Wastewater Disinfection Using Peracids: Simulation of System Performance and Process Control Alternatives Using Batch Inactivation Kinetics from a 10-Plant North American Study

Over the last two decades, peracetic acid has gained popularity for municipal wastewater disinfection, as reported by several investigators who have conclusively demonstrated good antimicrobial properties against a wide range of microorganism models including bacteria. More recently, performic acid (PFA) has been studied as a substitute for PAA. In this study, we present recent disinfection and demand/decay and microbial inactivation kinetic results from ten North American wastewater treatment plants for PAA, PFA and total chlorine. These results are utilized in a simulated contact chamber where we consider five different dose control strategies; from simple constant disinfectant dosing to advance controls where demand and decay are measured online and adjustments to the dosing are made in real time. System performance when compared to five control strategies anticipate a lesser demand for a disinfectant for advanced control strategies at the expense of higher geomean microbial counts at the outlet. However, it is observed that using an advanced control strategy for chemical disinfection results in a steady performance and requires less quenching to meet regulatory compliance.