PROMOTHE MBR - Process water recycling with a thermophile membrane bio reactor installation for treatement of hightemperature waste water, containing recalcitrant cod -varying in load, concentration and composition-

In the chemical sector, wastewater often contains biodegradable organic compounds and the traditional aerobic activated sludge process is still the most common way to treat such wastewater. The project aimed to demonstrate and disseminate the effectiveness and efficiency of a thermophile operated membrane bio reaction for aerobic digestions of sludge that: originates from the chemical industry (chemical carbon activation); strongly varies over time in flow, load and constitution (due to plant operation); is thermally polluted (approximately 50-55°C) and contains hard biodegradable (recalcitrant) organic compounds. The project established an MBR plant and tested the bioreactor and the results of the mesophilic operation were well above expectations and met all the project objectives, although the transfer to thermophilic operation has not been successful. However, the hybrid design of the MBR plant enabled mesophile operations far beyond expectations, i.e. 97% of COD removal, 100% solids removal and only 7% sludge yield on COD removed. Economically the project has demonstrated an overall saving. Assuming that the plant could reach optimal (design) capacity rather than 51%, the overall annual savings would be in the region of £300 000 giving a payback period on the overall investment cost [€2 231 000] of between 5 and 6 years.