Effectiveness of chitosan as natural coagulant in treating turbid waters

Abstract

Aluminum, Lime and iron coagulants are commonly used in most industries for many decades to coagulate particles in surface water also removing turbidity from the water prior to flocculation, sedimentation or filtration. Although effective, inorganic coagulants have several disadvantages, there has been a concern about the relation between aluminum residuals in treated water and Alzheimer disease and toxic effects of metallic coagulants on the aquatic environment. Hence nowadays, there has been great attention in the improvement of natural coagulants in treated water such as chitosan; chitosan is a natural linear cellulose-like copolymer of glucosamine and N-acetyl-glucosamine widely distributed in nature. The present study was aimed to investigate the effects of chitosan on the removal of suspended solids (bentonite clay) from water. A series of batch flocculation tests with chitosan under different conditions was conducted. The results indicate that chitosan is a potent coagulant for bentonite suspension. Coagulation of chitosan showed efficiency of 96.9%. The coagulant performed well at concentration of 1g chitosan/100 ml water at PH=6.