteria cells, grit etc. Suspended solids do not include dissolved chemicals that might remain after drying wastewater.

STP Sewage Treatment Plant

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CONTACT DETAILS Emma Waterhouse Environmental Manager Antarctica New Zealand Private Bag 4745 Christchurch Phone: 358 0200 Fax: 358 0211 Email: e.waterhouse@antarcticanz.govt.nz

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NONTECHNICAL SUMMARY The Initial Environmental Evaluation (IEE) relates to the proposal by Antarctica New Zealand to start treating wastewater produced at Scott Base, Pram Point, Ross Island, Antarctica. The wastewater at Scott Base is currently macerated and discharged through a short ocean outfall. This process meets the minimum requirement under Article 5.1 (b) of the Antarctica (Environmental Protection) Act 1994, to treat sewage by maceration. However, Antarctica New Zealand has decided that treatment of the wastewater should be provided, to minimise environmental effects on the receiving environment. Currently, sewage from Scott Base is not treated in any way to reduce the content of solids, the organic strength (BOD), or the bacterial concentration. A number of wastewater treatment system options that would improve the quality of the wastewater from Scott Base have been considered. Four wastewater treatment options have been identified that would meet appropriate treatment standards. These include:

Reaman (rotating biological contactor) Blivet Aerator (rotating biological contactor) Smith & Loveless “FAST” (aerated fixed media) Innovative Water Systems (aerated fixed media)

Tenders have been invited for all four systems from the suppliers. Specific actions associated with the proposal causing impacts include; visual intrusion from the pipeline and insulated containers housing the system, ground disturbance through earth moving activities and construction of foundations for the system. The environmental impacts (including the benefits) of the proposal are discussed in the context of the highly disturbed nature of the Pram Point environment and the marine environment surrounding the area. The results of the evaluation of impacts of the proposal indicate that the activities are likely to have no more than a minor or transitory impact on the environment and will in fact significantly minimise the environmental effects on the receiving environment as compared to current practices.

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1. INTRODUCTION 1.1 Background This Initial Environmental Assessment (IEE) has been prepared in accordance with the requirements of the Protocol of Environmental Protection to the Antarctic Treaty, and the specific obligations contained in Annex I (Environmental Impact Assessment). The Protocol’s obligations are implemented in New Zealand law through the Antarctica (Environmental Protection) Act of 1994, and this IEE aims to meet these requirements. The proposed activity will further meet, and exceed the obligations of the Protocol, which includes compliance with the standards of Annex III (Waste Disposal and Waste Management), and the wider obligations of Annex IV (Prevention of Marine Pollution). It also aims to meet the wider obligations of Annex II – Conservation of Antarctic Flora and Fauna and Annex IV – Prevention of Marine Pollution, which focuses predominantly on ships but could be used for an indication for standards for other marine waste discharges. Antarctica New Zealand is committed to maintaining high standards of environmental compliance. The wastewater at Scott Base is currently macerated and discharged through a short ocean outfall. This process meets the minimum requirement under Article 5.1 (b) of the Antarctica (Environmental Protection) Act 1994, to treat sewage by maceration. However, Antarctica New Zealand has decided that treatment of the wastewater should be provided, to minimise environmental effects on the receiving environment. Sewage from Scott Base is currently not treated in any way to reduce the content of solids, the organic strength (BOD), or the bacteria concentration and treatment would result in a considerable and significant reduction in the potential pollutant load of this discharge. 1.2 Scott Base and existing wastewater disposal. Scott Base (77°51’S; 166°46’E) is located on Pram Point, Hut Point Peninsula, Ross Island, Antarctica (Figure 1). The base was constructed in 1957 and is the primary support facility for New Zealand’s activities in the Antarctic and provides logistic and operational support to science and related activities organised through Antarctica New Zealand.

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Ross Island

Hut Point

Ross Ice Shelf

Ross Sea

McMurdo Station

Hut Point

Scott Base

Hut Point Peninsula

Figure 1. Location of Scott Base, Ross Island, Antarctica

Ross Island

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Scott Base consists of a number of interconnected buildings, plus additional individual buildings and service areas (Figure 2). The maximum summer occupancy (Oct-Feb inclusive) is approximately 85 people (mean approximately 50). This number reduces to a core staff of 10 over winter (Mar-Nov inclusive).

Figure 2. Scott Base. Top: Aerial photo, October 2000, © Craig Potton. Bottom: Map of existing Scott Base buildings and existing wastewater outlet.

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The current Scott Base sewage and wastewater system consists of a reticulation network and three effluent storage tanks located near 3A ablutions, the lower base ablutions, and the recently built Q-Hut ablutions (Stage 8) (Figure 2). Effluent is discharged from the end of a heated, insulated pipe, extending from the base to the shore directly in front of the base. For the main part of the year the sea in front of Scott Base is frozen over, but this seasonal sea-ice does dissipate to form open water for a short period each season. Up until 14 April 1999, sewage and grey water were discharged onto the foreshore from separate lines, approximately 13m back from the shoreline. The effluent flowed overland and into the sea. On 14 April 1999, the two lines were combined at the foreshore site and the outfall was extended to a sea ice discharge point approximately 15m off shore. The sea ice outfall became blocked on 19 July, 1999 so a new shorter extension, terminating at the present outfall site was installed on 9 August, 1999. Between 19 July and 9 August 1999, the outfall was discharging from the old foreshore location. The outfall line was upgraded in early 2000, and now discharges through an ice hole/tide crack in the sea ice approximately 5m offshore.

