Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6333731 | Science of The Total Environment | 2012 | 6 Pages |
Rainwater harvesting being an alternate source in water scarce areas is becoming a common practice. Catchment contact, however, deteriorates the quality of rainwater making it unfit for potable purposes. To improve the quality of harvested rainwater, silver was used as antimicrobial agent in this study. Rainwater samples were taken from underground storage tank of a rooftop rainwater harvesting system installed in one of the buildings at Seoul National University, Seoul, South Korea. The target microorganisms (MOs) were Pseudomonas aeruginosa and Escherichia coli which were measured by using plate count method and standard MPN method, respectively. The efficiency of silver disinfection was evaluated at concentrations, ranging from 0.01 to 0.1Â mg/l; the safe limit approved by WHO. The experiments were performed for 168Â h with different time intervals to evaluate the parameters including inactivation rate, residual effect of silver and re-growth in both MOs at lower (i.e. 0.01-0.04Â mg/l) as well as the higher concentrations of silver (i.e. 0.08-0.1Â mg/l). Results showed the re-growth in both MOs was only in the case of lower concentrations of silver. The possible reason of re-growth at these concentrations of silver may be the halting of bacterial cell replication process for some time without permanent damage. The kinetics of this study suggest that higher inactivation and long term residual effect towards both MOs can be achieved with the application of silver at 0.08Â mg/l or higher under safe limit.
⺠Silver, an effective antimicrobial agent for Pseudomonas aeruginosa and E. coli. ⺠Higher inactivation and long term residual effect of silver is at 0.08 mg/l or higher. ⺠Re-growth of both MOs is at lower concentrations of silver. ⺠E. coli is more sensitive to silver than P. aeruginosa. ⺠Silver disinfection of harvested rainwater, a step ahead towards potable water.