Location: US - United States
This dataset represents the production of softened water by ion exchange.It is used in many sectors, such as the drinking water preparation, in breweries and in sodas, but also for cooling- and boiler feed. The main purpose of hard water is to prevent the precipitation and build-up of minerals in equipment and piping (Lenntech,2017). The process comprises a cation exchange resin on which the mobile ion inside the bed is typically sodium. When hard water passes through the resin, hardness ions (Mg2+ and Ca2+) move into the resin bed and each cation is replaced by two sodium ions getting out of the resin. Water salinity does not change, only the constituents of salinity. The system includes the process with consuption of raw materials,energy,and infrastructure, as well as the generation of emissions to air and water. Transient or unstable operations like starting up or shutting-down, are not included, but the production during stablen operation conditions. Storage and transportation of the final product are not included. The emissions into water are assumed to be emitted into river. Raw materials as well as energy consumption values are based on LCA studies. Emissions are calculated from the input properties. Infrastructure is assumed to be the same as the deionised process as a first approximation.
Data was based on two main reports: Case Study And LCA of coastal utility experiencing saltwater intrusion (Saetta, Ishii, Pine III, & Boyer, 2015) and The Sustainability of Ion Exchange Water treatment Technology (Amin, 2016). Both describe soften water process based on cationic membranes, able to exchange hardness ions (Mg2+ and Ca2+) by sodium.
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.