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With the rapid development of urbanization in China, the amount of municipal solid waste (MSW) is increasing. In the process of MSW compression and transshipment, some water in MSW is squeezed out, and together with ground flushing water, the landfill leachate of the Transshipment Station is formed. It is a kind of high concentration organic wastewater. If it is not treated properly or flows into the soil, rivers or other places, the harm to us can not be easily ignored. But now what are the landfill leachate treatment processes? What are the characteristics of landfill leachate treatment?

Sources and Characteristics of Landfill Leachate from Urban Waste Transfer Station

The leachate of municipal refuse transfer station is composed of leachate raw liquor produced in the process of garbage compression and ground flushing sewage in the operation area in the process of transportation. Its nature depends on the composition of garbage, collection and transportation time, compression mode, transfer station function and other factors. The following are the characteristics in water quantity, water quality and discharge standards.

I. Characteristics of Water Volume

The amount of leachate is determined by the type of garbage compression device, the degree of compression, the main components of garbage and the density of garbage. Generally, the amount of leachate is 5%-10% of the garbage quality.

II. Water quality characteristics

Landfill leachate contains 93 organic compounds, 22 of which are listed in EPA environmental priority control pollutants list in China and the United States. In addition, leachate contains more than 10 kinds of metals and ammonia nitrogen, and its composition is very complex. Typical water quality ranges from COD20000 to 60000mg/L, BOD58000 to 30000mg/L, NH3-N400 to 1800mg/L, SS2500 to 20000mg/L, and pH5 to 8. In addition to high concentration of COD, BOD5, NH3-N and S S, leachate also contains heavy metals, grease and sand. Leachate quality is also affected by seasonal factors, and the water quality fluctuates greatly. In summary, the leachate water quality shows the characteristics of complex composition, high pollutant concentration and large fluctuation.

III. Outflow characteristics

Based on the water quality characteristics, leachate should be discharged after treatment so as to avoid the damage to the surrounding environment.

Due to the special nature of landfill leachate, a single treatment method can not achieve the desired treatment effect, so the conventional leachate treatment process mostly adopts the combination of pretreatment + biological treatment + Advanced treatment, It is generally pretreatment + Anaerobic + membrane bioreactor + nanofiltration / reverse osmosis.