Effect of COD/SO42- Ratio on UASB Treatment of Synthetic Organic Chemical Industrial Wastewater

• Published in: Journal of Japan Society on Water Environment Vol. 36; no. 6; pp. 165 - 173
• Main Authors: HU, Yong, JING, Zhaoqian, SUDO, Yuta, HOJO, Toshimasa, LI, Yu-You
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Japan Society on Water Environment 2013; Japan Science and Technology Agency
• Subjects: Acetates; Acetic acid; Anaerobic digestion; Anaerobic treatment; Archaea; Chemical industry wastewaters; Chemical oxygen demand; Chemical wastewater; COD/SO42- ratio; Electron flow; Ethanol; Fermentation; Industrial wastes; Industrial wastewater; Influents; Load distribution; Loading rate; Methane; Organic chemicals; Organic chemistry; Ratios; Removal; Sulfate; Sulfates; Upflow anaerobic sludge blanket reactors; Wastewater; Wastewater treatment
• ISSN: 0916-8958; 1881-3690
• DOI: 10.2965/jswe.36.165

The effect of the chemical oxygen demand/sulfate (COD/SO42-) ratio on the anaerobic treatment of synthetic chemical wastewater containing sulfate, acetate, and ethanol was investigated using a UASB reactor. The experimental results show that at a COD/SO42- ratio of 20 and a COD loading rate of 25.2 g-COD·L-1·d-1, the COD removal rate was maintained at as high as 87.8%. However, at a COD/SO42- ratio of 0.5 (sulfate concentration 6000 mg·L-1), a COD removal rate of 79.2% and a methane production rate of 0.20 L-CH4·g-COD-1 were obtained. The conversion of influent COD to methane dropped from 80.5% to 54.4% with a decrease in the COD/SO42- ratio from 20 to 0.5. At all the COD/SO42- ratios used, over 79.4% of the total electron flow was utilized by methane-producing archaea, indicating that methane fermentation was the predominant reaction.