Long-term evaluation of the effect of peracetic acid solution on anaerobic wastewater treatment: Process performance and microbial community structure

Abstract

Peracetic acid (PAA) has been extensively used in poultry processing as an effective disinfectant. However, PAA-bearing poultry processing wastewater can lead to severe upsets of biological wastewater treatment processes. The objective of this study was to assess the long-term effect of PAA solution (PAA and hydrogen peroxide, H2O2) on the anaerobic treatment of poultry processing wastewater. Five reactors were operated for 177 d, semi-continuously fed with poultry processing wastewater and gradually increased levels of H2O2 or PAA solution, added either to the wastewater before feeding (indirect addition), or to the reactors immediately after feeding (direct addition). Indirect, well pre-decomposed H2O2 and PAA had limited effect on biogas production and COD destruction. Biogas production was completely inhibited with direct addition of H2O2 at 227 mg/L, but recovered in ca. 2 d. Direct addition of PAA solution at 500/100 mg/L PAA/H2O2 completely inhibited biogas production and required ca. 18 d incubation for recovery. Methanogenesis was more impacted than fermentation. Long-term H2O2 or PAA solution addition led to a relatively low shift in both bacterial and archaeal communities. The major methanogenic orders were Methanosarcinales and Methanomicrobiales. Direct PAA solution addition decreased both acetoclastic and hydrogenotrophic methanogenic activity; acetoclastic methanogenesis was affected the most.