过氧乙酸和亚铁联用调质强化活性污泥过滤脱水性能

Enhancement of activated sludge dewatering performance with combined peroxyacetic acid and ferrous iron

尝试采用过氧乙酸和亚铁联用来改善活性污泥过滤脱水干化效率,分析了调理过程中污泥比阻（SRF）和泥饼含水率、絮体粒径分布以及胞外聚合物（EPS）组成和分布的变化特征,深入研究了过氧乙酸（peracetic acid,PAA）和亚铁离子联合调理污泥对其脱水性能的作用机制.研究表明,投加适量PAA后,污泥pH降至2.5 ～4,加入亚铁离子会与PAA解离后产生的H2O2形成Fenton氧化体系,从而有效地氧化裂解污泥,降解EPS中蛋白质和多糖,促使其中结合水的释放.当亚铁与过氧化氢摩尔比和PAA投加量分别为221和0.1g/gTSS时,污泥脱水性能达到最佳.最后,将污泥pH值调为中性后,由于反应过程中原位形成的三价铁的混凝作用,污泥脱水性进一步改善.本研究说明过氧乙酸和亚铁组合调理可以有效提高污泥的过滤和干化效能.

We attempted to use peracetic acid （PAA） and Fe^2＋ to improve activated sludge filtration dewa- tering and drying efficiency. The specific resistance to filtration （SRF）, cake moisture content and particle size distribution were determined for understanding the underlying mechanism of combined conditioning process. The results showed that sludge pH was reduced to 2.5 - 4 after addition of peracetic acid. A further addition of Fe^2＋ resulted in formation of formed Fenton oxidation system. Thus, sludge was effectively solubilized and protein and polysaccharide of EPS were significantly destroyed under combined conditioning process, consequently leading to release of bound water. Sludge dewaterability reached the maximum when the molar ratio of 2＋ Fe and H2O2 in PAA and PAA dosage were 2：1 and 0. 1 g/g TSS. Finally, when the sludge system was readjusted to neutral, the further improvement of sludge dewatering performance was observed due coagulation process of in-situ produc- tion ferric ions. Our study revealed that combined use of PAA and ferrous iron was very effective in improving sludge filtration and drying performance of activated sludge.