A sensor-based device capable of quickly measuring E. coli levels in water samples has been developed in the US.
Current methods to detect Escherichia coli, a bacterium highly indicative of the presence of fecal matter in water, typically require 24–48 hours to produce a result.
The autonomous, wireless, in-situ (AWISS), battery-powered device is said to contain a prototype optical sensor that can measure changes in fluorescence intensity in a water sample.
In the presence of E. coli bacteria, an enzymatic reaction will cause an increase in fluorescence. The AWISS can detect high concentrations of bacteria in less than one hour and lower concentrations in less than eight hours.
The detection system is able to collect and analyse a water sample every six hours and to employ wireless transmission to send the data collected to remote monitoring stations.
Jeffrey Talley of Johns Hopkins University and colleagues from Environmental Technology Solutions and the US Army Corps of Engineers presented the results of a seven-day demonstration project using the AWISS device in the journal Environmental Engineering Science.