This study focuses on the electrochemical precipitation (EP) process to reduce excess water hardness from the Lower Rio Grande Valley (LRGV) tap water using electrically conductive concrete as cathode in a continuous flow condition. LRGV tap water is extremely hard with hardness more than 350 mg/L as CaCO3. Humans can pleasantly consume water with hardness less than 150 mg/l as CaCO3 according to World Health Organization (WHO). Hard water is also known to cause mechanical problems to boilers and heat exchangers. In this process, electricity is passed through electrodes submerged in electrolyte, which causes an alkaline environment around the cathode and precipitate water hardness. Conventional studies on electrochemical hardness removal have used sacrificial metal cathodes which makes the treatment very expensive and unsustainable. However, electrically conductive concrete cathode in this study is made with conductive graphite flakes thus making the system more durable and sustainable. In this study, data will be collected with changes in Current density, flow rate/hydraulic retention time, the total reaction time to analyze their impact on water hardness concentration in tap water. Preliminary research findings showed that an increase in applied current density, reaction time, and a decrease in flow rate achieved greater water hardness removal. If successfully developed, proposed technology will enable municipalities and industries to significantly reduce water hardness on site
