After sitting idle for 13 years, Clinton’s four septage lagoons are on track to be closed.

Septage lagoons hold waste pumped from residential septic systems by private haulers. Common in less densely populated areas where municipal water pollution control facilities aren’t readily available, lagoons are typically constructed in a simple, two-cell configuration. The primary lagoon serves as a basin for solids to settle—like a septic tank—and a secondary lagoon receives overflow.

Clinton’s lagoons, which began operating in September 1974, are located near a tributary of the Hammonasset River at the end of Knollwood Drive, just before the old Stanley Bostitch manufacturing plant. Periodically, sludge from the lagoons has been transferred to a landfill; however, the lagoons haven’t operated for at least the past decade, according to Matthew Kennedy, chairman of Clinton’s Water Pollution Control Commission (WPCC).

The WPCC is responsible for the planning, design, and oversight of Clinton’s water pollution control facilities to comply with federal, state, and local regulations.

A Long History

A plan to close the lagoons was first submitted to the Connecticut Department of Energy and Environmental Protection (DEEP, then called the Department of Environmental Protection) in 2003. The plan called for removing approximately 450,000 gallons of septage liquid waste from the existing lagoons, transporting it to an approved treatment facility, and testing soil samples to determine whether any contaminants remained in the lagoon basins.

If the soil samples exceeded the limits for the heavy metals arsenic, barium, cadmium, chromium, lead, mercury, selenium, or silver (known as RCRA 8 metals), the soil in those areas would be disposed of in a landfill and the underlying soil retested. The process would continue until soil sampling came back clean, at which point the lagoons would be prepared to receive clean fill.

The plan called for final grading to promote surface drainage away from Knollwood Drive and adjacent properties into an earthen swale sloped to convey the runoff offsite. Topsoil capable of supporting vegetation would be placed and seeded as the uppermost layer, for erosion control.

Despite continued efforts by the WPCC to push the closure plan forward over the years, DEEP failed to review and approve it. Meanwhile, the town continued paying a permit fee for the idle lagoons and monitoring groundwater nearby, as required by state regulations, pending approval of the closure plan.

In 2015, Hal Dolan, former WPCC chair and a vocal advocate for the lagoon closure, notified DEEP that since the town hadn’t been using the lagoons, it would no longer pay permit fees while waiting for approval to close them.

When a federal EPA lawsuit against Unilever resulted in a $500,000 settlement to be split between Clinton and Madison to fund water quality or ecosystem restoration projects in the lower Hammonasset River watershed, Dolan saw an opportunity to jumpstart the project. He proposed that a portion of the money from the Unilever settlement be used to close the lagoons, and in July 2015, the town reached an agreement with DEEP that the lagoon closure proposal met the objectives of the funding language.

Unanimous Decision

At a special town meeting on Feb. 3, the town unanimously passed a resolution to fund a shellfish restoration initiative and close the town’s septage lagoons using a portion of the Unilever settlement. Consulting and engineering firm CDM Smith prepared a scope of work for additional sampling and testing necessary to update the 2003 lagoon closure plan, and on Feb. 17, Clinton’s Board of Selectmen approved the scope of work.

“Before removal of the septage waste, a round of groundwater sampling will be conducted to establish a baseline” of soil chemistry, Kennedy said. “Composite soil samples will be done by the Department of Public Works and overseen by the consultant, to keep the costs down, and the WPCC hopes the lagoons can be filled in and overseeded.

“Thanks to Mr. Dolan’s persistence and the combined efforts of the WPCC, the town, and the Department of Public Works, the sampling required to update the plan and begin closure is anticipated to begin early this summer,” he continued.

According to Kennedy, the lagoons are now overgrown with vegetation and contain no liquid septage.

“They were used in several configurations throughout the years and currently consist of two primary and two secondary chambers. We don’t believe they have been used since at least 2006, when they may have been used in a limited capacity for pump-outs of a couple of the schools. They appear to have had a minor to moderate impact on groundwater conditions, but nothing near the amount of work that was needed to clean up similar structures at the Bostitch plant,” Kennedy said. “I took a look at the historical data a while back, and I believe we will be able to make a case that the groundwater meets the remediation standard regulations. Additional testing will be performed prior to formal closure. Formal closure will include the testing of any remaining sludge and any underlying soils in the demolition of the existing structures, and any backfilling grading and seeding that are necessary.”

After the lagoons are filled with clean material and final grading has been done, groundwater sampling will take place on a quarterly basis for up to a year or until DEEP deems sufficient.