Figure 3. Photo of recently upgraded Scott Base outfall line All sewage and greywater is discharged raw and macerated, without any form of treatment.

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2. PROPOSED ACTIVITY 2.1 The purpose of and the need for the activity The current method of disposal of sewage and wastewater at Scott Base meets the minimum requirement of the Antarctica (Environmental Protection) Act 1994. However, there is a precedent from other Antarctic Treaty nations and current New Zealand best practice to provide treatment of wastewater being discharged into the marine environment. In the Ross Sea region, Italy have led the way and have been treating its wastes, both by chemical and physical treatment and UV disinfection since 1987. The United States, at their McMurdo station, are currently in the process of installing a new plant, which consists of extended aeration/activated sludge secondary treatment and UV disinfection. There are a number of other stations throughout Antarctica of similar size to Scott Base, that already treat their wastes (URS, 2000). Consequently, to reduce the effects of the wastewater on the environment and associated ecosystems, and to avoid detrimental effects on aspects of aesthetic value, wilderness experience, scientific and biological significance, Antarctica New Zealand has decided to treat Scott Base wastewater. This decision is in keeping with Antarctica New Zealand’s ongoing commitment through its environmental policy, to limit any adverse impacts on the environment of the activities it supports. Antarctica New Zealand has resolved to provide treatment of the sewage before discharge to the ocean, to a nominal standard of <30m/L BOD and SS and <200 cfu/100ml faecal coliforms. It is proposed that this will be achieved by providing secondary treatment to the standard indicated, or better, followed by disinfection by UV light to achieve the required level of disinfection. Sludge generated by the treatment process will be dewatered to approximately 20% solids and taken back to New Zealand for disposal. Although there is minimal information on the existing wastewater composition at Scott Base, limited evidence from work carried out at other Antarctic coastal stations and from Redvers (2000) work, indicates that contamination of the local marine fauna is occurring. In particular, viruses, bacteria and genetic material pose the highest potential impacts. There have also been, and continue to be, health and safety issues associated with the location of the seawater and potable water intake sites and contaminants from the wastewater discharge. Contamination at the potable and aquarium seawater intake has also been recorded. A number of issues were considered when determining which treatment system should be implemented at Scott Base. These included effluent quality, size of the system and building requirements, staff inputs for sludge management, capital and operating costs and the “track record” of each system. The chosen system must be reliable and will have to be capable of producing a consistent output with minimum maintenance, given the variation in loadings over the year.

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The performance requirements specified for the system chosen are as follows: The treatment plant and disinfection system shall provide treatment of the sewage before

discharge to the ocean, to a nominal minimum standard of <30mg/L BOD and SS, and <200 cfu/100ml faecal coliforms.

A higher degree of treatment than the minimum standard indicated above will be preferred,

but judged on a cost benefit basis. The dewatering plant shall dewater the sludge generated by the treatment process to

approximately 20% solids (80% moisture) or better. The sewage treatment systems offered must be capable of treatment of sewage containing

up to 28% of seawater. Sludge production must be minimal.

UV disinfection is required by the tender for all processes.

Four systems have been shortlisted and tenders have currently been let. The four systems all meet the chosen criteria.

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2.2 Description of the Activity The project will involve the installation of a new wastewater system for Scott Base. The main features of the four systems under consideration are described in Table 1. Table 1. Description of the wastewater systems under consideration for Scott Base. System Description Reaman RBC

A Rotating Biological Contactor (RBC) is a disk of plastic mesh or similar open material (media) that provides a surface for bacteria to cling to. The disk rotates around a horizontal axle, so that it alternatively rotates into the air and then into the wastewater. Oxygen is supplied to the bacteria fixed on the disk when it passes through the wastewater. Excess bacteria are regularly shed from the disks and have to be settled out of the treated effluent in order to produce a high standard of effluent, free of solids, just as the conventional activated sludge process. But it is much easier to maintain well-settling bacteria when they grow on media surfaces. Surface-attached bacteria are more stable to varying loads, and produce more reliable treatment than the conventional activated sludge process. RBC systems have low power requirements as aeration is provided by the rotation of the disks. No air blowers are required. RBC plants are used at the Australian bases at Mawson, Casey and Davis. An RBC plant is also used at Terra Nova Bay.

Blivet Aerotor

The Blivet Aerotor is a modified form of the RBC process. It differs in that the Aerotor discs are sealed on the outside, and wastewater is pumped through the media inside the Aerotor along with air. The pumping action is similar to an Achimedes screw, and actually lifts the wastewater to a higher head at the end of the process. This can be useful for facilitating flow through a system without the need for pumps.

Innovative Water Systems (IWS)

These systems are modifications of the conventional sludge process in that plastic grids or specially shaped plastic media are placed in the aeration tank. The bacteria develop on the plastic media, in the same way as they develop on the RBC disks. The same benefits of greater stability to varying flows and less risk of development of poor-settling bacteria are obtained. Excess bacteria must be removed from the treated effluent to produce a solids-free discharge. A clarifier is therefore required, and waste sludge is generated and requires disposal. Air must be supplied by a blower to the bacteria that grow on the media and that are present in the wastewater in the treatment tank. These aerated and moving media systems will require more mechanical servicing than some other systems.

