ZINC REDUCTION STUDY AT HOCKANUM RIVER WATER POLLUTION CONTROL FACILITY

The Town of Manchester Water and Sewer Department (Department) is soliciting proposals from qualified consulting firms to develop a plan to reduce the amount of zinc in our Hockanum River Water Pollution Control Facility (HRWPCF) wastewater effluent to meet our latest National Pollutant Discharge Elimination System Permit (NPDES).

The HRWPCF has issues meeting the zinc limits placed on it by the Connecticut Department of Energy and Environmental Protection (DEEP) for many years during certain months. Issues into the zinc loading goes as far back as 2000, when the Department studied the problem an formulated the report entitled “Report on the Investigation of Zinc Loadings to the Hockanum River Water Pollution Control Facility”, September 2000. The result of the study was it was best to reduce the amount of zinc orthophosphate use in treating our drinking water for lead and copper to lower our effluent zinc levels. This change did have a reduction in the zinc loadings at the HRWPCF, but it is not sufficient to meet the current limit place on it by the new NPDES permit dated December 1, 2023. The reduction in the amount of zinc orthophosphate used in our drinking water did not have an adverse effect on our compliance with the Lead and Copper Rule.

As part of the Department’s investigation into the zinc loading on the HRWPCF it was found that the Department’s inventory of Significate Industrial Users (SIU) and Miscellaneous Industrial Users (MIU) is inadequate. Because of this we are unable to collect zinc data from industrial users within our collection system to determine if there are other contributions to the zinc loading on the HRWPCF.