DURHAM — Wastewater entering Great Bay will soon be cleaner.
Area legislators along with town officials toured the Durham and Newmarket wastewater treatment plants on Friday to review the efforts to reduce nitrogen in the Great Bay Estuary that many believe is the cause for the dwindling eel grass.
Jeff Barnum, the Great Bay-Piscataqua waterkeeper of the Conservation Law Foundation organized the tour. In Durham, Rep. Michael Cahill, D-Newmarket, and Sen. Martha Fuller Clark, D-Portsmouth, toured the Durham facility with treatment plant Superintendent Dan Peterson, Town Engineer April Talon, Town Administrator Todd Selig and Tim Vadney, senior project manager for Wright-Pierce that is a consultant with many wastewater treatment plants. Barnum and the three legislators toured the new Newmarket plant after.
“The Durham plant has been a standard for some time,” Barnum said at the beginning of the tour. Many area facilities that discharge into Great Bay were considered out of compliance with the federal Clean Water Act because it was allowing high levels of nitrogen into the estuary. However, Durham was not one of those municipalities out of compliance with the Department of Environmental Services and the U.S. Environmental Protection Agency orders earlier this decade. Selig cited the town’s commitment to funding ongoing maintenance that kept the plant operating efficiently and under the mandated nitrogen discharges.
To become in compliance with regulations, there are new wastewater treatments in the works. Newmarket has a new $14 million wastewater treatment plant will come online in the coming months. Exeter has a $55 million facility coming online in 2018. Portsmouth’s new plant is expected to be operational by the end of the decade. Dover and Rochester have made recent upgrades that have eliminated tons of nitrogen from entering into Great Bay, Barnum said.
“Great Bay is a tremendous asset that in our backyard,” Barnum said. “It’s an estuary of national significance.” He called it a “nursery of the sea,” but because of the pollution, “Eelgrass has taken it on the nose.”
Peterson brought the group around to the different stations at the Durham plant. One of the challenges for the plant is the fluctuating Durham population. It peaks at about 25,000 when the University of New Hampshire is in session but will drop to about 7,000 during the summer and major holidays, like Thanksgiving and Christmas. Peterson said workers are well aware of the school calendar to prepare for changes in wastewater flows. Even days of the week can change flows. Selig said flows increase on Friday and Saturday nights during school when many students are partying. Because UNH provides about two-thirds of the wastewater load, it pays for two-thirds of the cost, Selig said.
Peterson spoke highly of the bacteria in the plant that helps break down the waste as it moves through different stages at the plant, calling the millions of bacteria his tiny friends. Workers monitor how the health of the bacteria, which is reused in the system. “When the bacteria is happy, I’m happy,” he said. Their life span can average between 6 to 9 days, depending on the weather and other factors.
The first part of the treatment is filtering out trash that should not be in the system. Balls of grease could be seen in the filters, along with disposable wipes, which Peterson said was the biggest issue. The wastewater then moves through a number of different pools which helps further clean the water before it is released into Great Bay. The initially dirty water leaves clean, giving Peterson great satisfaction in his work.
Barnum said efforts will continue to reduce nitrogen after the new plants come online. “We need to continue this (nitrogen) reduction and address storm water in a big way,” he said.