Smith & Loveless “FAST”

FAST stands for Fixed Activated Sludge Treatment. The FAST system uses an aerated fixed-media activated sludge process like the IWS system. The treatment tank is packed with the proprietary plastic media with a space below for sludge settlement and wastewater circulation. An air distribution system below the media provides oxygen to the bacteria growing on the surface of the media and also aids circulation. Bacteria biofilm that falls off the media and solids remaining in the wastewater area settled out in a clarifier and aerobically digested before being dewatered in a sludge press. Clarified, treated wastewater is passed through a tube-type in-line UV disinfection system before being discharged to the ocean outfall.

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Sites Two potential locations for the wastewater system have been identified (Figure 4). Several criteria were used to determine site suitability including topography (slope information), proximity to existing services, prevailing wind direction (odour issues), proximity to buildings, location relative to the existing pipeline, and degree of existing disturbance modification at the site. Figure 4. Existing layout of Scott Base with the two site options for the wastewater system.

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Site 1 The first potential location is to the west side of the new Q-Hut ablutions block (Stage 8), south of the Hatherton Geosciences Laboratory (Fig. 4). This location is a fairly flat area and was the site of the old B-Hut which was removed in the summer of 1998-1999. However, the land directly in front of this site slopes away so that the earthworks around this site would include the construction of a crib wall. If this site is chosen then the alignment of the existing pipeline would need to be modified slightly but the outfall will remain in the same location (Appendix A). The re-alignment of the existing pipeline is also dependent on the choice of system. Site 2 The second potential location was identified and evaluated following on site inspection. This site is in a south-easterly direction from the TAE Hut. A short track will need to be constructed at this site to allow vehicle access. As with site 1, the alignment of the existing pipeline will be modified slightly but the outfall will remain in the same location (Appendix A). The re-alignment of the existing pipeline is dependent on the choice of system.

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2.3 Construction Requirements All materials, including the wastewater system itself, will be transported to Scott Base from Lyttelton by resupply ship (US Greenwave) in January 2002 and installation will take place the next summer (Table 2). All buildings at Scott Base are constructed on raised piles to prevent snow build up against the walls and are required to be anchored. Construction requirements for the new system are set out in Table 3. Table 2. Timeline for procuring of the wastewater system for Scott Base Tenders Close 29 June 2001

Fabricate wastewater plant August 2001-November 2001

Earthworks December 2001-January 2002

Place Foundations and set plant November 2002

Connect engineering services 15 December 2001

Commissioning 31 January 2003-10 February 2003

Table 3. Construction requirements for each of the wastwater systems under consideration

Construction Requirements

SYSTEMS

Reaman RBC Blivet Aerotor IWS FAST Size of installation (total area occupied) and types of materials

11.5m by 6.1m (70m2) by 3.05m high Four ISO20 containers Concrete foundations

5.8m by 10m (58m2) by 3.6m high Supplied in one ISO40 container and one ISO20 container Concrete foundations

5m by 6.1m (25m2) One ISO10 and one ISO20 container plus a bin of 6m3

Concrete foundations

2.44m by 12.1m (30m2) by 3.15m high Single ISO40 container Concrete foundations

Transportation from McMurdo to Scott Base by wheeled trailer.

Up to four trips

Up to two trips

Up to two trips

One trip.

Delivery from supplier.

18-20 weeks 12-16 weeks 10-12 weeks 18 weeks

Commissioning and Personnel

Installation will be 10 days. Includes a 2 day staff training programme. Base engineer/ electrician needs to help in connecting services.

Commissioning will take 2-3 days plus time for civil works, most of which will be carried out in advance.

Commissioning will take 14 days.

Commissioning engineer needs to be on site for 2 weeks. Return after 3 months for 2 more weeks.

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Equipment Use and Earthworks Heavy equipment is required to carry out the earthworks to level the potential sites. An area of approximately 15m x 15m of earthworks involving 10m3 will be needed for each site. The most significant earthworks that will take place around site 1 will be the construction of a crib wall. Earthworks are also needed at site 2 to prepare the site. Major equipment and vehicle needs for the project are set out in Table 4. Table 4. Major Equipment and Vehicle Needs

Equipment Site 1 Site 2 Caterpillar D-8 crawler tractor with dozer and rippers

16 hours 16 hours

60 tonne mobile crane 16 hours 16 hours Caterpillar 926E front end loader 16 hours 4 hours Track drill and pneumatic air compressor

8 hours 8 hours

Jack hammer & pneumatic air compressor

16 hours 24 hours

Tip Truck 8 hours 4 hours Earthworks area 15m x 15m 15m x 15m Earthworks volume 10m3 10m3 Fuel and Energy Requirements Additional plant hours occasioned by this project is a small proportion of the total hours for Scott Base operations annually. For example, loader operations are approximately 1000 hours per year, tip truck typically 200 hours per year. Emissions The additional hours of vehicle operations will produce a corresponding increase in exhaust emissions but are comparatively small and one-off. No increase is expected in generator base exhaust emissions. Dust levels will increase in association with earthworks and transport (may be up to four trips to get containers across to Scott Base). 2.4 Operational Requirements Operational requirements for each of the proposed wastewater systems are set out in Table 5. Operational constraints on the selection of a system include that it be economical in power requirements (including the requirements for heating the process air) that it should require a low staff input in sludge management (no more than monthly) as well as in operating and maintenance. The plant must operate reliably with a low probability of operating problems and should have simple operations, maintenance and testing requirements.

