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Wastewater Questions Left Unanswered

During its deliberations last year, the Wastewater Discharge Citizens Advisory Committee (CAC) raised critical, clarifying questions that ultimately went unanswered by town officials—leading a majority of the committee to vote against proceeding with the expansion. The CAC Clerk, a licensed Professional Environmental Engineer holding a Master’s in Chemical Engineering, compiled these technical gaps into a comprehensive summary. These unresolved issues were mailed and presented directly to the Select Board on March 3rd; however, the Board ultimately rejected the committee’s expert recommendation, voting 4-1 to press forward with the wastewater licensing request

Please RSVP (click here)

To the May 31st, 3:45 – 5:15 Sundays @the Barn where we will discussion the CAC’s documented concerns below in preparation for the town’s June 4th Environmental Justice meeting:

  • Draft Environmental Impact Report (DEIR)
    • The CAC was not provided with a revised draft DEIR, incorporating comments, for review prior to the final vote.
  • Public Comments
    • 100% of the comments from the public attendees at the CAC meetings were against changing the effluent discharge location from the ocean outfall to the infiltration beds
    • Public comments made during the “listening session” CAC meeting received no response, even though many commenters requested responses
  • Appropriate chemical monitoring was not conducted
    • Treatment plant influent and effluent were not sampled for contaminants common in sewage such as pharmaceuticals, hormones, microplastics, artificial sweeteners, illicit drugs, etc
    • Monitoring wells were not installed between the infiltration beds and Warren Wells Brook; no data are available for this critical area
    • Historical phosphorus data had quality control issues
  • “Forever Chemicals” (PFAS) present in plant influent and effluent
    • PFOA is present in plant effluent at concentrations higher than safe drinking water levelsThe treatment plant is creating higher PFOA concentrations in the effluent by chemically transforming longer chain compounds to PFOA.
    • PFAS constituents have been detected in downgradient groundwater and private wells.
  • Tertiary treatment
    • Tertiary treatment was only discussed for phosphorus and nitrogen, not for other contaminants likely present in the effluent. 
  • Disinfection
    • There was no consideration given to changing chlorination/dechlorination of effluent to ozonation, which was requested by one CAC member who owns shellfisheries in the harbor
      • ozone is a stronger oxidizer and, in addition to effectively destroying viruses and bacteria, could possibly degrade other contaminantsozone dissociates quicker and does not create disinfection by-productsozone can be generated on-site so there is no need for chemical deliveries
    • Impacts of chlorination on groundwater and surface water were not addressed
  • Loading test inadequate
    • only one loading test was conducted for a short time period (40 days), at one flow rate (1.5 MGD), and at only one infiltration bed
    • dataloggers in six monitoring wells were disturbed during the test period and one monitoring well was destroyed; data were manipulated based on results in other wells 
    • significant rainfall occurred during the test
    • questionable data were used in refining the USGS regional model which is a critical element of predicting fate and transport of contaminants (i.e. of phosphorus) as well as hydraulic impacts (groundwater and surface water level rise)
    • The loading test should have been reaccomplished for a longer timeframe at multiple flow rates and at multiple beds.
  • Phosphorus modeling
    • It is unclear if the groundwater model and phosphorus estimates include the mass of phosphorus that has been discharged to date since the infiltration beds have been used.
    • It is impossible to establish a phosphorus baseline since there are no monitoring wells between the infiltration beds and Warren Wells Brook
  • Hydraulic impacts
    • Impacts of increasing water levels near infiltration beds were not assessed on some nearby infrastructure including the wind turbine and new building construction, particularly on Mary B Lane
    • Impacts of increasing water levels, temperature, or low dissolved oxygen on the downgradient trout hatcheries were not assessed
  • Odors and ponding water
    • The DEIR did not address possible odor and biological concerns (pest proliferation) from ponding water in the infiltration beds due to a higher flowrate.
    • Observations by a CAC member indicate the infiltration beds do not percolate as designed.
