[Removal of fluoride from drinking water using an electrocoagulation reactor, batch experiments]

Usage electrocoagulation methods for removal chemical contaminants are widely used in the recent years. The aim of this research is to investigate fluoride removal, agent dental and skeletal fluorosis, from drinking water by batch electrocoagulation reactor with using aluminum electrode. In this study, the drinking water sample is prepared by plastic batch reactor by monopole electrode. Removal efficiency is studied in different conditions, included pH [4, 7, and 10], reaction time [5, 10, 15, 30, and 45 min], distance between electrode [2 cm], and current density [1.5, 3, and 4.5 mA/cm[2]]. In electrocoagulation reactor, percentage of removal fluoride 2 mg/L, current density 4.5 mA/cm[2] and reaction time 30 min in pH 4, 7 and 10 are obtained 96.5%, 100% and 90.5%, respectively. In electrocoagulation reactor, percentage of removal fluoride 12 mg/L removal in distance 2 cm, current density 4.5 mA/cm[2], and reaction time 30 min in pH 4, 7, and l0 are obtained 60.7%, 64%, and 56% respectively. The findings indicated that fluoride removal efficiency is increased with increasing current density and reaction time. The results indicate that increasing the concentration of fluoride ions, the time required to achieve good efficiency should also increase. It can be concluded that the electrocoagulation technology is an effective process for defluoridation of drinking waters.

[Investigation of E. coli removal from polluted water using electrolysis method]

The conventional chemical and physicalmethods for water disinfection include the application of ultraviolet [UV], chlorination, and ozonation. Water disinfection by electrochemical methods has been increasingly carried out recently. The goal of this applied - analytical research is to investigate the removal of E. coli bacteria, as the index of water microbial contamination, from drinking water by electrochemistry method. In this study, the contaminated water sample was prepared through adding 102 and 103 E. coli bacteria per ml of drinking water. The contaminated water entered into the electrochemical reactor and different conditions were studied, included pH [6, 7, and 8], number of bacterium [102 and 103 per milliliter], time [5, 10, 20, and 40 min], distance between electrodes [2, 2.5, 3, and 3.5 cm], and voltage [10, 20, 30, and 40 volts]. The findings indicated the indirect correlation between bacteria removal efficiency and the variable distances between two electrode. The results indicated the direct correlation between bacteria removal efficiency and the variables voltage and electrolysis times. The results showed that the best conditions for removal of 102 and 103 bacteria per milliliter obtained at pH 7, electrolysis time of 10 min, distance between electrodes 2 cm, in the voltage 20 and 30 volts, respectively. The results of this study indicate that voltage and electrolysis time have the most significant effect on electrolysis efficiency. Research findings showed that electrolysis is a promising method for removal of E. coli bacterium from drinking water