Anaerobic Treatment of N, N-dimethylformamide-containing Wastewater with a Co-cultured Sludge

摘要

Complete methanogenic degradation of high concentration of N, N-Dimethylformamide (DMF) was realized in this study. A specially designed anaerobic co-cultured sludge (ACS) made by artificially mixing activated sludge with anaerobic sludge was successfully domesticated by a long term repeated batch experiment. The results demonstrated that ACS could effectively degrade over 5000 mg/L DMF for high methane recovery. The metabolic pathway and stoichiometric equation of DMF methanogenic degradation were also revealed and verified in detail. It was also confirmed that under the anaerobic condition, with the help of enzyme, DMF converts into dimethylamine and formic acid, and the intermediates are effectively fermented through methylotrophic/hydrogenotrophic methanogenesis. Analysis of the microbial community suggested that some facultatively anaerobic bacteria played the key roles in methanogenic degradation due to their DMF-hydrolyzing ability. By co-culturing two sources of inoculum under the anaerobic condition, the symbiosis of facultatively anaerobic DMF-hydrolyzing bacteria and methylotrophic/hydrogenotrophic methanogens makes methanogenic degradation of DMF available. This study provided a new sludge cultivation method for anaerobic treatment of degradation-resistant organics.