Water Disinfection Using Tulsi Leaves

Abstract

Disinfection is the important water treatment process used to remove pathogens from drinking water. In this study, effectiveness of tulsi leaves juice as a disinfectant were evaluated by spread plate and membrane filter method. Tests were conducted both for batch as well as continuous flow. In batch study, dose and contact time were evaluated. It was revealed that as the dose is increased, there is decrease in contact time and vice-versa. The effective contact time was found to be 17, 12, 9, 5 and 4 hours for the tulsi leaves juice dose 1.5, 2.0, 2.5, 3.0 and 3.5ml respectively. The optimum contact time of 5 hours for 3.0ml dose was considered for continuous flow study. In continuous flow, effectiveness of tulsi was evaluated for 0-25, 25-50, 50-75, 75-100 CFU/100ml range at flow rates 14.40, 12.00 and 10.28 litre/hr and at a distance of 0.2, 0.4, 0.6, 0.8, 1.0 m. E. coli removal efficiency of tulsi in continuous flow is 86.67%, 91.11% and 93.33% at lower flow rates 14.40, 12.00 and 10.28 litre/hour respectively. For 0-25 CFU/100 ml range, E. coli removal efficiency is highest upto 100% while for other CFU ranges 25-50, 50-75 and 75-100 CFU/100 ml ranges, E. coli removal efficiency is maximum upto 93.33%, 93.22%, 93.10% respectively. In conclusion, the study indicates that tulsi has the potential merits for reduction of bacterial contamination in water.