| Since the 1970s, our country began to use the landfill disposal to dispose living waste. Gradually the method became the main disposal method of city living waste of our country and the amount of waste being disposed in this way is more than 70% of total. With the acceleration of urbanization process, landfill disposal face the problem of land waste and approaching residential area. The method now has increasingly environmental problems.This project will study on landfill site at Jiangdu District in Yangzhou City to classify and analyze old waste. According to the components and properties of waste and under the precondition of environment security, we will discuss the feasibility of recycling use and the method of recycling use to provide reference decision for old waste recycling and saving landfill land.According to the study:(1) Examine environmental safety around landfill site at Jiangdu District, including several indexes as following:exhaust gas, penetrating fluid, safe condition of surface water and underground water, etc. And the results show that although advanced method of safety landfill has been taken at the time the site was built, it still is a hidden danger now for surroundings and local residents, which is because some standards are out-of-date and the residential area is approaching landfill site.(2) CH4?NH3 can be collected as raw materials. The main source of Waste water is leachate. Leachate are rich in organic matter, total phosphorus and ammonia nitrogen. But Heavy metal content is too high. Although waste water reached the standards, surface water and groundwater is in the pollution state. It is necessary to check landfill facilities.(3) The gas can be collected as materials for methanol. Heavy metal content in leachate is too high and is hazardous to the environment. We can concentrate leachate as materials for the methane. The rest of the waste water will be piped to sewage treatment plant.(4) The construction waste in landfill accounts for 25% to 35%, which is 900-1000 tons approximately.The category of combustible rubbish are very abundant in the landfill, accounting for 40% to 50%, which is 1300-1600 tons approximately.(5) It is useful to filter domestic waste before sent to burn. On garbage sorting, construction waste can be the materials for road. The government shall transport combustible rubbish to Yangzhou. It can save energy, reduce harmful gas emissions and realize full recycling in this way.(6) Heavy metal content is on the high side.Chromium, zinc in landfills exceeds bid generally. Mercury, arsenic, cadmium, copper exceeds bid in part of landfill. Heavy metal content is different in different landfills.(7) The analysis on the feasibility of landfills utilization, includes the physical properties, chemical properties and biological properties. Basic nutrients meet the requirements. Microbial quantity and species is rich in landfills. Wheat germination test showed that seeds of grasses and legumes can germinate normally.(8) Since organic waste could provide large amount nutrients for plants and at the same time has some excessive heavy metal, we suggest combine its recycle with flowers and tree industry for it can be used as basic material in producing artificial soil (substrates) that will be used in urban greening and forestry nursery, etc. Thereby, under the precondition of environmental security, we can get some economic benefits while find the solution of old waste recycle. |
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