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一、Features of landfill leachate
Refuse leachate is sewage leached out due to fermentation, rain washing and surface water and groundwater soaking in the process of garbage stacking and landfilling. There are four main sources: garbage itself, water produced by garbage biochemical reactions, groundwater reverse osmosis, and atmospheric precipitation. Atmospheric precipitation is concentrated, short-term and repeatable, and accounts for most of the total leachate. Leachate is a kind of high-concentration organic wastewater with complex composition. Generally speaking, it has the following characteristics:
2. New type of landfill leachate treatment process-anaerobic + aerobic + two-stage DTRO technology
1. Process content A new type of landfill leachate treatment process-anaerobic + aerobic + two-stage DTRO technology process is as follows:
1) As the water quality and quantity of landfill leachate varies greatly, the leachate enters the regulating tank after removing large suspended matter through the grid, and the regulating tank is used to store the leachate to adjust the water quality and water volume of the leachate treatment plant.
2) After the water quality and quantity are adjusted by the regulating tank, the leachate will evenly enter the water distributor at the bottom of UBF (upflow sludge bed filter) for anaerobic treatment. The UBF reactor is mainly composed of water distributor, sludge layer and filler layer. . The suitable environment in the reactor is: temperature 25-30 degrees Celsius, pH 6.5-7.8, volumetric load 5-15kg/COD (m3.d), etc. In the process of anaerobic microorganism decomposition of organic matter in UBF reactor, a large amount of methane, carbon dioxide and other gases can be produced, of which methane accounts for 75%-85%, which can be recycled. A gas hood is installed on the upper part of UBF reactor to collect the produced methane. gas.
1. The water quality is complex and harmful: it not only contains a large number of organic substances, but also contains a large number of dissolved solids, such as sodium, calcium, chloride, sulfate, etc.;
2. The concentration of COD and BOD is high, and the content of ammonia nitrogen is high, and they increase with the extension of the landfill time;
3. Water quality changes greatly; landfill leachate changes greatly with factors such as landfill time and rainfall;
4. High metal content: The landfill leachate contains more than ten kinds of metal ions, and changes with the landfill time of the landfill. Among them, iron and zinc are higher in the acid fermentation stage;
5. The ratio of microbial nutrient elements in the leachate is imbalanced: mainly the imbalance of C, N, and P.
Analyzing and summarizing the water quality characteristics of landfill leachate, the main difficulties in the treatment of landfill leachate are the high concentration of ammonia nitrogen and poor biodegradability.
.三、 Prospects and conclusions
The new type of landfill leachate treatment process-anaerobic + aerobic + two-stage DTRO technology is a technical improvement on the basis of the current application of more two-stage DTRO to treat landfill leachate. It retains the advantages of the two-stage DTRO technology and is quick to start. , Strong adaptability, stable operation and other advantages. At the same time, it makes up for the shortcomings of the two-stage DTRO treatment of landfill leachate. It can not only remove organic matter, suspended matter and other pollutants in the landfill leachate, but also effectively remove ammonia nitrogen and total nitrogen. , To ensure that the effluent meets the discharge standards, and is suitable for the advanced treatment of landfill leachate, but at the same time, the technology should be continuously improved in actual engineering applications to meet the actual needs of the project
