Enhanced biological phosphorus removal in low-temperature sewage with iron-carbon SBR system

Abstract

This study proposed an AO-SBR combined with iron-carbon micro-electrolysis (ICME) particles system for sewage treatment at low temperature and explored the dephosphorization mechanism and microbial community structure. The experimental results illustrated that ICME particles contributed to phosphorus removal, metabolic mechanism and microbial community structure. The optimal treatment effect was achieved under the conditions of pH 7, DO 3.0 mg/L and particle dosage of 2.6 g Fe-C/g MLSS, and the removal rates of COD, TP, NH 4 + -N and TN reached 80.56%, 91.46%, 69.42% and 57.57%. The proportion of phosphorus accumulating organisms (PAOs) increased from 4.54% in SBR system to 10.89% in ICME-SBR system at 10°C. Additionally, metabolic rate of PAOs was promoted, and the activities of DHA and ETS both reached the maximum value of 13.34 ug•mg − 1 VSS•h − 1 and 102.88 ug•mg − 1 VSS•h − 1 . These results suggest that the ICME particles could improve the performance of activated sludge under lowtemperature conditions. This technology provides a new way for upgrading of the performance of sewage treatment in cold area