The city of Portsmouth has the opportunity to finally construct a modern sewage treatment plant to protect the Piscataqua River and other important waters in our Great Bay estuary. After a public hearing on Monday evening, March 7, the City Council will vote on the second reading of a bond that will finance the construction of the new facility at Peirce Island, which serves Portsmouth, New Castle, and part of Rye. The vote has been almost a decade in the making.
Of the 16,000 plus sewage treatment plants in this country, only a handful still offer the low level of treatment that we see at Peirce Island — so-called “primary” treatment. Hundreds of tons of biologically oxygen demanding pollution and suspended solids, and high levels of viruses, are discharged from the existing plant every year — and will continue to be discharged until a higher level of treatment, called “secondary” treatment, is operational. That pollution moves up and down the estuary with the tides. Recreational shellfishing downstream from Pierce Island, all around New Castle Island and south to the Seacoast Science Center in Rye will be prohibited until a new sewage plant is built.
Ninety percent of the plant’s cost is for secondary treatment. The other ten percent of the cost is for the infrastructure that will treat for nitrogen, a pollutant of major concern for the health of our waters. The weight of evidence links too much nitrogen to the profound loss of eelgrass in all parts of the Great Bay estuary. The loss of eelgrass — which is the glue that holds the whole ecosystem together — results in other problems like increased turbidity and a disruption to the food chain. Once the plant is built, it is expected to treat nitrogen to a level of 8 mg/liter, though it will be able to meet lower levels with operational changes.
When Exeter voters go to the polls on Tuesday, March 8, they too, will be in a position to support clean water. A super majority is required to pass a bond that will fund a new sewage plant that will dramatically reduce nitrogen pollution. Last year, voters overwhelmingly supported funding for design and engineering of a new plant, which will replace the current, outdated lagoon style facility. Passage of Article 7 will allow Exeter to stay on schedule and help restore the health of the Squamscott River and Great Bay.
Exeter’s wastewater permit also requires Exeter to address the nitrogen issue from sources other than the sewage plant. To that end, there are articles on the warrant that restrict fertilizer use in proximity to certain bodies of water. Much work has gone into developing these worthwhile reductions, and they also deserve support.
Other communities around the estuary are already reducing pollution — a new plant in Newmarket is under construction, upgrades are planned in Newington, and dramatic reductions of nitrogen in Dover and Rochester are ongoing. Positive votes in both Portsmouth and Exeter will help move the Great Bay estuary down the road to recovery.
Jeff Barnum is the Great Bay-Piscataqua Waterkeeper for the Conservation Law Foundation. He can be reached at jbarnum@clf.org.