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

Since promulgating changes to the state's water quality standards in 2001, the South Carolina Department of Health and Environmental Control (SCDHEC) is seeking to interpret the new rules and apply them to wastewater treatment projects underway in the state. Changes to state standards have been described by the SCDHEC Bureau Chief as “the most extensive changes in 10 years” and link other water quality requirements in new ways.The water quality standards provide new requirements, as well as links and interpretations of the Source Water Protection requirements, Total Maximum Daily Load and 303(d) List requirements, the state's Toxics Control Strategy, waste load allocation modeling, and permitting. In short, permitting requirements and the process of determining the cost and level of treatment have become quite challenging. In addition, proposed standards for total nitrogen and phosphorus for many river basins in the state and the cost of treatment are escalating at a rapid rate. Master planning, adjusting rates and fees, understanding the regulatory requirements, and providing additional time for permitting have become more important than ever.Source Water Protection requirements are impacting human health criteria; and reliability criteria, including plant emergency storage (new requirements for spill containment), standby power, clarifier sizing, and biological treatment capacity. Ultimate oxygen demand limits, phosphorus limits and pending total nitrogen limits are requiring the addition of biological nutrient removal and effluent filtration.The 303(d) List parameters and the newly revised state water quality standards will impose new limits for effluent metals that will require additional treatment processes such as chemical treatment and tertiary filtration.The new requirements are affecting ongoing upgrades and expansions of wastewater treatment plant projects for Western Carolina Regional Sewer Authority, a utility serving a population of 350,000. The new requirements and the interpretation of related standards and policy documents impact as many as five WCRSA regional plants totaling over 75 mgd of treatment capacity. WCRSA has budgeted over 200 million to comply with these requirements and will spend millions more on the impacts of strict interpretations of the requirements and reduced waste load allocations.