Hurricane Harvey brought record rainfall to the Houston-Galveston region and the Texas coast. After making landfall near Rockport, Texas as a Category 4 storm on August 25, 2017 and lingering for more than four days, Harvey dropped more than 50 inches of rain in parts of Houston, leaving behind a devastated region.
In 2016 the HARC Environmentally Friendly Drilling Program (EFD) successfully concluded a multi-faceted $4 million research effort to understand and mitigate the environmental impact of oil and gas activities. The Coastal Impacts Technology Program (CITP) focused on developing cost-effective technologies and practices addressing environmental issues and workforce development along the coast. EFD’s direct engagement with the oil and gas industry brought unique insights into the investigation of these questions, basing research on practical needs and solutions.
CITP was funded from the Coastal Impact Assistance Program (CIAP), a multi-year research program authorized by the Energy Policy Act of 2005, administered by the US Fish and Wildlife Service. Roughly $960 million from Outer Continental Shelf oil and gas revenue sharing was appropriated to offshore oil and gas producing states for the benefit of coastal communities, economies, and ecosystems. CITP addressed a comprehensive suite of topics and areas of research need. These research and demonstration projects accomplished so much because of the partners who took part in the program. In addition to the important work of academic researchers, it was the oil and gas industry that responded with important feedback and willingness to participate in workshops and field studies. These efforts yielded invaluable information, tools, and technologies to improve environmental performance and foster conservation, prosperity, and resilience in the coastal areas of Texas.
By engaging a diverse range of stakeholders EFD identified opportunities for environmental impact mitigation, conservation, protection and restoration of Texas coastal ecosystems. Results of this effort became the basis for solicitation and selection of projects in support of attaining program objectives. A total of 16 projects were funded in various disciplines focusing on air emissions, water resources, site restoration, and workforce development. In this, the first in a series of articles, selected CITP projects will be highlighted.
The featured project was carried out at the Texas A&M University Kingsville campus under the guidance of Dr. Kim Jones, Professor and Director, Institute for Sustainable Energy and the Environment. The project, entitled “Innovative Biological Emissions Treatment Technology to Reduce Air Pollution” designed and tested a bioreactor to treat air emissions at oil and gas facilities. Tanks that store oil and produced water at production facilities often vent to the atmosphere. These emissions can contain hydrocarbon vapor and volatile organic compounds (VOCs), some of which are hazardous. In some cases these emissions are captured and flared. The biological treatment system tested in this project represents a breakthrough in providing an effective alternative to flaring.
Researchers developed and tested a two-stage biofiltration technology that destroys pollutants at ambient temperatures and does not generate secondary pollutants that result from flaring. In this approach, two types of biological treatment are used together in tandem. Microorganisms use the contaminants as food, transforming them into carbon dioxide, water, and biomass. An industrial collaborator accomplished in the use of this technology in other applications assisted in the design and construction of experimental equipment as well as data analysis.
The two-stage bio-oxidation process utilized a bio-tricking treatment unit and a biofilter. Air emissions captured from the storage tank vents are blown into the process, while water is circulated through the system to help nourish the microbes that do the work of removing contaminants. While both stages of the treatment process make use of microbes, the function in each stage is different.
In the first stage, the bio-trickling filter, microbes live on the surfaces of a solid 3D matrix. Water is sprayed onto the matrix as air is blown through the unit, exposing it to the microbes. In the second stage, the biofilter, microorganisms such as bacteria and fungi that have been cultured in a compost media do the work of treating emissions. To improve performance the compost is packed into small, open plastic spheres to prevent the media from becoming compacted.
In laboratory experiments the process was refined to develop a pilot scale unit that could be tested in the field. The pilot scale unit was then fabricated for use at an oil production facility to test with vapor from the storage tanks. In a splendid example of industry collaboration, an EFD industry partner stepped forward to offer a field test site.
In the field, vapor samples were collected from the storage tanks and analyzed to determine what substances were present in the emissions. Additional samples were collected at various points in the treatment process to assess treatment effectiveness. On average, 50-60% of the VOCs were effectively removed during the pilot test. Removal efficiency continued to increase over time as the microbes became acclimated and more able to metabolize the substances present in the emissions.
The field trial also revealed characteristics that can be improved upon in future designs to further increase treatment efficiency. Subsequent phases of this project would be optimization of air flow, water flow and residence time for the most effective contaminant degradation. Further improvements could incorporate controls for operation and monitoring at remote oil and gas facilities.