An alternative interpretation of disinfection kinetics

Abstract

During the past 100 years, several mathematical models have been developed and used to represent the dose‐response behavior observed when a microbial population is exposed to a disinfectant. These models are based on the premise that the interaction between a microorganism and a disinfectant is a kinetic process identical to that between chemicals undergoing a kinetic reaction. The rate of microbial inactivation has been expressed as a function of disinfectant concentration, microbial count, and water quality (such as temperature and pH). This article revives an alternative explanation to the dose‐response behavior of microbial disinfection, one that was also considered but abandoned about 100 years ago. The author argues that the relationship of continual decline in viable microbial count upon increased exposure to a disinfectant is not the result of a chemical‐type reaction process but rather attributable to the diversity of the microbial population in its resistance to the disinfectant. Using this hypothesis, the author provides example scenarios illustrating how environmental stresses to microbial populations could significantly alter their disinfection dose‐response curve.