RELIABILITY OF BIOLOGICAL PHOSPHORUS REMOVAL

Enhanced biological phosphorus removal (EBPR) has been used for decades to remove phosphorus from municipal wastewater. The anaerobic/aerobic activated sludge process associated with EBPR is attractive to utilities because it allows facilities to meet strict water quality requirements while minimizing costs for chemical addition and its related increases in sludge processing demands.. Despite its growing use, there is still substantial variability in both the practices applied to achieve EBPR and the results of these practices in terms of soluble phosphorus removal. There is also a lack of understanding of the interaction between EBPR and other processes such as anaerobic digestion used at many municipal wastewater treatment plants.The Water Environment Research Foundation (WERF) commissioned this research project to develop information that will help municipal wastewater treatment plants more efficiently and cost-effectively remove phosphorus through processes that involve EBPR. The goals of the project were to develop a database of plants using EBPR, determine the ability of EBPR to reliably meet effluent phosphorus limits without chemical addition, identify factors impacting EBPR performance, determine how well contemporary biological process simulators predict performance, and conduct in-depth full-scale research at select facilities. The ultimate objective of the research is to develop a better understanding of specific processes that could lead to more reliable or cost-effective operation. This paper focuses on the results of the first year of this study, which evaluated performance information from surveys of over 45 wastewater treatment facilities with EBPR.