Supporting a drinking water contaminant warning system using the adenosine triphosphate test

Abstract

A contaminant warning system (CWS) with the capability to detect aberrations in drinking water in real-time or near real-time represents significant value for protection of consumers from accidental or intentional contamination of drinking water. The capabilities of a two-tier CWS are examined, the first including nonpurgeable organic carbon (NPOC), free chlorine, turbidity, pH, and conductivity, followed by a confirmatory adenosine triphosphate (ATP) analysis, to control false positives. The utility of the confirmatory analysis is improved by use of a continuous ultrafiltration system, which improves the detection and the correlation between the concentration of Escherichia coli in the sample and measured ATP. The sample was concentrated one hundredfold in 22 min increasing the ATP value of the sample from 980 to 9.8 × 104 CFU/mL as microbial equivalents. The two-tier system is shown to be a successful method for confirmation of biological contamination in near real-time, while controlling false positives and (or) false negatives.