Arsenic removal from water has been receiving considerable attention in the field of water supply engineering. To develop the optimal coagulation protocol ,the effectiveness of several operation options such as coagulants, coagulant aids and additives ,as well as Adsorption. It is noted from this study that arsenic adsorption isotherm under water operation condition could be describe by Langmuir equation. An efficient flocs separation system subsequent to coagulation was essential to achieve the effectiveness of overall arsenic removal. I.INTRODUCTION Arsenic contamination in natural water is a worldwide problem because of its known toxicity and health hazards. The US Environmental Protection Agency (USEPA) has classified arsenic as a Class 'A' human carcinogenic and because of the serious health problems caused by arsenic in 2001, it reduced the maximum arsenic content in drinking water from 50 ppb to10 ppb[1]. Thus several technologies such as oxidation and filtration [2], A wide range of physical and chemical treatment methods have been applied for arsenic removal from contaminated waters fall into the following categories: (a) precipitation-coagulation processes, such as coagulation with iron or aluminum salts or Lime softening (b) membrane processes, such as reverse osmosis, ultrafiltration, Nano filtration, and electro dialysis. (c) adsorption processes, such as adsorption on activated or modified materials (d) ion exchange [3]. In these methods, the adsorption techniques are simple and convenient and easily available and have the potential for regeneration and sludge-free operation. Various adsorbents for arsenic removal have been developed that include such materials as activated carbon[4], agricultural products and by-products e.g. waste rice husk [5], eggshell [6] and shrimp shell [7], industrial byproducts/wastes e.g. fly ash [8] and red mud [9]), oxides e.g. iron oxide [10], manganese oxides [11] and alumina [12], bio sorbents [13,14] II. MATERIALS AND PROCEDURES A. Arsenic Chemistry and Mobility Arsenic occurs in Free State. Arsenic is situated in the 33 rd spot on the periodic table, right next to Germanium and Selenium. Arsenic has been known for a very long time and the person who may have first isolated it is not known but credit generally is given to Albertus Magnus in about the year 1250. The element, which is classified as a metalloid, is named from the Latin arsenicum and Greek arsenic on which are both oxygen and chlorine to from inorganic pent avelent arsenate and trivalent arsenite. Arsenic can occurs in the environment in several oxidation (-3, 0, +3 and +5) as a sulphide (WHO 2008). B. Reaction of Arsenic With Hydrogen Arsenic trioxide can be reduced by hydrogen gas to form arsine. Arsine, AsH 3 , is a very toxic gas that is denser than air. When arsine is heated, it breaks down to arsenic and hydrogen. Reaction of arsenic trioxide with hydrogen gas to form water and arsine. As 2 O 3 (s) + 6H 2 (g) → 3H 2 O (l) + 2AsH 3 (g) (1) C. Reaction of arsenic with oxygen Solid arsenic is oxidized...
