酸-碱处理对剩余污泥水解酸化的影响

剩余污泥中富含有机质和营养元素可回收利用物质,污泥水解酸化液中的有机酸在去除或回收利用氨和磷后可作为进水化学需氧量(COD)不足的污水处理厂的补充碳源。通过控制pH,对比分析了不同处理方式(单独碱处理、酸-碱处理和碱-酸处理)对污泥水解酸化的影响。结果表明,单独碱处理的溶解性化学需氧量(SCOD)溶出量比酸碱联合处理要大16%左右,预处理第8天,达到5 406.1 mg/L。采用先酸(pH 4.0,4 d)后碱(pH 10.0,4 d)预处理,乙酸产量达到74.4 mg COD/g VSS,占总SCFAs的60.5%,产量及其占总短链脂肪酸(SCFAs)百分比含量均高于其他预处理方式。且酸-碱处理方式下NO4+-N和PO34--P溶出要优于其他处理方式。而单独碱处理方式下污泥减量效果最好,VSS去除率为36.6%。

Impact of acid-alkali pretreatment on hydrolysis and acidification of excess sludge

Waste activated sludge is rich in recyclable resource such as organic matters and nutrients. After removing and recycling the ammonia nitrogen and phosphorus, the organic acid solution generated in the process of hydrolysis acidification can serve as the carbon source for wastewater treatment. We investigated the effects of three kinds of pretreatment methods (alkali treatment alone, alkali-acid treatment and acid-alkali treatment) on hydrolysis acidification of the waste activated sludge by changing solution pH. The results showed that after alkali treatment, the SCOD dissolving out was 16% higher than that of the combination of alkali and acid treatment,and SCOD reached 5 406.1 mg/L after 8 d. Applying the acid-alkali treatment (pH 4.0 for 4 d first and then pH 10.0 for 4 d), the yield of acetic acid could reach 74.4 mg COD/g VSS, accounting for 60.5% of the total SCFAs, the yield and content of acetic acid in the SCFAs was higher than that of other treatment methods. Moreover, the dissolution of nitrogen and phosphorus was obvious with the acid-alkali treatment. Besides, the most effective method for sludge reduction was the alkali treatment, the removal rate of VSS was 36.6%.