GROUNDWATER EVALUATION OF INFORMAL LANDFILLS BASED ON WATER QUALITY IDENTIFICATION INDEX METHOD

In order to accurately evaluate the difference between poor Class V water quality and similar water quality, the water quality identification index method was introduced to evaluate the groundwater quality of typical informal landfill. The results showed that the single factor water quality evaluation results of ammonia nitrogen, permanganate index and chloride index were from 66.362 to 255.3251, 13.89 to 40.036 and 15.111 to 21.417, respectively, due to the direct contact between shallow groundwater and domestic garbage leachate. The comprehensive evaluation results of groundwater quality at each monitoring point are 9.645~25.9521, all of which are inferior category V. The lowest values were found in the pre-2005 landfill area. Due to the effective barrier effect of the water barrier layer on the pollutants, the water quality of the micro-confined water is significantly better than that of the diving layer, and the comprehensive evaluation results of groundwater quality at each monitoring point are 3.100~3.700. From the spatial distribution characteristics, there are significant differences in the single factor water quality evaluation results of submersible or microconfined water in different landfills. There are significant differences in the comprehensive evaluation results of diving water quality in different landfill areas, but there is no significant difference in the comprehensive evaluation results of microconfined water. The research results can be used as reference for groundwater quality assessment and environmental management of landfill sites in China.