wASTEWATER dESIGN

dEPARTMENT OF CORRECTIONS

The projects involved design and installation of chemical and ultraviolet light disinfection systems to treat effluent from Wastewater Treatment Plants at two North Carolina Department of Correction facilities. The disinfection systems were designed to improve effluent water quality through removal of Fecal Coliform from existing wastewater treatment processes. The systems employed ultraviolet light and chemical (chlorination and de-chlorination) disinfection processes, and were designed for peak flows of 0.5 MGD and 1.83 MGD, respectively. The ultraviolet light disinfection system employed a bank of lights installed within a stainless steel open channel, with outlet serpentine weir flow control and built-in automation. The chemical disinfection system employed tablet dissolution into a liquid feed injection system through a baffled open channel flow regime, with built-in automation (variable feed through ORP control). Both systems were permitted through the North Carolina Division of Water Quality’s Construction Grants and Loans Section. The ultraviolet light system was installed in late 2007, and is performing as designed. The chemical disinfection system began operation in Spring, 2009.