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Table 5. Operational Requirements of the Four Wastewater Systems Under Consideration Reaman S&P Blivet Aerotor IWS FAST Operational Requirements and Personnel

Sludge de-watering is one day per month. Clean UV tubes weekly.

Clean UV tubes weekly. De-water sludge monthly.

Remove Screenings weekly. Process sludge weekly 2-3hrs. Clean UV tubes weekly.

Sludge wasting and treatment daily in summer 1 hr, monthly in winter. Check pumps and blowers daily. Clean UV tubes weekly.

Maintenance Requirements Replace UV tubes yearly. Replace filter rings and filter cloth every 3 years. Replace RBC bearings every 5 years.

Grease rotor bearings monthly. Replace UV lamps every year.

Service pumps and blowers every 6 months. Replace UV tubes every year.

Service pumps and blowers – serviced every 6 months

Transport of sludge cake back to New Zealand

No extra transport during operation. Dewatered cake loaded into 25kg plastic lined bags for return to NZ

No extra transport during operation 20%dm cake – winter = 7.5kg cake per week summer = 93kg per week

No extra transport during operation Above 20% dry solids will result. A mobile 6m3 tank will be returned to NZ.

No extra transport during operation Dewatered sludge stored in plastic lined 200lt drums and then returned to NZ. Summer = 5-10kg per dayof sludge cake 25-35% dry solids

Energy

8.75 kW or 25,230 kWh/year 4.0 kW or 20,000 kWh/year 8.24kW winter 15.30kW summer or 50,232kWh/year

7.64 kW or 35,000 kWh/year

Emissions (odour)

Air flow rate is low and less dilution is achieved. However, vented air does not carry far.

No malodour. Fixed bed technology produces very little odour however all gas will be passed through an anthracite filter.

The FAST system offers the aerated state which is the most satisfactory method of odour control for an activated sludge process.

Timing considerations

10 working days on-site to carry out installation and pre-commissioning.

2-3 days plus time for civil works

14 days commissioning time 2 weeks to initiate start-up and run check-ups

Life Cycle Cost and Reliability

$600,000 - $700,000 Cook Islands, extensive record in Germany and Europe, including ski fields and cold climates.

$800,000 - $900,000 Tasmania, extensive number of systems in Asia, Europe and the UK.

$600,000 - $700,000 Extensive track record in Germany with other applications in Europe and Chile.

$700,000 - $800,000 Extensive track record in UK and Europe. Developed in Norway and a number of plants operate in very cold areas

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Decommissioning Considerations The container/s and the pipeline could all be removed should Scott Base be decommissioned. Limited earthworks may be needed to remediate the site of the container/s. 3. ALTERNATIVES This section identifies and evaluates the alternative options to the proposed activity. In doing so it facilitates a wider field of analysis, in the extent to which the proposed solution is the “best fit”, can be evaluated. 3.1 Do Nothing The wastewater at Scott Base is currently macerated and discharged through a short ocean outfall. This process meets the minimum requirement under Article 5.1 (b) of the Antarctica (Environmental Protection) Act 1994, to treat sewage by maceration. However, it is considered that maceration is the minimum level of treatment, and that a higher level of treatment is desirable in order to reduce the effects on the environment and associated ecosystems, and avoid detrimental effects on aspects of aesthetic value, wilderness experience, scientific and biological significance. Considering the potential ecological effects of sewage discharges on the polar marine environment, and the potential risk to human health at Scott Base, it has been recommended that sewage undergoes at least a secondary treatment prior to discharge in the Antarctic marine environment (Redvers, 2000). Consequently, the option to do nothing is unacceptable given New Zealand’s commitment to maintaining high standards of environmental compliance.

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3.2 Alternative Systems Several other alternative wastewater systems were considered for Scott Base and are discussed briefly in this section with a general overview of these systems summarised in Table 6. Table 6. Alternative Wastewater Systems for Scott Base

Type of System System Reasons not chosen for Scott Base Electrolytic Oxidation

OMNIPURE

probably generates chlorinated compounds which may

be toxic in the receiving environment high power requirement may exceed SS limit of <30 mg/L

Activated Sludge with Membrane Separation of

Solids

ZenoGem

high capital cost high operating cost needs special high (7m) building

Aerated Fixed or

Moving Media

TYPEPAK2

(fixed)

requires building high capital cost

Extreme

Technology “Black Box”

(fixed)

proposal not well detailed and late sludge-processing equipment included at last minute requires building and large space

