Reducing Wastewater Treatment Costs for a New Deink Mill using Water Quality Modeling, 1997 Environmental Conference Proceedings

In 1992, Bay West Paper Corporation (Bay West), a wholly-owned subsidiary of Mosinee Paper Corporation, began operating a new deink mill in Middletown, Ohio. To handle the new deink mill’s higher wasteloading, the company also constructed a secondary wastewater treatment system that could produce effluent meeting the pretreatment limitations of a wastewater discharge permit issued by the city of Middletown. The new plant was designed to treat the mill’s wastewater for BOD and to remove suspended solids, the two limiting parameters in the discharge permit issued by the city. The treatment plant, designed to provide secondary treatment, consists of primary clarification, an activated sludge system, secondary clarification, and sludge thickening and dewatering. The plant produced effluent that not only met the city’s pretreatment standards, but also did not benefit from additional treatment by Middletown’s publicly-owned treatment works (POTW). Because annual sewer charges exceeded $700,000, Bay West applied for an NPDES permit to allow a direct discharge of its high-quality effluent to the Great Miami River. The city of Middletown, midway between Dayton and Cincinnati, lies along Segment 2 of the Great Miami River, as designated by the Ohio Environmental Protection Agency (OEPA). The OEPA had completed field work, conducted steady state modeling, and issued a 1992 report declaring that Segment 2 was fully allocated for BOD, discharges. Based on data from its QUAL2E model using critical design river conditions, the OEPA then stated it could not issue Bay West an NPDES permit for both its direct discharge and the city’s permitted discharge without the model predicting violations of the state’s water quality standards for dissolved oxygen. However, the permit that was requested for Bay West’s discharge was not for a new discharge, but for an existing discharge that would no longer pass through the POTW....