Early Detection of Microbes from Prototype Water Recovery System Samples Using Real Time Conductivity Instrumentation

Early detection of microbial contaminants in reclaimed water was investigated using conductivity measurements of cultured samples. Culture data were obtained by using conductivity electronics and a personal computer equipped with an analog-digital converter and multiplexer. The software was programmed to monitor 54 cultures. The cultures were incubated for up to 48 hours at 35°C. The real-time conductivity data obtained from these cultured samples produces curves comprised of multiple data points over time. Using laboratory cultures for conductivity measurements, growth was detected within 12-24 hours with inocula in the range of less than 10⁰ to 10⁵ colony forming units per ml (CFU/ml). Detection times ranged from 20-35 hours for reclaimed water samples, and bacteria in untreated waste-waters were detected in 2-15 hours. The data show that conductance technology reliably detected contamination by viable bacteria in both untreated and treated water samples from the prototype water recovery system in less time and with less effort than traditional laboratory methods.