Chemical Process – High

pH

no solids would be removed lime would be added no organic matter would be removed significant quantities of lime would have to be

transported to Scott Base

Composting

low air temperatures would make composting difficult there could potentially be a high energy input only treats solids, not water content itself a bulking agent such as sawdust would be needed and

have to be transported down to Scott Base

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Electrolytic Oxidation , (OMNIPURE) The OMNIPURE process requires that wastewater be mixed with seawater in the ratio of 10L of seawater to 6.2L of wastewater. In the treatment cell the mixture is subjected to an electric current which produces chloride and chlorate from the seawater. The chlorine oxidises the organic matter in the wastewater and at the same time kills pathogenic bacteria. This system is offered mounted complete on a skid for rapid installation at Scott Base. The biggest risk is of generating chlorinated compounds that may have toxic and long term presence in Antarctica. Aerated Fixed or Moving Media , (TYPEPAK 2, The Extreme Black Box System) ATYPEPAK2 system has been selected by the British Antarctic Service for installation at their Rothera Base. For Scott Base this system would have been supplied in three ISO20 containers and would have to have been installed in heated insulated buildings constructed for the purpose. This system was discounted because of the necessary building and also the very high capital cost. The Extreme Black Box System, although offering the highest standard of treatment would require a large building to be constructed to house it. This system is a proven system and produces very good effluent quality. This system also has a high life-cycle cost. Activated Sludge with Membrane Separation of Solids, (ZenoGem) The conventional “activated sludge process” relies on the settling characteristics of the bacteria to separate them from the treated effluent. Careful control of the activated sludge process is required, otherwise poorly settling bacteria develop and the process does not operate well. This system is offered as a number of individual components that need to be installed in heated insulated buildings of appropriate size. Construction and supply of a number of components is not done by the supplier. The operational difficulties of this system include cleaning of the membranes in their cartridges every 3-6 months. This requires a high building for clearance and the operation is likely to be messy and awkward. High operating effort and cost. This system has a high potential to create odour if the air supply is not well controlled. High capital cost.

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Chemical Processes – High pH Involves adding lime to the wastewater to make it strongly alkaline (pH of 11 to 12). The high pH kills bacteria in the wastewater, which also prevents further decay of the organic matter (BOD) and solids in the wastewater. This process would not be considered suitable for Scott Base for a number of reasons. Firstly, no solids would be removed and more would be added in the lime. The solids content of the wastewater would therefore increased. Secondly, no organic matter would be removed. Lastly, significant quantities of lime would have to be transported from New Zealand to Scott Base and stored. Composting Composting is a process applied to solids rather than wastewater. The process is carried out by the same aerobic bacteria that provide treatment in the activated sludge process and its variants. When occurring with solids, with relatively low water content, the bacteria generate heat which helps break down the organic matter and kills pathogenic bacteria. Composting can only be used as a treatment process for the solids in the wastewater and can not provide treatment for the water content. Composting of faecal matter alone would mean that a bulking agent, such as sawdust, would be necessary. Low air temperatures would also make composting difficult and would require a significant energy input to be effective. 3.3 Alternative Sites Two possible sites have been identified (see section 2.2 Sites) with the final decision on a site being dependent on several criteria including site suitability and topography, proximity to services, prevailing wind direction in case of odour, proximity to services and buildings, and location to existing pipeline and degree of existing disturbances. A third site, to the north of the base was also considered but as the prevailing wind comes from this direction and because of odour issues this site was disregarded. The problem of accessibility to this site was also a problem as it is not good for heavy equipment which needs to able to access the system both for construction and routine maintenance. 3.4 Alternative Pipelines and Outfall There will be a slight realignment of the current pipeline. The outfall will remain the same. Wastewater Outfall There are two alternatives to the current outfall of the wastewater at Scott Base. A submerged outfall, as far as practicable from the shoreline, is likely to achieve the best opportunity for effluent to become well mixed in receiving waters and transported offshore. However, a submerged outfall was not deemed feasible in terms of cost, or the

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significant practicalities involved with construction and ongoing operation and maintenance. A trade-off would be a surface outfall from Scott Base on the sea ice. However, a sea ice based surface discharge also poses operational and safety difficulties associated with running an outfall line over the semi-permanent seasonal ice and this option was therefore discounted. Given these alternatives it was decided that the outfall should remain in its present location and that the wastewater be treated to reduce potential effects on the receiving waters.

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4. POTENTIAL ENVIRONMENTAL IMPACTS OF PROPOSED ACTIVITY The actual and potential environmental impacts of the proposed activities are identified and discussed, including any indirect and cumulative impacts. Any uncertainties and unknowns are also discussed. Irrespective of the specific system chosen most of the impacts will be the same. Where the impacts differ substantially between the four systems, this is identified and described. 4.1 Terrestrial Environment Physical Disturbance The terrestrial environment at Scott Base has been significantly modified over a period of more then 40 years as a result of activities associated with the operation of Scott Base. However, it is desirable to keep the treatment plant footprint within this area to a minimum. Should site 1 be chosen then its relative flatness will mean that only minor disturbances in the form of earthworks should be incurred. A building (B-Hut) has been located on this site previously. The majority of earthworks will result from the construction of a crib wall for added support. Should site 2 be chosen then earthworks will be required to level the site for the new wastewater system. Overall the amount of earthworks required for both sites is about the same. Timber or concrete blocks will form the foundations at both sites, and are the same for all four systems. Holes will be drilled through the permafrost for the steel rods that hold the concrete blocks in place. A maximum of 25 holes will be drilled and each hole will measure about 90mm in diameter and be about two metres deep. The physical impacts of the excavation of the foundation piles are likely to be minimal. The laying of the foundation piles is expected to take 4-5 days. It is expected that once the foundations have been layed, the actual transferral of the container/s onto the foundation will be relatively fast (several hours). Flora Few areas of vegetation have remained undisturbed on Pram Point. However, small and remnant patches of moss and lichen have been noted in the vicinity of Scott Base mainly to the west and north of the main buildings. Major earthworks have already taken place on site 1 as this area was the location of B-Hut (removed in 1998/99). No mosses or lichens are growing on or near this site. Site 2 is also a heavily impacted site. Construction of the existing pipeline runs near this area and no visible vegetation has been observed on or near this site.

