Landfill Leachate Treatment Without Membrane Concentrate: A Different Route

The stream that keeps landfill operators awake

Landfill leachate is what happens when rainfall, waste moisture and decomposition products mix inside a landfill body. The result is a stream with high salinity, high COD, a complex pollutant profile and poor degradability — all four at once. Press liquor from incineration plants is close behind it. Treating either with a membrane train produces clean permeate and a concentrate that must then be managed separately, which is why operators increasingly look for a route that destroys pollutants instead of concentrating them.

The SINOKLE answer is an integrated treatment system built around homogeneous and heterogeneous multi-catalytic oxidation, combining CDFU cyclonic dissolved-air flotation, CDOF ozone advanced oxidation flotation and ozone micro-nano bubble generation. The design objective was explicit: break the technical ceiling of conventional membrane treatment and deliver high efficiency without the operating cost spiral.

Two catalyst families working on the same stream

The system's oxidation performance comes from running homogeneous and heterogeneous catalysis together. The homogeneous catalyst generates hydroxyl radicals quickly and efficiently. The heterogeneous catalyst combines a range of active metal oxides with high-porosity micro-pore forming technology, so reactive species are produced at a solid surface as well as in solution. Acting in concert, they generate hydroxyl radicals, superoxide radicals and other highly active species at a rate no single catalyst reaches.

Ozone micro-nano bubble generation then lifts gas-liquid mass transfer efficiency and ozone utilisation, so oxidation performance runs several times better than conventional methods. That is what makes refractory macromolecular organics — the fraction that survives biological treatment and passes straight through membranes — treatable within a single process chain.

A tiered purification pathway

Because leachate composition varies so widely, the system works in stages rather than in one pass: rapid chain scission, then strong adsorption, then deep mineralisation. Homogeneous catalysis attacks the chemical bonds of macromolecular organics and cuts them into readily degradable small molecules. Heterogeneous catalysis then deeply oxidises those intermediates through its high-porosity structure. The endpoint is harmless end products rather than accumulated toxic intermediates, which is the failure mode that catches out simple oxidation schemes.

The same pathway gives strong removal of difficult pollutants such as dissolved oil, phenols and sulphides, with colour and odour removal consistently above 90%. The catalyst itself is hydrophilically modified for anti-fouling performance and broad pH applicability, so it keeps stable activity even in the high-salinity conditions that characterise leachate, and resists shock loads when influent quality moves suddenly.

Speed, capacity and footprint

Based on the patented CDOF design, the system provides ample reaction interface so pollutants and active species stay in contact long enough to react. Effective reaction time in the core oxidation unit is about 15 minutes, against the long cycles conventional equipment needs, which allows rapid on-site compliant disposal rather than stockpiling. Treatment capacity reaches 200m³/h, so the same platform scales from a small transfer station to a full-size landfill.

Cost and consumables

Multiple catalytic pathways working together cut overall oxidant dosing. Ozone utilisation reaches 99.98% or more, while the ratio of ozone dose to COD removal drops to between 0.5 and 1.2, far below the conventional 2 to 4. The specially modified heterogeneous catalyst is mechanically strong and long-lived, with a service life beyond five years, which removes frequent replacement from the cost model. Fully automated operation then trims labour and energy consumption, giving the process a clear economic advantage over membrane routes.

Skid integration and sealed operation

The system is highly integrated and skid-mounted, with a simplified flow that occupies roughly one fifth of the footprint of conventional leachate treatment equipment and needs no large-scale civil works. It can be custom-fabricated to project requirements, which suits transfer stations, landfills and incineration plants where the site is already congested. Operation is pressurised and fully sealed, eliminating ozone leakage and any odour release on site, and a dedicated backwash, activation and regeneration sequence keeps catalytic performance stable over the long term. Remote monitoring supports unattended running.

Because the process does not rely on reverse osmosis membranes, there is no difficult concentrate to manage and no waste residue stream created by the treatment itself. Sludge production falls by more than 90% compared with conventional alternatives, and effluent quality is clear and consistent. For a waste treatment facility, avoiding a secondary pollution stream of its own is not a small consideration.

For operators weighing the choice, the deciding factor is usually not peak removal efficiency but what has to be managed afterwards. A process that destroys pollutants on site instead of concentrating them into a tanker load changes both the permit picture and the monthly disposal bill, and it removes the concentrate handling step that so often becomes the bottleneck on a retrofit.

Where it has been applied

The platform incorporates multiple patented technologies, with dedicated solutions for landfill leachate and press liquor, and it extends to pre-treatment and advanced treatment of high-difficulty wastewater in pharmaceuticals, metallurgy and oilfields. It also serves wastewater treatment plant upgrades, which is often where the economics look best: an existing site with fixed land and a tightening permit is exactly the situation this configuration was designed for.