Reuse of Grey Water for Flushing Purpose

Abstract

Grey water is the wastewater that is being discharged from a house, excluding black water (toilet water). This includes water from showers, bathtubs, sinks, kitchen, dishwashers, laundry tubs, and washing machines. It generally contains traces of soap, shampoo and toothpaste, food scraps, cooking oils, detergents and hair in minor quantities. Grey water makes up the largest proportion of the total wastewater flow from household in terms of volume. Typically, 50-80% of the household wastewater is grey water. If a composting toilet is also used, then 100% of the household wastewater is grey water. Studies in different countries have estimated that the usable domestic grey water resource could amount up to 35% of the total domestic demand. Non-domestic establishments such as swimming pools, restaurants, hotels, schools, and other public buildings produce clean grey water. This grey water can be collected before it goes to the septic tank or the municipal wastewater system, and may be reused to irrigate plants after providing a simple treatment. With a little additional treatment, this water can also be used for toilet flushing and other applications. Some safeguards are required.