【作者】 潘胜；

【导师】 黄光团；

【作者基本信息】 华东理工大学 ， 环境科学与工程， 2012， 硕士

【摘要】 剩余污泥含水率高,体积庞大,需对其进行脱水处理以减小污泥体积,方便后续运输和处理处置。本论文研究了Fenton试剂调理城市污水处理厂剩余污泥,通过测定污泥毛细吸水时间(CST)、污泥比阻(SRF)和泥饼含水率来表征污泥脱水性能的变化,分别考察了污泥初始pH、H2O2投加量、H2O2/Fe2+、反应温度和反应时间对污泥调理效果的影响。综合考虑,确定Fenton调理污泥的最佳条件为：pH=3、抽滤脱水和离心脱水H2O2最佳投加量分别为3g/L和9g/L、H2O2/Fe2+(质量比)最佳范围为8～12、反应温度50℃、反应时间60min。对污泥离心上清液中胞外聚合物(EPS)含量的研究表明,Fenton调理后污泥上清液中蛋白质和多糖含量有大幅升高,说明Fenton试剂能有效氧化破解EPS,从而提高污泥的絮凝性,改善污泥的脱水性能。Fenton氧化后污泥颗粒粒径变小,比表面积增大。研究了剩余污泥在中温厌氧消化条件下污泥脱水性能的变化及其作用机理。剩余污泥厌氧消化过程中,消化污泥比阻(SRF)相比于剩余污泥有一定的减小,消化污泥的过滤速度有一定的改善,但改善不明显。PAM、FeCl3和PAC三种絮凝剂调理实验显示,消化污泥的最佳投药量相对于剩余污泥均有所增加,说明消化污泥脱水性能变差。分析了2种污泥中胞外聚合物(EPS)含量及污泥颗粒特性的变化,表明消化过程导致EPS的降解并向液体中释放。随着EPS含量的减少,由EPS架桥形成的较大絮体解体成为较小的污泥颗粒,污泥中小颗粒的比例增加,污泥的脱水性能变差。开展了板框压滤机污泥深度脱水试验,结果显示,Fenton试剂+铁盐调理和铁盐/石灰调理污泥脱水效果较好,压滤脱水后泥饼含水率低于60%。Fenton试剂+铁盐调理与铁盐/石灰调理相比,Fenton试剂+铁盐调理虽然进泥时间偏长,但是污泥稳定效果更好；加入的无机质较少,最终泥饼干固体量少；泥饼热值较高,泥饼pH值偏中性,有利于泥饼的资源化利用。更多还原

【Abstract】 Sludge with high moisture content needed to be dewatered to reduce the sludge volume for facilitating transportation and subsequent disposal. The parameters for the condition of excess sludge by Fenton reagent were investigated, and the capillary suction time (CST), the specific resistance to filtration (SRF) and the water content of sludge cake were measured to examine sludge dewatering performance. The effects of initial pH of sludge, H2O2 dosage, H2O2/Fe2+ ratio, reaction time and temperature on sludge conditioning were investigated. The optimal condition parameters for sludge conditioning were determined as follows:pH=3, H2O2 dosages of filtration and centrifugal dehydration were 3g/L and 9g/L respectively, H2O2/Fe2+ ratio (mass ratio)=8-12, temperature T=50℃, and reaction time was 60min. The protein and polysaccharide contents in extracellular polymeric substances (EPS) increased after the excess sludge was conditioned by Fenton reagent, which demonstrated that Fenton oxidation could effectively break EPS structure and improve the flocculation and dewatering performance of sludge. After Fenton oxidation, sludge particle size became smaller and the surface area increased.The change of dewatering performance of digested sludge was studied as well here. The result showed that SRF value of digested sludge was a little smaller than that of raw excess sludge, the filtration rate of digested sludge increased a little. PAM, FeCl3, and PAC were used in the sludge conditioning experiment, which revealed that the optimal dosages of digested sludge all increased compared to excess sludge and dewatering performance of digested sludge became worse. Through analyzing extracellular polymeric substances (EPS) content and the characteristics of sludge particle, it was found that digestion process led to the degradation of EPS and releasing into liquid. With the decreasing of EPS content in sludge, the larger floc formed by the bridging of EPS was disintegrated into smaller particles. The proportion of smaller particles in sludge increased and dewatering performance of digested sludge became worse.Pilot scale experiment of sludge deeply dewatering with frame filter press had carried out, the result showed that the combination of Fenton reagent and ferric salt and the combination of ferric salt and lime had a good conditioning performance, the water content of sludge cake was below 60%. Compared with ferric and lime, the combination with Fenton reagent and ferric salt showed higher performance on sludge conditioning, such as more stability of sludge, less amount of sludge, higher caloric value and closer to neutral pH value of sludge cake even though it cost more time for sludge to get to the filter press.更多还原