Landfill leachate is a highly concentrated, highly polluted organic wastewater left behind during the waste decomposition process. It is called organic wastewater because it contains a large amount of organic matter, ammonia nitrogen, heavy metal ions, and suspended solids, in addition to a multitude of pathogenic bacteria. Due to the organic nature of landfill leachate, improper treatment can seriously pollute the surface environment and water resources. Therefore, to protect the natural ecological environment, great importance must be attached to the treatment of landfill leachate. Currently, the main treatment technologies for landfill leachate include the following four methods.

1.Effective Microorganisms (EM) Technology:

EM technology was initially applied in agriculture and animal husbandry, and in recent years has begun to be applied in the environmental protection field. This technology is simple to operate. In research on treating landfill leachate using effective microorganism technology, relevant experts found that the EM microbial solution is significantly effective in treating highly toxic, concentrated landfill leachate and shows remarkable results in treating leachate that is difficult to biodegrade, providing new technologies and methods for landfill leachate treatment.

2.AMT System Treatment Technology:

AMT is a new type of wastewater treatment system that uses physico-chemical treatment methods. This method involves introducing negative oxygen ions (O⁻) into the water to react with it and ultimately produce highly oxidative hydroxyl radicals (OH·). Simultaneously, it utilizes the energy of ultrasonic waves and electromagnetic fields to alter the structure of water molecules and pollutant molecules, generating reactive free radicals that react with hydroxyl radicals, thereby oxidizing pollutants in the water to CO₂ and H₂O. Xu Fanfan et al. used the AMT system to treat landfill leachate, conducting bench-scale and pilot-scale tests to study its removal efficiency of organic pollutants and degradation patterns.

3.Land Treatment Method:

Land treatment methods for leachate mainly include leachate recirculation (backfilling) and soil-plant treatment. The recirculation method treats the landfill as a huge biofilter with waste as the filter material. This method involves recirculating collected leachate back to the landfill area, using the stable system formed by the landfill itself to filter the leachate through the cover soil layer and the waste layer, where it undergoes a series of biological, chemical, and physical processes to be degraded and retained, while also reducing the leachate volume through evaporation. The recirculation method offers advantages such as low investment, simple management, good effectiveness, ability to curb the spread of heavy metal pollution points, and acceleration of landfill stabilization. There are many methods of circulatory leachate recirculation treatment, mainly including: directly spraying or irrigating leachate onto the waste surface during the landfilling period, and subsurface recirculation or inner layer recirculation.

4.Membrane Bioreactor (MBR) Method:

The Membrane Bioreactor (MBR) method is a new, highly efficient biological treatment technology that combines membrane filtration and biological treatment, which has emerged in recent years. It has broad application prospects in treating high-concentration, refractory organic wastewater and can also be combined with reverse osmosis to treat leachate. This method features a high degree of automation, low technical risk, low process investment, ability to effectively reduce the total amount of pollutants, and convenient management, making it favored by the market.