    • In an AECOM 2012 report, which was part of the Town’s Request for Proposal (RFP) for the Comprehensive Wastewater Management Plan (CWWMP) development, the consultant stated that any flow above 2.5 million gallons per day (MGD) will require construction of new beds (reference pdf pg 52 of 1052 of the RFP).  This was not acknowledged in the DEIR.
  • Private wells
    • The Town Water and Wastewater Engineer reported five private wells present downgradient of the infiltration beds.
    • PFAS compounds are present in one private well and insulin has been detected in Warren Wells Brook.
    • During a listening session at a CAC meeting, a resident living on Kingfisher Lane noted all residences (approximately 19) have a private well.
    • The DEIR did not address all private wells.  
  • Sole Source Aquifer
    • The Plymouth Carver Aquifer is designated as a sole source drinking water aquifer by EPA. Infiltration of partially treated wastewater effluent will contaminate groundwater which takes decades to remediate and is costly.  Attenuation of contaminants is higher in the ocean and there are no hydraulic concerns (i.e. no impacts to surface water levels).
    • The Town of Falmouth is pursuing ocean discharge of treated wastewater due to concerns with impacting the health of ecosystems and groundwater. 
  • Fate and Transport of Infiltrated Wastewater Discharge
    • The treated wastewater sent to the infiltration beds will percolate down into the subsurface groundwater and migrate downgradient intercepting Warren Wells Brook, Russell Mills Pond, and Eel River eventually discharging to an area of Plymouth Harbor that does not flush out as well as the location of the current ocean outfall.
    • Some phosphorus will adsorb to the subsurface soil and some nitrogen may be mitigated along the way; however, other contaminants in the effluent may impact the groundwater and the surface water.
    • Eventually the subsurface soils will be saturated with phosphorus and may require remediation to prevent eutrophication of downgradient/downstream surface water bodies.  
    • The Town’s consultant indicates it will take approximately 70-80 years before the phosphorus reaches Warren Wells Brook; however, this estimate is based on a loading test with suspect data and did not account for phosphorus already in the subsurface where there are no monitoring wells.
  • Harbor Outfall Impacts
    • Impacts of the treated wastewater discharge to the harbor were not adequately explained in the DEIR. 
    • A comment from MassDEP stated “the current discharge of the Plymouth POTW is not violating surface water quality standards”.
      • Per Mr. Bill Doyle, CAC member and shellfisheries owner, the FDA reclassified a portion of the harbor after a 2018 dye study from Approved to Conditionally Approved due to the wastewater discharge.  https://www.mass.gov/news/dmf-reclassifies-the-three-bays-2018-dye-study-results-in-shellfish-area-classification-change
        • This reclassification prevents shellfish in the Conditionally Approved area from being sold to Europe. Shellfish in this area can still be sold to the rest of the world.
        • Some of the shellfisheries kept their beds in the Conditionally Approved waters and started new beds in the Approved areas so they could sell to Europe.
        • FDA will not change the classifications even if discharge of treated wastewater is moved to the plant, because the Town plans to keep the harbor outfall as an emergency discharge location.
        • The shellfisheries have not expressed concern over the harbor discharge other than changing from chlorination/dechlorination to ozonation and making sure there are no violations of the wastewater discharge permit that could disrupt their operations.  
        • It is notable that members of the shellfisheries present for the first part of the Select Board meeting did not stay to voice any concerns during the wastewater discharge agenda item.  One of the oyster growers even commented that the oyster business is booming and expected to grow under current conditions.
  • Energy costs
    • The DPW reported one of the reasons for moving the discharge to the infiltration beds was to reduce the cost associated with pumping the treated wastewater to the harbor outfall. This is notable and the costs could be offset by installing renewable energy (such as solar carports) at the wastewater treatment plant.  The renewable energy could help reduce electricity costs across the Town electricity accounts. 
  • Additional plant capacity
    • The DPW also stated they need to increase the capacity to 3 MGD; however, to-date they have not exceeded 1.6 MGD. 
    • The DEIR did not demonstrate the need for additional capacity up to 3 MGD.  If additional capacity is needed, the DPW could eliminate receiving waste from other Towns and additional package treatment plants could be constructed closer to the sources of sewage generation. 

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