Update on the Comprehensive Wastewater Management Plan
Transcript of Update on the Comprehensive Wastewater Management Plan
Update on the Comprehensive Wastewater Management Plan
David Young, P.E.
Michaela Bogosh, P.E.
June 29, 2021
Select Board Meeting
Agenda
▪ Overview of the problem and sources
▪ Dennis’s Comprehensive Wastewater Management Plan▪ Non-infrastructure components
▪ Effluent Recharge
▪ Costs
▪ Next Steps
Controllable Nitrogen Sources –Swan Pond River Watershed
Overall Load
72%
3%
6%
12%
5%
2%
Wastewater
Landfill/Solid Waste
Fertilizers
Impervious Surfaces
Water Body Surface Area
"Natural" Surfaces
Stormwater
Watershed SepticLoad Reductions
▪ Figure shows required septic load reduction to meet Total Maximum Daily Load
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CWMP and Program Status
▪ Draft CWMP submitted to Commonwealth of Massachusetts Environmental Policy Act (MEPA) Office and the Cape Cod Commission (CCC) (Summer 2017)
▪ Bass River Railroad/Cape Cod Rail Trail Bridge Abutment Widening (2016-2018)
▪ Economic Study conducted
▪ Aquaculture Pilot Project in Swan Pond (Summers 2018-2019)
▪ Initial Archeological Surveys of
future pumping stations completed
▪ Effluent recharge field
investigations (Aug. & Oct. 2020)
▪ Final CWMP to be submitted 20219
Watershed Septic Load Reduction Required
Bass River 60%
Herring River 58%
Swan Pond 100%
Chase Garden Creek
+24%
Sesuit Harbor Awaiting MEP Report
CWMP Alternatives
▪ Seven collection and treatment scenarios (1A to 7D) were initially evaluated based on:▪ Current and future community development
▪ TMDLs for embayments
▪ Seven screened down to five
▪ Scenario 6A was selected by WIC
▪ Highlights of Scenario 6A:▪ Meets MEP and TMDL nitrogen reduction thresholds;
▪ Allows for effluent recharge sites in multiple watersheds (Bass River and Swan Pond);
▪ Provides a phasing plan that provides for implementation flexibility;
▪ Allows for a potential regional solution between Dennis, Harwich, and Yarmouth; and
▪ Supports desired smart economic development.
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Phasing Plan
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1. Buildout Average Daily Flow with Planning District and I/I (GPD)
Phase Estimated Flow (gpd) 1
1 305,000
2 671,000
3 205,000
4 67,000
5 347,000
6 99,000
7 120,000
8 146,000
Total 1,960,000
Non-Infrastructure Components
▪ Public Outreach
▪ Fertilizer Education▪ Brochure
▪ Presentation
▪ Stormwater Best Management Practices
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Swan Pond Aquaculture Demonstration Project
Route 6 Bass River Bridge(s) - Proposed Widening
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▪ Potential solutions evaluated to help improve the Bass River water quality ▪ Removal of the flow restrictions from the former railroad bridge south
of Route 6 (completed) and the Route 6 east and west bound bridges
▪ Removing both restrictions would result in a 25 percent reduction in total time required to exchange water in that area
▪ Removing both restrictions will decrease concentrations by approximately 6-percent
▪ Removing restriction of railroad
bridge results in a 2-percent
reduction in concentration
Route 6 Bass River Bridge(s)- Proposed Widening cont.
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▪ Larger restriction is from the Route 6 east and west bound bridge▪ Currently no plan to widen to pre-bridge conditions
▪ Reached out to MassDOT several times
▪ Dennis and Yarmouth in 2016
▪ Dennis, Harwich and Yarmouth in 2018
▪ MassDOT stated that bridge is neither functionally obsolete or structurally deficient and therefore will not be considered for widening at this time
Effluent Recharge and Recharge Sites
▪ Concentration of 35 mg/L-N in septic systems
▪ Wastewater Treatment Plant reduces concentration to 3 mg/L-N
▪ Treated effluent is sent to the subsurface
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Effluent Recharge
DISCHARGE
Effluent Recharge Site Overview
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DHY Shared Facilities Comparison
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WWTF and
Effluent
Recharge Cost
Comparison
Capital Costs O&M Costs Equivalent Annual
Costs1
Annual Savings
Town Regional Town Regional Town Regional $ / year %
Dennis $109 M $72 M $5.0 M $2.8 M $9.9 M $6.0 M $3.8 M 39%
Harwich $82 M $44 M $2.8 M $1.7 M $6.5 M $3.6 M $2.9 M 44%
Yarmouth $152 M $136 M $9.6 M $5.0 M $16.4 M $11.1 M $5.3 M 32%
Total $343 M $252 M $17.4 M $9.5 M $32.8 M $20.7 M $12.0 M 37%
1. Equivalent annual costs based on 30-year loans at 2% interest.2. 2024 Costs with projected ENR of 13,060.
Dennis Recommended Program Comparison
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Dennis Capital Costs O&M Costs
Equivalent Annual
Costs1
Annual
Savings
Town Regional Town Regional Town Regional $ / year %
Collection System $225 M $225 M $2.8 M $2.6 M $12.8 M $12.7 M $0.2 M 1.2%
WWTF $71 M $49 M $4.7 M $2.5 M $7.9 M $4.7 M $3.2 M 41%
Effluent Recharge
with PRB$39 M $24 M $0.3 M $0.3 M $2.0 M $1.3 M $0.7 M 34%
Non-Traditional
Technologies$10.4 M $10.4 M $0.1 M $0.1 M $552,000 $552,000 $0 0%
Total $345 M $308 M $7.9 M $5.5 M $23.3 M $19.3 M $4.1 M 17%1. Equivalent annual costs based on 30-year loans at 2% interest.2. 2024 Costs with projected ENR of 13,060.
Dennis Recommended Program - Phase 1
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DennisCapital Costs O&M Costs
Town Regional Town Regional
Collection System $49.0 M $49.0 M $ 0.70 M $ 0.61 M
WWTF2$53.5 M $39.1 M $ 0.74 M $ 0.39 M
Effluent Recharge with PRB $20.7 M $12.7 M $ 0.16 M $ 0.10 M
Non-Traditional Technologies $1.3 M $1.3 M $ 86,400 $ 86,400
Total $124.5 M $102.1 M $1.69 M $1.18 M 1. 2024 Costs with projected ENR of 13,060.2. Estimated design flow of 1.3 MGD
Next Steps
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Next Steps
▪ WIC endorsed Town-only solution in March 2021 Meeting
▪ Need confirmation from Select Board
▪ Finalize CWMP
▪ Begin following next WIC Meeting, July 12th
▪ 2 months
▪ MEPA begins review upon submission of CWMP
▪ 30-40 days to issue certificate
▪ CCC begins review following MEPA Certificate
▪ 208 Consistency Plan Review completed to become eligible for 0% interest State Revolving Fund (SRF) loans
▪ 30-40 days to review
▪ ~5 months to finalize CWMP process and receive final approval
▪ Mid November 2021