Response to: Lindquist, E. D., Norman, W. R., & Soerens, T. (2015) A review of: Fouling in hollow fiber membrane microfilters used for household water treatment (2015) Murray, A., Goeb, M., Stewart, B., Hopper, C., Peck, J., Meub, C., Asatekin, A. & Lantagne, D. J. WASHDEV 5 (2), 220–228 doi:10.2166/washdev.2015.206

Abstract

We thank Lindquist and colleagues (Lindquist et al. 2015) for their critical review of our research article on fouling in hollow fiber membrane microfilters used for household water treatment (HWTS) (Murray et al. 2015). We welcome intelligent discourse which furthers efforts to provide microbiologically safe and reliable drinking water to those currently without it. Although we feel the original article provides clear background information, we would like to re-iterate the conditions under which this study was undertaken, as Lindquist et al. (2015) raised several questions indicating misunderstanding: Pure Water for the World (PWW) distributed Sawyer PointOne filters (Sawyer Products, Inc.) following their standard training and distribution program, and not as a controlled field trial. To monitor and evaluate the pilot project, PWW conducted household surveys and microbiological and turbidity testing of both source and filtered water at various times post-distribution. This in situ testing identified six filters that demonstrated >99% mean Escherichia coli removal 2 months following distribution and 54% mean E. coli removal 23 months following distribution (Goeb 2013), despite users demonstrating the correct backwashing procedure and self-reporting backwashing with adequate frequency. PWW's concern about reduced performance prompted this laboratory investigation of those six filters . The critical review identified concerns about the laboratory study methodology with …