Solving the Landfill Leachate Treatment Challenge with Zero Concentrated-Liquid Discharge — CDOF Technology and Applications
Landfill leachate is known for its complex quality, extremely high pollutant concentration, high ammonia-nitrogen content and unbalanced C/N ratio. Hailed as the "king of high-concentration wastewater", it has long been one of the most technically difficult and environmentally risky links in China's solid-waste treatment. For a long time, the dual-membrane process represented by "MBR + NF/RO (membrane bioreactor + nanofiltration / reverse osmosis)", with its excellent rejection performance, became the industry mainstream and could quickly bring effluent to strict discharge standards.
Yet behind the seemingly clear effluent hides an increasingly severe chronic industry disease — the disposal dilemma of membrane concentrated liquid (hazardous waste). This has become the "Achilles' heel" constraining the sustainable development of the industry.
1. The essential dilemma of the traditional membrane method: pollution transfer and cost trap
The core of the traditional membrane process is "physical screening" rather than "thorough degradation". While producing about 70%–80% of clear liquid, it concentrates most of the inorganic salts, heavy metals and refractory organics of the leachate into the remaining 20%–30% of concentrated liquid. This concentrate often has a COD above 5000 mg/L, deep color and high toxicity — the very "essence of pollution".
The past common practices of "reflooding the landfill" or "reflowing to the equalization tank" are in fact "drinking poison to quench thirst":
System toxicity accumulation: long-term reflooding causes salts and refractory pollutants to circulate and enrich in the system, severely inhibiting or even poisoning the microbial activity of the front-end biochemical unit, causing the whole treatment system's efficiency to plummet or even collapse.
Membrane life plummeting and high O&M: high-salt, high-hardness concentrate accelerates membrane scaling and fouling, forcing frequent chemical cleaning, sharply shortening membrane life, with replacement cost becoming a heavy burden.
Tightening policy red line: as environmental regulations tighten (e.g., the landfill pollution control standard and its revision trends), concentrated-liquid reflooding has been explicitly restricted or prohibited. Turning to evaporation-crystallization and other end-of-pipe treatments brings new problems: extremely high energy consumption, equipment corrosion and scaling, and crystalline mixed salt that is difficult and costly to dispose of as hazardous waste.
Thus the traditional membrane process falls into a vicious cycle of "pollution transfer — system deterioration — cost escalation — secondary pollution". The industry urgently needs a disruptive technological innovation to achieve true "demembranization" and "total-quantity" treatment.
2. The breakthrough: SINOKLE CDOF's "total-quantity, membrane-free, zero-concentrate" process
Facing the concentrated-liquid dilemma, SINOKLE has taken a different path, abandoning the idea of relying on membrane separation and launching a patented process system centered on CDOF (Cyclonic Dissolved Ozone Flotation integrated unit), truly realizing the total-quantity treatment of landfill leachate and the thorough degradation of pollutants.
(1) Core mechanism: from "separation" to "mineralization". SINOKLE's CDOF technology creatively fuses ozone advanced oxidation with cyclonic dissolved air flotation.
Multi-catalytic oxidation: the unit uses a proprietary heterogeneous catalyst to efficiently catalyze ozone decomposition into hydroxyl radicals (·OH) with a redox potential as high as 2.8 V. This strong oxidant can indiscriminately attack and break the large refractory organic molecules in leachate (such as humic acid and fulvic acid), ultimately mineralizing them into carbon dioxide and water, eliminating pollutants at the molecular level.
Cyclonic flotation synergy: during deep oxidation, the system uses the synergy of a cyclonic field and micro-nano bubbles (5–30 μm) to simultaneously complete decolorization, deodorization, sterilization and efficient suspended-solids separation; the total reaction retention time can be shortened to within 15 minutes.
(2) Addressing the pain points: four disruptive advantages. Compared with the traditional membrane method, CDOF shows comprehensive leadership — thorough degradation and mineralization rather than mere interception; a membrane-free process that produces no concentrated liquid; a short retention time of under 15 minutes; and simultaneous decolorization, deodorization and sterilization. This fundamentally resolves the "concentrated-liquid" chronic disease.
Conclusion
The treatment of landfill leachate should not be an ineffective game of "relocating pollutants elsewhere", but a tough battle in pursuit of thorough "purification annihilation". While the traditional membrane process is stuck deep in the concentrated-liquid mire, SINOKLE's CDOF total-quantity membrane-free treatment process, with its mature and reliable techno-economics, points the industry to a green, economical and sustainable breakthrough. Farewell to the concentrated-liquid troubles and achieving the dual optimization of environmental benefit and operating cost — a clear solution now exists.
