Water Security Sensor for Automatic Measurement of Micrograms of Heavy Metals in Drinking and Waste Water

There is a growing concern regarding the susceptibility of U.S. water systems to terrorist attack. This concern stems both from recent attacks against targets in the United States and from the inherent characteristics of U.S. water supply systems, which are spatially diverse, subject to intrusion, and contain many components. An important aspect of risk mitigation is implementation of smart early warning systems. The most effective warning systems provide constant automated monitoring and use advanced identification techniques in combination with computer-based software to help utility operators immediately identify contaminants. Early warning systems are particularly beneficial when they promote safe water even in nonthreat situations. ITN Energy Systems, Inc. (ITN) will adapt its advanced x-ray fluorescence (XRF) technology to create an automated smart sensor for trace amounts of toxic heavy metals in water. ITN’s technology is proven in solar cell manufacturing, where the sensor continuously monitors very small amounts of metal in products and automatically provides feedback to process control. The technique is inexpensive, very sensitive, and nearly maintenance free, and it generates a continuous signal for automatic monitoring. The sensor detects multiple metals simultaneously, including mercury, arsenic, and lead. ITN’s XRF technology succeeds in applications where XRF previously has been inappropriate. Unique geometry allows the sensor to view a large portion of the sample, and therefore obtain a larger signal and higher sensitivity. ITN’s novel sensor encapsulation allows component operation in close proximity to liquids. The goal of this research project is to adapt ITN’s XRF technology to provide a smart, automatic, early warning sensor for trace levels of toxic metals in water on a μg/L scale. In Phase I, the feasibility of this approach will be proven by showing that the sensor can detect 20 μg/L Hg in water without interference from other metals, chemical state of the metals, or organic material. In Phase II, sensor capabilities will be expanded. These improvements may include higher sensitivity, calibration for more elements, portability, remote communication of data, participation in EPA’s Environmental Technology Verification program, or cost reduction. In Phase III, the sensor will be sold as a smart, automatic, early warning sensor for trace metals in water on a μg/L scale. This will be useful for water security, plant discharge monitoring, and possibly drinking water.