Eliminating process water discharge to stormwater outfalls at a 75-year old steel mill

摘要

To terminate a facility's National PollutionDischarge Elimination System (NPDES) permit, new owners of a75-year old steel mill had to eliminate all nonstormwater dis-charges through the facility's stormwater outfalls. An investigationwas conducted to identify the sources of the nonstormwaterdischarges and to develop options for eliminating the discharges.Components of the study included compiling existing data,performing a water balance study, identifying and inventorying allexisting manholes, conducting a mass balance flow study,performing physical and chemical testing of the nonstormwaterflow to aid in identifying the source areas, and performingadditional investigation as necessary to identify the sources of theremaining flows.Methods for remediation of the discharges included elimination ofthe discharges at the source areas, reusing the water in otherprocesses or areas and rerouting the discharges to the publiclyowned treatment works.Following completion of this project, the facility's NPDES permitwas terminated by the state regulatory agency.