Effect of COD/SO (4) (2-) ratio and alkalinity on COD removal and sulfate reduction in two-phase expanded granular sludge bed
Li, J.; Xiang, T.; Wei, J.; Chen, D.; Ashraf, A.
Journal of Environmental Biology 37(Special Issue 5): 1117-1124
2016
ISSN/ISBN: 0254-8704 PMID: 29989743 Document Number: 687237
In the present study, a bench-scale two-phase expanded granular sludge bed (EGSB) reactor was applied for treatment of high-sulfate wastewater. The reactor was operated continuously at 35°C. The EGSB 1, as sulfate-reducing phase, and EGSB2, as methane-producing phase, were combined after successful start-up. The treatment characteristics, including the effect of influent COD/SO(4)(2-) ratio and alkalinity in reactor have been discussed for EGSB1 and EGSB2 respectively. When total COD removal was 85%, the influent COD/S0(4)(2-) ratio was 2.8. When the ratio was less than 2.8, the COD removal descended quickly. The total sulfate removal then raised to 90% and the ratio exceeded 4.4. When influent alkalinity was kept at 8-10 mmol l(-1), the total COD and SO(4)(2-)removal reached 93.3% and 94.0% respectively. The results presented in the study provide some useful information for optimization of COD removal and SO(4)(2-) reduction process in wastewater treatment.