【摘要】 为考察混凝-软化工艺对南方某市垃圾渗滤液膜浓缩液的预处理效能，利用小试试验对市场上常用混凝剂（PAC、PAFC、FeCl₃）、助凝剂（PAM）和软化组合药剂（Ca（OH）₂+Na₂CO₃、NaOH+Na₂CO₃）进行比选，并在优化药剂投加量和初始pH值基础上，对预处理工艺的污染物(以COD、Ca²⁺、Mg²⁺为主)去除效能和药剂成本进行分析，确定组合工艺的最佳契合点，同时，对预处理工艺的有机物去除机制进行了分析。试验结果表明，FeCl₃为较适宜的混凝剂，混凝段较优的参数为：混凝剂FeCl₃投加量为2.5 g/L，助凝剂PAM投加量为60 mg/L，初始pH值为7.5（不调节），此时出水COD质量浓度和色度分别为880 mg/L和300 PCU；软化段较优的组合及参数为：烧碱-纯碱法（NaOH+Na₂CO₃），其中NaOH和Na₂CO₃投加量分别为0.3和0.5 g/L时，此时出水总硬度为92.1 mg/L。除污机理分析表明，混凝-软化工艺对DOM中的腐殖酸类物质去除效果最明显，同时能够去除大分子酯类、胺类有机物和芳香族挥发性有机物。更多还原

【Abstract】 To investigate the pretreatment efficiency of coagulation-softening process on leachate membrane concentrate from a southern city′s landfill,a pilot-scale study was conducted to compare commonly used coagulants（PAC,PAFC,FeCl₃）,flocculants（PAM）,and softening agents（Ca（OH）₂+Na₂CO₃,NaOH+Na₂CO₃）.By optimizing the dosage of chemicals and the initial pH value,the removal efficiency of pollutants(primarily COD,Ca²⁺,Mg²⁺) and the cost of chemicals in the pretreatment process were analyzed.The optimal matching point of the combined process was determined,and an analysis on the organic matters removal mechanism in the pretreatment process was also carried out.The test results indicated that FeCl₃was a suitable coagulant,the optimal parameters for the coagulation stage were FeCl₃dosage of 2.5 g/L,PAM dosage of 60 mg/L,and initial pH value of 7.5（unadjusted）,resulting in effluent COD mass concentration of 880 mg/L and chroma of 300 PCU.For the softening stage,the optimal combination and parameters were as follows:adopting caustic soda-soda ash method （NaOH+Na₂CO₃）,the dosage of NaOH and Na₂CO₃were 0.3 and 0.5 g/L respectively,resulting in a total hardness of 92.1mg/L in the effluent water.The analysis on the pollutants removal mechanism showed that,the coagulation-softening process was most effective in removing humic acid substances from dissolved organic matters,as well as large molecular esters,amine compounds,and aromatic volatile organic compounds.更多还原