Abstract: The current microwave pretreatment of waste activated sludge is limited to sludge hydrolysis ratio and the effect to anaerobic digestion, soluble COD is often used to evaluate pretreatment effect, and volatile fatty acids recovery from sludge is rarely reported. In order to determine the optimal process conditions of volatile fatty acids recovery from waste activated sludge using microwave pretreatment process, the factors and their levels were established by single factor experiment first, and response surface methodology of four factors and three levels was used based on the center combination design. The four factors included heating temperature, heating time, dosage of H₂O₂, and dosage of acetic acid. The optimal process conditions were as follows:microwave heating temperature of 180℃, microwave heating time of 21min, H₂O₂ dosage of 0.18g/(gSS), acetic acid dosage of 49mg/(gSS). Under these conditions, the maximum predicted acetic acid concentration was 581mg/L, the relative deviation was 0.033—0.074 between the predicted values and the experimental values. The results showed that this method could effectively improve volatile fatty acids recovery from sludge, the predicted values were in accordance with the experimental values, and this method could provide theoretical and practical guidance for in situ carbon source production from sludge.

Key words: waste treatment, radiation, optimal design, microwave pretreatment, waste activated sludge, acetic acid

摘要： 目前微波预处理污泥主要局限在污泥水解率及其对厌氧消化的影响, 常用溶解性COD来进行表征预处理效果, 在污泥产酸方向少有报道。为了确定微波热解剩余污泥产酸的最佳工艺条件, 通过单因素实验选取实验因素与水平, 根据中心组合设计原理, 在单因素试验的基础上采用四因素三水平的响应面分析法, 考察了微波加热温度、微波加热时间、过氧化氢投加量和乙酸投加量对污泥产酸的影响。微波热解剩余污泥产酸的最佳工艺条件为:加热温度180℃, 加热时间21min, 过氧化氢投加量0.18g/(gSS), 乙酸投加量49mg/(gSS), 最大预测乙酸增量值581mg/L, 试验值与预测值之间的相对偏差在0.033～0.074之间。研究结果表明:本工艺可有效提高污泥有机酸产率, 试验值与预测值吻合较好, 可为污泥原位碳源开发提供理论和实际指导。

关键词: 废物处理, 辐射, 优化设计, 微波预处理, 剩余污泥, 乙酸