ChemP or BioP? Why Not Both?

The Rock Creek Advanced Wastewater Treatment Facility (AWTF) near Portland, Oregon has traditionally relied on a chemical approach for phosphorus removal and dosed alum at multiple locations to meet a 0.1 mg/L total-phosphorus limit. However, a biological phosphorus removal (BPR) process could drastically reduce chemical costs and can also reduce sludge handling and hauling costs. Additionally, for the Rock Creek AWTF BPR could reduce the need for additional tertiary clarification facilities and thus save on future capital costs. Based on these potential benefits, the Rock Creek Facility Plan evaluated the feasibility of BPR and found that with an innovative “multipurpose” basin concept, the Rock Creek AWTF could operate with both a chemical and biological approach, providing the greatest amount of reliability and flexibility.