城市生活垃圾焚烧厂渗滤液资源化利用技术及展望

Technologies and Prospect of Resource Utilization of Leachate in Municipal Solid Waste Incineration Plant

采用混凝/沉淀/过滤/吹脱联合工艺对城市生活垃圾焚烧厂渗滤液进行预处理。结果表明:当Fe Cl3投加量控制在0.1%、Ca O投加量控制在20 g/L时,对COD、TN、NH+4-N和TP的去除率分别达到6.0%、33.3%、32.0%和71.3%,重金属含量均满足《污水排入城镇下水道水质标准》(CJ 343—2010)的要求;之后将渗滤液在50℃下吹脱6 h,对TN和NH+4-N的去除率分别提高到83.9%和91.4%。当预处理后的渗滤液与城市生活污水按1∶200混合时,混合污水的COD/TN值和COD/TP值分别由2.4和27.7提高到3.7和46.4,表明预处理后的渗滤液具备了作为城市污水处理厂补充碳源的可能性。在此基础上,提出了垃圾焚烧厂渗滤液资源化利用的工艺路线,预计每年该厂可节约购置碳源费用为153万元左右。

The combined process of coagulation, sedimentation, filtration and air stripping was used for the pretreatment of leachate from municipal solid waste incineration （MSWI） plant. The results showed that when the dosages of FeCl3 and CaO were controlled at 0.1% and 20 g/L respectively, the removal rates of COD, TN, NH4 -N and TP were 6.0% , 33.3%, 32.0% and 71.3% respectively, and the heavy metal content could meet the requirements in the Wastewater Quality Standards for Discharge to Municipal Sewers （CJ 343 -2010）. The removal rates of TN and NH4 -N in the leachate increased to 83.9% and 91.4% respectively after air stripping for 6 h at 50 ℃. When the mixing ratio of the pretreated leachate to municipal sewage was 1 ： 200, the values of COD/TN and COD/TP of the mixed sewage increased from 2.4 and 27.7 to 3.7 and 46.4 respectively, which indicated the feasibility of using pretreated leachate as supplementary carbon source in urban sewage treatment plant. On this ba- sis, the process route of resource utilization of leachate in MSWI plant was put forward. It was estimated that the cost of purchasing the carbon source could be saved by about 1.53 million yuan annually.