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Kathryn Gies, PE, ENV SP, LEED AP BD+C

Achieving the City of Davis WWTP Sustainability Goals Using Envision™

May 15, 2013 | 8:00 a.m.

APWA Sustainability in Public Works

San Diego, CA

Presentation Outline

Existing WWTP

WWTP Secondary and Tertiary Improvements Project

WWTP Improvements Project Sustainability Elements

Envision™

Envision™ and the Design Build Process

2

Presentation Outline

Existing WWTP

WWTP Secondary and Tertiary Improvements Project

Envision™

Envision™ and the Design Build Process

WWTP Improvements Project Sustainability Elements

Where is Davis ?

3

Existing WWTP Processes

Restoration Wetlands

Willow Slough Bypass

Primary Treatment, Disinfection, and Anaerobic

Solids Digestion

001

002

A Blending of Conventional and Natural Treatment Processes to Achieve High Water Quality Standards

Treatment Ponds

Overland Flow

System

Conventional Treatment:Primary Clarification

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Digester Gas Utilization/Cogeneration for Building Heat

Natural Treatment: Ponds

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Natural Treatment: Overland Flow

Pump Station

Wastewater Ponds

Natural Treatment: Restoration Wetlands

002

Plant Effluent

Stormwater

Optional Effluent/Stormwater Connection

Wetland EffluentStormwater

Ponds

Stormwater Ponds

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Presentation Outline

Existing WWTP

WWTP Secondary and Tertiary Improvements Project

Envision™

Envision™ and the Design Build Process

WWTP Improvements Project Sustainability Elements

New Effluent Limitations Cannot Be Met with Existing Treatment Facilities

• Title 22 Tertiary Filtration and Disinfection

• Ammonia/Nitrate

• Metals and Selenium

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Title 22 Filtration and Disinfection Ensures Downstream Water Bodies are Protected for Recreational Uses

Ammonia and Nitrate Removal Requires Conventional Activated Sludge Processes

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Metals and Other Priority Pollutants Impacted By Natural Systems

Existing natural systems are very effective at reducing selenium concentrations and are likely to perform better than conventional processes

Natural systems contribute iron and aluminum (from soil) and can increase salinity

Presentation Outline

Existing WWTP

WWTP Improvements Project Sustainability Elements

Envision™

Envision™ and the Design Build Process

WWTP Secondary and Tertiary Improvements Project

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Envision’s™ Sustainability Categories

17

Purpose, Community, WellbeingQuality of Life

Collaboration, Management, PlanningLeadership

Materials, Energy, WaterResource Allocation

Siting, Land & Water, BiodiversityNatural World

Emissions, ResilienceClimate and Risk

Envision’s™ Award LevelsRecognition

Level

Minimum Applicable

Points

Points(Based on 708 Total)

Bronze 142

Silver Award 212

Gold Award 283

Platinum Award 35418

30%

40%

50%

20%

No minimum category percentage required

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Presentation Outline

Existing WWTP

WWTP Improvements Project Sustainability Elements

Envision™

Envision™ and the Design Build Process

WWTP Secondary and Tertiary Improvements Project

• Comprehensive planning process to maximize available resources

• Creates local jobs

• Improved access to public areas (i.e. restoration wetlands)

• Identify and implement meaningful enhancements to the Restoration Wetlands

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Quality of Life

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Comprehensive Planning Evaluation Found the Most Sustainable Approach

• (2005) Master Plan

• (2008) Preliminary Design –$200 Million!

• (2009) Comprehensive Reuse Evaluation

• (2010) UC Davis Alumni Complete Charrette Report - cuts project costs in half

• (2011) Design-Build to be used to maximize project efficiencies

Quality of Life

Local Jobs Are Created as a Direct Result of the Upgrade Project

• Two key planning team members are headquartered in Davis

• DB teams will be required to maintain a local hiring program

Quality of Life

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220 Acres of Permanent Wetlands

44 Acres of Seasonal Wetlands

26 Acres of Riparian Woodlands

108 Acres of Upland Habitat

Seeded With All Native Species

The Davis Restoration Wetlands Will Continue Provide a Valuable Community Asset

Quality of Life

• A Sustainability Management Plan will be developed that will be followed by the entire project team

• Significant City-wide commitments to sustainability

• Regular stakeholder communications

• Considered other related community infrastructure elements

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Leadership

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City-Wide Sustainability Leadership

City Leadership Actions:

• Sustainability Program Manager

• Comprehensive Bicycles Program

• Cities for Climate Protection (CCP)/Climate Change Resolutions

• Zero Waste Resolution

Community Input:

• Climate Action Team

• Natural Resources CommissionLeadership

Infrastructure Synergies: Davis-Woodland Water Supply Project

New Drinking Water Intake On

Sacramento River

Treatment FacilityCity of

Woodland

City of Davis

Leadership

Davis WWTP

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Water Supply/Wastewater Linkages

Parmeter

Current/Future

Discharge Limits

Water Supply Water Quality

Current Woodland

Current Davis

ProjectedWDCWA

Salinity (EC), uohms/cm

700-1,000 (future)

1,660 1,700 <700

Boron, ppb 700 (future) ~2,550 ~1,800 <100

Selenium, ppb

4.4 (Davis)3.2 (Woodland)

<2 – 8.4 1.2 – 5.6 < 0.1

Leadership

• Comprehensive Maintenance and Monitoring Plan

• Resolution to conflicting regulations is sought

• Directed extensions in the design, addressing flexibility, durability and resilience

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Leadership (cont.)

