Isolation Of Efficent Biodesulfurization And Denitrification Strains And The Corresponding Bioaugmentation On Efficiencies

The isolation of desulfurization and denitrification bacterias is very important for improving the efficiency of denitrifying sulfide removal. In this study, five strains with the function of desulfurization and denitrification, were isolated from well-performed expanded granular sludge bed reactors which had high efficiency of simultaneous desulfurization and denitrification. 16 S r RNA gene based similarity identification indicates that the isolates which include a autotrophic strain named ADD1 and four heterotrophic strains, HDD1, HDD2, HDD3, and HDD4, have closest relatives as Thiobacillus sp., Thauera sp., Alkaliflexus sp., Azoarcu sp. and Pseudomonas sp. respectively.The strain HDD1 has the highest efficiency of desulfurization and denitrification. The desulfurization and denitrification characterization of the strains showed that the strain HDD1 biodegraded acetate, nitrate and sulfate within 16 h rapidly, with the Na2 S, KNO3 and CH3 COONa concentrations of 1.5, 0.75 and of 1.0 g/L, respectively. The final removal efficiency of sulfate, nitrate and acetate were all above 95%.The optimum molar ratio of CH3COONa-C/KNO3-N was 1.26:1 for the strain HDD1. The results showed that the strain HDD1 could remove acetate, nitrate and sulfate efficiently at the CH3COONa-C/KNO3-N molar ratios of 1.26:1 within 15 h. The removal efficiencies of sulfate, nitrate and acetate were all above 90%. The maximum tolerated concentration of S2- was 200 mg/L for the desulfurization and denitrification of the strain HDD1.Bioaugmentation had some good impact on the final removal efficiencies of sulfate, nitrate and acetate. Contaminants could be removed completely within 6-7 h when the number of the strain HDD1 cells was approximately 4.92×1010 in the bioaugmentation simulated systems, and the degradation time was shortened by 1 h compared with that of the control group.The strain HDD1 is a potential functional microbiol resource for the improvement of the efficiency in simultaneous desulfurization and denitrification process. The bioaugmentation study of the strain HDD1 played an important role in guiding the regulate and control of denitrifying sulfide removal process.