The Town of Plainville owns and operates the Water Pollution Control Facility (WPCF) that provides treatment of wastewater prior to discharge to the Pequabuck River. The plant is designed for an average flow capacity of 2.6 million gallons per day (mgd) and is permitted for a flow of 3.8 mgd. The WPCF is a Class IV Facility consisting of preliminary and primary treatment, secondary biological treatment using sequential batch reactors (SBRs), and ultraviolet (UV) disinfection. Solids handling processes consist of un-thickened sludge pumping and storage, sludge thickening using a rotary drum thickener (RDT), and off-site disposal of thickened sludge.
The WPCF underwent a facility upgrade that was completed in 2009 to eliminate failing rotating biological contactors and replace them with the SBRs for biological treatment and nitrogen removal. The plant upgrade was focused on the removal of conventional pollutants and nitrogen. As such, provisions were not made for phosphorus removal at that time. The sludge thickening equipment (rotary drum thickeners, thickened sludge pump, etc.) was not upgraded at that time either.