Chongqing Landfill Groundwater Pollution Investigation And Evaluation

With the rapid development of social economy and continuous improvement of living standards, the domestic waste output has increased year by year. Landfill is a main method of current domestic waste disposal in our country. It generates a lot of leachate during the operation and closure of landfill. The destruction of impermeable layer and poor collecting system could lead to the pollution of groundwater by the leachate, and thereby threatening the safety of ecological environment and human health. The pollution survey and quality evaluation of landfill groundwater would be necessary.At present, there are 31 landfill in Chongqing city, the total volume of domestic waste disposed in landfills in 2011 amounted to 4.03 ×106t, which would take on a growth trend. The vast leachate produced poses a great threat to groundwater resource. According to the groundwater sampling and detection analysis of municipal landfill in Chongqing, the statistical analysis of groundwater pollution index was proposed by using the single factor evaluation method. The groundwater quality of municipal landfill site in Chongqing was evaluated through the fuzzy evaluation based on step analysis. The main contents include the following:1)The groundwater pollution investigation municipal landfill in Chongqing was carried out with "The Quality Standard of Underground Water" as evaluation criteria, using the method of single factor evaluation. The results showed that the main exceeding pollution indicators were nitrite, ammonia nitrogen, and permanganate. The excessive degree of sulfate, chloride and nitrate were all less than 1, and hardly changed over time. Some indicators changed greatly over time, such as nitrite, ammonia nitrogen and potassium permanganate, which exceed the standard seriously. The maximum excessive degree of ammonia exceeded 3655 times.2)The groundwater quality of 31 landfill in Chongqing City were analyzed through hierarchical clustering analysis and principal component analysis, the study area was divided into 4 different types. The fuzzy evaluation based on step analysis was used to evaluate the water quality of four representative landfill. The result showed the whole landfill groundwater water quality in Chongqing was good.3)According to the pollution survey and evaluation result, some prevention and control suggestions to landfill leachate-polluted groundwater in Chongqing were put forward. It was suggested that we should start with engineering and management measures and control the groundwater pollution caused by municipal landfill, in order to improve the groundwater quality.