Greywater recycling: A review of treatment options and applications

Wastewater is an immense resource which could have significant applications in regions of water scarcity. Greywater has particular advantages in that it is a large source with a low organic content. Through critical analysis of data from existing greywater recycling applications this paper presents a review of existing technologies and applications; collating a disparate information base and comparing / contrasting the strengths and weaknesses of different approaches. Findings suggest that simple technologies and sand filters have been shown to achieve only a limited treatment of the greywater whereas membranes were reported to provide good removal of the solids but could not efficiently tackle the organic fraction. Alternatively, biological and extensive schemes achieved good general treatment of greywater with a particularly good removal of the organics. The best overall performances were observed within the schemes combining different types of treatment to ensure effective treatment of all the fractions.