Application of Membrane Bioreactors for Enhanced Nutrient Removal at a Large wastewater Treatment Facility with Significant Peaking Events

The Cox Creek Water Reclamation Facility (WRF) is a 15.0 million gallon per day (mgd) average daily flow municipal wastewater treatment plant, located in Curtis Bay, Maryland, and is owned and operated by Anne Arundel County. The facility currently achieves biological nutrient removal (BNR) with an effluent goal of 8.0 mg/L total nitrogen from May 1 through October 31. The new NPDES permit will set annual waste loading allocations for the discharge of nitrogen and phosphorus, as well as contain an optimization provision which will require the facility to achieve an annual average concentration of 4.0 mg/L TN and 0.3 mg/L TP each year regardless of flow. Anne Arundel County is upgrading the facility for enhanced nutrient removal (ENR) to meet these limits. The existing activated sludge process will be converted into a membrane bioreactor (MBR) to achieve the ENR limits. The project is currently under design with construction anticipated to begin in 2008 and be completed by 2010.