June 29, 2020 - The Town of Charlton MA owns and operates a wastewater treatment facility (WWTF) that is covered by a 2011 EPA-issued NPDES permit authorizing the discharge of pollutants to Cady Brook. The AO, issued on June 29, 2020, addresses zinc effluent limit exceedances at its WWTF and requires the Town to conduct a pilot study for three months using aluminum-based chemicals to determine if zinc discharge concentrations can be lowered using different chemicals in the treatment process. The Town will also continue to monitor and sample for zinc in the collection system to identify sources of zinc. The AO contains interim limits for total zinc and total aluminum (monthly average) which will remain in effect for one month after the completion of the pilot study.