Comparative study between aluminium sulphate and Lemna perpusilla as coagulants for water treatment: Case study Lake Cibuntu, West Java

Abstract

Coagulation is a key process in water treatment. The ability of two coagulants, aluminium sulphate (alum) as inorganic coagulant and Lemna perpusilla as natural coagulant was assessed using standard jar test measurement. Both coagulants were evaluated with turbidity, Total Organic Matter (TOM) and Total Suspended Solid (TSS) parameters. The results showed that both coagulants were able to remove 100 % of water turbidity with initial turbidity 13.56 NTU. However increasing the coagulants doses, also will increase the concentration of TSS. The use of alum and L. perpusilla as a coagulant will increase concentration of TSS by 12.68% and 252.11% respectively. Application of alum tends to reduce the concentration of TOM by 20.25%, while L. perpusilla will actually increase the concentration of TOM by 74.85%. Although not as effective as alum, L. perpusilla showed sufficient removal capability for treatment of turbid waters from Cibuntu Lake. The optimum dose of L. perpusilla should be considered to minimize side effects on produced water such as increasing TOM and TSS concentration.