The Clinton Wastewater Treatment Plant provides advanced wastewater treatment, including nutrient removal, for the towns of Clinton and Lancaster, Massachusetts. With an average daily flow of 3 MGD, Clinton removes phosphorus through a conventional activated sludge system followed by chemical coagulation. Discharged phosphorus can reduce oxygen levels in water bodies as a result of eutrophication. It can also decrease aquatic life.
The current regulation for the Clinton Wastewater Treatment Plant states that 1.0 mg/L of total phosphorous (TP) can be discharged into the Nashua River. The Massachusetts Department of Environmental Protection released a draft National Pollutant Discharge Elimination System (NPDES) permit stipulating phosphorus regulation changes beginning in 2014. The permit requires that the facility discharge less than 0.15 mg/L of TP from April through October, and less than 1.0 mg/L between November and March. For a safety margin and to improve environmental quality, Clinton set a treatment goal of < 0.1 mg/L phosphorus year-round.
With the change in phosphorus regulations, Clinton needs to upgrade their system and increase phosphorus removal. After Clinton’s decision to use small footprint disc filters, a series of pilot studies were completed to find the most cost effective and efficient phosphorous removal filter.