GREENFIELD DEVELOPMENT AND TMDLS: NPDES PERMITTING OF A NEW FACILITY DISCHARGING TO A NUTRIENT-IMPAIRED STREAM

摘要

State environmental agencies, working in conjunction with the United States Environmental Protection Agency (USEPA), are developing total maximum daily loads (TMDLs) for surface waters listed on State 303(d) lists. Of particular concern to the pulp and paper industry is the development of nutrient TMDLs that can result in National Pollutant Discharge Elimination System (NPDES) permit limitations for nitrogen and phosphorus. In developing nutrient TMDLs, loadings from both point (process wastewater) sources and non-point (storm water) sources are evaluated to assess the current nutrient loading to the stream. Often, TMDLs reference existing numeric water quality standards in establishing target concentrations for nitrogen and phosphorus. When water quality standards are narrative in nature and not numeric, alternative TMDL development methods such as the use of a reference stream or "ecoregion" are employed by state agencies to establish discharge standards. This paper will discuss the basics of TMDL development and will use the NPDES permitting of wastewater discharges from a greenfield facility to a nutrient-impaired stream, Buxahatchee Creek, in Alabama as a case study.Prior to development of the nutrient TMDL, the National Council for Air and Stream Improvement (NCASI) collected a considerable amount of dissolved oxygen and nutrient data from the Buxahatchee Creek watershed over a 5-year period (NCASI, 2004). The purpose of the NCASI work was to quantify the resources required to develop a technically sound TMDL. The data collected by NCASI are referenced in the nutrient TMDL issued by the Alabama Department of Environmental Management (ADEM) for Buxahatchee Creek.In response to development of the TMDL, the greenfield facility developed options for wastewater treatment and disposal to mitigate impacts of the TMDL. This paper will discuss the use of water quality modeling to justify the removal of the nitrogen TMDL and the revisions of the ecoregion analysis to increase the target concentration for total phosphorus.