AWWA WQTC62484

This slide presentation outlines information on a portable system for the detection of the trihalomethane group (THMs) of disinfection byproducts in water that was developed by Sandia National Laboratories. This system provides a small footprint, low cost, sensitive, and quickly deployable water sensor. The self contained system weighs less than 32 pounds, occupies a carry-on luggage sized case, and performs THM analysis in less than four minutes. The technique of purge and trap (P&T) is performed on a water sample followed by isothermal gas chromatography. A three sensor surface acoustic wave (SAW) detector array, which provides a set of three responses for additional confidence, detects the THMs. An inexpensive programmable integrated circuit (PIC) processor handles heating, timing, valve control and data collection functions for the system. Plotting and analysis are performed with a portable computer. Sandia's detection system is meant to fill the need for a rapid, portable, and sensitive low cost analysis. The system and components will be described, along with results from both laboratory tests and field tests. Current and ongoing improvements will also be discussed, such as the use of microfabricated components to reduce the power and size of the overall system, and efforts to expand the analyte set to other volatile and semi-volatile regulatory and terrorism related compounds.