Site-Specific Nitrous Oxide Isotope Analyzer for Measuring Bioremediation

DOE is responsible for the remediation of 1.7 trillion gallons of contaminated ground water and 40 million cubic meters of contaminated soil generated at over 7000 discrete sites from past weapons production activities. This remediation involves a variety of methodologies including bioremediation, in which substances are injected into the subsurface to enhance microbial decomposition, and natural attenuation, in which natural, unaided processes are used to remediate waste. One of the challenges involved in this work is quantifying the rate of bioremediation. Several methods have been utilized by DOE researchers; however, these techniques require extensive sample handling and preparation, making them unsuitable for field deployment or rapid measurements. Improved methods are required to quantify bioremediation rates and bacterial activity. Recent studies have shown that denitrifying bacteria (e.g. found at the DOE IFRC Oak Ridge and Rifle sites) produce N2O with a distinct isotope ratio (e.g. 15N/14N and site-specific isotope ratio). Thus, by measuring the isotope ratio of N2O gas extracted from the soil, researchers can obtain a measure of bacterial activity and bioremediation rates. However, current measurement technology for N2O isotopes involves extensive sampling and a custom isotope ratio mass spectrometer (IRMS). In this SBIR program, Los Gatos Research proposes to develop a field-deployable analyzer for the accurate determination of 15N/14N and site-specific isotope ratios in nitrates (15N and 15N14NO vs. 14N15NO). The system will utilize LGRs proprietary mid-infrared Off-Axis ICOS technology to develop an analyzer to rapidly ( & lt; 5 minutes) determine N2O concentration and isotope ratios to better than 1% and 0.5 respectively. In Phase I, LGR will demonstrate technical feasibility by fabricating a prototype system and testing it to determine the instruments accuracy, precision, linearity, dynamic range, and time response. Then, LGR will work with Professor Joe von Fischer to deploy the analyzer for preliminary bacterial denitrification studies in soil. In Phase II, LGR will develop a fully autonomous sensor for the isotope determination of ambient nitrous oxide from soils. The sensor will include provisions for batch gas sampling, periodic calibration, and data reporting. At the conclusion of the program, LGR will deploy the analyzer at a DOE IFRC site (e.g. Rifle, Colorado) for long-term, continuous monitoring of bacterial denitrification in soils. Commercial Applications: During Phase III, LGR will sell the N2O isotope analyzers to isotope measurement laboratories, environmental research groups, global monitoring stations, and water quality management agencies. A market analysis suggests a 5-year commercial revenue exceeding $15 30M for these four markets alone.