Efficiency of natural coagulant obtained by ultrafiltration of common bean (Phaseolus vulgaris) seed extract
in water turbidity removal was experimentally evaluated. Prepared ultrafiltration fractions have shown
differences in behavior regarding pH values and dosages at which they expressed their highest efficiency
in turbidity removal. The highest obtained coagulation activities were at pH 9.5 with crude extract and
fraction containing molecules with molecular weight less than 10 kDa, 50.6% and 49.1%, respectively. The
organic load that remained in water after treatment was reduced when natural coagulant processed by
ultrafiltration instead of crude extract was applied. Moreover, fraction with molecules between 10 kDa and
30 kDa, decreased chemical oxygen demand by 9% relative to blank at conditions this fraction expressed
its highest coagulation activity.