Advanced treatment of the reverse osmosis concentrate by the Fenton and O3/UV oxidation processes

摘要

Due to their process stability and the excellent effluent quality, the use of membrane processes for wastewater treatment and reuse is rapidly expanding. However, a drawback of the membrane processes is the production of concentrates and their proper disposal. In this study, an industrial wastewater is treated by an activated sludge process combined with reverse osmosis (RO). The RO concentrate is characterised by recalcitrant COD and a low biodegradability. The effect of partial Fenton and ozone/UV oxidation of RO concentrate to increase the concentrate biodegradability is examined. Comparing all the investigated dosages of Fenton reagent, the hydrogen peroxide dosage of 2.4 mM has the most positive impact on both the BOD/COD ratio and the biodegradation rate. However the partial Fenton oxidation results in a better mineralisation of the organic matter in the concentrate, the oxidation by ozone and UV achieves a more positive effect on the enhancement of the biodegradability. Finally, a similar degradation of AOX compounds in the concentrate by both oxidation processes can be observed. Hence, it can be concluded that the partial oxidation is more selective in the degradation of complex, non-biodegradable compounds compared to the mineralisation of organic matter.