Comparison of polyaluminum silicate chloride and electrocoagulation process efficiency in removal Of nitrate from aqueous solutions

Providing safe water for consumption with low cost is one of the main objective of water supply systems. A main source of nitrate in water is using excessive fertilizer. The high amounts of nitrate in water has a deteriorating effect on the environment and health so nitrate removal must be below the recommended levels of WHO guidelines. The purpose of this study is nitrate removal from aqueous solution by Poly Aluminum Silicate Chloride (PASIC) and Electro Coagulation process (EC). This experimental study was aimed to examine efficiency of the effects of various operating parameters such pH (4-11), initial nitrate (25-100 mg L-1), contact time (5-60 min), residual aluminum in finished water by application of EC process and PASIC.. The results showed that the applied methods have the ability to remove nitrate from aqueous solutions to levels less than standard those of WHO. PH and electrical potential difference had direct effect while contrast initial nitrate concentration had reverse effect of nitrate removal. The results showed that the coagulant PASIC and EC process, can reach nitrate removal respectively 65% and 55%, so that the optimum condition of the nitrate removal for EC was contact time of 60 min, a voltage of 30 W, pH = 10 and for PASIC was Concentration in 5 mg /L, contact time of 15 min, pH = 10. Our results showed significant differences between the mean concentration in all variables of the raw water before and after doing all process (P ≤ 0.05). According to our findings PASIC coagulants in removing nitrates AD better performance than electro coagulation process. Given the higher performance of PASIC in the low concentration and natural pH of water than the EC process, it would be more cost- effective and economical. Residual aluminum in finished water was below the recommended WHO guidelines and Iranian standard institute. In terms of cost and efficacy this method could be considered as an alternative method to the drinking water treatment plant.