Long-Term Performance of Pilot-Scale Aerobic Granular Sludge at the Noman M. Cole Pollution Control Plant

The Fairfax County Noman M. Cole Pollution Control Plant (NCPCP) is a 67 million gallon per day (MGD) facility that employs primary, secondary and tertiary treatment to meet effluent total nitrogen (TN) and total phosphorus (TP) limits of 3.0 mg N/L and 0.18 mg P/L, respectively. Currently, nitrogen removal is performed via step-feed biological nutrient removal (BNR) and a tertiary denitrifying moving bed bioreactor (MBBR) supplemented with methanol. Phosphorus control is achieved via ferric chloride addition, tertiary clarification and filtration. In consideration for expansion of the facility from 67 to 80 MGD, the AquaNereda® Aerobic Granular Sludge (AGS) process was identified as a promising treatment alternative. The AquaNereda process consolidates infrastructure by performing secondary BNR and solids separation in the same tankage. The process has been implemented at full-scale in Europe, South America and Africa; however, there are only two full-scale facilities in operation in the USA. A 9-month piloting effort was therefore conducted to understand performance of the AquaNereda® process at NCPCP.