The feasibility of the electrochemical method in removing the hardness of the underground waters

Water, which is the source of life for all living things, has great importance in domestic uses, agricultural irrigation and many industrial processes, especially cooling. Over time, the importance of water increases with the increase in population, the development of technology, the increase in industrialization, and climate change. One of the parameters that are effective in determining the water quality is hardness. Water hardness depends on the concentration of divalent ions such as Ca+2, Mg+2, Sr+2, Fe+2, Mn+2 dissolved in water. The compounds formed by these ions with anions such as HCO3-, SO42-, Cl-, NO3-, SiO3- create hardness. Hard water causes destruction on the surfaces it comes into contact with, the formation of scale, the contamination of the membranes of the treatment systems, the clogging of the pipes and the loss of their functions. In order to reduce and eliminate such undesirable problems, the water must be softened, that is, the hardness must be removed. Although electrochemical treatment is used effectively in the removal of many pollutants, studies on hardness removal from water are limited. This situation reveals the originality of the study. The study conducted with this process, which has the advantages of using less chemicals, being economical, and obtaining high efficiency, will contribute to the literature and provide the opportunity to compare with other hardness removal methods. Hardness removal by electrochemical treatment; It is based on the principle that as a result of cathodic reactions in the presence of OH− ions, Ca and Mg ions that cause hardness precipitate on the cathode surface in the form of CaCO3 and Mg(OH)2. Three-dimensional stainless steel wool was preferred as the electrode type which is one of the parameters affecting the removal efficiency, instead of the currently used two-dimensional plates. As a result of the experiments, initial pH of 7.24, current density of 3A, addition of 0.462 g of NaHCO3, and treatment time 20 min. were determined as optimum conditions. The total hardness removal efficiency was obtained as 90% under these conditions.