BIO-COAGULANTS, A SUBSTITUTE OF CHEMICAL COAGULANTS

Abstract

Coagulants are substances which cause particles in a liquid to curdle and clot together. Different types of common coagulants such as aluminium sulphate, polyaluminium chloride (PAC) and iron salts, are used in potable water treatment. These coagulants are usually very expensive and can affect human health. These chemical coagulants change the pH of the treated water and also produce non biodegradable sludge. Moreover, the increase of global awareness about environmental issues is acting as a driving force behind the interest toward the use of green resources as valuable products for water treatment. Natural coagulants have the potential to be effective in water treatment which is sustainable and environmentally appropriate. The bio-coagulation process proved to be efficient in turbidity and colour removal. A number of natural coagulants from plants or animal origin can be effectively used for the treatment of drinking water. Many plant materials have been used over the years, the seeds from Moringa oleifera have been shown to be one of the most effective coagulants for water treatment. Seeds of Carica papaya and leaves of Cactus opuntia showed effectiveness in coagulation. This review tries to find out readily available natural products which are cheap, appropriate and sustainable solutions for producing potable water in some developing nations. This paper also includes advantages and disadvantages of natural coagulants prior to identifying several potential research gaps to provide a platform towards the need of further study.