Abstract: A separation process is described for separation of a nutrient from divalent ions of an aqueous solution. The aqueous solution is contacted with an ion exchange resin that includes monovalent ions until the concentration of divalent ions in the aqueous solution has been depleted and an eluate is collected. The eluate is then subjected to a process, preferably a nanofiltration membrane process, capable of separating monovalent ions to obtain a permeate fraction including monovalent ions and a retentate fraction including the nutrient. The retentate fraction is then separated into fractions with at least one fraction including a major portion of the nutrient. The ion exchange resin is then regenerated by contacting it with a solution including the permeate fraction until a major portion of the divalent ions have been replaced by monovalent ions.