Addition of external carbon to biological nutrient removal processes to enhance denitrification to meet more stringent effluent nitrogen limits (e.g., total nitrogen

The document presents a list of basic parameters that should be obtained or measured to determine the potential of a carbon source. These parameters are often available from the supplier. These basic parameters are used to determine the carbon-to-nitrogen demand ratio and process performance monitoring varies for field testing different nitrogen removal processes. Therefore, the guidance document first provides protocols for evaluating denitrification performance in a general anoxic denitrification reactor. Then, more configuration-specific examples are given for the most commonly used denitrification processes, including the modified Ludzack–Ettinger (MLE) process and 4-stage Bardenpho, either as a suspended-growth system or a fixed-film system. The final selection of the external carbon source is based on a combination of literature review information, bench test parameters, and full-scale testing results.