Photocatalytic oxidation of grey water over titanium dioxide suspensions

Grey water reuse is an attractive alternative to the sustainable management of water especially under water scarcity situations. In this work, photocatalysis over titanium dioxide particles has been applied as a novel alternative to already studied treatments of grey waters such as filtration, biological processes, disinfection and/or coagulation technologies. Grey waters coming from two different sources, a hotel and a household have been employed in this study. The treatment efficiency has been followed through the evolution of the organic matter content expressed as dissolved organic carbon (DOC). Best results were obtained in the treatment of hotel grey waters with 65% DOC removal after 150 min. Anionic surfactants, that are usually present in grey waters coming mainly from personal care products and laundry detergents, were completely removed from hotel grey waters and from household low strength grey waters. Therefore after the applied treatment grey water could be further reused in some of the studied cases.