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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Removal of High Specific Activity Fission Products from Uranyl Sulfate Waste Solutions

The Savannah River National Laboratory (SRNL) is currently providing support to SHINE Medical Technologies (SHINE) which plans to deploy a low energy, accelerator-based neutron source to fission low enriched U in a uranyl sulfate target solution for 99 Mo production. The 99 Mo is initially separated from the fission products and target solution by an extraction column. Subsequent washing of the column will generate waste solutions containing residual U and fission product activity. A small number of high specific activity fission products (e.g., 90 Sr, 137 Cs, and 144 Ce) in these streams will likely control the classification of the low level waste (LLW). If a sufficient amount of the high specific activity isotopes are separated from the SHINE waste streams and concentrated into a waste form, it would be possible to treat a majority of the wash solutions from the column operations as a lower class of LLW (Class A versus Class B or C or Class B versus Class C). The high specific activity fission product elements could then be dispositioned as a much smaller volume of waste rather than requiring the disposal of the entire waste stream at the higher waste classification. The Savannah River Site (SRS) has experience with using monosodium titanate (MST) and crystalline silicotitanate (CST) to remove Cs and Sr from high salt content waste solutions generated during the reprocessing of nuclear fuels and targets. Both of these materials have worked very well for their intended purposes at the SRS where the fission product elements are removed from highly alkaline waste. On the other hand, SHINE waste streams from the extraction column contain H 2 SO 4 which makes the solution acidic. Additionally, the SRS waste streams do not contain other fission product elements such as transition metals or lanthanides because they precipitate upon neutralization of the SRS waste and are not present in the supernate which is dispositioned as LLW following treatment. As such, there are inherent differences between SHINE and SRS waste treatment strategies. Savannah River National Laboratory was tasked with performing scoping studies to see if MST and CST would remove Sr, Cs, and Ce from an acidic mixed metal simulant solution. Batch contact experiments were performed using MST and two CST type materials. The MST material is a 15 wt % powder in 0.15 M NaOH slurry. The MST showed low adsorption for elements of interest from acidic solution. Furthermore, the powder size makes MST non-ideal for column operations. A CST IE-911 ion exchange material had high Cs adsorption, moderate Sr, and marginal Ce adsorption. Based on adsorption of all species, the ion exchange capacity was found to be 0.032 meq/mL. A bench-top column experiment to measure elemental breakthrough curves was performed using CST IE-911 where chromatographic separations of the mixed simulant were expected to occur. While most elements behaved as expected, the lanthanide series, containing Ce, broke though the column earlier than expected. The second CST material, CST R9120, displayed high adsorption for all elements in the acidic mixed simulant solutions in a batch contact study, and had a calculated loading capacity of 0.091 meq/mL. Future studies to develop a waste treatment flowsheet should focus on CST R9120 to treat SHINE waste solutions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1971

Detection of Pollution Caused by Solid Wastes

To develop a means of detecting pollution, it s necessary to know something about the source and nature of the pollution. The type of pollution rising from solid wastes differs considerably from hat from liquid wastes or that from gaseous wastes ni its effect on the immediate environment. It may be "defined" by a series of negatives. When solid wastes are discarded on land, the resulting pollution is not land pollution in the sense of air and water pollution. For one thing, the solid wastes do not become a "part" of the land in that the wastes are neither intimately mixed nor homogenized into the land as are liquid and gaseous wastes into their respective media. The waste particles retain not only their chemical identity but also their visible (i.e., physical) characteristics. When buried, for example, the soil is under, above, and around the solids, because the wastes are there as discrete units. Secondly, solid wastes neither diffuse nor are they carried from the place at which they were deposited. In other words they remain stationary, providing of course the disposal site is land and not moving water. In a given area, solid wastes be not distributed uniformly over that area. Even the solid wastes falling into the specification of letter meets these specifications. In contrast liquid and gaseous wastes become intimately mixed, homogenized, and even dissolved in their media. Because solid wastes remain stationary, pollution constituted by their presence is highly localized and heavily concentrated, even to the extent that the pollution could be termed "micro" when compared to the macro-pollution arising from liquid and gasequs wastes.

Golueke, Clarence G.↗
NASA NTRS2005

Issues that Drive Waste Management Technology Development for Space Missions

Waste management technologies for space life support systems are currently at low development levels. Manual compaction of waste in plastic bags and overboard disposal to earth return vehicles are the primary current waste management methods. Particularly on future missions, continuance of current waste management methods would tend to expose the crew to waste hazards, forfeit recoverable resources such as water, consume valuable crew time, contaminate planetary surfaces, and risk return to Earth of extraterrestrial life. Improvement of waste management capabilities is needed for adequate management of wastes. Improvements include recovery of water and other resources, conversion of waste to states harmless to humans, long-term containment of wastes, and disposal of waste. Current NASA requirements documents on waste management are generally not highly detailed. More detailed requirements are needed to guide the development of waste management technologies that will adequately manage waste. In addition to satisfying requirements, waste management technologies must also recover resources. Recovery of resources such as water and habitat volume can reduce mission cost. This paper explores the drivers for waste management technology development including requirements and resource recovery.

