DIFFUSION CHAMBER METHOD FOR IN-SITU MEASUREMENT OF PATHOGEN INACTIVATION IN GROUNDWATER

A method has been developed to measure pathogen inactivation in ground water in situ by installing diffusion chambers in wells. This method h as advantages over others in terms of utility, reduction of artefacts, and the ability to accommodate porous media. The diffusion chambers h ave been tasted in the laboratory for their ease of sterilization, and the effect of pressure on leakage. Exchange processes across the memb ranes were examined, and the effective diffusion coefficients for move ment of KCI through two different pore-size membranes are given. An ex pression to account for the dilution in microbial concentrations due t o periodic subsampling from the chamber has been determined. Finally, an example in a held application of the use of diffusion chambers in s itu provided inactivation rates for Enterococcus faecalis from chamber s with and without a porous medium. (C) 1998 Elsevier Science Ltd. All rights reserved.