A review on greywater reuse: quality, risks, barriers and global scenarios

Greywater is wastewater collected from household sources without input from toilet or commode streams. Greywater represent ca. 65% of total household wastewaters globally. Different aspects of greywater, including its production sources, its characteristics, the barriers and the global scenarios of its reuse, have been critically reviewed in this paper. Given the current projections on acute water scarcity in many regions of the world, the importance of water management cannot be overlooked and a decentralized approach, segregating wastewater streams of a household with proper sanitation is a potential option for recycling greywater. This paper aims to explore the improvements achieved in the reuse of greywater. Therefore, reutilization rates were estimated, hazards and risks associated with the use of untreated greywater were analyzed were summarized. Guidelines for greywater treatment were established and barriers for successful implementation of reuse strategies were identified. Global scenarios of successful implementations of greywater reuse were presented.