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Conflicting Regulatory Issue #1: Existing Levees Recently Decertified

Leadership

Willow Slough Bypass

• Existing levees have protected the WWTP site since 1930

• The City will eventually fix/replace them

• Regulatory standards require that WWTPs be protected from flooding – adding $4 million in project costs

• Regional Board is considering relaxing requirements

Conflicting Regulatory Issue #2: No More Wastewater Discharged From the City’s Wetlands

Leadership

• Wetlands “reduce” water quality

• Discharge to water bodies surrounding the wetlands must meet high quality standards

• Desired strategy would use “recycled water” instead of valuable groundwater resources

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Conflicting Regulatory Issue #3: Municipal Drinking Water Designation

Willow Slough Bypass

Yo

lo B

ypass

001

002

Leadership

Regulatory standards require a higher level of treatment for discharges to Willow Slough Bypass because state law technically designates this water body as a drinking water source (but not the downstream Yolo Bypass)

Without regulatory relief, the City will incur an additional $3 million in project costs to construct new outfall pipeline and will put critical habitat at risk

Design Will Provide Flexibility For Future Needs

• Expansion of major treatment facilities by ~25% as a first stage, and by another ~25% in a second stage

• Advanced nutrient removal

• Alkalinity adjustment (potential impact from new water supply)

Leadership

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• Renewable energy resources used: digester gas and solar panels

• No net impact on water supply volumes by extensive recycled water use

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Resource Allocation

Expanded Energy Generation

• More than double the biogas generator capacity

• Expand cogeneration system to heat new building spaces

• Look to expand solar power system to offset increased energy usage

Resource Allocation

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Recycled Water Use Will Minimize Demands on Potable Supplies

• Only use well water for critical areas and where public safety is a concern

• Change all existing non-critical well water connections to recycled water

• All irrigation with recycled water

Resource Allocation

• At least75% greyfield site and avoids “prime habitat”

• Require plant species that are locally appropriate and that minimize need for fertilizers and pesticides.

• Groundwater protection with ongoing monitoring

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Natural World

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Vegetation Management• The City currently

practices non-chemical vegetation control when possible

• Replace turf with water-tolerant trees, shrubs, and ground covers that can tolerate irrigation with recycled water and alkaline clay soils

Natural World

Groundwater Monitoring

Wells

Yolo County Landfill

MW-4

MW-1

MW-6

MW-5

MW-3MW-2

Groundwater Quality Objectives:

EC = 0.9 dS/m

NO3-N = 10 mg/l

Natural World

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• Restore 100% of disturbed solids

• Ensure existing habitats are not harmed, and compensate for losses.

• Maintain or enhance at least two ecosystem functions downstream of the discharge point.

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Natural World (cont.)

Seasonal Wetlands

Burrowing Owls

Giant Garter Snakes

Swainson’s Hawk

Biological Resources Near the Project Site

Natural World

21

Discharges From the WWTP Create and Maintain Valuable Habitats

Natural World

Meet California standards for air quality control

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Climate and Risk

Although the project includes many strategies to limit emissions by defining the most sustainable project, documentation and quantification of the impacts of these strategies is not anticipated.

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Presentation Outline

Existing WWTP

WWTP Secondary and Tertiary Improvements Project

Envision™

Envision™ and the Design Build Process

WWTP Improvements Project Sustainability Elements

Resource Allocation

Leadership

Quality of Life

• Local job creation requirements

• Conformance with Sustainability Management Plan

• Develop comprehensive Maintenance and Monitoring Plan

• Document how required flexibilities are built into the design

Design-Build Team Requirements

• Use recycled water for all non-critical uses

• Limit digester gas flaring to less than 10 percent

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Climate and Risk

Natural World

• Landscaping requirements

• Restore 100% of disturbed soils

• Maintain established separation distances from all identified habitat areas

• Meet all California Air Quality Standards

Design-Build Team Requirements

Estimated Number of Envision™ Points From on Planning Tasks Only

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Quality of Life

Leadership

Resource Allocation

Natural World

Climate and Risk

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48

21

18

52

2

The City could be awarded estimated

142 Credits Based on

Planning Efforts Completed to

Date Bronze

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Design Build Team Incentives

• Minimum of 75 points must be achieved through the design and construction process

• City to define categories where points are allowed to avoid duplication with City efforts

• Extra “credit” given if DB team can achieve a minimum of 150 points without significantly increasing project costs

Envision™ Provides Metrics for Assessing DB Team Proposals and

Ensures Accountability

• DB Teams proposals will identify the number of credits that can be achieved for a guaranteed price

• DB Teams will submit documentation needed to earn credits as the project is designed and constructed

• Clearly define submission standards ensures the City that sustainability objectives are achieved

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Kathryn Gies, PE, ENV SP, LEED AP BD+C

Achieving the City of Davis WWTP Sustainability Goals Using Envision™

Kathryn GiesWest Yost Associateskgies@westyost.com(925) 461-6795Westyost.com