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Fauna Skuas are a regular sight around the base in summer and one pair has recently nested in the vicinity of the base. It is possible that skuas and invertebrate soil fauna may be disturbed by the proposed activity. However, only one pair of birds currently makes breeding attempts in the area well away from the immediate area of most activity. These birds are so habituated to the activities around Scott Base that it seems unlikely that the instalment of another building would create significant disturbance. 4.2 Marine Environment Receiving Waters Antarctica New Zealand conducted sea water monitoring immediately offshore from Scott Base between 1995 and 1997 and Redvers continued this work in his 1998 and 1999 studies. The extent and concentration of the Scott Base effluent plume (degraded water quality) has been shown to vary in space and time. The Antarctica New Zealand water quality results were generally consistent with Redvers from 1998. The monitoring identified an effluent plume zone extending approximately 25-35m offshore, and approximately 100-150m long-shore. Antarctica New Zealand monitoring has also shown the plume extending up to approximately 100m off shore, and approximately 300m west of the outfall. Sampling of water entering the reverse osmosis intake line has been undertaken by Antarctica New Zealand on a more regular basis than the yearly sampling from sea ice sites. Results confirm that the spatial extent of the effluent plume regularly extends to reach the drinking water intake located approximately 75m east of the outfall. Faecal coliform concentrations measured in the reverse osmosis intake by Antarctica New Zealand ranged from 0-5550 cfu/100ml (median 55 cfu/100ml, n=119). It is expected that the receiving waters of the effluent discharge impacts will be greatly reduced with the introduction of wastwater treatment. The wastewater will be treated in an effort to reduce concentrations of the major sewage contaminants which cause degraded water quality in the vicinity of the discharge point. Although it is not possible to define a precise standard of effluent that would be acceptable for discharge to the Antarctic ocean, an effluent quality of <30mg/L BOD5 and <200 cfu/100ml faecal coliforms is considered to be reasonable as a nominal standard for a wastewater treatment plant to achieve. Obviously, the better the effluent quality, especially lower bacteria concentrations, the lesser effect on the receiving waters off Scott Base. Table 7 shows a comparison of the effluent quality of the four systems under consideration. In each case a significant increase in effluent quality will result and the major difference in quality between the systems is with the concentrations of faecal coliforms.

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Table 7. Composition of Effluent Quality for the Various Systems

BOD5 (mg/L) SS (mg/L) FC (cfu/100ml)

FAST 15 15 <50

Reaman S&P 15 15 <25

IWS <15 <20 <80

Blivet Aerotor <10 <15 <10

Biochemical oxygen demand on the receiving waters The biochemical and chemical oxygen demand (BOD and COD respectively) are a measure of the potential pollution effect of the effluent and provide an indication of the degree of degradation of the effluent. Untreated, the BOD discharge into the ocean will exert an oxygen demand on the water and will effect the local and possibly wider marine ecosystem. Redvers (2000) carried out studies on the concentrations of contaminants from the untreated wastewater being discharged in the seawater off Scott Base. His study leads us to the assumption that if the BOD5 concentration of untreated discharge of 700 mg/L in an outgoing tide, is reduced to a concentration of 30 mg/L then the concentration of BOD5 in the ocean will be reduced from 6mg/L to 1mg/L at a distance of 20m from the shoreline and reduced to 0.1mg/L at a distance of about 40m from the shore (Figure 5). This represents a considerable reduction in the extent of the effluent plume with a corresponding increase in receiving water quality offshore from Scott Base. In all four systems the effluent quality standard for BOD5 is less than 30 mg/L and an even greater reduction in the extent of the plume could be expected. Suspended Solids and faecal coliforms in receiving waters The concentration of suspended solids (SS) in receiving waters will be reduced at a similar level to the concentrations of BOD. However, the biggest reduction will be in faecal coliform concentrations. A substantial reduction in bacteria numbers will be achieved by treatment, from about 20,000,000 cfu/100ml to <200 cfu/100ml. The exact level of reduction will depend on the system chosen (see Table 7) but in each case the area of degraded water as a result of faecal coliform contamination out from the discharge point will be dramatically reduced. Nutrients (phosphorous and nitrogen)in receiving waters. The concentrations of nitrogen and phosphorus will show lesser reductions because treatment will not reduce their concentrations in the wastewater to the same extent as BOD5, SS and faecal coliforms. However, the environmental impact of nutrient loadings on the marine environment is minimal at present with very high dilution rates following initial disposal. This is due to the presence of the upwelling of nutrients from the ocean floor in Antarctica, which is a natural cycle.

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Figure 5. (Top) Contours of BOD5 concentration at 1m depth measured by Redvers with an outgoing tide and discharge of untreated wastewater from Scott Base. (Lower) Predicted contours of BOD5 concentration at 1m depth under the same tide conditions but with wastewater treated to contain 30mg/L BOD5. (Figure 1 from Montgomery Watson, March 2001).

