Novel bio-degradation shortcut for the treatment of acrylonitrile-containing wastewater using column bio-oxidation with Sulfurovum bacteria in activated sludge

Currently, there is a paucity of research focused on the column bio-oxidation of organic wastewater containing acrylonitrile. Consequently, it is imperative and meaningful to investigate the application of column biooxidation for the treatment of this specific type of wastewater. To initiate the study, microorganisms were enriched from activated sludge obtained from a chemical plant. These microorganisms were subsequently acclimated by introducing essential nutrients and optimizing reaction conditions such as the liquid-to-solid ratio, oxygen concentration, pH, and temperature. The resulting microbial consortium was then evaluated for its capacity to degrade acrylonitrile. The results show that at the solid to liquid ratio 3:40 (g/L), anaerobic environment (O-2<5%), pH 7.5, 30 degrees C, nutrients (glucose 5 g, MgSO4 center dot 7H(2)O 0.5 g, KH2PO4 1.0 g, KNO3 1.0 g) and hydraulic retention time 96 h. The average removal rate of acrylonitrile can reach 86.95 %. The evolution of the microbial community was characterized by 16S rRNA gene analysis. It revealed that Sulfurovum gradually replaced other microorganisms as the dominant species over time in the response. In conjunction with the monitoring of elemental nitrogen during the reaction, it was found that Sulfurovum showed a two-step pathway in the process. In the first stage, Sulfurovum converted acrylonitrile as the nitrogen source to R-COOH and produced NH3/NH4- in the presence of acrylonitrile. In the second stage, Sulfurovum used exceed NO3- as the nitrogen source, enabled the nitrogen cycle to proceed.