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Simulated Distribution Nitrification: Nitrification Index Evaluation and Viable AOB
Citation:
Schrantz, K. A., J. G. Pressman, AND D. G. Wahman. Simulated Distribution Nitrification: Nitrification Index Evaluation and Viable AOB. JOURNAL OF THE AMERICAN WATER WORKS ASSOCIATION. American Water Works Association, Denver, CO, 105(5):E242-E254, (2013).
Impact/Purpose:
Lab-scale reactors evaluated the impact of increasing temporal influent monochloramine (NH2Cl) concentrations (0.0 to 3.2 mg Cl2 L-1) and chlorine to nitrogen mass ratios (0:1 to 3.2:1) on nitrification.
Description:
Lab-scale reactors evaluated the impact of increasing temporal influent monochloramine (NH2Cl) concentrations (0.0 to 3.2 mg Cl2 L-1) and chlorine to nitrogen mass ratios (0:1 to 3.2:1) on nitrification, allowing evaluation of the recently proposed nitrification index (NI) for chloraminated drinking water distribution system operation control. Nitrification (based on chemical parameters) was severely impacted with a 1.5 mg Cl2 L-1 NH2Cl residual, becoming undetectable when the NH2Cl residual reached 3 mg Cl2 L-1. The calibrated NI was successful in simulating nitrification occurrence. In addition, temporal biofilm samples allowed monitoring of viable and total ammonia-oxidizing bacteria (AOB) and found that the dominant viable AOB were (1) related to Nitrosomonas europaea for a NH2Cl residual less than 0.4 mg Cl2 L-1, (2) related to N. oligotropha for NH2Cl residuals between 0.4 and 1.5 mg Cl2 L-1, and (3) no viable AOB were detected at approximately 3 mg Cl2 L-1 NH2Cl residual.
