1,136 research outputs found

    Guiding the development of a controlled ecological life support system

    Get PDF
    The workshop is reported which was held to establish guidelines for future development of ecological support systems, and to develop a group of researchers who understand the interdisciplinary requirements of the overall program

    Controlled Ecological Life Support System: Research and Development Guidelines

    Get PDF
    Results of a workshop designed to provide a base for initiating a program of research and development of controlled ecological life support systems (CELSS) are summarized. Included are an evaluation of a ground based manned demonstration as a milestone in CELSS development, and a discussion of development requirements for a successful ground based CELSS demonstration. Research recommendations are presented concerning the following topics: nutrition and food processing, food production, waste processing, systems engineering and modelling, and ecology-systems safety

    Organic compounds in hydraulic fracturing fluids and wastewaters: A review

    Get PDF
    High volume hydraulic fracturing (HVHF) of shale to stimulate the release of natural gas produces a large quantity of wastewater in the form of flowback fluids and produced water. These wastewaters are highly variable in their composition and contain a mixture of fracturing fluid additives, geogenic inorganic and organic substances, and transformation products. The qualitative and quantitative analyses of organic compounds identified in HVHF fluids, flowback fluids, and produced waters are reviewed here to communicate knowledge gaps that exist in the composition of HVHF wastewaters. In general, analyses of organic compounds have focused on those amenable to gas chromatography, focusing on volatile and semi-volatile oil and gas compounds. Studies of more polar and non-volatile organic compounds have been limited by a lack of knowledge of what compounds may be present as well as quantitative methods and standards available for analyzing these complex mixtures. Liquid chromatography paired with high-resolution mass spectrometry has been used to investigate a number of additives and will be a key tool to further research on transformation products that are increasingly solubilized through physical, chemical, and biological processes in situ and during environmental contamination events. Diverse treatments have been tested and applied to HVHF wastewaters but limited information has been published on the quantitative removal of individual organic compounds. This review focuses on recently published information on organic compounds identified in flowback fluids and produced waters from HVHF

    The use of microbial community fingerprinting as a marker for tracking the source of water: Application to pathogen and groundwater source tracking

    Get PDF
    Microbial community structure in groundwater is extremely complex and constitutes a fingerprint of water. Terminal restriction fragment length polymorphism (T-RFLP) analysis is a polymerase chain reaction (PCR)-based fingerprinting method that is commonly used for comparative microbial community analysis, and to track specific bacterial markers in complex environments.;The Objective of this research was to propose an innovative approach for tracking the origin of groundwater, microbial source tracking and origin of surface water, based on the specific structure of the microbial community using T-RFLP analysis, which can be used for microbial source tracking.;The first specific aim was to validate the use of T-RFLP profiles of deep and shallow waters in Huntingdon, PA, Great Valley, WV and Berkeley springs, WV, as a marker of the groundwater source. Alternatively, a 16S ribosomal DNA genomic library was constructed to identify bacterial species that can inform about the source of groundwater. It was observed that clustering based on screening a clone library gave more reliable information of the groundwater source than the T-RFLP profiles.;The second specific aim focused on the characterization of the microbial community from different streams along the Left Fork Mud River watershed in Lincoln County, WV. T-RFLP analyses were carried out for determining the source of contaminated water. Results showed that different streams of the Mud River watershed has a specific microbial terminal restriction fragment (TRF) profiles, which helps in determining the origin of water.;The third specific aim was to characterize the entire microbial community in several streams in Corridor-H watersheds, WV using T-RFLP analysis. It was observed that water samples collected from different locations of the same stream carried a very specific signature that can be used for microbial source tracking analysis. The T-RFLP method application on spring waters and Mud River watersheds was based on the preliminary results obtained from the analysis of the microbial community structure of several streams in Corridor-H watersheds.;Our results, thus provide the evidence that natural waters has a \u27microbial signature\u27 (T-RFLP profile) that can be used as a marker for pathogens and groundwater source tracking

    Treatment Of Bakken Produced Water Using Supercritical Water Desalination

    Get PDF
    Recent advances in horizontal drilling and hydraulic fracturing have significantly increased freshwater usage. Oil and gas wells in the United States tend to generate over 23 billion barrels of produced water per year of which about 32 million b/day are high total dissolved solids (TDS \u3e 200,000 mg/L) while the world is gradually running short of fresh water. Environmental concerns associated with water usage and concentrated wastewater disposal have led to the growing consideration to treat and recycle brine for reusable purposes like crop irrigation, livestock watering and hydraulic fracturing. In this study, an emerging and promising technology called supercritical water desalination (SCWD) has been developed. The aims of this study were to treat Bakken oil field brine, examine the applicability of the product water for reuse and evaluate the performance of supercritical water desalination. The results showed that at 240 bar water recovery efficiency from Bakken produced water increased with critical temperatures T_c above 400⁰C. Subsequently, the investigated additives proved to be excellent in the destruction of organics (~ 98% reduction efficiency) and targeted salt precipitation (~ 99% salt removal). The resulting ion analysis of the effluent stream demonstrates the SCWD approach as a highly efficient means for water recovery (~ 99% efficiency) with potential for zero liquid discharge (ZLD). SCWD is the most efficient, reliable and environmentally friendly technology, compared to conventional desalination treatments like reverse osmosis (RO), multistage flash (MSF), multieffect distillation (MED) and vapor compression distillation (VCD). The evaluation of the product water for livestock watering, irrigation and hydraulic fracturing demonstrates the SCWD technology as the most robust standalone method to treat hypersaline brine and produce high-quality product water

    Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants

    Get PDF
    Reproduced with permission from Environmental Health Perspectives."This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants." doi:10.1289/ehp.1002497Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Superfund-relevant CECs can be characterized by specific attributes: they are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites.Support for the workshop, from which this article evolved, was provided by the National Institute of Environmental Health Sciences Superfund Research Program (P42-ES04940)

    Biogeochemical characterisation of extreme environments

    Get PDF
    There is currently a considerable interest in characterising extreme environments, since they offer the opportunity to envision practical applications and to understand microbial diversity as an adaptive response that reflects environmental diversity. It is now well recognized that microorganisms thrive in extreme conditions such as contaminated soils/sediments and the pressurised depth of the Earth. Morphological, physiological, biochemical and genetic adaptations to extreme environments by these microorganisms have generated immense interest amongst scientists who continuously discover new occurrences and modes of microbial life on Earth. In this thesis, biogeochemical processes are investigated in two different extreme environments. (i) The deep biosphere, with a focus on shale gas basin and coal-bed methane (CBM). These environments are currently gaining momentum across the scientific community for the production of gaseous fuel. (i) [sic] Coal tar-contaminated soil and concentrated organic-phase coal tar, which was studied for bioremediation purposes. The core of this thesis consists of three articles dedicated to combination of different molecular and chromatographic methods of experimentation, analysis and interpretation. These include molecular tools such as DNA extraction techniques, PCR, 454-pyrosequencing and culturing-based approaches. The chemical experiments were metabolomic and isotopic chromatographic analyses. This study presented an extensive review of the biogeochemistry of unconventional gas systems, which provide an improved level of information of such environments. A robust culture-independent methodology was developed for the characterisation of microbial life in extreme environments, which was applied to describe, for the first time, the presence of bacteria in concentrated organic-phase coal tar. The deep sequencing methods were then used in combination with multidimensional compound specific isotope analysis (CSIA) to investigate community structure. The combined approach of deep sequencing methods with multidimensional CSIA was confirmed by statistics. Thus, high-throughput 16S rRNA gene sequencing and multidimentional CSIA, can be applied to investigate microbial community structure in extreme environments.There is currently a considerable interest in characterising extreme environments, since they offer the opportunity to envision practical applications and to understand microbial diversity as an adaptive response that reflects environmental diversity. It is now well recognized that microorganisms thrive in extreme conditions such as contaminated soils/sediments and the pressurised depth of the Earth. Morphological, physiological, biochemical and genetic adaptations to extreme environments by these microorganisms have generated immense interest amongst scientists who continuously discover new occurrences and modes of microbial life on Earth. In this thesis, biogeochemical processes are investigated in two different extreme environments. (i) The deep biosphere, with a focus on shale gas basin and coal-bed methane (CBM). These environments are currently gaining momentum across the scientific community for the production of gaseous fuel. (i) [sic] Coal tar-contaminated soil and concentrated organic-phase coal tar, which was studied for bioremediation purposes. The core of this thesis consists of three articles dedicated to combination of different molecular and chromatographic methods of experimentation, analysis and interpretation. These include molecular tools such as DNA extraction techniques, PCR, 454-pyrosequencing and culturing-based approaches. The chemical experiments were metabolomic and isotopic chromatographic analyses. This study presented an extensive review of the biogeochemistry of unconventional gas systems, which provide an improved level of information of such environments. A robust culture-independent methodology was developed for the characterisation of microbial life in extreme environments, which was applied to describe, for the first time, the presence of bacteria in concentrated organic-phase coal tar. The deep sequencing methods were then used in combination with multidimensional compound specific isotope analysis (CSIA) to investigate community structure. The combined approach of deep sequencing methods with multidimensional CSIA was confirmed by statistics. Thus, high-throughput 16S rRNA gene sequencing and multidimentional CSIA, can be applied to investigate microbial community structure in extreme environments

    Latest in modelling symposium - in honour of professor Pertti Koukkari's 65th birthday

    Get PDF

    Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants

    Get PDF
    Reproduced with permission from Environmental Health Perspectives."This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants." doi:10.1289/ehp.1002497Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Superfund-relevant CECs can be characterized by specific attributes: they are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites.Support for the workshop, from which this article evolved, was provided by the National Institute of Environmental Health Sciences Superfund Research Program (P42-ES04940)
    corecore