Local water supply systems pose the greatest risk from a public health perspective because water is delivered to consumers without any treatment and often even without disinfection. The most common causes of contamination are microbiological contamination and elevated concentrations of heavy metals. Such water must be treated to be safe for human consumption. The most common water disinfection process used in drinking water treatment is disinfection with chlorine-based compounds. However, the by-products of the reaction of chlorine and organic matter are chlorinated hydrocarbons and nitrosamines, which can be extremely carcinogenic. The accumulation of these by-products along with the accumulation of heavy metals in the human body increases the risk of adverse effects on human health. Electrocoagulation (EC) is an alternative method of raw water treatment. Electrocoagulation uses an electric field and sacrificial electrodes to generate coagulants that separate, aggregate, and precipitate contaminants from the water. This method has proven successful in removing heavy metals from water, but also as a disinfection method. The objective of this study was to use EC to remove arsenic and chromium and to disinfect raw water enriched with Escherichia coli. The process took place in a batch reactor with 2 electrodes (1 anode and 1 cathode) at a voltage of 62 V. The efficiency of the process as a function of electrode material (Fe, Al, Cu and graphite) and treatment time was studied. With the exception of graphite, all electrodes showed 100% efficiency in the removal of As and Cr, while the disinfection efficiency varied.
Keywords: water treatment, electrocoagulation, heavy metals, disinfection.
