Chemical conditioning of drinking water to reduce Ca precipitation using water pinch methodology for sources with different Ca and Mg hardness composition

A mixture of drinking water sources with different chemical characteristics could encourage calcium precipitation. High Ca concentration and/or high Ca/Mg ratio cause recurrent piping scaling. Water pinch is a methodology used to reduce the concentration of contaminants through the mixture of water sources with different compositions; this approach might be used to reduce calcium concentrations. Another option is the reduction of Ca/Mg ratio through the Mg increase concentration. Both cases were developed and discussed using water pinch methodology and a modified procedure, respectively. Kinetics of precipitation of Ca2+ at different Ca/Mg ratios were performed to determine the ratio that minimize the Ca precipitation. Increase of Mg2+ concentration resulted better option compared to the reduction of Ca2+ concentration because the Ca/Mg ratio obtained reduces the precipitation of salts with a lesser amount of water treatment.