Grey water reclamation for urban non-potable reuse - challenges and solutions a review

Abstract

The study shows the sustainable and effective way of managing growing water and wastewater problem is to reclaim and use greywater from bath/shower, hand basin and washing machine for outdoor and indoor non-potable purposes. A detail wastewater characterisation study by the past researchers indicates that grey water is polluted, but the quality is not similar to the domestic wastewater and therefore the traditional design criteria cannot be used for greywater reclamation. The study by the past researchers show grey water with detergent inhibit grey water reclamation process such as aerobic biological process and the appearance of reclaimed water with cloudiness, colour and excessive bubble formation reduce willingness especially for in-house uses than outdoor uses. Partially or untreated soapy grey water are useful for outdoor use and has useful nutrients, but some study shows excess detergent and other cleaning materials may cause harmful effects to the growth of plants and degrades soil structure. It may cause risk to the environment and human who makes close contact with grey water or inhale the spray. Currently most of the grey water reclamation systems are based on traditional wastewater and/or water treatment design and some have no proper design at all. In addition, due to the public perception (“yuck effect”), it is not acceptable for using reclaimed grey water for direct potable use. Also, globally there are standards for potable water quality and regulated widely, whereas only a few countries have non-potable water quality or grey water reuse standards and regulated properly. Therefore, when designing grey water reclamation, the above challenges needed to be considered. This paper presents review on grey water characteristics, health and environmental risks, public acceptability, regulatory requirement for non-potable use and on current grey water reclamation processes, particularly about the treatment of detergent and other cleaning materials and also identify natural geo or waste material for synthetic detergent removal from grey water.