228 research outputs found
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A PROPOSED FRAMEWORK FOR PLANNING DEACTIVATION AND DECOMMISSIONING ENGINEERING AND DESIGN ACTIVITIES TO MEET THE REQUIREMENTS OF DOE ORDER 413.3A, PROGRAM AND PROJECT MANAGEMENT FOR THE ACQUISITION OF CAPITAL ASSETS
This paper provides guidance in applying the requirements of DOE O 413.3A to Deactivation and Decommissioning (D&D) projects. A list of 41 engineering and design activities relevant to D&D projects was generated. For several activities in this list, examples of the level of development and/or types of deliverables that might be expected at the completion of the conceptual, preliminary and final project design phases described in the Order are provided
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FULL-SCALE TREATMENT WETLANDS FOR METAL REMOVAL FROM INDUSTRIAL WASTEWATER
The A-01 NPDES outfall at the Savannah River Site receives process wastewater discharges and stormwater runoff from the Savannah River National Laboratory. Routine monitoring indicated that copper concentrations were regularly higher than discharge permit limit, and water routinely failed toxicity tests. These conditions necessitated treatment of nearly one million gallons of water per day plus storm runoff. Washington Savannah River Company personnel explored options to bring process and runoff waters into compliance with the permit conditions, including source reduction, engineering solutions, and biological solutions. A conceptual design for a constructed wetland treatment system (WTS) was developed and the full-scale system was constructed and began operation in 2000. The overall objective of our research is to better understand the mechanisms of operation of the A-01 WTS in order to provide better input to design of future systems. The system is a vegetated surface flow wetland with a hydraulic retention time of approximately 48 hours. Copper, mercury, and lead removal efficiencies are very high, all in excess of 80% removal from water passing through the wetland system. Zinc removal is 60%, and nickel is generally unaffected. Dissolved organic carbon in the water column is increased by the system and reduces toxicity of the effluent. Concentrations of metals in the A-01 WTS sediments generally decrease with depth and along the flow path through the wetland. Sequential extraction results indicate that most metals are tightly bound to wetland sediments
Full-Scale Treatment Wetlands for Metal Removal from Industrial Wastewater
Acknowledgements This research was conducted and the document was prepared in connection with work under U.S. Department of Energy contract DE-AC09-96SR18500. Extensive collaboration with Clemson University and Weston Engineering were essential during the design and construction phases of the wetland facility. Abstract The A-01 NPDES outfall at the Savannah River Site receives process wastewater discharges and stormwater runoff from the Savannah River National Laboratory. Routine monitoring indicated that copper concentrations were regularly higher than discharge permit limit, and water routinely failed toxicity tests. These conditions necessitated treatment of nearly one million gallons of water per day plus storm runoff. Washington Savannah River Company personnel explored options to bring process and runoff waters into compliance with the permit conditions, including source reduction, engineering solutions, and biological solutions. A conceptual design for a constructed wetland treatment system (WTS) was developed and the full-scale system was constructed and began operation in 2000. The overall objective of our research is to better understand the mechanisms of operation of the A-01 WTS in order to provide better input to design of future systems. The system is a vegetated surface flow wetland with a hydraulic retention time of approximately 48 hours. Copper, mercury, and lead removal efficiencies are very high, all in excess of 80% removal from water passing through the wetland system. Zinc removal is 60%, and nickel is generally unaffected. Dissolved organic carbon in the water column is increased by the system and reduces toxicity of the effluent. Concentrations of metals in the A-01 WTS sediments generally decrease with depth and along the flow path through the wetland. Sequential extraction results indicate that most metals are tightly bound to wetland sediments. Introduction The ability of natural wetlands to improve many aspects of water quality has been recognized for many years. This natural process has been utilized in many different forms and applications to use constructed treatment wetlands for the purpose of water quality improvement Removal of metals from the water occurs by two primary mechanisms: sorption and precipitation. Sorption of metal ions to organic matter and/or clay particles begins immediately
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Production of ent-kaurene from lignocellulosic hydrolysate in Rhodosporidium toruloides.
BACKGROUND:Rhodosporidium toruloides has emerged as a promising host for the production of bioproducts from lignocellulose, in part due to its ability to grow on lignocellulosic feedstocks, tolerate growth inhibitors, and co-utilize sugars and lignin-derived monomers. Ent-kaurene derivatives have a diverse range of potential applications from therapeutics to novel resin-based materials. RESULTS:The Design, Build, Test, and Learn (DBTL) approach was employed to engineer production of the non-native diterpene ent-kaurene in R. toruloides. Following expression of kaurene synthase (KS) in R. toruloides in the first DBTL cycle, a key limitation appeared to be the availability of the diterpene precursor, geranylgeranyl diphosphate (GGPP). Further DBTL cycles were carried out to select an optimal GGPP synthase and to balance its expression with KS, requiring two of the strongest promoters in R. toruloides, ANT (adenine nucleotide translocase) and TEF1 (translational elongation factor 1) to drive expression of the KS from Gibberella fujikuroi and a mutant version of an FPP synthase from Gallus gallus that produces GGPP. Scale-up of cultivation in a 2 L bioreactor using a corn stover hydrolysate resulted in an ent-kaurene titer of 1.4 g/L. CONCLUSION:This study builds upon previous work demonstrating the potential of R. toruloides as a robust and versatile host for the production of both mono- and sesquiterpenes, and is the first demonstration of the production of a non-native diterpene in this organism
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