Fisher, John W.↗
DOE OSTI2013

Electronic waste management approaches: An overview

Highlights: ► Human toxicity of hazardous substances in e-waste. ► Environmental impacts of e-waste from disposal processes. ► Life Cycle Assessment (LCA), Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) to and solve e-waste problems. ► Key issues relating to tools managing e-waste for sustainable e-waste management. - Abstract: Electronic waste (e-waste) is one of the fastest-growing pollution problems worldwide given the presence if a variety of toxic substances which can contaminate the environment and threaten human health, if disposal protocols are not meticulously managed. This paper presents an overview of toxic substances present in e-waste, their potential environmental and human health impacts together with management strategies currently being used in certain countries. Several tools including Life Cycle Assessment (LCA), Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) have been developed to manage e-wastes especially in developed countries. The key to success in terms of e-waste management is to develop eco-design devices, properly collect e-waste, recover and recycle material by safe methods, dispose of e-waste by suitable techniques, forbid the transfer of used electronic devices to developing countries, and raise awareness of the impact of e-waste. No single tool is adequate but together they can complement each other to solve this issue. A national scheme such as EPR is a good policy in solving the growing e-waste problems.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Environmental impacts and benefits of state-of-the-art technologies for E-waste management

Highlights: • The most promising e-waste management scenario features integrated e-waste processes. • Treatment of mobile phones in an integrated e-waste management provides the best environmental performance. • Incineration of the hazardous portion of PCBs with energy recovery is an option that deserves attention. • Landfills of e-waste should be avoided, especially for washing machines, TVs, and refrigerators. • If landfill to be used, a recycling scheme with precious metals can notably mitigate the impacts of landfills. - Abstract: This study aims to evaluate the environmental impacts and benefits of state-of-the-art technologies for proper e-waste handling using Jordan as a case study. Life Cycle Assessment (LCA) was employed to evaluate five advanced management systems represent state-of-the-art treatment technologies, including sanitary landfilling; proper recycling of metals, materials, and precious metals (PMs); and incineration of plastic and the hazardous portion of printed circuit boards (PCBs). Six e-waste products that contribute the most to the e-waste in Jordan were included in the assessment of each scenario, which resulted in 30 total cases of e-waste management. The findings indicated that landfills for the entire components of the e-waste stream are the worst option and should be avoided. The most promising e-waste management scenario features integrated e-waste processes based on the concept of Integrated Waste Management (IWM), including recycling materials such as non-PMs and PMs, incinerating plastic and the hazardous content of PCBs using the energy recovered from incineration, and using sanitary landfills of residues. For this scenario, the best environmental performance was obtained for the treatment of mobile phones. Incineration of the portion of hazardous waste using energy recovery is an option that deserves attention. Because scenario implementation depends on more than just the environmental benefits (e.g., economic cost and technical aspects), the study proposes a systematic approach founded on the IWM concept for e-waste management scenario selection.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

2016 Los Alamos National Laboratory Hazardous Waste Minimization Report

Waste minimization and pollution prevention are goals within the operating procedures of Los Alamos National Security, LLC (LANS). The US Department of Energy (DOE), inclusive of the National Nuclear Security Administration (NNSA) and the Office of Environmental Management, and LANS are required to submit an annual hazardous waste minimization report to the New Mexico Environment Department (NMED) in accordance with the Los Alamos National Laboratory (LANL or the Laboratory) Hazardous Waste Facility Permit. The report was prepared pursuant to the requirements of Section 2.9 of the LANL Hazardous Waste Facility Permit. This report describes the hazardous waste minimization program, which is a component of the overall Pollution Prevention (P2) Program, administered by the Environmental Stewardship Group (EPC-ES). This report also supports the waste minimization and P2 goals of the Associate Directorate of Environmental Management (ADEM) organizations that are responsible for implementing remediation activities and describes its programs to incorporate waste reduction practices into remediation activities and procedures. This report includes data for all waste shipped offsite from LANL during fiscal year (FY) 2016 (October 1, 2015 – September 30, 2016). LANS was active during FY2016 in waste minimization and P2 efforts. Multiple projects were funded that specifically related to reduction of hazardous waste. In FY2016, there was no hazardous, mixed-transuranic (MTRU), or mixed low-level (MLLW) remediation waste shipped offsite from the Laboratory. More non-remediation hazardous waste and MLLW was shipped offsite from the Laboratory in FY2016 compared to FY2015. Non-remediation MTRU waste was not shipped offsite during FY2016. These accomplishments and analysis of the waste streams are discussed in much more detail within this report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Toward a lean analysis for waste to support the decommissioning operation - 15321

