Chitosan, a biodegradable compound, is used as an eco-friendly coagulant in water and wastewater treatment to avoid production of the large amounts of sludge using conventional chemical coagulants. Conditioning of chitosan using four different salts (Na 2 SO 4 , NaHSO 4 , (NH 4 ) 2 SO 4 , and KHSO 4 ) along with H 2 SO 4 and treatment condition optimization were investigated to enhance coagulating efficiency for bentonite suspension. Chitosan dissolved in acetic acid was used for coagulation of 5g/l bentonite suspension. The optimum concentration of chitosan required for maximum coagulation of bentonite suspension was 5mg/l. Among the five additives used for conditioning, NaHSO 4, at all concentrations, was found to be the most effective for enhancing the coagulating efficiency of chitosan and it was at its maximum when conditioned by 0.05mM NaHSO 4 . NaHSO 4 conditioned chitosan showed better coagulating efficiency than unconditioned chitosan at all pHs (3–8) tested in this study. The coagulation of bentonite by chitosan was found to decrease with increase in pH of the suspension. Using 5mg/l of NaHSO 4 conditioned chitosan at pH 6, the removal percentage of bentonite was increased from 76% to 88 % compared to unconditioned chitosan.