Optimization of Biological Nutrient Removal Systems in Response to Increased Loadings

Many rapidly growing communities are facing increased wastewater strength at their wastewater treatment plants (WWTPs). Increased wastewater strength results in higher loadings, which can have adverse effects performance of existing plants. For a given loading capacity, increased wastewater strength can reduce the hydraulic flow capacity of WWTPs. For existing plants, adjustments in plant operational strategies are the simplest solutions in response to increased loadings, as they often involve minor capital expenditures, and they can be readily implemented. The Greenfield Water Reclamation Plant (GWRP) located in Gilbert, Arizona, has experienced increased wastewater strength compared to the criteria developed during the plant design. A process modeling evaluation made it possible to evaluate the effects of the increased wastewater loadings. Different operational strategies were evaluated in response to the increased influent loadings at future flow conditions. Operational strategies for process optimization were proposed based on the results of the process modeling analysis, involving operational adjustments and not capital expenditures.