ENVR 191 |
| The efficacy of continuously monitoring free chlorine concentrations as a surrogate indicator of microbial contamination in water distribution systems was investigated. A model distribution system was constructed of 1 inch PVC pipe and valves, equipped with a Hach amperometric free chlorine sensor and fed with tap water from the City of Pittsburgh distribution system. Suspensions of Escherichia coli were experimentally injected into the model distribution system under varying conditions and free chlorine concentrations were continuously monitored at a rate of once per 10 seconds before, during and after each injection. The magnitude of the chlorine demand signal generated by each injection scenario was proportional to the injected cell concentration, the background free chlorine concentration, the system Reynolds number and the contact time. These results provide guidance on the limitations of free chlorine as a surrogate indicator of microbial contamination in distribution systems and on decision support for sensor placement. |
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Recent Developments in Sensors and Sensor Networks for Contaminants in Environmental Systems
6:00 PM-8:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster
Sci-Mix
Division of Environmental Chemistry |