Fundamental Tools for the Evaluation and Optimization of Nutrient Removal Systems

Research projects under the Water Environment Research Foundation (WERF) Nutrient Removal Challenge Program have identified fundamental tools for the evaluation of persistent effluent nitrogen and phosphorus components after extensive biological, chemical, and physical treatment processes. An ion exchange resin technique can be used to assess the amount of hydrophobic dissolved organic nitrogen (DON) in effluent DON that is not available for algae growth and the use of a total reactive phosphorus measurement provides a simple, quick conservative estimate of the bioavailable phosphorus in effluent total phosphorus. A protocol to assess alternative external carbon sources also provides a useful tool for determining the carbon dose based on biokinetic considerations and the postanoxic tank hydraulic retention time (HRT). The postanoxic HRT and biodegradation kinetics under anoxic conditions are major factors affecting the carbon dose in contrast to assuming the dose is related to the biomass yield coefficient value for the respective substrate.