The control of waterborne pathogenic bacteria in fresh water using a biologically active filter

Abstract

Abstract The aim of this study was to investigate the control of three species of bacteria commonly associated with biologically contaminated water, using biofiltration. In this study, a laboratory-scale biofilter system was used to investigate the control of Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa in fresh water. Simulated fresh water was inoculated with the test pathogens at a starting inocula of ~1000 CFU 100 mL−1 to challenge the biofilters. Biofilter systems operating within a recirculation configuration demonstrated significant reduction of E. coli (99%), E. faecalis (99%), and P. aeruginosa (92%) after 24 h. Conversely, all sterile control systems did not show any significant reduction in pathogens. Subsequent analysis of the biofilter media after circulation showed that 0% of E. coli was recovered from the biofilter, whereas 0.06% and 1.26% of E. faecalis and P. aeruginosa were recovered respectively. Further investigation demonstrated the reduction of E. coli and enterococci from an environmentally-derived surface water of 99.8% and 99.4% respectively. In conclusion, this work demonstrates that biofilter systems can be used to significantly reduce waterborne pathogenic bacteria within fresh water. The potential application of low-cost, energy efficient biofilter systems for the management of waterborne bacterial pathogens in water supplies is discussed.