Peracetic Acid: A Tool for Wastewater Disinfection Compliance

AbstractPeracetic acid (PAA) has emerged in North America as a cost-effective alternative to other mature disinfection technologies with its ability to eliminate the use of chlorine, address disinfection by-product formation, and meet disinfection compliance at facilities. There are now several US installations of PAA disinfection that have been deployed to meet either Escherichia coli or Enterococcus limits for wastewater discharge; however, there is limited information related to use of PAA disinfection to meet fecal coliform compliance either as a stand-alone process or in conjunction with ultraviolet (UV) disinfection. This research studies bench-scale and pilot investigations to evaluate the feasibility of PAA as a disinfectant, alone as well as in conjunction with an existing UV disinfection system. Bench-scale results indicated PAA could be used as a stand-alone technology or as a backup to UV disinfection; thus pilot testing was implemented. During pilot testing, fecal coliform limits were met with a dose of 0.6 mg/L PAA and four UV reactors in operation on medium power. Additionally, these effluent limits were also met with a dose of 1 mg/L PAA and the UV system turned off. Effluent carbonaceous biochemical oxygen demand (cBOD5) was indistinguishable between pre- and post-PAA, and all pH data points fell within a range of 6.03–7.72. These results show that municipalities can utilize bench-scale kinetics to adequately implement PAA disinfection at their facilities.