Utilization of Captor sponges to maintain nitrification and denitrification in BNR activated sludge at low aerobic MCRTs

The performance of Captor media integration into the aerobic zone of an activated sludge wastewater treatment system operated at low MCRTs was evaluated using a pilot scale Virginia Initiative Project (VIP) process. Two separate trains were operated, one with Captor media incorporated into the aerobic zone of the system, referred to as an Integrated Fixed Film Activated Sludge (IF AS) system, and the other as a control system, i.e., with no media in the aerobic reactors. The wastewater used for this research was pumped from a main municipal sewer of the Blacksburg-VPI Sanitation Authority Collection System. The TKN of the wastewater was supplemented by the addition of urea to maintain the influent ammonia concentration around 55 mg/L as nitrogen. Sodium acetate was added to maintain the influent COD around 450 mg/L and Sodium bicarbonate was added to maintain the pH in the aerobic zone around 7. The system was operated at MCRTs of 1.7, 1.0 and 0.3 days with the operating temperature around 12 C.