EPA and Mass DEP issued a permit renewal to Winchendon on February 25, 2011 that includes reduced total copper limits of 2.1 ug/l for monthly average concentration and 2.6 ug/l for daily maximum concentration. These low levels are necessary because of the chemical hardness of the Millers River and low available dilution of the Town?s effluent at the point of discharge.
The copper limits in the Town?s permit are among the most stringent NPDES copper limits in Massachusetts.
The ORDER establishes interim copper limits and requires the town to submit an engineering report with cost analysis for the feasability of additional control equipment to the existing treatment plant in order to control copper to meet the current permit limits.