不同预处理方法对污泥厌氧发酵产酸效果的影响

EFFECTS OF PRETREATED METHODS ON VOLATILE FATTY ACIDS PRODUCTION THROUGH SLUDGE ANAEROBIC FERMENTATION

预处理污泥厌氧发酵不仅可有效处理污泥,而且可产生挥发性脂肪酸(VFAs),实现污泥资源化利用。通过批式试验,探究酸(pH为3、4)、碱(pH为10、11)和低温(70,90℃)预处理条件下污泥厌氧发酵产酸效能。研究发现,在不同预处理污泥厌氧发酵过程中,VFAs的积累主要发生在发酵前24h,产酸效果表现为pH=11>90℃>pH=10>70℃>pH=3>pH=4>控制组,碱处理产酸有较明显优势,酸处理效果最差。乙酸为VFAs的主要成分,pH=11组的乙酸浓度最高达到1232.31 mg/L,为控制组的5.2倍。甲烷产量在厌氧发酵后期逐步上升。考虑到嗜酸产甲烷菌对VFAs的消耗以及经济性,选取24 h为最佳发酵时间。

Anaerobic fermentation of different pretreated sludge for volatile fatty acids production can not only effectively treat sludge problems but also realize resource cycling.In this paper,batch tests were conducted to investigate the volatile fatty acids production efficiency from anaerobic fermentation by acid(pH=3 and pH=4),alkali(pH=10 and pH=11)and low temperature(70℃,90℃)pretreatment.The results showed that the accumulation of volatile fatty acids mainly occurred in the first 24h during anaerobic fermentation process,and ranked as pH=11>90℃>pH=10>70℃>pH=3>pH=4>control group,and acid production by alkali treatment had the most obvious advantages,while the effect of acid treatment was the worst.Acetic acid was the main component of volatile fatty acids,and its highest concentration was 1232.31 mg/L(pH=11),which was 5.2 times higher than that of control group.Methane production rose slowly at the later stage of anaerobic fermentation,and volatile fatty acids was consumed in the methanogensis process.Therefore,considering the economy and consumption of volatile fatty acids by acidophilic methanogens,24 hours was the best fermentation time.