冻融处理对预脱水净水污泥脱水性能的影响  

Effect of Freeze-Thaw Treatment on Dewaterability of Pre-dewatered Drinking Water Treatment Sludge

作　　者：刘鹏程 王东田[1,2] 魏杰[2] LIU Pengcheng;WANG Dongtian;WEI Jie(School of Environmental Science and Engineering,Suzhou University of Science and Technology;School of Chemistry and Life Sciences,Suzhou University of Science and Technology,Suzhou 215009,China)

机构地区：[1]苏州科技大学环境科学与工程学院 [2]苏州科技大学化学与生命科学学院,江苏苏州215009

出　　处：《水处理技术》2022年第8期72-78,82,共8页Technology of Water Treatment

基　　金：国家自然科学基金资助项目(51778392)。

摘　　要：针对净水污泥含水率高、脱水性能差的问题,采用具有良好脱水效果的冻融法调理,并进一步调理经过预脱水的低含水率污泥,以期提高脱水效能。考察冷冻温度、时间和初始含水率对冻融调理的影响,并分析污泥各方面的变化,探究冻融作用机理。结果表明,净水污泥经冻融调理后脱水性能有明显提升,在-12℃下冷冻12 h后,其污泥比阻(SRF)、泥饼含水率和污泥沉降比(SV_(30))分别可降至1.57×10^(12)m/kg、59.9%和20.2%。而预脱水污泥的冻融调理效果相较于原泥直接冻融有进一步提升,且初始含水率越低(80%以上),脱水效果越好,最佳冻融条件下(含水率82%,-12℃,6 h),其泥饼含水率、SRF分别为46.5%和1.51×10^(11)m/kg,相较于原泥降低了50.8%和99.5%。而冻融改善污泥脱水性能的可能机理为在生长冰晶的不断作用下破坏了污泥原有的絮体结构,并相互团聚成大颗粒污泥,同时增强了污泥增溶性和疏水性,使自由水以不可逆的方式显著增加。To address the problems of high water content and poor dewatering performance of drinking water treatment sludge,freeze-thaw conditioning with good dewatering effect was used,and further conditioning of pre-dewatered low water content sludge was carried out to improve the dewatering performance.The effects of freezing temperature,time and initial moisture content on freeze-thaw conditioning were investigated,and the changes in various aspects of sludge were analyzed to investigate the mechanism of freeze-thaw action.The results showed that the dewatering performance of drinking water treatment sludge was significantly improved after freeze-thaw conditioning,and the specific resistance to filtration(SRF),sludge cake moisture content and sludge settling ratio(SV_(30))could be reduced to 1.57×10^(12)m/kg,59.9%and 20.2%,respectively,after freezing at-12℃for 12 h.In contrast,the dewatering performance of pre-dewatered sludge was significantly improved after freeze-thaw conditioning.The freeze-thaw conditioning effect of the pre-dewatered sludge was further improved compared with the direct freeze-thaw of the original sludge,and the lower the initial moisture content(above 80%),the better the dewatering effect.Under the optimal freeze-thaw conditions(82%moisture content,-12℃,6 h),the sludge cake moisture content and SRF were 46.5%and 1.51×10^(11)m/kg,which were reduced by 50.8%and 99.5%compared with the original sludge.The possible mechanism for the improvement of sludge dewatering performance by freeze-thaw is that the original floc structure of sludge was destroyed under the continuous action of growing ice crystals and agglomerated into large particles of sludge with each other,while enhancing the sludge solubility and hydrophobicity,so that free water increased significantly in an irreversible manner..

关 键 词：净水污泥 脱水性能 冻融 预脱水 

分 类 号：X703[环境科学与工程—环境工程]