In the Netherlands the calcium content of drinking water is reduced by all suppliers, making the water softer. At the request of two suppliers, Evides and Waternet, CE Delft has assessed the climate impact of various softening processes. Drinking water suppliers can use the results of this study to reduce that impact.
Softening can be carried out either centrally, by drinking water supplier, or in homes. There are various methods available and this study examines five central softening technologies: pellet reactor, precipitation, reverse osmosis, nanofiltration and ion exchange, as well as the situation in which consumers use a domestic ion exchanger to soften all the incoming water. The climate impact is assessed both exclusive and inclusive of impacts at the household level.
The analysis shows that centralized softening has a lower climate impact than home softening. The results inclusive of household impacts show that all the softening technologies apart from reverse osmosis and home ion exchange have climate benefits.