Cassia alata as a potential coagulant in water treatment

Cassia alata or locally known as “pokok gelenggang” is a wild legume species found in Kelantan. Cassia alata based
coagulant-flocculant was tested for surface water collected from the Kelantan River. The plant leaves was used to test
coagulant rate and dose. The turbidity and other physico-chemicals of surface water sample were measured before and after
the jar-test by using portable instruments. Turbidimeter Hanna Model 2100P was used to measure turbidity, while, portable pH
meter hand-held Model C535 was used to measure pH. Meanwhile, iron and manganese were measured by using
spectrophotometer model DR 2800. Total suspended solids were analyzed using method used by Michaud. The experiments
were carried out with coagulant dosage of 0.5, 1.0, 1.5, 2.0, 2.5 and 3 mL/L with the intervals of 0.5 mL/L. The results have
shown that Cassia alata leaves can remove turbidity up to 93.33% at the optimal dosage of 1.0 mL/L. In addition, the potential
of Cassia alata leaves to remove other pollutants presence in the river water like suspended solids, ferum, manganese and pH
was also identified. On the other hand, the leaves of Cassia alata can remove suspended solids by 56.4% but not other
parameters.