Background Incineration is a way to environmentally treat heavily polluted waste waters, but plants working on this principle need to be very large to be both competitive on the market and to keep to legal thresholds, especially concerning chlorinated dioxins and furans. Furthermore, the costs are high due to the need for extra transportation, as such plants are very rare. Objectives The aim of this LIFE project was to demonstrate the feasibility of a special technology to incinerate liquid wastewaters containing organic and inorganic compounds in a small plant. The new CONOX oxidiser would use compressed oxygen instead of air for oxidising, which would make it possible to be far below the legal thresholds. It would come close to a zero emission plant and the energy recovery system developed would allow competitive treatment prices. In short the objectives were to: • provide proof of the operational reliability of such a new incinerator on a small scale plant; • assess the suitability of this device to eliminate several kinds of pollutants; • demonstrate its ability to eliminate heavy metals and inorganic substances in a solid state; • high thermal efficiency: the thermal energy released was to be recovered by 90 %; • “Zero emission plant”: the exhaust CO2 would be purified, condensed and could then be sold on the market; • costs of this technology were to be 40–50 % less than those used in present incineration technologies. Results The project was not successful, however the technology remains promising for the future. The main technical result of the project was a considerably improved plant design, which was finalized by the end of the project. However the project did not go beyond the planning stage, the actual construction work did not take place. The main reason for this was that the original waste supplier could not guarantee the supply of liquid wastes in sufficient quantities over a period of several years and delayed the negotiations considerably. In the end, the beneficiary found a new supplier, who was willing to supply the plant. But the remaining time of the LIFE project was too short to acquire enough liquid wastes to start with the plant construction. The price for removal of the wastes decreased due to the export of these wastes into regions with less strict environmental regulations. Therefore to achieve economic feasibility the plant was redesigned: the planned throughput was considerably increased (five fold) and an additional CO2-recovering and purification plant was added. This was done to ensure, that the plant receives the status of "waste utilization" rather than "waste disposal" and therefore enhance the market value of the process. The outlook is promising: the project will most probably be carried out by the new group of companies, without EC funding, as soon as guarantees for the delivery of enough liquid waste over several years make the investment economically feasible.