... A commercial laundry is considering constructing an ion exchange process to remove hardness from water used in laundering operations. The laundry uses 1000 m³/d of city water with Ca²⁺ at 4.5 meq/L and Mg²⁺ at 2 meq/L. Their goal is to reduce total hardness (TH) to 1 meq/L. The softening resin has a TH capacity of 60 kg-TH/m³ of media with a recommended hydraulic loading rate of 0.4 m³/(m² min). Regeneration can be accomplished using 100 kg NaCl per m³ of ion exchange media in a 15% solution at a hydraulic loading rate of 0.04 m³/(m² min). The exchanger tanks available to the laundry have a diameter of 1 m.