A lab-scale upflow anaerobic sludge blanket (UASB) has been run for 250 days to investigate the influence of influent COD/SO42- ratios on the biodegradation behavior of starch wastewater and process performance. Stepwise decreasing COD/SO42- ratio enhanced sulfidogenesis, complicating starch degradation routes and improving process stability. The reactor exhibited satisfactory performance at a wide COD/SO42- range ≥2, attaining stable biogas production of 1.15-1.17 L L-1 d-1 with efficient simultaneous removal of total COD (73.5-80.3%) and sulfate (82.6 ± 6.4%). Adding sulfate favored sulfidogenesis process and diversified microbial community, invoking hydrolysis-acidification of starch and propionate degradation and subsequent acetoclastic methanogenesis; whereas excessively enhanced sulfidogenesis (COD/SO42- ratios <2) would suppress methanogenesis through electrons competition and sulfide inhibition, deteriorating methane conversion. This research in-depth elucidated the role of sulfidogenesis in bioenergy recovery and sulfate removal, advancing the applications of UASB technology in water industry from basic science.
ASJC Scopus subject areas
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal