Enhanced sludge reduction during swine wastewater treatment by the dominant sludge-degrading strains Chryseobacterium sp. B4 and Serratia sp. H1.

Abstract Sludge reduction is considered a main target for sludge treatment and an urgent issue for wastewater treatment. In this study, two dominant sludge-degrading strains, identified as Chryseobacterium sp. B4 and Serratia sp. H1, were used for inoculation in swine wastewater treatment to investigate the enhancement of sludge reduction. The results showed the volatile suspended solid (VSS) removal rate in experimental groups inoculated with Chryseobacterium sp. B4, Serratia sp. H1, and a combination of the two strains improved by 49.4%, 11.0%, and 30.5%, compared with the control with no inoculation. Furthermore, microbial community structure and functional prediction analyses indicated Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria could play an essential role in sludge reduction, and the dominant sludge-degrading strains B4 and H1 enhanced sludge reduction by strengthening carbohydrate, nucleotide, amino acid, and lipid metabolism and membrane transport functions. This study provides new insights into sludge reduction during wastewater treatment with dominant sludge-degrading strains.