—This work investigated simultaneous removal of sulfur and nitrogen compounds under micro oxygen. Different ranges of dissolved oxygen (DO) concentration were used, from 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.25 and 0.25-0.30 mg/L, to study the effect of DO on specific microbial activities and their metabolic products. The results indicated that the optimal DO concentration was 0.10-0.15 mg/L. This condition provided removal efficiency of SO4 2-
-S and NH4 +
-N at 71.2% and 62.8%, respectively. In addition, S0
gas were the required end products for this study. The yield of S0
was 0.63 g-S0 produced/g
and 0.57 g-N2 produced
/g- NH4 +
, respectively. Activities of sulfate reducing bacteria (SRB), sulfide oxidizing bacteria (SOB), nitrifier and denitrifier were 0.098, 0.361, 0.080 and 0.169 g-substrateconsumed/g-VSS/d, respectively. At the lowest DO of 0.05-0.10 mg/L, nitrifier was inhibited, leading to decreasing NH4 +
-N removal efficiency and N2
yield. However, sulfate removal and S0
yield slightly increased. When DO concentrations reached 0.15-0.30 mg/L, sulfate removal efficiency and S0
yields decreased significantly. In addition, SRB activity was inhibited significantly while activity of SOB was not significantly different. In contrast, the activity of nitrifier was enhanced by increasing oxygen to peak removal of ammonium. However, N2
gas production was increased slightly because nitrate reduction to N2
was inhibited at high DO concentrations.
—Simultaneous removal, sulfate, ammonium nitrogen, specific microbial activity, metabolic product.
W. Thongnueakhaeng is with The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Thailand, 10140 (e-mail: email@example.com).
P. Chaiprasert is with the Division of Biotechnology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Thailand, 10140 (e-mail: firstname.lastname@example.org).
Cite:W. Thongnueakhaeng and P. Chaiprasert, "Effect of Dissolved Oxygen Concentrations on Specific Microbial Activities and Their Metabolic Products in Simultaneous Sulfur and Nitrogen Removal," International Journal of Environmental Science and Development vol. 6, no. 4, pp. 235-240, 2015.