The theme related to water reuse has been debated and discussed worldwide. And it is not surprising, given that water availability is declining every year in different parts of the world, due to the contamination of water resources (especially in developing countries lacking public policies) and increasing of water demand.
To alleviate the problem of water shortages, several cities around the world have adopted systems that allow them to treat and reuse the effluent (industrial and domestic) in their own urban areas to complement the public supply. In addition, several industries have begun to adopt systems that aim to treat the effluent and reuse it in its own production line. It is through the purpose with which reuse water will be utilized that one chooses the type of treatment system. In cases where reuse water will be used for human consumption, a more sophisticated plant will be required. Already in situations where water will be used for recreational purposes, a less sophisticated plant will be enough.