Evaluation of Nitrification Kinetics and Biological Phosphorus Removal using Batch Rate Testing, Profile Sampling, and Process Simulation Modeling

The Nansemond Treatment Plant (NTP) operated by the Hampton Roads Sanitation District (HRSD) has experienced sporadic nitrification for a number of years, and some indication of continuous nitrification inhibition, as demonstrated by calibration of a process simulation model to historical data. A study was undertaken using a wide variety of NTP, targeted industry, and control wastewater and biomass samples to evaluate, understand, and identify sources of inhibition through batch rate measurements, profile sampling and process simulation modeling. Using plant performance data, a calibrated dynamic model was generated over the period of profile samples and compared to the profile sampling data to better estimate the level of continuous nitrification inhibition. Experimental results confirmed the sporadically inhibitory nature of NTP primary effluent when combined with other nitrifying biomasses. Based on this work, there was definitely some degree of continuous nitrification inhibition characterized by an apparent reduction in AOB μmax