TMDLS, SWPAS, AND REALLY LOW METALS LIMITS IN THE UPSTATE – NAVIGATING THE NEW WATER QUALITY REQUIREMENTS IN SOUTH CAROLINA

摘要

Since promulgating changes to the state’s water quality standards in 2001, the SouthrnCarolina Department of Health and Environmental Control (SCDHEC) is seeking torninterpret the new rules and apply them to wastewater treatment projects underway in thernstate. Changes to state standards have been described by the SCDHEC Bureau Chief asrn“the most extensive changes in 10 years” and link other water quality requirements inrnnew ways.rnThe water quality standards provide new requirements, as well as links andrninterpretations of the Source Water Protection requirements, Total Maximum Daily Loadrnand 303(d) List requirements, the state’s Toxics Control Strategy, waste load allocationrnmodeling, and permitting. In short, permitting requirements and the process ofrndetermining the cost and level of treatment have become quite challenging. In addition,rnproposed standards for total nitrogen and phosphorus for many river basins in the staternand the cost of treatment are escalating at a rapid rate. Master planning, adjusting ratesrnand fees, understanding the regulatory requirements, and providing additional time forrnpermitting have become more important than ever.rnSource Water Protection requirements are impacting human health criteria; and reliabilityrncriteria, including plant emergency storage (new requirements for spill containment),rnstandby power, clarifier sizing, and biological treatment capacity. Ultimate oxygenrndemand limits, phosphorus limits and pending total nitrogen limits are requiring thernaddition of biological nutrient removal and effluent filtration.rnThe 303(d) List parameters and the newly revised state water quality standards willrnimpose new limits for effluent metals that will require additional treatment processesrnsuch as chemical treatment and tertiary filtration.rnThe new requirements are affecting ongoing upgrades and expansions of wastewaterrntreatment plant projects for Western Carolina Regional Sewer Authority, a utility servingrna population of 350,000. The new requirements and the interpretation of relatedrnstandards and policy documents impact as many as five WCRSA regional plants totalingrnover 75 mgd of treatment capacity. WCRSA has budgeted over $200 million to complyrnwith these requirements and will spend millions more on the impacts of strictrninterpretations of the requirements and reduced waste load allocations.