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- Crop Irrigation with Treated Produced Water
- Produced Water Toxicity and Chemical Characterization
- Citrus Greening Disease
- Quantification of Soil Organic Carbon and Nitrogen with Novel Spectroscopy Technique
- Impact of Forest Fires on the Formation of Toxic Disinfection Byproducts during Drinking Water Treatment
- Controls on Soil Organic Matter Sorption on Mineral Surfaces
- Effect of Catalyzed Iron Oxide Recrystallization on Carbon Stabilization
- Transformation of Hydraulic Fracturing Fluid Additives under Downhole Conditions
Wheat Irrigation with Treated Produced Water
Postdoctoral researcher Hannah Miller and masters student Yuheng Qiu, in collaboration with PhD student Erin Sedlacko at Colorado School of Mines, are conducting a wheat greenhouse study to evaluate the potential beneficial reuse of produced water for agriculture. Oil and gas operations produce large volumes of wastewater, containing high salt contents, hydrocarbons, chemical additives, and naturally occurring heavy metals. This produced water has potential to be a valuable irrigation resource for drought-stricken agricultural fields. However, it is unclear if the resulting wheat is safe for human consumption and if irrigation with produced water leads to compromised plant immune systems. Our greenhouse study addresses these questions by growing wheat with various dilutions of produced water, as well as controls, while measuring plant metabolic responses and physiologic parameters. Preliminary results indicate that wheat cannot produce sufficient yields when watered with a 50% dilution of produced water and tap water.
Produced Water Toxicity and Chemical Characterization
The water that exists in oil and gas (O&G) reservoirs and is brought to the surface during resource extraction, called produced water (PW), is the largest volume waste stream associated with O&G extraction, with over 3 trillion liters produced annually in the U.S. Because of its origins in O&G reservoirs, PW contains elevated levels of toxic petroleum hydrocarbons, salts, heavy metals, naturally occurring radioactive materials and any remaining drilling, stimulation or well maintenance chemicals. Many water-scarce western states can take advantage of the National Pollutant Discharge Elimination System (NPDES) which permits PW to be released to the environment for agricultural uses if it is “of good enough quality.“ Some states, including California, also permit releases of this water, after minimal treatment, for use in agriculture. The requirements for releasing this water are not clearly defined through permissible concentrations, however, and the locally and temporally varying composition of PW discharges is largely unknown.
Optimizing Pesticide Management Strategies for Citrus Greening Disease
Citrus greening, or Huanlongbing (HLB) disease, causes citrus trees to produce smaller, green-colored, sour oranges. HLB is spread through psyllids, small flying insects that suck on new flush (leaves), infecting the phloem of the trees with HLB bacteria. Early detection of infected trees is primarily accomplished through molecular techniques, but as the trees become completely infected they are identified by asymmetrical, yellow leaf discoloration and weakened root systems, along with green oranges. Currently, there is no cure for citrus greening, leading to wide-scale abandonment of citrus groves in Florida. Our interdisciplinary team at CSU is focusing on determining the best management strategies to establish sustainable citrus production in Florida.
- Develop analytical methods to quantify spatial distribution of pesticides by both aerial and ground application
- Characterize pesticide fate and transport in citrus groves using sorbents to capture pesticide concentrations
- Optimize pesticide application strategies
- Determine pesticide resistance by psyllid populations within groves impacted by citrus greening
- Track psyllid population movement within citrus groves to determine best strategies for limiting population growth
Quantification of Soil Organic Carbon and Nitrogen with Novel Spectroscopy Technique
ARPA-E’s Rhizosphere Observations Optimizing Terrestrial Sequestration (ROOTS) program supports the development of advanced technologies and crop cultivars that will increase soil carbon accumulation, decrease greenhouse gas emissions, and improve crop and water productivity. We are participating in a project led by John McKay (Associate Professor, Department of Agricultural Biology) and funded by the ROOTS program, which includes the application of a novel “Doppler” Raman spectroscopy technique, developed by Randy Bartels (Professor, Electrical and Computer Engineering), to soils. Because Doppler Raman spectroscopy avoids the limitations of other common spectroscopy techniques (i.e., strong fluorescence or labor intensive sample preparation), we expect to be able to quantify soil organic carbon and nitrogen with unprecedented speed and accuracy.
Impact of Forest Fires on the Formation of Toxic Disinfection Byproducts during Drinking Water Treatment
Forest fires affect the chemistry of surface waters, which are commonly treated to provide safe drinking water to nearby communities. During treatment, the organic matter in surface waters can react to form toxic disinfection byproducts, and their formation appears to increase when fire-impacted waters are treated. In collaboration with Fernando Rosario-Ortiz (Professor, Civil, Architectural and Environmental Engineering, University of Colorado Boulder), we are using high resolution mass spectrometry to examine the effects of fire on organic matter chemistry and disinfection byproduct formation.
Controls on Soil Organic Matter Sorption on Mineral Surfaces
In moist soils, short-range ordered minerals such as iron oxyhydroxides are strong predictors of carbon storage. Therefore, understanding the interactions between organic carbon and iron under various conditions is key to accurate carbon modeling and comprehensive knowledge of nutrient cycling. We have evaluated the impacts of temperature, hydrology, and redox conditions on carbon storage, organo-metal complexation, and iron bioavailability. Investigating these systems involves multiple approaches, including sample collection in mountain wetlands, chromatography and batch experiments in the laboratory, and a host of analytical techniques such as synchrotron-based X-ray absorption spectroscopy, high resolution mass spectrometry, ion chromatography, nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectroscopy.
Effect of Catalyzed Iron Oxide Recrystallization on Carbon Stabilization
Natural organic matter and iron oxides strongly associate in soils and sediments, and these associations, in turn, affect carbon storage in soils. The dissolution of iron oxides, whether by ligand-promoted reactions or by changes in redox and pH conditions, can release organic matter to the soil solution. Alternatively, the precipitation of iron oxides can trap organic matter in co-precipitates and other mineral-organic associations. Reduced iron (Fe(II)) catalyzes the recrystallization of iron oxides, but the influence of this process on organic matter stabilization, and the influence of organic matter on this process, are unknown. In a collaboration with Michelle Scherer (Professor, Civil and Environmental Engineering, University of Iowa), Clark Johnson (Professor, Department of Geoscience, University of Wisconsin-Madison), and Aaron Thompson (Associate Professor, Crop and Soil Sciences, University of Georgia), we are using high resolution mass spectrometry to examine the influence of Fe(II)-catalyzed recrystallization on organic matter stabilization.
Transformation of Hydraulic Fracturing Fluid Additives Under Downhole Conditions
Hydraulic fracturing is a gas and oil extraction process by which gas- and oil-containing rock layers are fractured using a pressurized fluid and sand mixture. In conjuncture with horizontal drilling, this practice is now commonly used to drastically increase the yield of natural gas from drilled wells. The fluid injected into these wells contains many chemicals which include biocides to control growth of sulfate-reducing bacteria. Currently it unknown if these biocides break down, transform, or persist in the high pressures and temperatures that exist underground. Using specialized reaction vessels capable of high temperature and pressure along with analytical techniques, we will attempt to elucidate the down-hole fate of certain biocides.
- Linking Climate Induced Vegetation Changes to Disinfection Byproducts Formation
- Environmental Fate of Pharmaceutical Micropollutants and their Metabolites
- Geochemical Characterization of Baseline Conditions at a Uranium In-situ Recovery (ISR) Mine
- Catalyzed Electrolytic Degradation of an Organic Contaminant
- Front Range Air Pollution and Photochemistry Experiment (FRAPPE)