Effect of influent COD/SO4(2-) ratios on UASB treatment of a synthetic sulfate-containing wastewater.
The effect of the chemical oxygen demand/sulfate (COD/SO4(2-)) ratio on the anaerobic treatment of synthetic chemical wastewater containing acetate, ethanol, and sulfate, was investigated using a UASB reactor. The experimental results show that at a COD/SO4(2-) ratio of 20 and a COD loading rate of 25.2gCODL(-1)d(-1), a COD removal of as high as 87.8% was maintained. At a COD/SO4(2-) ratio of 0.5 (sulfate concentration 6000mgL(-1)), however, the COD removal was 79.2% and the methane yield was 0.20LCH4gCOD(-1). The conversion of influent COD to methane dropped from 80.5% to 54.4% as the COD/SO4(2-) ratio decreased from 20 to 0.5. At all the COD/SO4(2-) ratios applied, over 79.4% of the total electron flow was utilized by methane-producing archaea (MPA), indicating that methane fermentation was the predominant reaction. The majority of the methane was produced by acetoclastic MPA at high COD/SO4(2-) ratios and both acetoclastic and hydrogenthrophic MPA at low COD/SO4(2-) ratios. Only at low COD/SO4(2-) ratios were SRB species such as Desulfovibrio found to play a key role in ethanol degradation, whereas all the SRB species were found to be incomplete oxidizers at both high and low COD/SO4(2-) ratios.
Graduate School of Environmental Studies, Tohoku University, Sendai 9808579, Japan.
Yong
Y
Hu
College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China.
Zhaoqian
Z
Jing
Graduate School of Environmental Studies, Tohoku University, Sendai 9808579, Japan.
Yuta
Y
Sudo
Graduate School of Engineering, Tohoku University, Sendai 9808579, Japan.
Qigui
Q
Niu
Graduate School of Environmental Studies, Tohoku University, Sendai 9808579, Japan.
Jingru
J
Du
Graduate School of Engineering, Tohoku University, Sendai 9808579, Japan.
Jiang
J
Wu
Graduate School of Engineering, Tohoku University, Sendai 9808579, Japan. Electronic address: yyli@epl1.civil.tohoku.ac.jp.
Yu-You
YY
Li
D000085:Acetates / Q000737:chemistry; D001105:Archaea / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D004275:DNA, Ribosomal / Q000737:chemistry; D003901:Desulfovibrio; D000431:Ethanol / Q000737:chemistry; D005285:Fermentation; D008697:Methane / Q000032:analysis / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry* / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
D000085:Acetates; D004275:DNA, Ribosomal; D000431:Ethanol; D008697:Methane; D010100:Oxygen; D013431:Sulfates; D062065:Wastewater
COD/SO(4)(2−) ratio; Chemical wastewater; Methane production; Sulfate; Sulfate reduction; UASB