Landfill leachate is a black or yellowish-brown liquid with a foul odor. Leachate contains a large amount of organic and inorganic substances, including various hard-to-degrade organic substances, inorganic salts, and metal ions.
Due to the complex composition of waste, one of the characteristics of waste leachate water is the high content of pollutants, and often contains biological toxicity, where the highest mass concentration of COD can be more than 20,000mg/L, including benzene and its various derivatives, and the mass concentration of ammonia nitrogen can be up to 2,000mg/L.
This wastewater containing toxic organic matter and high ammonia nitrogen poses great difficulties for its treatment, especially biological treatment. In addition to toxic aromatic compounds, leachate also contains a large amount of humic substances and humic acids and other large-molecule organic matter, which are not biotoxic but have good chemical stability due to their large molecular weight and cannot be effectively degraded by microorganisms.
Therefore, the effective removal of COD from leachate cannot be achieved by using only activated sludge method, but the depth treatment process must be added. Another characteristic of waste leachate is that its water quality varies greatly, and geography has a great influence on the water quality of leachate. This may be related to the different cultures and living habits in different regions, and the quality of leachate produced at different times in the same location varies greatly as well.
The treatment process of waste leachate currently consists of the followings：
- Combined treatment with municipal wastewater;
- Physical treatment;
- Land treatment;
- Evaporation treatment.
The centrifuge is currently involved in the sludge dewatering section of the biological treatment method, which mainly treats sludge from secondary sedimentation tanks or sludge thickening tanks. The water content of the raw sludge is about 97% and the water content of the treated sludge cake is reduced to about 80% (depending on the material).
In a landfill leachate project in Taizhou, the ZK decanter played an important role in the sludge dewatering section. ZK developed the LW450X1845D centrifuge specifically for landfill leachate, with stable separation performance, continuous separation and long service life. Wear-resistant and corrosion-resistant protection is adopted at vulnerable locations; the equipment can start and stop with one key; spiral unloader BD plate technology is adopted as well. Also by increasing the extrusion plate between the spiral blades, it reduces the water content of the sludge, and also effectively improves the depth of the liquid layer, increases the effective settling area, and improves the processing capacity of the centrifuge. It helps customers to reduce the water content of sludge, which is convenient to be transported out to landfill or compost; the supernatant also achieves the standard discharge.
- Model: LW450X1845D
- Main motor: 30kw
- Sub-motor: 7.5kw
- Capacity: ≥15m³/h (depending on the solid rate of the material)
- Weight: 4500kg