[1] Eawag, Dept Water Resources & Drinking Water, Dubendorf, Switzerland
[2] Swiss Fed Inst Technol, Dept Civil Environm & Geomat Engn, Zurich, Switzerland
[3] Univ British Columbia, Dept Microbiol & Immunol, Vancouver, BC V6T 1Z3, Canada
[4] Univ British Columbia, Sch Biomed Engn, Vancouver, BC V6T 1Z3, Canada
[5] Desert Res Inst, Div Hydrol Sci, Reno, NV USA