Journal article
Kinetics of inactivation of giardia lamblia by free chlorine
Water research (Oxford), v 24(2)
1990
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The experimental data of Hibler on the inactivation of Giardia cysts by free chlorine was analyzed by the method of maximum likelihood. It was found that the Hom model with an
m value less than 1 (indicative of “tailing off”) more precisely characterized the inactivation than the Chick-Watson model. The Hom model was found to fit the data using a Monte Carlo procedure to obtain the sampling distribution of the log likelihood statistic.
The jackknife procedure was used to produce interval estimates for inactivation rate parameters and
et values at various concentrations, temperatures, pH values and degrees of inactivation. The
et values increase as concentration increases due to coefficients of dilution less than one. The computed
et values are generally lower, and, particularly at 2–3 logs inactivation substantially lower, than those previously estimated from the same data by Hibler and by Clark
et al. The difference is attributed to the manner in which these workers lumped results in which from 1 to 4 (of 5) animals were infected and interpreted them as arising from 4 logs inactivation.
At both 2.5 and 5°C, there is a consistent increase in the required
et value with pH. However at 0.5°C, the
et values at pH 8 are less than those required at pH 7, contrary to anticipated. At pH 6, there is a consistent decrease in required
et values as temperature increases. However at pH 7 and pH 8, the effect of temperature is more irregular.
Due to the apparent anomalies in the pH and temperature dependence of the
et values no procedure for extrapolation of the inactivation results outside the range of conditions used by Hibler can be recommended.
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Details
- Title
- Kinetics of inactivation of giardia lamblia by free chlorine
- Creators
- Charles N. Haas - Pritzker Department of Environmental Engineering Chicago, IL 60616, U.S.A.Barbara Heller - Illinois Institute of Technology
- Publication Details
- Water research (Oxford), v 24(2)
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Civil, Architectural, and Environmental Engineering
- Web of Science ID
- WOS:A1990CU97200013
- Scopus ID
- 2-s2.0-0025387711
- Other Identifier
- 991019189191304721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Engineering, Environmental
- Environmental Sciences
- Water Resources