剩余污泥发酵产酸特征及基质释放规律研究

剩余污泥发酵既能实现污泥减量,又能获得污水生物脱氮除磷所需的挥发性脂肪酸VFAs等。采用序批式污泥发酵实验,在(30±1)℃的条件下,研究剩余污泥投配比对序批式污泥发酵系统污泥减量、产酸以及基质释放过程的影响,探索VFAs生成最大化的条件。实验结果表明:投加接种污泥不能明显提高序批式污泥发酵系统剩余污泥的减量效果,但可以改善污泥的产酸特性;当污泥投配比大于50%时,发酵过程中将出现2个VFAs浓度峰,且第二次峰浓度更大;较为理想的序批式污泥发酵投配比是60%~80%、发酵时间为5 d或25 d,前者VFAs表观转化率最大(约24%),后者发酵液中VFAs浓度最高(约600 mg/L);发酵过程中,NH4+-N总体呈上升趋势,磷浓度发酵5 d时达到最大值。

Characteristic of acidogenesis and substrate release during fermentation of excess activated sludge

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.