PRI-SC® Sulfide, Phosphorus and UV Fouling Improvements at Raleigh, NC

The City of Raleigh has been using ferrous sulfate (FeSO4) for years in their collection system for hydrogen sulfide and plant phosphorus control. Several years ago the Neuse River wastewater treatment plant upgraded their ultraviolet disinfection (UV) system to a higher intensity lamp technology. Although the UV system was equipped with mecha ical wipers, manual cleaning by plant personnel was required due to the elevated iron levels carrying over to the disinfection stage coupled with the lamp sleeve's higher temperature. In 2008, the City of Raleigh implemented Peroxide Regenerated Iron Sulfide Control (PRI-SC®) as a means to improve collection system sulfide control and maintain plant phosphorus removal while reducing the amount of iron salts in the collection system. PRI-SC® chemical savings were found to be 80,300 per year. Manual UV sleeve cleaning frequency was reduced from 2 weeks to 2 months, saving 32 man hours per cleaning or 25,600 per year