Evaluation of Real-Time Water Quality Sensors for the Detection of Intentional Bacterial Spore Contamination of Potable Water

Abstract

Water utility treatment failure, as well as intentional or accidental water intrusions can introduce biological and/ or chemical contaminants into public drinking water distribution systems. However, recently developed real-time water quality sensors can be implemented to detect such contamination events. The overall objective of this study was to evaluate the potential for real-time monitoring of bacterial spore contamination of potable water using several different water quality sensors including: the HACH Monitoring Platform; the JMAR BioSentry unit; and the S::CAN spectro::lyser technology. For this, Bacillus thuringiensis spores were used as a surrogate for Bacillus anthracis. The minimum threshold response of sensors to the microbial contaminant was determined by injecting B. thuringiensis spores into Deionized (DI), filtered or unfiltered tap water. Out of these three evaluated sensors, the BioSentry sensor was capable of detecting introduced spores and responded to B. thuringiensis spores over a concentration range of 10 2 -10 5 spores/ml. In contrast, The HACH and S::CAN units were not capable of direct detection of spores. However, these two sensors can detect changes in water quality parameters such as turbidity, pH, temperature, total organic carbon and conductivity, due to media that may be associated with spores. Thus, these sensors can be integrated into a contaminant warning system for monitoring intrusion events in water distribution systems.