J.B. Neethling, Ph.D., Brian Bakke, P.E., Mario Benisch, April Gu, Ph.D, and Heather Stephens, P.E.
The Water Environment Research Federation (WERF) recently published the results of a study completed by HDR examining the reliability of enhanced biological phosphorus removal (EBPR) in removing phosphorus to low levels in wastewater effluent. The objective of this research project was to develop information that can be used to help municipal wastewater treatment plants more efficiently and cost-effectively remove phosphorus through EBPR processes.
The project included detailed analysis of routine water quality and operating data, field testing observations, and special studies conducted over the course of the project to evaluate the variability of EBPR, factors influencing EBPR performance, and the relationship between EBPR and the presence of glycogen accumulating organisms (GAOs).
The study showed that EBPR is capable of achieving very low effluent phosphate concentrations. When operating well, it is possible to achieve soluble phosphate concentrations under 0.1 mg/L. However, many facilities struggle to routinely achieve soluble phosphate concentrations under 1.0 mg/L. For this reason, most facilities experience significant variability in EBPR performance, requiring augmentation of EBPR through the use of substrate addition or polishing with iron- or aluminum-containing chemicals.
The benefits of the study are described below:
Documents the performance of full-scale EBPR systems.
Evaluates reliability of facilities with history of EBPR based on key influent characteristics and operational parameters.
Documents phosphorus release and uptake for facilities with a history of EBPR and shows the lack of relationship between phosphorus release and performance.
Documents the difficulty associated with predicting successful EBPR in full-scale plants based on a single parameter.
Identifies the need for chemical addition for long-term, stable phosphorus removal to high levels.
Quantifies the importance of recycle streams and controlling the return loads to maintain good EBPR performance.
Evaluates presence of glycogen accumulating organisms in full-scale facilities and summarizes research on conditions that may lead to the proliferation of glycogen accumulating organisms.
The Final Report is available for purchase from the Water Environment Research Foundation Web site, http://www.werf.org/. The WERF Stock number is 01CTS3. The Final Report is available to WERF subscribers at the special price of $10.00.
The report may also be purchased from the IWA (International Water Association) Web site: www.iwapublishing.com. IWA Members Price: £77.25 / US$124.00 / €116.25. Non Members Price: £103.00 / US$165.00 / €155.00.