E1: A process for treating a water stream comprising: feeding a water stream through a desalination process to produce a by-product stream, the by-product stream containing dissolved calcium ions and sulfate ions.

E2: Contacting the by-product stream with a cation-removal device and an anion-removal device to remove a substantial portion of the calcium ions and the sulfate ions, the calcium ions passing into a first salt stream, the sulfate ions passing into a second salt stream, the first salt stream containing chlorine ions, the second salt stream containing sodium ions;

E3: Separately feeding the first salt stream and the second salt stream to a calcium sulfate precipitation chamber for precipitating calcium sulfate. Collecting the precipitated calcium sulfate.