Sulfate Reduction in an Upflow Anaerobic Sludge Blanket Bioreactor and Optimization of Operational Conditions: pH, Hydraulic Retention Time, Sulfate Loading Rate, COD/SO42- Ratio | ||||
| Egyptian Journal of Chemistry | ||||
| Volume 66, Issue 12, December 2023, Page 379-386 PDF (405.15 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejchem.2023.191793.7563 | ||||
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| Authors | ||||
M. Hamdy El Awady   ; Ahmed A. Dahaba
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| Water Pollution Research Department, Environmental Research and Climatic Changes Institute, National Research Centre, P.O. Box 12622, El-Buhoth St., Dokki, Cairo, Egypt | ||||
| Abstract | ||||
| This paper introduces an application of biological treatment for industrial wastewater (IWW) contaminated with sulfate ions. Lab-scale up-flow anaerobic sludge blanket (UASB) bioreactor was fabricated for detecting the optimal operational conditions of sulfate ions removal with other impurities from IWW. Sulfate reducing bacteria (SRB) was effectively reduced sulfate into sulfide and let H2S gas liberated. The experiment has been carried out along 345 days of operational time. Results showed that, at pH 6.2, hydraulic retention time (HRT) between 24-18 h on increasing sulfate loading rate (SLR) up to 1.3 g SO42- L-1 d-1, the sulfate reduction efficiency (SRE) was increased from (53±11) up to (87±7) %, in addition to 99% heavy elements removal, respectively. However, on decreasing HRT to 12.0 h with increasing SLR up to 3.6 g SO42- L-1d-1, the sulfate reduction (SR) rate decreased to 66±3 %. On increasing the temperature from 25 to 35oC, the SRE was increased from 68 to 83%. When COD/SO42- ratio was increased from 2.0 to 5.0, the SRE was slightly decreased from 74±10 to 68±6%, respectively. Moreover, when COD/SO42- ratio was increased from 5.0 to 10.0, (SRE) decreased from 68±6 to 66±3%. Consequently, the optimal operational conditions of the UASB reactor for maximum SRB at temperature, HRT, SLR, and COD/SO42- ratio of 35oC, 18h, 1.3g SO42-L-1d-1, and 2.0, respectively, while Fe2+ is essential. | ||||
| Keywords | ||||
| Sulfate removal; Biological treatment; Anaerobic treatment; Industrial wastewater; Sulfate reducing bacteria; Up-flow anaerobic sludge blanket | ||||
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