Exploring the Effect and Mechanism of Benzalkonium Bromide on Short Chain Fatty Acid Production from Waste Activated Sludge

Quaternary ammonium compounds (QACs) was frequently detected in wastewater treatment plants and leads to potential toxicity to the related biological processes. In this study, the effect of benzalkonium bromide (BK) on anaerobic sludge fermentation process for short chain fatty acid (SCFAs) production was investigated. Batch experiments indicated that BK exposure significantly enhanced the SCFAs production from anaerobic fermentation sludge and the maximum concentration of total SCFAs increased from 474.40 ± 12.35 mg/L to 916.42 ± 20.35 mg/L with BK increasing from 0 to 8.69 mg/g VSS. Mechanism exploration exhibited that the presence of BK enhanced much more bioavailable organic matters release but little affected on hydrolysis, acidification, and methanogenesis. Microbial community investigation revealed that BK exposure importantly enhanced the relative abundances of hydrolytic-acidifying bacteria and the metabolic pathways and functional genes for sludge lysis were also increased. This work further supplement the information for environmental toxicity of emerging pollutants