Characteristic of acidogenesis and substrate release during fermentation of excess activated sludge
剩余污泥发酵产酸特征及基质释放规律研究

The fermentation of excess activated sludge can reduce the yield of excess sludge, and produce volatile fatty acids (e. g. VFAs) that are needed for biological denitrification and phosphorus removal of wastewater. A batch experiment was conducted to study the characteristic of sludge reduction, acidogenesis and substrate release during excess activated sludge fermentation under different adding ratios when the acclimated anaerobic fermentable sludge was inoculated in anaerobic reactors at (30 ± 1) ℃ . The results show that inocula-ting anaerobic fermentable sludge can improve production of VFAs though it has no apparent effect on excess sludge reduction in sequencing anaerobic fermentation system. Two peaks of VFAs concentration, the second peak higher than the first peak, were found during the fermentation at the adding ratio of excess activated sludge was over 50qo . A fairly satisfactory effect could be attained by dosing 60% ~(6+) 80% and the optimum fermentation time is 5 days or 25 days. The apparent conversion of VFAs is the highest in the former while the concentration of VFAs is the highest in the latter. The NH_4~+ -N concentration generally exhibited an increase, the PO_4~(3-)-P con-centration reached their maximum after 5 days ' fermentation.