I think this depend of the production process objectives. Probably the company set this objectives based in an market, costs and production possibilities analysis, taking care of environmental costs too (this is the correct way). If it is necessary, is possible to swich the process to obtain one or the other final products (I think you jut need one reactor, temperature control and a mixing system). One important point is the amount of sludges and wastes generated with each process. If you has so much Ca(2+) you must think wath to do with it.