Removal of turbidity in water treatment using natural coagulant from Lemna perpusilla

Abstract

Lemna perpusilla (duckweed) is aquatic plant that easily to spread. This plant contains of high protein. The ability of L. perpusilla to act as natural coagulants was tested using a synthetic turbid water. Active components were extracted from L. perpusilla using NaCl solution. Experiments was conducted in batch mode for initial turbidity such as 50 NTU (low turbidity), 150 NTU (medium turbidity) and 300 NTU (high turbidity). Jar test procedure with the coagulation time of 1 min and flocculation 15 min was optimized, irrespective of the initial turbidity. The optimum settling time for 300, 150, and 50 NTU water samples were 30 ppm. The influence of several parameters such as pH and coagulant dose and also its optimization were exploited. The highest value of turbidity removal were achieved at pH 11 and 30 ppmv in coagulant dose. This coagulant can removed 85.02%; 88.98%; and 92.48% of turbidity from water having in turbidities of 50, 150 and 300 NTU, respectively. Thus, the natural coagulants extracted form L. perpusilla revealed to be effective for turbidity removal.