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

摘要

To terminate a facility's National Pollution Discharge Elimination System (NPDES) permit, new owners of a 75-year old steel mill had to eliminate all nonstormwater discharges through the facility's stormwater outfalls. An investigation wasconducted to identify the sources of the nonstormwater discharges and to develop options for eliminating the discharges.Components of the study included compiling existing data, performing a water balance study, identifying and inventorying all existing manholes, conducting a mass balance flow study, performing physical and chemical testing of the nonstormwater flow to aid in identifying the source areas, and performing additional investigation as necessary to identify the sources of the remaining flows.Methods for remediation of the discharges included elimination of the discharges at the source areas, reusing the water in other processes or areas and rerouting the discharges to the publicly owned treatment works.Following completion of this project, the facility's NPDES permit was terminated by the state regulatory agency.