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Fauna Weddell seals occur in significant numbers (maximum 30-40 animals) year round on the sea ice in front of Scott Base. They maintain breathing holes throughout the winter months. Seals occasionally haul themselves up onto Pram Point itself. Both minke and orca whales have been sighted in McMurdo Sound and occasionally come close to the shore in front of Scott Base late in the season in open water. Leopard seals and swimming Adélie penguins are seen at times (Harrowfield, 1997). It is unlikely that the marine fauna will be impacted by the proposed activity as the levels of contaminants being discharged into the sea are being significantly reduced. Weddell seals, while coming up onto Pram Point itself, do not haul themselves up to the proposed site of the wastewater system. Benthic Biota Depth soundings conducted at all sites during 1998 and 1999 sampling provided information relating to the local bathymetry in the vicinity of Scott Base (Figure 6). The steep and regular drop off of the sea bed from the shoreline reaches a depth of approximately 100m at a distance of approximately 150m offshore.

Figure 6. Bathymetry immediately offshore from Scott Base (From Redvers, 2000, Figure 20).

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The sea floor immediately in front of Scott Base slopes steeply away to a depth of 20-30 metres. Here the substrate is unstable with little encrusting life. Anemones have been recorded in this zone. Below 30 metres the reef slope eases. This area supports a rich marine benthic community which includes species of bryozoans, sponges, echinoderms, anemones, bivalves and up to 10 species of fish (Battershill, 1992). Faecal contamination of benthic biota in the Antarctic marine environment has not been studied extensively. However, from the studies conducted it appears that significant but localised levels of contamination do occur but that observed impacts cannot be linked to specific sources, instead reflecting the cumulative effects of multiple inputs such as contaminated meltwater, historical marine dumping and sewage discharges. There is evidence of significant ecological disturbance in the marine environment close to other Antarctic bases which reflects these multiple inputs although no studies have specifically focused on Scott Base (Kennicutt et al. 1995, Lenihan et al. 1990). 4.3 Air Environment Odour Odour is a potential issue at all wastewater treatment plants. Most biological treatment plants are based on aerobic treatment principles in which air is required as a source of the oxygen, which is required by the bacteria that carry out the wastewater treatment process. These types of plant have processes which do not produce an objectionable odour but do have a musty type smell. The aeration processes also produce aerosols which can contain viruses. Emissions The construction phase of the wastewater system will increase vehicle fuel use with an associated increase in emission levels. However, this impact is one-off and minor. During the operational phase it is not expected that emissions levels will differ appreciably from normal levels at Scott Base. Dust Heavy machinery work is required to prepare the site and then install the container/s to the proposed site. Greater quantities of dust are likely to be produced at this stage than what would be considered normal. However, this impact is one-off and minor and during the operational phase there is not expected to be any increase in dust emissions as a result of the proposed activities.

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4.4 Visual and Aesthetic Values Visual Pram Point is a relatively highly impacted site. However, siting and colour of buildings and of the pipework still require consideration. There are differences in visual impacts between the different systems (due to size) and the different sites. In particular, if site 2 is chosen then this could impact the view from the existing facilities especially the mess and bar. All systems will “fit” on site 2 and will appear at a similar, if not lower, height to the existing foreshore laboratories (see Fig. 2). However, wider and more distant views from the base will not be adversely effected or “blocked” in any significant way as the treatment plants will be sited below the line of site to Black or White Islands and Mount Discovery from the mess and bar. The larger systems, will cause a greater visual impact than the smaller systems in particular the Reaman RBC and to a lesser extent the Blivet Aerotor. Site 1 is immediately adjacent to the existing ablutions block (Stage 8) and would in effect be an extension of this building. No views from the base itself would be effected and the visual impact of a system on this site would be less than for site 2. The system will increase the ground area over which facilities have been built at Scott Base by approximately 1-2%. However, the recent removal of several bulk fuel tanks has decreased the area covered by structures so that the overall increase, even for the largest system is less than 1%. The colour of the system will match the colour already used for all other buildings. Noise Noise levels during the construction phase are likely to increase, in particular during the earthworks phase. However, the noise will be comparable to that experienced at Scott Base during annual snow removal activities. The noise will occur in January/February rather than in October/January when this sort of noise usually occurs. Once operational, ambient noise levels are not expected to be effected. 4.5 Indirect Impacts Transport to and from Scott Base It is expected that the wastewater system will be transported to Scott Base from Lyttelton by resupply ship, in January/February 2002. Materials for the foundations will also be transported down at this time. The container/s will then be loaded onto a truck and trailer unit at McMurdo and transported across to Scott Base. Up to four trips will be made depending on the system chosen. A crane will be used to put the container/s into place. The truck and trailer and the crane will use existing tracks around Scott Base.

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Impacts on Base Activities Careful programme planning should prevent any significant impact on base life. Impacts on Science Activities The proposed activity is set to create minimal impact on science activities. The site of the wastewater treatment system would be to the east of the science area and would therefore not interfere with any science projects taking place at this time. 4.6 Cumulative Impacts The proposed activity will have the effect of increasing the overall area of human impact on Pram Point, especially the visual impact. The system (largely made up of shipping containers) will be located a short distance away or very close to existing buildings depending on the site chosen and does not represent an expansion of the area of Pram Point over which Scott Base and its associated activities are carried out. The total area of physical ground disturbance, while not increasing, will be intensified at the chosen site of the treatment system. 4.7 Evaluation of Potential Impacts The previous section has identified, and to a certain extent evaluated, the impacts of the proposed activities. Table 8 summarises the impacts identified in Section 4 and further evaluates their significance in the context of the Pram Point environment. Account has been taken of the extent, duration, intensity and probability of the potential impacts and the existing disturbance to the area in determining their significance. The environmental impacts of the four systems have been evaluated together as the wastewater systems under consideration are expected to have similar impacts. However, a key difference between the four systems will be the size of the ground footprint. As detailed in Table 2 the floor area of the systems shortlisted range from 70m2 to 25m2. The difference in size of the systems will result in different environmental impacts, in particular the footprint and visual aspects will be intensified with increasing size. However, because the terrestrial environment has already been so heavily disturbed, the impacts of all four systems for these aspects are still considered to fall within the same category of low-medium. Finally, mitigation strategies are put forward, many of which are integral components of the proposed activities. Proposed mitigation measures should ensure that these potential impacts are of a minor nature only. In performing the evaluation, the disturbed nature of the site was a significant factor as was the considerable environmental benefits to arise from the project.

