Yongjiang Basin Simple Rural Living Garbage Landfill Pollution Status And Its Control Techniques

Waste dumping site is the specific phenomenon which developing country has at certain stage, and was widely distributed in the Yongjiang River basin in the past 30 years. This kind of waste dumping site which was not built according to the construction and lack of management, has caused certain pollution to the environment. This research insvestigated the locations, utilization and pollution conditions of these waste dumping sites and attempted to explore the rehabilitation technology through the laboratory test research. The results were as follows:(1) Through insvestigating 10 waste dumping site, we got that the kind of waste dumping site may divide into four types:the plain, the mountainous region, the piedmont and the coastal area.Some of these waste dumping sites were mixed with the industrial refuse, so that leachate pollutant density from those waste dumping sites could not reach the emission standard though pollutant density were not very high. The leachate from the waste dumping site has created pollutions to the environment.(2) Take Laozishan waste dumping site at Ningpo Yinzhou District Gaoqiao Town as the example, its nearby paddy soil heavy metal density is excessively high, the Cd content surpasses the national secondary standard, and the pollution is serious. Around the waste dumping site there was paddy rice. The heavy metal in the plant had a tendency to move to the grain as it grew. After harvestation, some of the paddy rice grain Cr and the Pb content surpasses the standard of pollutant limit in food.(GB 2762-2005).(3) Two lab-scale constructed wetland systems using sands as their substrates, with plants Acorus calamus were used to investigate CODCr, nitrogen and heavy metal removal efficiency of the leachate from waste dumping site. The findings indicated that he mean removal efficiency of CODCr, NH3-N were 40.8%,57.7% when influent CODCr, NH3-N were 250 mg/L,180mg/L, and 48.3%,72.3% when influent CODCr, NH3-N were 150mg/L,140mg/L. Both the CODCr concentration of the effluent met the emission standard (GB8978-1996). At different influent nitrogen concentrations, little differences were found in matrix residual nitrogen content. At different influent nitrogen concentrations, along the flow direction there were significant differences in the biomass and nitrogen accumulation in different regions, which could be important in guiding the rational allocation of plants. The removal efficiency of heavy metals Cu, Zn, Pb and Cd of constructed wetlands were good, especially for Cd and Pb, above 98%. The constructed wetland have certain application prospect to the leachate from the dumping sites.