The Worth of Water

Abstract

This chapter considers the historical concept of the Linear Economy of Water (LEW). This viewed the water/wastewater process as linear moving from abstraction to treatment to use to treatment and then discharge. The increased emphasis on sustainability and also recent global demographics has resulted in the movement away from the LEW and to the adoption of the Circular Economy of Water (CEW). This lays the emphasis on recycling and reuse of water. It also views water and all of the contents of domestic, industrial and agricultural waters as a resource, be this water itself, brines, heat, organics or fertilisers. The CEW also considers multiple water sources including surface water, ground water, together with alternative sources such as rainwater, brackish and saline water, brines and used water. These sources of different water qualities are available for different water use applications. Therefore the CEW supplies multiple waters for multiple purposes for multiple users. In contrast to the LEW which focused on potable water quality, the CEW deals with varying water qualities and the principle of multiple waters gives rise to the term “fit for purpose”. This denotes that the water from the used water source can be utilised by an application (domestic, industrial or agricultural) without the used water requiring treatment.