AQUA PATH: Safe Water for Soldiers and Civilians

By October 24, 2011October 17th, 2014General, Science and Technology
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By Dr. Clint Smith

ERDC Research Biologist Dr. Clint Smith prepares the first six prototypes of AQUA PATH wireless geospatial networked biosensors for field testing and evaluation at Belmont Bay of the Potomac River in Woodbridge, VA in the summer of 2008. (Photo courtesy of U.S. Army Corps of Engineers.)

Water supply safety and quality for human use create major challenges for both our deployed forces and homeland security. Current operations in Afghanistan, U.S. Africa Command, U.S. Pacific Command, and other worldwide locations need safe water supplies to ensure stability and security for local populations.

Water for the warfighter in theater is a limited resource and can halt major military operational support through lack of availability, tainted supplies, or ignorance of water resources for infrastructure analysis. The transition of a wireless waterborne pathogen detection system, called AQUA PATH (Autonomous Querying Threat Agent Sensor for Potable Water Handling), focuses on significantly reducing the costs and time associated with potable water monitoring and threat reduction for Soldiers and civilians.

AQUA PATH consists of a patented optical biosensor that is sensitive and selective. It can operate for extended periods of time using minimal power and is easily tailored in the field to detect a variety of pathogens by swapping modular cartridges. The device is connected to a floating buoy with wireless networking capability, tamper detection sensors, and additional sensor capabilities to monitor water quality parameters such as pH, turbidity, luminescence dissolved oxygen, and conductivity. Wireless communications aggregate data and allow a first tier of data analysis. This allows for the rapid detection and notification of natural or human tainting of the water supply.

AQUA PATH reflects major improvements over current detection systems, including more rapid testing (within two hours vs. 16 hours), high sensitivity (10 Colony Forming Units per 100 milliliters (CFU/100mL) for detection of the bacterium Escherichia coli), rapid detection of waterborne pathogens and toxins (with a lowest reported time of less than 20 minutes in the field for presence or absence), and 2.5-hour high-sensitivity detection.

The U.S. Environmental Protection Agency (EPA) completed its assessment of the AQUA PATH in-line sensor in August. The assessment showed that the sensor can successfully detect various levels of E. coli within 2.5 hours. The EPA will soon publish results of the test and the evaluation. These sensing limits and built-in communications reporting are not available to the Army or U.S. Department of Homeland Security using current systems.

Geo-enabled sensors are currently limited by present technology, but the AQUA PATH System has matured quickly within the Army’s TerraProbes and Watchman 6.2 (applied research) work packages. The packages also helped to validate the sensitivity of AQUA PATH to 10 CFU/100mL for detection of E. coli within a 2.5-hour timeframe, which is an order of magnitude better —about 16 hours faster—than current standards set by all 50 states, the EPA, and Standard Methods for the Testing of Water and Wastewater Guidelines, a joint publication of the American Public Health Association, the American Water Works Association, and the Water Environment Federation. Furthermore, it removes the need to take water samples back to a laboratory and thus saves time for the user.

“The transition of … AQUA PATH focuses on significantly reducing the costs and time associated with potable water monitoring and threat reduction for Soldiers and civilians.”

The U.S. Army Engineer Research and Development Center (ERDC) plans to expand the capabilities of AQUA PATH to accomplish detection of additional pathogens of interest, including Vibrio cholera, Enterococcus, E. coli 0157: H7 ,and others. The production of new targets of interest will be investigated and developed by a joint collaboration between the U.S. Army, small business, and Idaho National Laboratory, which collaborated in evaluating the wireless communication units.

Based upon ERDC studies, the distance between AQUA PATH nodes can range from 1,500 to 3,000 meters. The distance between the gateway interface and the nodes is about 500 meters (line of sight). Further studies are planned on non-line-of-sight distance, with and without vegetation, as well as with variations in topography and stream or reservoir localities.

The small business Sporian Microsystems Inc. is collaborating with ERDC, as well as with NanoSonic Inc., to improve stability of the biosensor by using flexible, conductive metal rubber-based materials for the thin-filmed construct. The manufacturing of this technology can be ramped up to larger output for further evaluation and use. Potential larger industrial partners for increased production include Thermo Fisher Scientific Inc., SRC Inc., Boeing, and Lockheed-Martin Corp.

In FY12, AQUA PATH continues to transition to commercial efforts via the research and development efforts of an ERDC Center Directed Research program: Watchman. Future test, evaluation, and assessments for the Watchman effort include demonstrations for the U.S. Marine Corps’ Cobra Gold Force protection exercise in Thailand and Exercise Balikatan, a joint U.S.-Philippines military exercise in which AQUA PATH will be demonstrated, as well as used, to track various levels of E. coli and Vibrio cholerain source waters.

For more information on the U.S. Army Corps of Engineers, visit, or for more information on ERDC, visit


  • DR. CLINT SMITH is a Research Biologist at ERDC. He holds a Ph.D. in environmental science and policy from George Mason University (GMU), a M.S. in environmental microbiology from Virginia Commonwealth University, and a B.S. in biochemistry from North Carolina State University. Smith is a Contracting Officer’s Representative and, through a Cooperative Research and Development Agreement, directs research efforts in geospatial distributed sensors in his laboratory at GMU’s Department of Environmental Science and Policy as part of the specialized Fluorescence Remote Sensing Team.


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