Plymouth: Wastewater Treatment Plant Proposal To Discharge to Aquifer

  Meg Sheehan  Aquifer

Town of Plymouth Proposes 300% Increase In Wastewater Discharge to Sole Source Aquifer

Google Earth Image showing proximity of Plymouth Wastewater Treatment Facility to the Eel River System


Good news! State rejects Town’s environmental “lite” study, requires full, 2 part environmental impact report and “robust” study of alternatives

State agrees with CLWC and coalition that the Town’s study is inadequate, must be redone according to standards

Read the Secretary of Energy & Environmental Affairs Dec. 22, 2023 Decision here:
16758 EENF Plymouth WWTF Treated Effluent Discharge PLYMOUTH (V2)

Read the 2023 Expanded Environmental Notification Form

In 2023, the Town of Plymouth announced plans to divert the effluent flow from the 131 Camelot Wastewater Treatment Facility (WWTF) from Plymouth Harbor to five groundwater infiltration beds located adjacent to the facility. The Plymouth WWTF currently discharges approximately 1.75 million gallons a day (mgd) of treated sanitary sewer  effluent (wastewater) into Plymouth Harbor and uses the groundwater infiltration beds as a backup discharge location; the proposed plan would reverse these two locations, and use the groundwater infiltration beds as the primary discharge location, and only use the Harbor as a backup discharge location when needed. The proposal also seeks to increase the permitted discharge to the ground to up to 3 mgd. The Town’s website about the proposal is here.

The goal of this diversion is to decrease or eliminate the discharge of treated wastewater entering into Plymouth Harbor. Proponents of the project state that the diversion will result in improved water quality in the harbor, with associated benefits to the harbor ecology, commercial aquaculture, and recreation. While diverting wastewater from the harbor and improving harbor water quality would be a benefit to the environment, the discharge of 3 mgd of wastewater into the ground must be carefully studied, so that all ecological consequences of this groundwater injection operation are understood. Alternatives to this discharge location should also be considered during this process.

When treated wastewater is discharged from the WWTF to the infiltration beds adjacent to the facility, the wastewater enters immediately into the Plymouth Carver Sole Source Aquifer, the only source of drinking water for the Town of Plymouth. The concentrations of and types of pathogens, pharmaceuticals, PFAS, endocrine disrupting chemicals, etc. as well as the concentrations of metals such as iron and manganese in the wastewater being discharged to the Sole Source Drinking Water Aquifer at the WWTF should be communicated to the public in advance. The Plymouth Carver Sole Source Aquifer is highly permeable, with little buffering or absorption capacity, and therefore vulnerable to contamination.

The Expanded Environmental Notification Form (EENF), an environmental review required by MEPA and the EPA, only experimented with discharging wastewater into the sediment infiltration beds once, with a discharge volume of only 1.6 mgd, and only during the months of August and September 2018, typically a dry period. Climate change impacts predict that this area will see an increase in rainfall with a potential for short term rises in the groundwater elevation. Therefore, more study should be done during wetter months of the year with an associated higher water table. Furthermore, the EENF relies on a 1997 Environmental Impact Report (EIR) for much of its scientific conclusions. While the 1997 EIR was a more in-depth environmental study of the region, relying on it ignores the significant land-use changes in the area since 1997, such as deforestation, residential, commercial and industrial development, sand and gravel mining, and ground-mounted solar installations, all of which have impacts on the local groundwater recharge rates.

When wastewater is discharged into the ground at the WWTF, the ultimate environmental receptor of the water is the Eel River System, located approximately 0.7 miles southeast of the WWTF. The Eel river system is a sensitive ecological environment, supporting populations of river herring, which return to the river from the Atlantic ocean each year to breed. River herring are a protected species under the Endangered Species Act. Historically, the Wampanoag People have made the Eel River system their home for hundreds of years, and used its waters for fishing, a subsistence practice that they continue to this day. Furthermore, Russell Mill Pond, seasonally impaired by harmful algae blooms, is also part of the Eel River system. Because of this historic, economic, and ecological sensitivity of this river system, any foreign discharges of water into the system needs to proceed with caution.

Finally, there are better alternatives for the wastewater than to be discharged into the Eel River System. In 1997, during the original EIR study, one of the alternatives proposed was discharging the wastewater to the Pine Hills Golf Course and other golf courses in Plymouth. Golf courses are one of the major water consumers in Plymouth, and the nutrients present in wastewater can potentially fertilize the greens. Discharging the wastewater to the golf courses would still provide the same benefits of returning the water to the aquifer. Saving water, and reducing pumping from the Sole Source Aquifer, is an immediate priority for the Town of Plymouth as it continues to see population growth. Discharging the wastewater from the WWTF to the golf courses in Plymouth should be seriously considered during this process.

Read Community Land and Water Coalition, Herring Pond Wampanoag, Eel River Watershed Association and Jones River Watershed Association’s full joint comments to MEPA on the EENF:

EEA 16758 Plymouth WWTP Comments_Dec 1 2023

Community Groups Also Monitoring this Proposal:

Chiltonville Community Group


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