Solutions for decentralized greywater treatment

As the world water resources continue to deplete, reuse and recycling of greywater has become an alternative potential sustainable solution to reduce the stress on fresh water resources. The objective of this thesis is to assess the different technological approaches for greywater treatments and to provide an extensive review on the application of compacted decentralized solutions to produce high quality treated water suitable for non-potable household uses. The paper reviewed various solutions of decentralised systems for greywater treatment. Various compacted treatment technologies have also been examined. Both physical, chemical and biological treatment systems and their combinations are assessed. Moreover, case studies mainly on nature-based solutions, constructed wetland, presented. The thesis revealed that these systems are effective and have the potential of treating greywater to the level of good quality for safe discharge or for non-potable fit-for-purpose uses. Constructed wetlands, green roofs and green walls are recently receiving more attention in decentralized urban greywater treatment and are proved to have high removal efficiency of suspended solids, organic matter, microorganisms and micro-pollutants. These technologies are eco-friendly, energy efficient, less expensive and easy to operate and maintain. Treating greywater is not only an important option to help manage the balance between the demand and supply of water and reduce the burden on fresh water reserves, but also it provides an opportunity to avert environmental, surface and ground water pollution