Three years of full-scale captorR process operation at Moundsville WWTP

Abstract

Three years of full-scale operation of the CaptorR process had been completed at the Moundsville/Glen Dale Wastewater Treatment Plant (WWTP) treating a design flow of 8706 m3/d (2.3 mgd). The CaptorR process applied a combination of attached and suspended growth processes by adding polyurethane foam media to activated sludge process, raising the equivalent MLSS concentration. The CaptorR system was designed as a separate front portion of the activated sludge process, with one third of the total HRT of the activated sludge process. The suspended MLSS in the Captor basin was around 900-1700 mg/L and the equivalent media based attached MLSS was maintained at 6,500-12,000 mg/L. It has been found that soluble CBOD5 removal, nitrification and partial denitrification occurred simultaneously in the Captor basin. The influent loadings to the Captor chamber were at 100-130 mg/L of soluble BOD5, 20-30 mg/L NH3-N, and 50-70 mg/L of TSS at flow rates of 5678-10031 m3/d (1.5-2.65 mgd). Over the last three years, 95% soluble CBOD5 removal, 70-90% nitrification and 40-60% denitrification were achieved at an HRT of 50-90 minutes in the Captor chamber. The plant effluent characteristics consistently met 2-4 mg/L of CBOD5, 1-4 mg/L of TSS, and 2-4 mg/L of Ammonia at low temperatures of 12°C-15°C. The HRTs were 2.5-5 hours for secondary aeration with a sludge age of 3-5 days for the activated sludge portion.