The secure, clean and sufficient fresh water is needed for the all living organisms. The surface water of many areas are highly polluted due to disposal of raw wastes from industry, textiles, tanneries and municipal wastes from water bodies and increased population. These type of polluted water contains dissolved and non dissolved particulates. Read more
These often affects the human healths. Discharge of heavy metal likes As, Cr, Cd, Pb, Hg, Cu, Zn, and Ni are toxic for human beings and plant. Al-based coagulants such as aluminium sulphate (Al2(SO4)3) (better known as alum) or polyaluminium chloride (PACl) are commonly used in drinking water treatment to enhance the removal of particulate, colloidal, and dissolved substances via coagulation processes. The treatment of surface water with aluminium sulphate has been in operation for over a hundred years all over the world. Typically, a portion of the alum added to the raw water is not removed during treatment and remains as residual aluminium in the treated water. There is considerable concern throughout the world over the levels of aluminium found in drinking water sources (raw water) and treated drinking water. This has arisen mainly for two reasons. First, acid rain has caused the aluminium level in many freshwater sources to increase (Schecher and Driscoll, 1988). A high (3.6 to 6 mg/l) concentration of aluminium in treated water gives rise to turbidity, reduces disinfection efficiency, and may precipitate as Al(OH)3 during the course of distribution Secondly, the possibility of an association between aluminium and
neuropathological diseases including
presenile dementia and
Alzheimer’s disease is frequently hypothesized.
It is becoming increasingly recognized that the nontoxic and biodegradable biopolymer chitosan can be used in water treatment. The Chitosan for coagulation and recovery of suspended solids in food processing wastes, with reduction of suspended solids of 65%-99% has been investigated. It have been applied as a chelating polymer for binding harmful metal ions, such as copper, lead, mercury, and uranium, from Wastewater. chitosan has been employed as an excellent adsorbent for sorption of dyes and polychlorined biphenyls (PCBs) from waste water. Adsorption is the ability of certain solids to selectively concentrate solute from solution onto their surface. Chitosan has demonstrated the potential to adsorb significant amounts of metal ions, and this has generated a large amount of interest in assessing its feasibility to remove metal ions over a wide range of effluent systems and types.
Because untreated or chemically treated water entries to streams, lakes and rivers directly affect the aquatic life system. It will severly affect aquatic population, not only affecting fishing activities, but also paves way for harmful chemicals entering the food chain. Policy makers around the world are now slowly waking up to this fact and trying to find a way to tackle this crisis. In USA, Washington State has strictly ordered to use Chitosan to treat the storm and drainage water. Chitosan also now finds way into swimming pool flocculation and cleaning, as consumers are now more aware of harmful effects of synthetic cleaning products.
No doubt that chitosan is a promising novel biomaterial of the future. More research and innovation in chitin science will definitely contribute to the benefit of the society.