Insights into efficiency of sulfate reduction and community structure in anaerobic biological systems based on suspended fillers under nutrient-poor conditions
It is a strong challenge for the anaerobic biological treatment of sulfate-laden wastewater under nutrient-poor conditions. In this study, the feasibility of anaerobic sulfate-reducing bioreactors based on suspended fillers operating under nutrient-poor conditions was investigated. The findings indicate that the presence of suspended fillers enabled anaerobic systems to achieve favorable outcomes even under nutrient-poor conditions. The Principal Coordinates Analysis (PCoA) results clearly demonstrated significant differences in species composition between sludge and filler samples at each stage. Further analysis of community composition revealed that Desulfobulbus and Desulfobacter, which are closely associated with sulfate removal, exhibited significantly higher relative abundances in the filler samples compared to the sludge samples. Furthermore, the functional genes associated with sulfate removal were found to exhibit more pronounced expression in the sample of fillers. These findings suggested that the presence of suspended fillers creates a favorable environment for certain microorganisms, particularly some sulfate-reducing bacteria, enhancing microbial activity and increasing sulfate removal efficiency.