Removal of ammonia and nitrates from contaminated water by using solid waste bio-adsorbents

Abstract

The presence of pollutants in aqueous solution mainly from hazardous heavy metals and metalloids is creating an environmental and social problem. The ammonia and nitrates are one of the major groundwater contaminants present in the rural areas. A nitrate was regulated in drinking water quality mainly due to excess amounts can cause methemoglobinemia disease. Ammonia in both gaseous and liquid form can be irritating to the eyes, respiratory tract failure and skin due to its alkaline nature. The biological effects of ammonia and nitrates in humans after acute exposures are dose-related depend on their concentration; the amount is taken by the body and duration of exposure. Biosorption is a physiochemical process that occurs naturally in certain biomass which allows it to passively concentrate and bind contaminants onto its cellular structure. It is metabolically passive process not require energy and amount of contaminants in sorbent can remove is dependent on kinetic equilibrium and composition of the sorbents at cellular surface. Every biosorbent had different physical, chemical and biological properties for heavy metals removal by biosorption from the water. The oxygen functional groups are very important characteristics of biosorbents because they measured the surface properties and hence their quality as biosorbents. The analysis of isotherm data by fitting them to different models is important to find a sustainable model that can be used. From the biosorption isotherms describe how the sorbate molecules are distributed between the liquid phase and solid phase when the system reaches equilibrium. The process can be made economical by regenerating and reusing of biosorbent after removing the metals. Various bioreactors can be used in biosorption for the removal of metal ions from large volume of water.