Evaluation of Nitrification Inhibition Using Sequencing Batch Reactors and BioWin Modeling, and the Effect of Aqueous Film Forming Foam on Biological Nutrient Removal

To evaluate nitrification inhibition at the HRSD Nansemond Wastewater Treatment Plant (NP), continuous sequencing batch reactors (SBRs) were run to simulate the full-scale plant. Four reactors were operated in this study:Reactor A: Fed NP raw influent.Reactor B: Fed NP Primary Clarifier Influent (includes raw influent, plant recycles, and septage, grease, and chemical toilet waste deliveries).Reactor C&D: Fed raw influent from a treatment facility that achieves reliable nitrification yearround (VIP).During SBR operation, there was no statistical difference between reactors A and B, and no signs of nitrification inhibition in either reactor when compared to the VIP control.In a simultaneous study, reactor C was spiked with aqueous fire fighting foam (AFFF), while reactor D served as a control. The AFFF reactor experienced a complete loss of denitrification, while nitrification rates were unaffected. This result was unexpected, and is one of very few cases of selective denitrification inhibition.