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Table 8. Evaluation of Potential Environmental Impacts of the Four Wastewater Systems under consideration for Scott Base.

Nature of Impact Evaluating Impact Mitigation of Impact Extent Duration Intensity Probability Significance Earthworks including site levelling

Site only, max 15x15m

Short term Medium Definite Low Keep to existing tracks Minimise earthworks required to site system

Cumulative impacts of increased human “footprints” at Pram Point.

Pram Point (less than 1% increase)

Long term Low Definite Low Concentrate facilities within current base “boundaries” Follow Antarctica NZ environmental procedures and

guidelines

Disturbance to terrestrial flora and fauna

Pram Point Medium to long term

Low Medium – Low

Low Site management to avoid fauna and minimise noise Keep to existing tracks Minimise earthworks required

Disturbance to marine flora and fauna

McMurdo Sound area

Long term Medium Definite Medium (positive)

Reduce the organic strength (BOD) content of the wastewater

Reduce the solids (SS) and faecal coliform content

Decline in air quality through odours

Site and vicinity

Long term Low Medium Low Correct maintenance of system Make sure system has a well controlled air supply Regular inspections

Local visual/aesthetic deterioration

Pram Point Long term Medium Definite Medium Size of system and colour (minimsed) Pipeline route and colour Specific site selection Determine outer limit of base facilities

Indirect activities on science activities

Vicinity of site Long term Low Low Low Ensure planning minimises or avoids potential impacts on science sites.

Adequate staff briefings and marking of site Increased energy use through new system

Scott Base Long term Low Low Low Maximise efficiency of system energy use.

Indirect impacts on base activities

Scott Base and vicinity

Short term Low Medium-definite

Low Ensure planning minimises potential impacts on base activities

Adjust timing of activities to minimise any potential disruptions

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5. MONITORING The proposed activity, while located in a heavily modified terrestrial environment, actually affects an environment that remains fairly pristine – the waters of McMurdo Sound. The proposed activity will be located at Scott Base on Pram Point, which has been subject to cumulative impacts associated with base activities for over 40 years. The effluent discharge from the proposed activity will be carefully monitored. Monitoring of water quality around Scott Base has been undertaken by Antarctica New Zealand since 1995. This water quality monitoring will continue. The efficiency of the waste treatment system will be assessed through the monitoring of effluent quality both before and after treatment. Continued regular monitoring of the potable water intake for faecal coliforms is also recommended. Faecal coliforms have proved to be an easy, reliable indicator of effluent contamination and an overall indicator of the extent of the sewage plume. Monitoring of benthic biota is also recommended. Faecal contamination of benthic biota in the Antarctic marine environment has not been studied extensively. However, from the studies conducted it appears that significant but localised levels of contamination do occur. 6. CONCLUSION Antarctica New Zealand proposes to make considerable improvements to the wastewater system currently employed at Scott Base. Evaluation of the environmental impacts of the proposal (irrespective of which of the four systems including the location, is chosen) indicate that the activities will not have more than a minor or transitory effect on the Pram Point environment. Ultimately, the introduction of a new wastewater system will significantly improve the overall impact that activities at Scott Base are having on the environment.

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7. REFERENCES Battershill, C. (1992). The ecology of the Pram Point reef slope, Ross Island, Antarctica. Antarctic Record 12: 17-18. Harrowfield, D. (1997). Scott Base, Antarctica. A History of New Zealand’s Southern-Most Station, 1957-1997. New Zealand Antarctic Society Inc., 1997. Kennicut, M.C.,S. J. McDonald, J.L. Sericano, P. Boothe, J. Oliver, S. Safe, B.J. Presley, H. Liu, D. Wolfe, T. L. Wade, A. Crockett, and D. Bockus. 1995. Human contamination of the marine environment – Arthur Harbour and McMurdo Sound, Antarctica. Environmental Science and Technology 29: 1279 – 1287. Lenihan, H. S., J. S. Oliver, J. M. Oakden, and M. D. Stephenson. 1990. Intense and localised benthic marine pollution around McMurdo Station, Antarctica. Marine Pollution Bulletin 21:422-430 Montgomery Watson (March, 2001). Wastewater Treatment for Scott Base. Selection of a Wastewater Treatment System. Redvers, G. (2000). Dispersion and Fate of Sewage and Wastewater Components from Scott Base, Antarctica. Thesis for Degree of Master of Science, The University of Auckland. URS New Zealand Limited (November, 2000). Scott Base Wastewater Treatment.

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APPENDIX A

Proposed piping between tanks, STP and new wastewater lines.