ABSTRACT
Thiothrix caldifontis was the dominant microorganism in a labscale system containing 100 mgS/L of sulphide in the influent, which achieved full enhanced biological phosphorus removal (EBPR). The EBPR process is broadly applied in sewage treatment plants to meet the phosphorus discharge standards of treated wastewater. In this process, phosphorus is removed by polyphosphate accumulating organisms (PAOs) that store phosphorus beyond their growth requirements and are enriched by recirculating the activated sludge mixed liquor through anaerobic and aerobic/anoxic conditions. Due to the increasing generation of saline wastewaters rich in sulphate and the commitment to reduce the phosphorus emissions, there is a need to assess the long-term effects of sulphide on the EBPR process. In view of the stable EBPR activity at relatively high sulphide concentrations, different microbiological characterization and identification analyses were performed to assess the potential selection or adaptation of sulphide-tolerant PAOs.
