News Feature | January 11, 2017

Rochester Uses 'Pickle Juice' Substance To Limit Nitrogen

Dominique 'Peak' Johnson

By Peak Johnson


Rochester, NH, is trying something new in order to reduce the amount of nitrogen that it discharges from its wastewater treatment plant. The city will be using acetic acid, which it likens to pickle juice.

Two years ago, according to SeacoastOnline, Rochester started implementing the substance. Acetic acid “is a byproduct of Pilgrim Foods, a food manufacturing company based in Greenville, N.H.”

Each week, Pilgrim Foods sends gallons of the acid to Rochester at no charge. The city then “uses the substance to denitrify the water being released into the Cocheco River through its wastewater treatment plant.”

"Through very little money we have been able to reduce that (nitrogen discharge level) by about 80 percent," Public Works Director John Storer told Seacoastonline.

Rochester is awaiting a new U.S. EPA permit “that will set the legal limit on the amount of nitrogen its wastewater treatment plant can discharge into the Great Bay.” Public Works Director John Storer stated that the main concern “is that the federal agency will set the permit at the ‘limit of technology,’ which is 3 milligrams per liter.”

Storer said that the procedure can lower nitrogen discharge levels from close to 40 milligrams per liter to about eight milligrams per liter. Storer added that “going down to three milligrams per liter would result in the costly upgrades that city officials are trying to avoid.”

Seacoastonline reported that the last time the EPA issued Rochester a permit for nutrient discharge for its wastewater treatment plant was in 1997. According to David Green, chief operator of Rochester's wastewater treatment facility, the permit expired in 2002 and Rochester is still operating under those standards.

According to Storer, the 2002 permit had no restrictions on levels of nitrogen or phosphorus being discharged. In January 2015, Storer said that the city agreed to an 18-month delay on obtaining a permit, however that delay has expired. Storer added that the city is expecting a draft permit any day now.

Image credit: "pickles!" Mara © 2008 used under an Attribution 2.0 Generic license: