In the process of stacking and landfill, due to biochemical degradation such as compaction and fermentation, and the seepage of precipitation, a kind of high concentration organic wastewater is produced, which is called leachate. The water quality of landfill leachate is complex and contains a variety of toxic and harmful inorganic and organic substances. Among them, there are 99 Kinds of organic pollutants through technical detection, and 22 kinds have been included in the key control list of China and the national environmental protection agency of the United States. One can directly cause cancer and five can induce cancer. In addition, the leachate also contains non chlorinated aromatic compounds such as naphthalene and phenanthrene, chlorinated aromatic compounds, phosphate esters, phenolic compounds and aniline compounds that are difficult to biodegrade. The highest concentration of CODcr and BOD5 in landfill leachate can reach thousands to tens of thousands. Compared with urban sewage, the concentration is dozens to hundreds of times. Therefore, leachate cannot be directly discharged into urban sewage treatment pipeline without strict treatment and disposal. If the landfill leachate is not properly treated in the treatment of domestic garbage, it is equivalent to that the garbage is not treated.

The two-stage disc and tube reverse osmosis process is based on the process application of disc and tube reverse osmosis membrane (DTRO). Its core technology is the unique structure of disc and tube reverse osmosis membrane, which makes it possible to directly treat landfill leachate by reverse osmosis membrane. It is a technology of treating landfill leachate by physical membrane method.

Conclusion:

In terms of engineering application, the two processes have their own advantages and disadvantages. To some extent, the two-stage DTRO process is more applicable to the treatment of landfill leachate. However, because its process is a physical process, on the premise that the clean water meets the discharge standard, the pollutants are only separated and concentrated, and the concentrated solution is still returned to the landfill for reinjection, The microorganism in the garbage heap is used for degradation, and its process unit does not realize the digestion of pollutants, so it is criticized by experts in the industry.

The combined process of lined MBR membrane and coiled NF and RO membrane realizes the partial degradation and digestion of pollutants in the activated sludge section, and secondary pollutants of sludge are generated along with the degradation process. Even so, the degradation is not completely realized, and the non biodegradable part still needs to be guaranteed by the subsequent membrane separation process. The microorganisms in the activated sludge carrier are vulnerable to temperature, pH value Salinity, oxygen content and the ratio of carbon, nitrogen and phosphorus affect the activity, which is difficult to control. Therefore, the whole process technology route is long, the operation is complex, the quality of operators is high, and the stability of project operation is poor.

Later:

In general, the two-stage DTRO technology and the combined process technology of MBR membrane with lining and coiled membrane have been successfully applied in China. In short, the former is essentially an electromechanical equipment, with a high degree of program control, short project construction cycle, flexible and simple operation, so as to achieve the purpose of harmless treatment of environmental protection projects. The latter realizes the partial reduction and digestion of pollutants, and realizes the purpose of harmless and reduction of environmental protection engineering. According to local conditions, climate and water quality conditions, financial revenue, project operation mode and technical personnel level, reasonable selection of landfill leachate treatment engineering technology is the premise to ensure the effectiveness of the project.

As the domestic waste leachate is a kind of sewage with high pollution, high concentration and complex components, its treatment is very difficult, which is a worldwide treatment technical problem. So far, the large-scale engineering application of completely reaching zero discharge can not be realized. As long as there are human activities, domestic waste will be produced every day, and due to the improvement of population and living standards, its output will be greater, which has caused serious harm to the environment. Therefore, at present, under the premise of no perfect treatment technology, it is still necessary to carry out engineering treatment to reduce the degree of harm. The greatest hazard of garbage is landfill leachate. Once it is allowed to enter surface water or groundwater, the consequences will be unimaginable and it will be more difficult to deal with.