碱性条件下温度对初沉污泥水解及产酸的影响

Influence of Temperature on Hydrolysis and Acidification of Primary Sludge under Alkaline Condition

控制pH值为10.0,研究初沉污泥在四种不同温度(10、20、25、35℃)下水解和厌氧发酵产酸的情况,对产酸的原因进行了分析,同时研究了该条件下溶出的氨氮和正磷酸盐的变化及挥发性悬浮固体削减情况。结果表明:温度升高有助于提高总短链脂肪酸的产量,最佳的产酸条件为控制室温在20~25℃,发酵时间为5 d;此条件下,总SCFAs中主要成分为乙酸和丙酸,其占比超过75%。该条件下产生大量的SCFAs,主要是因为在碱性条件下,温度促进了PS的水解和酸化。温度升高有利于氨氮和磷酸盐的溶出,但磷酸盐的释放量远小于氨氮;温度升高同时也有利于提高VSS的削减率,25℃和20 d时,污泥减量最明显,其VSS削减率为44.8%。

The hydrolysis and short-chain fatty acids（ SCFAs） production of primary sludge（ PS） are investigated in a series of batch reactors under different temperature（ 10,20,25,35 ℃） at pH value of 10. 0. The cause of SCFAs production is analyzed. Meanwhile,ammonia nitrogen,phosphate concentration and volatile suspended solid（ VSS） reduction rate are all studied,when temperature varies between 10 ℃ and 35 ℃ in the fermentation of PS. Results show that higher temperature is benefit for total SCFAs production. The room temperature of 25 ± 2 ℃ and fermentation time of 5 d are the optimal condition with economy and practicability for SCFAs production with regard to PS fermentation,in which condition acetate and propionate rank the top two constituents with the percentage of excess 75%in most of the fermentation time. The cause of total SCFAs production increment under the optimal condition is that higher temperature contributes to the hydrolysis and acidification of PS. The temperature increasing at alkaline fermentation of PS contributes to the release of NH＋4-N,PO3-4-P and VSS reduction. However,the release concentration of PO3-4-P is much less than that of NH＋4-N. The reduction rate of VSS increases with temperature. The optimal VSS reduction rate of 44. 8% occurs at the temperature of 25 ℃ and fermentation time of 20 d.