Arsenic may be found in water that has flowed through arsenic-rich rocks. Arsenic is a toxic, trace element that is ubiquitous in nature. It can easily be transported from the sediment to the surrounding pore-water. Severe health effects have been observed in populations drinking arsenic-rich water over long periods in countries worldwide. A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water. In groundwater, arsenic combines with oxygen to form inorganic pentavalent arsenate and trivalent arsenite. Most arsenic treatments fall into four process categories: ion exchange, membrane process, adsorption, or chemical precipitation. This study investigates the potential of removing arsenic from groundwater by using two process categories – activated alumina and lime softening. Arsenic adsorption by commercially available activated alumina is surveyed and its efficiency investigated. We have incorporated some of the valuable literature on arsenic remediation by adsorption. According to results of three activated alumina pilot studies, considering influence of adsorption time, temperature, pH, alumina quantity, arsenic concentration, and different alumina production resources, it has high efficiency for arsenic removal. Adsorption isotherm for both species of arsenic (III and V) is compatible with both Freundlich and Langmuir models (correlation coefficient >0.93). The prevalent pH range for arsenate was between 6 and 8. Modified activated alumina can remove arsenate at the influent pH of 8.1 ± 0.4 to below the maximum concentration level (MCL). The exhausted media passed the Toxicity Characteristic Leaching Procedure (TCLP) test with respect to arsenic. Lime softening operated within the optimum pH range of more than 10.5 is likely to provide a high percentage of arsenic removal (90%) for influent concentrations of up to 0.05 mg/L. It may be difficult to reduce consistently to 0.01 mg/L by lime softening alone. Systems using lime softening may require secondary treatment to meet that goal.
activated alumina, arsenic contamination, groundwater, removal efficiency, softening
 Kurdistan Province Rural Water and Wastewater, Report, 2005.
 Haque, A.A.M., Thwe, H.M., Jayasuriya, H.P.W., Hossain, H.Z., Rahman, M., Harun-ur-Rashid, M. & Matsumura, K., Groundwater arsenic contamination: food safety and human health hazards in Bangladesh. Chiang Mai University Journal of Natural Science, 6(2), pp. 321–339. 2007.
 World Health Organization (WHO), Arsenic in drinking water, www.who.int/mediacenter/factsheets/fs210/en/index.html. 2010.
 World Health Organization, (1996, 1999, 2001), Guidelines for Drinking Water Quality, Arsenic and Arsenic Compounds, Arsenic in Drinking Water, Geneva.
 Mohan, D., Pittman Jr., C.U., Arsenic removal from water/wastewater using adsorbents, a critical review, Elsevier, 1–42. 2007.
 US Environmental Protection Agency (EPA), (1998, 1999, 2000, 2001), Research Plan for Arsenic in Drinking Water - Treatment, Technologies and Costs for Removal of Arsenic from Drinking Water, National Primary Drinking Water Regulation, Offi ce of Ground Water & Drinking Water.
 Smedley, P.L., Kinniburg, D.G., A review of the source, behavior and distribution of arsenic in natural waters, Applied Geochemistry 17, pp. 517–568. 2002.
 Idswater, ActiGuard AAFS50 Activated Alumina for the Removal of Arsenic from Potable Water, www.idswater.com/water/us/activated_alumina/457/products.html. 2010.
 Reynolds, T.D., Richards, P.E., Operational and Process Units in Environmental Engineering. PWS Publishing Company, Boston, London, 2000.
 Jain, C.K, Ali, I., Arsenic: Occurrence, Toxity and Speciation Techniques. ater Research 34 (17), pp. 4304–4312. 2000.
 Badalians Gholikandi, G., Water Chemistry, 2nd edition, Publ. Nopardazan, Tehran, Iran, 2006.
 Vu, K.B., Kaminski, M.D., Nunez, L., Review of Arsenic Removal Technologies for Contaminated Groundwaters, ANL-CMT-03/2, Argonne National Laboratory, Illinois 60439,University of Chicago, USA. 2003.
 Johnston, R., Heijnen, H., Safe Water Technology for Arsenic Removal, citeseerx.ist. psu.edu/…/arsenic/…/Mohan_As_removal_adsorbents.pdf. 2002.
 Ravenscroft, P, Homepage, Documents. www.rgs.org/.../Arsenic+the+geography+of+a +global+problem.htm, 2010.
 Reynolds, T.D., Richards, P.E. (2000), Operational and Process Units in Environmental Engineering, Boston, London: PWS Pub. Co.
 Mosaferi, M., Mesdaghinia, A.R., Removal of Arsenic from Drinking Water Using Modifi ed Activated Alumina, Iranian Water and Wastewater Journal, No. 55, Esfahan, Iran. 2005.
 Wang, L., Chen, A., Fields, K., Arsenic Removal from Drinking Water by Ion Exchange and Activated Alumina Plants, USEPA/600/R-00/088, Cincinnati, USA. 2000.
 Badalians Gholikandi, G., Abbaspour, R., Technical and Financial Analysis of Groundwater Remediation System, Chemical Contaminants Treatment, national research program, PWUT, Tehran, 2006.
 APHA., Standard Methods for the Examination of water and wastewater. American Public Health Association: Washington, D. C. 2005.
 Badalians Gholikandi, G., Sadrzadeh Ardebili, M., Riahi, R., Orumieh, HR., Arsenic Polluted Groundwater: Epidemiological Study and Effi cient Removal Method, Environmental Health Risk V, Proceeding book, WIT, UK, pp. 133–142, 2009.
 Clifford, D., Lin, C.C. (1991), Arsenic III and Arsenic V Removal from Drinking Water in San Ysidro, New Mexico, USEPA/600/2-91/011, Cincinnati, USA.
 Clifford, D., Ion Exchange and Inorganic Adsorption. In American Water Works Association (AWWA)(Eds.),Water Quality and Treatment: A Handbook of Community Water Supplies. 5th ed., NY, McGraw-Hill. 1999.
 Clifford, D., Rosenblum, E., The Equilibrium Arsenic Capacity of Activated Alumina, USEPA CR-807939-02, Cincinnati, USA. 1982.
 Fox, K., Field Experience with Point-of-Use Treatment Systems for Arsenic Removal, J. AWWA, pp.94–101. 1989.
 UStoday Arsenic in drinking water seen as threat, http://www.ustoday.com/news/ world/2007-08-30-553404631_x.htm, 2007.