Date: Jun 01, 2013 Author: press release Source: Company Data (
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Richland, WA -- The U.S. Department of Energy Office of Science awarded Freestone Environmental Services, Inc. a Phase II -- Small Business Innovation Research (SBIR) Grant to develop a sensor capable of measuring hexavalent chromium while submerged in a groundwater monitoring well. Hexavalent chromium is a carcinogen and industrial contaminant found in groundwater. The $1Million research grant follows the successful demonstration of a Phase I SBIR proof-of-principle feasibility study that Freestone conducted in 2012. The Phase II grant will be applied over a two-year period and is intended to advance the development of new, promising technologies in areas deemed critical to the Department of Energy's mission. The ability to provide real-time, direct measurement of hexavalent chromium in groundwater, and send that data out via radio signals from a remote monitoring location has world-wide application.
Hexavalent chromium is used for the production of stainless steel, textile dyes, wood preservation, leather tanning, and as anti-corrosion and conversion coatings. The popular movie, "Erin Brockovich" led to the wide spread notoriety of the extensive hexavalent chromium contamination found in groundwater beneath Hinckley, California and health effects attributed to exposure to industrial workers and residents.
At the U.S. Department of Energy's Hanford Site, enormous quantities of sodium dichromate (which dissolves in water to hexavalent chromium) were shipped in by rail tanker cars for use as an anticorrosion agent in reactor cooling water systems. Spills and leaks of dichromate solutions and direct discharge of cooling water to the ground adjacent to the Columbia River resulted in over 5 square miles contaminated at levels above 10 parts per billion. Sodium dichromate was also used in the plutonium separation process performed in the central plateau of the Hanford Site and is found in groundwater contaminant plumes there as well.
Hexavalent chromium readily moves with groundwater. Its concentration in groundwater contaminant plumes is affected by proximity to the spill source, interactions with surface water, or when drawn toward a pumped well. The ability to measure hexavalent chromium plumes is important in determining whether drinking water supplies or sensitive species such as young salmon may be exposed to harmful amounts of the contaminant. Measuring plume movement and distribution is also important for determining the approach taken to remediating a contaminated site, and in evaluating the effectiveness of a cleanup.
Inspiration for this sensor springs from Freestone's experience investigating chromium contaminated soil, groundwater, and river bed sediments at the Department of Energy's Hanford Site over a number of years. Conventional methods for measuring hexavalent chromium concentration require collecting a sample and then performing multiple steps to prepare the sample for analysis either in the field or for shipping to an off-site laboratory. That conventional process is time consuming, cumbersome, and subject to human error. The costliness of conventional methods limits the quantity of measurements that can be practically obtained.
Freestone's Senior Geochemist, Steve Hall is the inventor of this novel technology which uses near-ultraviolet absorbance spectrophotometry and compensates for turbidity interference. The sensor does not require addition of chemical reagents or sample filtering like conventional methods. It is also sensitive across a broad range from a few parts per billion to very high concentrations, while conventional methods must first be carefully diluted before measuring high concentrations.The sensor will be equipped so data can be transmitted from remote locations to a data management platform for visualization, analysis, and real-time input to treatment system operations.
A team of Freestone scientists and locally based engineers and fabricators are working together to develop and test sensor prototypes. Freestone plans to begin field testing sensor prototypes this summer. After engineering refinements are made, the firm hopes to demonstrate the sensor at various chromium cleanup sites. In addition to its configuration as a submersible sensor, a portable field test kit has been developed, and a flow-through cell for direct in-line measurement will be built for use in water treatment and industrial wastewater treatment systems.
