Study On Pollution Distribution And Leachate Adsorption Characteristics Of A Non-standard Landfill In Northern Area

With the rapid development of China’s economy and the continuous improvement of people’s living standards,the production of municpal waste is increasing.However,due to the relatively underdeveloped treatment technology,some of the waste can not be effectively and properly disposed,and the informal landfills were formed.These wastes were piled up and filled randomly with the natural landform.They hadn’t any engineering measures such as seepage prevention,leathate drainage and landfill gas discharge system,it is urgent to deal with them effectively.This paper takes an informal landfill in northern China as the research object,investigates the distribution of main pollutants in the garbage dump,analyzes the micro environmental characteristics of landfill leachate,soil and microbial community during the stabilization treatment of the dump,reveals the adsorption and migration mechanism of pollutants,analyzes the microbial community structure,and selects the dominant degradation bacteria of the characteristic pollutants,The results provide the basics for the directional regulation of microbial community structure function,and provide theoretical support for the in-situ treatment and restoration technology of informal landfill in arid areas of the northern China.The main conclusions are as follows:(1)The overall moisture content of the refuse heap is low,and the organic matter and moisture content in the middle of the heap are relatively high,and the p H increases with the increase of landfill depth.The content of Cu,Zn,Hg and Ni increased vertically in the garbage dump,while the content of Ni in some of the soil in the lower part of the heap was higher than the background point,while Hg content was generally higher than the background point.Compared with the standard for risk control of soil pollution in agricultural land,the content of heavy metals in the soil at the bottom of garbage dump is far lower than the limiting values.(2)The content of dissolved organic matter in garbage samples increases with the increase of landfill depth,and the pollution component is mainly humic acid.The soil at the bottom of garbage is greatly affected by humic acid.The correlation analysis showed that tyrosine like substances were positively correlated with as,while microbial metabolites were negatively correlated with Cr,Hg,Ni and Zn.(3)The species and quantity of microbial communities in the garbage dump were higher than that of soil samples,and the soil at the bottom of the garbage dump was similar to that of the microbial community in the heap.Proteobacteria,Firmicutes and Bacteroidetes were the dominant bacteria in the samples.Five dominant species were closely related to aromatic protein like substances,and three dominant species were closely related to microbial metabolites.(4)The adsorption of humic acid in the waste leaching solution on kaolin was in accordance with Freundlich model.The temperature was positively correlated with the adsorption capacity of humic acid,while p H was negatively correlated with the adsorption amount.When the concentration of humic acid in the solution to be adsorbed is 10mg/L,the adsorption effect is the best.