[Performance of biological phosphorus removal in anaerobic pre-fermentation and intermittent aerated biofilm system treating domestic wastewater].

A fixed-film system composed of anaerobic biofilter and intermittent aerated biofilter (IABF) was developed for enhanced biological phosphorus removal (EBPR) in treatment of domestic wastewater. Influence of hydraulic, organic, and phosphorus loading on performance of the system was investigated in this study. The result indicates that the system is efficient for the removal of organic and P in the treatment. At a hydraulic retention time of the system of 23.3-4.6 h, the effluent concentration and reduction efficiency of TP and COD are 0.59 mg/L, 68 mg/L in average and 85.2%, 73.6% in average, respectively. A stable performance of EBPR in the system is achieved with a good adaptability of fluctuations of the loadings. An innovative method instead of traditional backwashing was applied to remove P in biofilm from IABF. The use of the method improves P-uptake capacity in biofilm during long-term operation without wasting, which prolongs operation duration and reduces backwashing frequency in IABF. Pre-fermentation of domestic wastewater in anaerobic biofilter increases concentration of volatile fatty acids in the influent of IABF.