Survey of Arsenic Removal fromWater by Coagulation and Dissolved Air Floatation Method

Backgrounds and Arsenic is one of the most toxic and dangerous elements in drinking water that with increase in its application in agriculture، development of applications in agriculture، livestock، medicine، industry and other cases its entry to water resources and environment is much easier. Arsenic is a poisonous، cumulative substance and inhibitor of SH group enzymes and various studies revealed a significant correlation between high concentrations of arsenic in drinking water and liver cancer، nasal cavity cancer، lungs، skin، bladder and kidney cancer in men and women and prostate and liver in men. The aim of this was survey of arsenic removed from water using dissolved air floatation mechanism. At present study in first step for determination best conditions of arsenic removal by dissolved air floatation method، optimum amount of coagulants determined and then synthetic solution of arsenic (50، 100 and 200 µg/L) prepared using sodium arsenate. In third step arsenic removal efficiency under various variables such as arsenic concentration، flocculation and floatation time and saturation pressure were analyzed. Finally residual arsenic concentration was determined by the silver diethyl dithiocarbamate method. Effect of optimum condition on arsenic removal efficiency at various initial concentration 50، 100 and 200 µg/Lshowed that the best coagulant for removal of arsenic is polyaluminumchloride. Also maximum efficiency (99. 4%) was obtained in initial concentration equal 200 µg/L. It can be concluded that dissolved air floatation method with poly aluminum chloride as coagulant have high efficiency for arsenic removal even at high concentrations and therefore this method can be used for removal of arsenic from water as a suitable and safe option.