Radical new sources for drinking water - Executive Summary - Use of alternative sources for drinking water requires taking account of entire water system

Developments in nature and society will have consequences for the drinking water provision. As a result, options like the use of alternative sources and small-scale treatment processes come into the picture. Which alternative sources can be employed, depends on specific, local conditions. Although small-scale treatment processes are, as a rule, more costly than centralised (drinking) water production, conditions might be such that the implementation of small-scale systems is nonetheless advantageous. Such changes have consequences for the drinking water utilities, the surrounding environment and society. In this process, it is necessary to take into account and weigh all interests in the entire water system. In this, a good collaboration between all stakeholders in the water system is essential.

Interest: preparation for the future – What impact will future developments have on the drinking water provision? Water utilities are keen to prepare the drinking water provision for the future, but what that future will look like is largely unknown. Exploratory research is therefore focused on getting a better picture of the future. It is clear that the current drinking water sources, groundwater and surface water, are coming under steadily increased pressure. For this reason, it is important to get an idea of the alternative drinking water sources that will be available in the future, the treatment steps that would be required to draw on these alternative drinking water sources, and the possible consequences of a switch to them for drinking water utilities, society and the surrounding environment.

Approach: scenario study for fictional environment – Three different scenarios were elaborated for a fictional environment (with a city, a village, farms and industry). The first scenario assumes the use of local sources, like rainwater, and maximum water conservation. The second scenario is based on a circular economy, in which WWTP effluent and residual water from the food industry are used as sources. Both these scenarios also involve the treatment of greywater and its reuse as household water. The third scenario takes into account a growing demand for water and major climate change, so that brackish groundwater is used as the most important drinking water source, complemented by residual water from the food industry. From 29 different alternative sources (originating from surface water, the subsurface, residual water, the atmosphere, or generated by fuel combustion), a selection was made of the most suitable ones based on availability, recoverability and quality. For this selection, different water treatment schemes were formulated and their costs estimated. In addition, the possible consequences of all the different configurations for the drinking water utilities, society and the surrounding environment were described.

Report – This research is described in the report VO Radicaal nieuwe bronnen voor drinkwater (BTO-2019.019).