Effect of peracetic acid on anaerobic treatment of poultry processing wastewater
Lin, Ding Hsiang
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Peracetic acid (PAA) is a powerful disinfectant against a wide spectrum of microbes, used in healthcare, water treatment, and food industry. In poultry processing plants, PAA is used in chicken chiller tanks as well as for the disinfection of processing equipment as an antimicrobial agent. Residual PAA in poultry processing wastewater may be carried to biological wastewater treatment systems with potential adverse effects. The overall goal of this research was to evaluate if anaerobic treatment of PAA-carrying poultry processing wastewater is feasible. The specific objectives of this research were to investigate: i) the effect of PAA on a mixed fermentative/methanogenic culture, acetoclastic methanogens, and hydrogenotrophic methanogens; and ii) the effect of PAA on the anaerobic treatment of poultry processing wastewater (dissolved air floatation effluent) and compare the effect of pre-decomposed and direct PAA addition to semi-continuously-fed, laboratory-scale anaerobic reactors, conditions reflecting normal operation and accidental spills, respectively, in poultry processing plants. The findings of the present study suggest that pre-decomposed PAA addition does not impact fermentative/methanogenic systems, especially acetoclastic methanogens, and hydrogenotrophic methanogens. On the other hand, direct 40 and 100 mg/L impacted the fermentative/methanogenic culture and acetoclastic methanogens, which recovered over time. Hydrogenotrophic methanogens were more resistant to direct PAA addition, given that hydrogenotrophic methanogens were not affected by direct 40 mg/L PAA addition. Thus, anaerobic processes can be used to treat poultry processing wastewater carrying PAA, at least up to 80 mg/L PAA. Even in the case of an accidental PAA spill, anaerobic treatment systems can recover over time providing that corrective measures are implemented (e.g., temporary wastewater diversion, pH adjustment).