Landfill leachate is a kind of high-concentration organic wastewater, its composition is complex, and its water quality and quantity vary greatly.
The sources of landfill leachate mainly include direct precipitation, surface runoff, surface irrigation, groundwater, the water content of the garbage itself, the moisture in the covering material, and the water generated by the biochemical reaction of the garbage.
The main factors affecting the composition of landfill leachate are: garbage composition, site climatic conditions, site hydrogeological rainfall conditions, landfill conditions, and landfill time. This determines that the water quality and quantity of landfill leachate vary greatly, and the change law is complicated. The contents of CODcr, BOD5, and ammonia nitrogen are relatively high. As the landfill time increases, the organic nitrogen in the refuse is converted to inorganic nitrogen, and the ammonia nitrogen concentration increases. Due to the dissolution of CO2 generated by the degradation of garbage, the landfill leachate is slightly acidic. This acidic environment has exacerbated the dissolution of insoluble carbonates, metals and metal oxides in the garbage. Concentration of metal ions.