冻融预处理填埋污泥的室内真空脱水试验  

Experimental study on vacuum dehydration of sludge in landfill by freeze-thaw pretreatment

作　　者：武亚军[1] 何心妍 张旭东 张云达 嵇佳伟 WU Yajun;HE Xinyan;ZHANG Xudong;ZHANG Yunda;JI Jiawei(Department of Civil Engineering,Shanghai University,Shanghai 200444,China;Shanghai Geological Construction Co.,Ltd.,Shanghai 200072,China)

机构地区：[1]上海大学土木工程系,上海200444 [2]上海市地矿建设有限责任公司,上海200072

出　　处：《哈尔滨工业大学学报》2021年第11期154-161,共8页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(41772303);上海市自然科学基金(17ZR1410100);上海市扬帆人才计划(19YF1415500)。

摘　　要：为了对填埋污泥进行进一步原位减量处理,研究冻融联合真空预压工艺的减量效果。从上海某填埋场取样,首先设定0、-6、-11、-14.5和-18.5℃5种不同冷冻温度对污泥进行冻融处理,分析冷冻温度对污泥的比阻和界限含水率的影响;然后进行冻融联合真空预压小型模型试验,通过与单纯真空预压试验进行对比,研究不同工况下排水量、排水速度、沉降量、减容比、含水率和无侧限抗压强度的变化规律。结果表明:冻融处理可以有效降低污泥比阻,从而改善其脱水性能,并在-11℃时达到最优处理效果;经冻融预处理的污泥在真空预压试验过程中表现出很好的排水固结效果,最优处理温度与污泥比阻试验结果一致,处理后污泥含水率最低可降至54.0%,无侧限抗压强度最高可达42.84 kPa,最大减容比为40%,达到了填埋污泥减量的目的。For the in situ reduction of landfill sludge,the reduction effect of freeze-thaw process combined with vacuum preloading was studied.Samples were taken from a landfill in Shanghai.First,five freezing temperatures(0,-6,-11,-14.5,and-18.5℃)were set during the freeze-thaw treatment of sludge to analyze the effects of freezing temperature on specific resistance of sludge and critical water content.Then,a model test was conducted to investigate the variation of displacement,dewatering rate,settlement,volume reduction ratio,water content,and unconfined compressive strength under different working conditions by comparing single vacuum preloading with freeze-thaw treatment combined with vacuum preloading.Results show that the freeze-thaw treatment could effectively reduce the specific resistance of sludge and improve its dehydration performance,and the optimum freezing temperature was-11℃.The sludge after freeze-thaw treatment showed a good drainage consolidation effect in the process of vacuum preloading,and the optimum treatment temperature was consistent with the results of sludge specific resistance test.The minimum water content of the treated sludge reached 54.0%,the unconfined compressive strength was up to 42.84 kPa,and the maximum reduction ratio was 40%,which achieved the purpose of sludge reduction.

关 键 词：冻融法 真空预压法 填埋污泥 比阻 含水率 

分 类 号：X703[环境科学与工程—环境工程]