2019 Volume 17 Issue 1 Pages 54-65
The effects of sulfates on enhanced biological phosphorus removal (EBPR) were investigated in three municipal wastewater treatment plants (WWTPs), which treat sewage containing several concentrations of sulfates. The behaviour of sulfates and phosphates in the anaerobic oxic process was analysed by considering the daily inflow rate and water quality. Although phosphorus release and uptake were recognized in all plants, phosphorus release from the WWTPs that were treating high-sulfate wastewater (high-sulfate WWTP), was lower than that of the WWTP treating low-sulfate wastewater (low-sulfate WWTP). In the high-sulfate WWTPs, sulfate decreased in the anaerobic zone and increased in the oxic zone. Analysis of the sulfate reduction and sulfur oxidation activities of the sludge showed that both activities were dependent on the influent sulfate concentration. The relative abundance of SRB which oxidize organic matters completely in high-sulfate WWTPs tends to be higher than that in low-sulfate WWTPs. On the other hand, a lower relative abundance of polyphosphate accumulating organisms (PAOs) was recognized in the high-sulfate WWTPs.
