Lombardo Associates Inc. Tom Fudala, Chair, Mashpee Sewer Commission
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Town of Mashpee, Popponesset Bay, & Waquoit Bay East Watersheds TM Nitrex Technology Scenario Plan Submitted to: Submitted by: Town of Mashpee Sewer Commission 16 Great Neck Road North Mashpee, MA 02469 April 2010 Town of Mashpee Sewer Commission April 2010 Table of Contents Executive Summary........................................................................................................ 1 1 Objective................................................................................................................ 11 2 Background............................................................................................................ 11 2.1 Wastewater Flows .......................................................................................... 12 2.2 Hydrogeology ................................................................................................. 14 3 Needs Definition .................................................................................................... 21 3.1 Data Management - Methodology .................................................................. 21 3.2 Planning Area Parcel Summary...................................................................... 30 3.3 Nitrogen Loading and TMDLs......................................................................... 32 3.3.1 Data Overview......................................................................................... 33 3.3.2 Popponesset Bay Nitrogen Removal Requirements ............................... 34 3.3.3 East Waquoit Bay Nitrogen Removal Requirements ............................... 37 3.3.4 Existing PPA Wastewater Treatment Facilities........................................ 40 3.3.5 Mashpee Nantucket Sound Discharge .................................................... 41 4 Wastewater Treatment Options & Cost Estimates................................................. 42 4.1 NitrexTM Technology Scenario 1: Cluster Systems.......................................... 42 4.2 NitrexTM Technology Scenario 2: On-Site Systems Only ................................ 51 4.3 NitrexTM Technology Scenario 3: Groundwater Treatment, Pump & Treat ..... 52 4.4 NitrexTM Technology Scenario 4: NitrexTM PRB .............................................. 56 4.5 NitrexTM Technology Scenario 5: Hybrid of Scenarios 1-4.............................. 59 4.6 Scenario 6: Sewering ..................................................................................... 60 5 Nitrogen Removal Conclusions.............................................................................. 61 6 Santuit Pond Phosphorous Removal ..................................................................... 61 7 Management Issues .............................................................................................. 65 7.1 NitrexTM Cluster Scenario ............................................................................... 65 7.2 NitrexTM On-Site Scenario .............................................................................. 65 7.3 Groundwater Treatment.................................................................................. 65 8 Regulatory Issues .................................................................................................. 66 8.1 Cluster Scenario ............................................................................................. 66 8.2 On-Site Systems............................................................................................. 66 8.3 Groundwater Treatment.................................................................................. 66 APPENDIX A – Database Metafile................................................................................ 67 APPENDIX B – Examples of NitrexTM Technology Projects.......................................... 69 APPENDIX C – MEP Technical Memos ....................................................................... 71 APPENDIX D – Lombardo Associates, Inc. Memos ..................................................... 73 Town of Mashpee Sewer Commission April 2010 List of Tables Table 1. NitrexTM Scenario Costs Compared to Complete WW System.......................... 1 Table 1b. NitrexTM Scenario O&M Costs Per EDU......................................................... 2 Table 1c. Other NitrexTM Technology Options for Specific Areas of PPA........................ 2 Table 2. Costs for Cluster Systems in PPA..................................................................... 7 Table 3. NitrexTM Scenarios Cost Estimates by Watershed ............................................ 7 Table 2.1.1. Existing and Future Average Annual Wastewater Flows for Entire PPA... 12 Table 2.2.1. East Waquoit Bay Groundwater Discharge............................................... 14 Table 2.2.2. Popponesset Bay Groundwater Discharge ............................................... 15 Table 3.2.1. Wastewater Flow & Nitrogen Loading Information by Town...................... 30 Table 3.2.2. Waquoit Parcel Information by Subwatershed (No Soil or Watershed Attenuation) .................................................................................................................. 31 Table 3.2.3. Popponesset Bay Parcel Information by Subwatershed (No Soil or Watershed Attenuation) ................................................................................................ 32 Table 3.3.1. Non-Wastewater Nitrogen Sources........................................................... 32 Table 3.3.2. TMDL Components for Popponesset Bay................................................. 35 Table 3.3.3. Nitrogen Removal Requirements – Popponesset Bay .............................. 36 Table 3.3.4. TMDL Components for East Waquoit Bay ................................................ 37 Table 3.3.5. Nitrogen Removal Requirements – East Waquoit Bay.............................. 39 Table 3.3.4.1. WWTF Total Nitrogen Concentrations ................................................... 40 Table 3.3.4.2. WWTF TN Concentration & Removal to TN = 4 mg/l............................. 41 Table 3.3.5.1. Mashpee Nantucket Sound Discharge Nitrogen Loads.......................... 41 Table 4.1.2. Nitrogen Loads Treated with Cluster Scenario (Includes the Return Loads) ...................................................................................................................................... 44 Table 4.1.3. NitrexTM Technology Cluster Systems Scenario Cost Estimate ................ 45 Table 4.1.4. Capital Cost Breakdown – Cluster Systems.............................................. 46 Table 4.1.5. O&M Cost Breakdown – Cluster Systems................................................ 47 Table 4.2.1 Town of Mashpee Year Built Data ............................................................. 51 Table 4.2.2. On-Site Systems Only Cost Estimate........................................................ 52 Table 4.2.3. NitrexTM Technology Scenarios O&M Costs.............................................. 52 Table 4.3.1. Pump & Treat Cost Estimate Summary .................................................... 55 Table 4.3.3. Pump & Treat O&M Summary .................................................................. 56 Table 4.3.4. Pump & Treat Compared to Cluster System Scenario Costs.................... 56 Table 4.4.1. Preliminary Cost Estimates for NitrexTM Technology PRB Scenario ......... 59 Table 4.6.1. Stearns & Wheler Sewer Cost Estimates for the Town of Mashpee ......... 60 Table 5.1. NitrexTM Alternatives Cost Comparisons ...................................................... 61 Table 5.2. Other NitrexTM Technology Options for Specific Areas of PPA .................... 61 Table 6.1. Santuit Pond Phosphorus Calculation.......................................................... 63 Table 6.2. Rough Estimated Phosphorus Removal Costs ............................................ 64 Town of Mashpee Sewer Commission April 2010 List of Figures Figure 1. Popponesset Bay – Existing Attenuated Watershed Behavior and Total Wastewater Nitrogen Contribution as % of N Removal Required ................................... 8 Figure 2. East Waquoit Bay – Existing Attenuated Watershed Behavior and Total Wastewater Nitrogen Contribution as % of N Removal Required ................................... 9 Figure 3. PPA Treated Areas........................................................................................ 10 Figure 2.1.1. Mashpee Existing Flows and Treatment Plants ....................................... 13 Figure 2.2.1. Mashpee Groundwater Discharge Model Runs 1, 2, 9 & 10 .................... 16 Figure 2.2.2. Mashpee Groundwater Discharge Model Runs 3, 4, 5 & 6...................... 17 Figure 2.2.3. Mashpee Groundwater Discharge Model Runs 7 & 8.............................. 18 Figure 2.2.4. USGS Groundwater Recharge Areas ...................................................... 19 Figure 2.2.5. USGS Groundwater Recharge Areas for Waquoit Bay and Popponesset Bay................................................................................................................................ 20 Figure 3.1: Database and Output Tables Flowchart..................................................... 21 Figure 3.2. Subwatersheds in Major Watersheds ......................................................... 23 Figure 3.3. Topographic Relief...................................................................................... 24 Figure 3.4. Topographic Relief with Groundwater Contour Lines ................................. 25 Figure 3.5. USGS Topography