OZONATION OF WASTE-WATER CONTAINING N-METHYLMORPHOLINE-N-OXIDE

Ozonation of synthetic wastewater containing: N-methylmorpholine-N-oxi de (NMMO) was investigated in batch experiments at different pH-values . Increasing pH caused higher initial elimination rates of NMMO as wel l as higher formation rates of nitrate. In mass transfer limited exper iments, the shortest time needed for NMMO removal was observed at pH 7 . This could be explained on the one hand through the importance of (O H)-O-.-radicals for the oxidation of NMMO and on the other hand throug h ozone decomposition reactions by (OH)-O-.-radicals at high pH-values . Dissolved ozone increased rapidly after elimination of NMMO at pH 7 and 8.5. High oxygen uptake rates of biomass with ozonation products s howed the increase of the biodegradability compared to the initial syn thetic wastewater. An improvement of ozone efficiency for elimination of NMMO and organic carbon can be expected in a process using a biorea ctor in a recycle system. Copyright (C) 1996 Elsevier Science Ltd