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A SYSTEMATIC STUDY ON THE SURFACE CHARGE OF MICROORGANISMS IN DRINKING WATER
Citation:
Lytle*, D A., E W. Rice, C H. Johnson, J H. Owens*, AND M. Marshall. A SYSTEMATIC STUDY ON THE SURFACE CHARGE OF MICROORGANISMS IN DRINKING WATER. Presented at 1999 AWWA Water Quality and Technology Conference, Tampa, FL, November 01 - 04, 1999.
Description:
The removal of microbiological pathogens from drinking water is an important function of water treatment. The mechanisms of particle and pathogen removal during coagulation/flocculation/filtration processes are well known. Surface charge is particularly important in particle destabilization and attachment processes. Although several researchers have reported the net surface charge of some microorganisms in aqueous environments, the extrapolation and usefulness of the information are limited by the specificity of the conditions under which the experiments were conducted. The objective of this study was to measure and compare the electrophoretic mobility of a number of microorganisms in aqueous suspensions. The impact of pH, ionic strength and cation valence state on the surface charge properties of the microorganisms was examined. The microorganisms studies include Bacillus subtilis endospores, Cryptosporidium parvum, wild-type Escherichia coli, Escherichia coli 0157:H7, Encephalitozoon intestinalis, and Vibrio cholerae (rough and smooth variants). The study results showed that microorganisms can have significantly different charge properties in water. The differences can effect their behavior in water such as their stability and likelihood to attach to surfaces. This study showed that surface charge is impacted by pH, ionic strength and ionic make-up of the water.