Landfill Leachate Without Membranes: An Ozone Oxidation Route Built on CDOF and CDFU
Landfill leachate is what forms when precipitation, moisture held in the waste itself, biological decomposition products and groundwater back-infiltration all meet inside a landfill and drain out as a dark, heavily loaded organic wastewater. It carries large amounts of organic matter, ammonia nitrogen, heavy metals, inorganic salts and a long list of toxic components. Research has identified 77 major organic pollutants and 17 heavy metal elements in this single stream — a fair measure of its diversity, and of the task facing any treatment train built for it.
Why the water quality never sits still
Leachate properties shift with landfill age, climate conditions, the regional environment and other factors, so the feed a plant sees this month will not match the feed it sees next season. Water quality fluctuates significantly, and that variability alone raises treatment difficulty before a single pollutant concentration is counted. Equipment sized for young, high-strength leachate can be swamped by old, refractory leachate — and vice versa — which is why unit operations that tolerate feed swings are worth their weight in design margin.
Why biology alone stalls
Conventional treatment falls into two camps: biological methods — 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.
The trouble is that leachate resists them. Biodegradability is poor, nutrient ratios are unbalanced, and the pollutant composition is complex and variable — all of which constrain microbial metabolic activity in biochemical treatment. The humic refractory components in particular are difficult for microorganisms to decompose, so the organic content of the effluent stays high. As national environmental requirements continue to rise and pollution control standards tighten, conventional biological processes can no longer ensure stable compliance. Improving existing technology and enhancing leachate biodegradability has become an urgent industry need.
The SINOKLE answer: ozone oxidation at the centre
SINOKLE has designed an efficient, low-cost, small-footprint and highly automated landfill leachate treatment process centred on advanced oxidation — ozone oxidation. The core equipment comprises the CDOF, the CDFU and a high-efficiency biological denitrification reactor. The CDOF (Cyclonic Dissolved Ozone Flotation) unit, a patented technology of SINOKLE, integrates ozone multi-catalytic oxidation, hydraulic cavitation and cyclonic flotation into one device — an original Chinese development with internationally leading performance that removes petroleum, suspended solids, colloids, COD, bacteria and many other pollutants from wastewater efficiently and rapidly.
How the train runs
The CDOF unit itself 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. Around it, the flow proceeds in stages:
- Leachate first passes through anaerobic oxidation, converting macromolecules into small molecules.
- The A/O process then greatly reduces ammonia nitrogen and total nitrogen, and the MBR tank separates sludge and water, providing adequate conditions for the physical-chemical treatment that follows.
- MBR effluent enters the CDFU, where ozone serves as the gas source to remove part of the COD and ammonia nitrogen, while the unique cyclonic dissolved-air design strips suspended solids from the water and improves water quality.
- Next, the CDOF combines cyclonic dissolved-air with ozone catalytic oxidation, oxidising and decomposing refractory organics into small molecules and improving the biodegradability of the wastewater.
- Finally, the biological denitrification reactor finishes the job: 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.
What the design buys the operator
- A full-quantification, membrane-free process that produces no concentrate and no secondary pollution.
- Integrated skid-mounted equipment in which the CDFU and 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.
- Core treatment equipment with low energy consumption, fast reaction, stable performance, high efficiency and a small footprint.
- A catalyst built on atomic deposition modification technology — super-hydrophilic and resistant to fouling and scaling.
- Fully automated, information-based operation with remote monitoring, low labour requirements and convenient, low-cost maintenance.
Proven on real projects
Membrane polishing is the usual escape route when biology falls short, but it trades one problem for another: every litre pushed through the membrane leaves a concentrate behind that still carries the pollutants — often at higher concentrations — and still needs a disposal route. The SINOKLE design sidesteps that loop entirely. This route gives landfill leachate an efficient and reliable technical alternative to membrane-based trains, and it has already been applied successfully across multiple projects. For sites battling tightening standards and unpredictable feed quality, a process that oxidises what biology cannot digest — without producing a concentrate stream that still needs a home — is a practical answer rather than a laboratory promise.