Potential of Psidium guajava shoots extract as Coagulant for drinking water treatment

The usage of alum-based coagulant in drinking water treatment process caused residues in completed drinking water treatment, which eventually supplied to consumers. This poses possible risk to their health. Furthermore, alum-based coagulant is expensive. Due to the risk and cost of using alum-based coagulant, natural coagulants which are environmental friendly, safe and cost effective, are needed. A plant-derived coagulant was successfully extracted from Psidium guajava by using physical extraction method. This study was intended to explore the effectiveness and optimum dosages of P. guajava needed for turbidity and heavy metals removal in surface water sources. Flavonoids and tannin are coagulating agent which are naturally present in P. guajava shoot and they are responsible for turbidity and heavy metals removal in water. Three types of heavy metals (Cuprum, Ferum and Manganese) and three level of turbidity were chosen for this study (500-700 NTU, 30-50 NTU and 5-20 NTU). The experiment was performed with crude extracts of P. guajava with different dosage (2.0 mg/L, 4.0 mg/L and 6.0 mg/L). Results demonstrated that the best and optimum turbidity removal is observed in low and moderate turbid water sample (5 – 50 NTU) up to 66.5 % at 2.0 mg/L of extract P. guajava shoot. However, there were no significant removal in Cuprum, Ferum and Manganese. It could be concluded that, P. guajava shoot extract has the ability to remove suspended solid in water, hence it has a great potential to replace chemical coagulant in drinking water treatment. Furthermore, P. guajava shoot extract is much cheaper and easy to prepare as compared to chemicals coagulant.