Use of Bacillus subtilis spores as model micro-organisms for ozonation of Cryptosporidium parvum in drinking water treatment
- 1 June 2002
- journal article
- Published by Thomas Telford Ltd. in Journal of Environmental Engineering and Science
- Vol. 1 (3), 173-186
- https://doi.org/10.1139/s02-012
Abstract
Spores of the aerobic bacterium Bacillus subtilis are potential models for evaluation of Cryptosporidium parvum inactivation by ozone processes in drinking water treatment. The kinetics of inactivation by ozone of prepared Bacillus subtilis ATCC 6633 spores were measured in a series of batch reactor experiments at temperatures of 3, 12, and 22°C and at a pH of 6 and 8. Spore inactivation curves were characterized by a pronounced lag phase at low ozone exposures followed by a logarithmic inactivation rate and, finally, by a tailing region at higher ozone exposures. A two-part kinetic model consisting of a multitarget term and a first-order term provided a good fit to observed inactivation at each temperature. Water pH had a statistically significant but limited effect on spore inactivation. When spore inactivation was compared to C. parvum oocyst inactivation predicted by a previously published kinetic model, substantial differences were observed. These differences may make it difficult to use this particular strain and preparation of spores to reliably predict C. parvum oocyst inactivation from the outcomes of B. subtilis seeding studies. Bacillus subtilis spores may otherwise serve as indicators of the hydrodynamic efficiency of ozone contactors. Key words: ozone, inactivation, Bacillus subtilis spores, Cryptosporidium parvum oocysts, drinking water, kinetics, modeling.Keywords
This publication has 27 references indexed in Scilit:
- Evaluating bacterial aerobic spores as a surrogate for Giardia and Cryptosporidium inactivation by ozoneWater Research, 2000
- Examining the use of aerobic spore-forming bacteria to assess the efficiency of chlorinationWater Research, 1999
- Inactivation of Cryptosporidium parvum oocysts with ozoneWater Research, 1999
- A modified method for the enumeration of aerobic spore-forming bacteriaCanadian Journal of Microbiology, 1997
- Disinfection under Dynamic Conditions: Modification of Hom's Model for DecayEnvironmental Science & Technology, 1994
- Micromixing and dispersion in chlorine contact chambersEnvironmental Technology Letters, 1988
- Kinetic modeling of U.V. disinfection of waterWater Research, 1983
- Determination of ozone in water by the indigo methodWater Research, 1981
- A REVIEW Tailing of Survival Curves of Bacterial SporesJournal of Applied Bacteriology, 1977
- The Fitting of Multi-Hit Survival CurvesBiometrics, 1953