Screening and characterization of mixotrophic sulfide oxidizing bacteria for odorous surface water bioremediation

Abstract Eight species of mixotrophic sulfide oxidizing bacteria (SOB) were isolated from activated sludge and identified using 16S rRNA sequence analysis. The effects of organic substances, dissolved oxygen (DO) and nitrate on sulfide oxidation and bacterial growth were studied in this work. The results showed that Paracoccus sp. (N1), Pseudomonas sp. (N2) and Pseudomonas sp. (S4) have strong adaptability to environments with low DO and high concentrations of organic substance. An SOB additive was optimized in artificial, odorous water. The optimized SOB additive is a blend of 80% N1 and 20% N2 bacteria solution with absorbance equal to 0.5 at a wavelength of 600 nm (OD600), and the optimal dose of the additive is 20 ml/L. Oxidation-reduction potential (ORP), ammonia-nitrogen (NH3-N) and released H2S in an odorous river were measured with and without SOB additive, and the results indicated that the optimized SOB additive has excellent performance for odorous river bioremediation.