Brewster Develops Sewer Plans – Just In Case

BREWSTER – Consultants Horsley Witten have unveiled plans to sewer over 300 homes in Brewster. But not to worry — it’s a concept not likely to be implemented.

The town still plans to meet its nitrogen reduction requirements for the Pleasant Bay and the Herring River watersheds through alternative actions such as reducing fertilizer application, septic system improvements, conservation restrictions and other non-sewer approaches. 

In order for Brewster to get its management plans approved for the two watersheds, the state requires a backup plan utilizing traditional wastewater treatment.

 “The town of Brewster’s approach solely relies on alternative strategies to achieve their allocated necessary nitrogen removal load,” the DEP wrote. “The town must submit a contingency plan for its nitrogen removal strategy to the department.” The sewering plan serves as that contingency in case something goes askew with Brewster’s alternative treatment plans, which have already been approved and are working in the Pleasant Bay watershed.

 “We’ve got the Pleasant Bay permit,” Mark Nelson of Horsley Witten told the select board June 1. “It was issued in 2018 and renewed this February through the work of the Pleasant Bay Alliance. The new permit regulations require if you’re using a strategy to remove nitrogen that’s not related to wastewater, it is considered alternative. So you have to come up with a conventional backup solution. That could be some sort of sewer and collection treatment system. It could be the use of approved innovative alternative septic systems.”

With that in mind, the consultants drew up a plan involving a small conventional wastewater collection and treatment system for 241 homes and innovative alternative septic systems for more far-flung homes where connections weren’t feasible.

 “This is highly unlikely to be needed with the strategies Brewster has in place,” Nelson said. “But the regulations require a basic design to show what’s feasible.”

 “We are not planning to install sewer anywhere in Brewster,” Select Board member Mary Chaffee emphasized. “We have to demonstrate the capability, but there is no plan to execute this.”

The Pleasant Bay watershed permit was issued in 2018 by the Department of Environmental Protection to the four towns of the Pleasant Bay Alliance: Chatham, Harwich, Orleans and Brewster. Each town was allocated a share of the nitrogen load going into the bay that it needed to reduce. By 2024 the four towns had removed 5,467 kilograms a year of nitrogen input, exceeding the five-year target of 4,914 kg/year. The agreement was renewed Feb. 10 and is good until 2046.

Because of future growth projections and new nitrogen attenuation rates, the reduction goal for Pleasant Bay was revised upward to 25,933 kg. When all the sewer construction is complete in Orleans, Harwich and Chatham, the total reduction of 37,480 kg will exceed that figure. Orleans and Chatham won’t hit their targets by 2038 (20 years after the initial permit) as sewer work will still be ongoing, but 75 percent will be completed by that date. 

Under the plan, Brewster, which contributes 13 percent of the nitrogen to Pleasant Bay, should achieve 97 percent of its goal of 2,040 kg/year by 2030 through the alternative approaches. That plan’s centerpiece involves reducing fertilizer at the town’s 36-hole public golf course, which has already supplied Brewster with a reduction credit of 930 kg/year. That is backed by 10 years of data. Another 519 kg was eliminated through alternative septic systems, fertilizer reductions at Cape Cod National Golf Course, and better measurements of water use and leaching rates.

 “Under the permit Brewster must remove 75 percent in the first 20 years. The town has already done that,” Nelson said. Taking the golf course credit of 930kg and adding it to the 1,520 kg of H&Ws conceptual sewer plan hits the state target and provides the town with a viable backup using conventional wastewater methods.

 “That more than makes up for the 520 kg that is missing from the wastewater treatment,” Nelson said. “[DEP] appears to be open to thinking about the fertilizer reductions.”

 “We just need to have a backup plan on hand to satisfy the new state regulations,” Town Manager Peter Lombardi agreed. 

Pleasant Bay Alliance Coordinator Carole Ridley presented an updated and revised intermunicipal agreement that has the new nitrogen requirements and other changes. Chatham has already approved it. The select board approved it 5-0. 

Horsley and Witten also prepared a final version of a plan for the Herring River Watershed permit.

 “It’s a very small area in Brewster that’s in the Herring River Watershed,” Nelson said, so the required reduction is far less than Pleasant Bay. 

Brewster is only responsible for nitrogen from new development in the Herring River watershed since 2004. That amounts to 86 homes through 2024, producing 105 kg of nitrogen a year. Future build-out possibilities add another 31 kg. Current fertilizer reductions and better information of actual water use can deliver a cut of 87 kg a year. In addition, Brewster voters approved $300,000 to purchase a conservation restriction on Thacher’s Bog in Harwich, which is worth a credit of 188 kg a year since the bog will no longer be fertilized. 

 “That far exceeds what needs to be done,” Nelson noted. “It’s 275 kg so it’s fully meeting the goal.” 

However, the state rules still require a wastewater backup. So Nelson showcased a collection system for 44 homes plus innovative septic systems that could cover that 209 kg a year.

The select board voted unanimously to approve the plan and apply for the permit from the DEP.