Abstract
Increasing population living in cities brings upon new challenges in water and wastewater management. It is therefore critical to improve the quality of urban water in a cost-effective and fossil-fuel approach in order to achieve a more sustainable future. Proper management of the natural water resources and its discharge back into the environment after use are of utmost importance due to its huge implication towards human developments. Hence, there have been ongoing investigations over the years in order to broaden the variety of methods for the treatment of urban water. Typical treatment processes to produce water safe for human consumptions include coagulation-flocculation, sedimentation, filtration and disinfection. In particularly, coagulation-flocculation process has always been a vital step to remove particulates, natural organic matters, microorganisms, inorganic ions, metals and others, thus significantly improves water quality. Increasing awareness of the health issues and environmental drawbacks regarding the use of conventional aluminium-based and iron-based coagulants shifted the interests towards plant- or animal- derived materials to be used as coagulants/flocculants. Unlike its inorganic counterparts, natural materials such as Moringa oleifera, tannin, chitosan, and seed gums were found to be effective, biodegradable, non- toxic to living organisms, and more environmentally friendly. This paper reviews the potential use of natural coagulants and flocculants in the treatment of urban waters for sustainable applications and consumptions in the cities.
