A New Solution for Landfill Leachate: Ozone Catalytic Oxidation Achieves Efficient Purification
Landfill leachate is a complex organic wastewater formed from multiple sources — precipitation, moisture within the waste, biological decomposition products and groundwater back-infiltration — with a dark appearance. It contains large amounts of organic matter, ammonia nitrogen, heavy metals, inorganic salts and many toxic components. Research has identified 77 major organic pollutants and 17 heavy metal elements in such wastewater, fully demonstrating the diversity of its pollutants. Meanwhile, leachate properties are affected by a combination of landfill age, climate conditions, regional environment and other factors; water quality fluctuates significantly, increasing treatment difficulty.
Conventional treatment technologies fall mainly into biological methods (including stabilization ponds, biological filters and activated sludge processes) and physical-chemical methods (covering adsorption, flotation, chemical precipitation, coagulation, ion exchange, membrane separation and advanced oxidation). Biological processes targeting nitrogen and phosphorus removal (such as the A/O-MBR combination) currently dominate leachate treatment. However, leachate has poor biodegradability, unbalanced nutrient ratios and complex, variable pollutant composition, which severely constrain microbial metabolic activity in biochemical treatment. In particular, the humic refractory components in leachate are difficult for microorganisms to decompose, so the organic content of the effluent remains high. As national environmental requirements continue to rise and pollution control standards tighten, conventional biological processes can no longer ensure stable compliance, so improving existing technology and enhancing leachate biodegradability has become an urgent industry need.
SINOKLE has designed an efficient, low-cost, small-footprint and highly automated landfill leachate treatment process centered on advanced oxidation — ozone oxidation. The process takes the CDOF, CDFU and a high-efficiency biological denitrification reactor as its core equipment; the process flow diagram is as follows. The CDOF (Cyclonic Dissolved Ozone Flotation) unit — a patented technology of SINOKLE integrating ozone multi-catalytic oxidation, hydraulic cavitation and cyclonic flotation — is an original Chinese development with internationally leading performance: an integrated high-efficiency oxidation and flotation device that can efficiently and rapidly remove petroleum, suspended solids, colloids, COD, bacteria and many other pollutants from wastewater.
Application case
The unit consists of an oxygen production system, an ozone generation system, a high-efficiency ozone injection system, a multi-catalytic reaction tank system and a cyclonic dissolved-air flotation system. The leachate first converts macromolecules into small molecules through anaerobic oxidation, then greatly reduces ammonia nitrogen and total nitrogen through the A/O process, and the MBR tank separates sludge and water, providing adequate conditions for subsequent physical-chemical treatment.
MBR effluent enters the CDFU, where ozone serves as the gas source to remove part of the COD and ammonia nitrogen, while its unique cyclonic dissolved-air design removes suspended solids from the water and improves water quality.CDFUThe effluent then enters the CDOF, which integrates cyclonic dissolved-air with ozone catalytic oxidation, oxidizing and decomposing refractory organics into small molecules and improving the biodegradability of the wastewater. The effluent from the CDOF unit then goes to the biological denitrification reactor, where microorganisms loaded on high-specific-surface-area bio-carriers degrade the pollutants efficiently, and the remaining contaminants in the water are removed quickly and effectively so that the effluent meets discharge standards.
Landfill leachate treatment process flow diagram
Compared with conventional processes, SINOKLE's patented unit offers the following notable advantages in landfill leachate treatment:
A full-quantification, membrane-free process that produces no concentrate and no secondary pollution.
The integrated skid-mounted equipment, in which the CDFU\CDOF operate fully enclosed and pressurized throughout, keeping the site environment friendly.
Low chemical dosage, minimal sludge (hazardous waste) generation and simple operation and management.
The core treatment equipment features low energy consumption, fast reaction, stable performance, high efficiency and a small footprint.
The catalyst adopts atomic deposition modification technology; it is super-hydrophilic and resistant to fouling and scaling.
Fully automated, information-based operation with remote monitoring, low labor requirements and convenient, low-cost maintenance.
This innovative solution provides an efficient and reliable technical route for landfill leachate treatment and has been successfully applied in multiple projects.
