Effect and mechanism of benzalkonium bromide on short chain fatty acid production from anaerobic sludge fermentation process

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, little affected on hydrolysis, acidification, but seriously inhibited methanogenesis. Microbial community investigation revealed that BK exposure importantly enhanced the relative abundances of hydrolytic-acidifying bacteria and also improved the metabolic pathways and functional genes for sludge lysis. This work further supplement the information for environmental toxicity of emerging pollutants.

Automated summary

This study investigated the effect of benzalkonium bromide (BK) on the production of short chain fatty acids (SCFAs) during anaerobic sludge fermentation. The results showed that BK exposure significantly increased the production of SCFAs. Mechanism exploration revealed enhanced bioavailable organic matter release and inhibition of methanogenesis due to BK exposure. Microbial community investigation indicated an increase in hydrolytic-acidifying bacteria and improved metabolic pathways and functional genes for sludge lysis.