Keywords: EBPR, enhanced biological phosphorus removal, MBR, membrane bioreactors, SRT, sludge retention time, EPS, extracellular polymeric substances, wastewater treatment, water pollution
Study on enhanced biological phosphorus removal using membrane bioreactor at different sludge retention times
An enhanced biological phosphorus removal process coupled with membrane bioreactor was proposed. Four runs were operated at different Sludge Retention Times (SRTs) of 20, 30, 40 and 50 d. Although average phosphorus removal tended to drop with SRT, the total phosphorus removal over 85% could be still achieved if the SRT was maintained under 40 d. Phosphorus-content in the sludge increased with SRT, but has a limit of around 5.6–5.8% mgP/gMLSS. Extracellular Polymeric Substances (EPSs) are a pool for phosphorus stored. Phosphorus-content in the EPS per EPS increased as the SRT increased.