All over the world, several nuclear facilities have been shut down few years ago and are now under dismantling or will be dismantled in the future. - Dismantling project takes place according to three major phases: - Study and definition of the dismantling scenario - Dismantling site operations - Decommissioning and final state characterization. Each step is lead in agreement with safety, security and waste management. This requires analytical tools appropriate to the radiological environment and aims. In the field of security, fissile products, explosives... will be researched and quantified while occupational safety requires quantification of radiological, carcinogenic, mutagenic and reprotoxic elements such as As, Se, Cr(IV)... or even asbestos in order to follow more and more strengthened rules. For waste management, radiological and chemical quantification are necessary but must be completed by determining physical and chemical properties such as reactivity, stability or dissolution of the waste... Required level of knowledge, analytical deadline, uncertainties, limits of detection and matrix varieties depend on the decommissioning phase. Setting up a dismantling scenario requires the most possible accurate knowledge of the initial source term present in the facility, in order to establish waste management flow-sheets, define dismantling intervention modes, and prepare the associated safety demonstrations. As history is often not sufficient, in-situ investigations and off-site laboratories are necessary to assign an initial waste and radiological inventory and propose some strategy operations. When a first scenario is chosen, more detailed samplings and analyses are required to fully prepare estimates of waste volumes and categories, and define and validate the waste recovery system that would be used during the dismantling operation. As the definition of the dismantling plan takes shape, data must be more and more accurate and reliable in order to define the waste outlet. The scaling factors for the waste must be defined in order to assure the refunding of the waste. This includes complete characterizations of various matrixes, with high precision, low detection limit in a limited time of few months, as sketchy data could lead to fix inappropriate plan Once site operations begin, it is necessary to control the safety operational conditions and waste production. Measurements requirement is under the safety threshold. Matrixes are often limited to filter. The most important factor is deadline, because operations delay is costly. Finally at the end of dismantling operations, analyses must be performed to demonstrate the successful clean-up of the work site. Analytical methods with low detection limit are required. Thus, characterization appears as a graded and iterative process and is a key issue for decommissioning and dismantling operations in term of efficiency and cost. In order to face this huge analytical demand, a strategy for sampling and characterization must be developed regarding the real needs. On site measurements are usually performed with existing hand-held instruments. A basic first level of knowledge is obtained without delay, feeding the dismantling scenario. On these bases, a sampling strategy permits to select some representative specimens to be more precise, and accurate analysis is performed on off-site laboratories introducing an additional difficulty: the sampling on the site and sub-sampling in the laboratory itself. Whatever the level of sampling, aliquots are small considering the dimension of the dismantling area. This step is crucial. Sampling strategy must be optimized according to objectives (scaling factors measurement, waste level). But in the particular case of high radioactive level waste, due to security manipulation constraints, the number and mass of samples collected are limited. At the opposite for low level waste, large number of samples is collected meaning that large analytical method capacity is necessary. Optimization of the analytical plan is critical. The analytical strategy (including control of sub-sampling, analysis sequence according to analytical capability and performances, especially for pure beta emitters) developed for real case will be detailed. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Optimised management of orphan wastes in the UK

Orphan wastes have properties preventing them from being managed according to existing or currently planned management routes, or lack characterisation so that their management is uncertain. The identification of new management opportunities for orphan wastes could realise significant benefits by reducing the number of processing facilities required, reducing waste volumes, reducing hazard or leading to the development of centres of excellence for the processing of certain types of orphan wastes. Information on the characteristics of orphan waste existing at nuclear licensed sites across the UK has been collated and a database developed to act as a repository for the information gathered. The database provides a capability to analyse the data and to explore possible treatment technologies for each orphan waste type. Thirty five distinct orphan waste types have been defined and possible treatment options considered. Treatment technologies (including chemical, high temperature, immobilisation and physical technologies) that could be applied to one or more of the generic orphan waste streams have been identified. Wiring diagrams have been used to highlight the waste treatment / lifecycle management options that are available for each of the generic orphan groups as well as identifying areas for further research and development. This work has identified the potential for optimising the management of orphan wastes in a number of areas, and many potential opportunities were identified. Such opportunities could be investigated by waste managers at waste producing nuclear sites, to facilitate the development of new management routes for orphan wastes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Chemical analysis of simulated high level waste glasses to support stage III sulfate solubility modeling

The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been a limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

The evolution of the Nevada National Security site waste acceptance criteria - 15312

The Nevada National Security Site Waste Acceptance Criteria (DOE/NV--325) is an evolution of requirements spanning almost three decades of waste acceptance at the Nevada National Security Site (NNSS). The original waste acceptance criteria (WAC) document was written in 1978 (document NVO-185) and underwent multiple revisions as time passed and disposal experience was gained. This document came into being when the NNSS first started receiving significant quantities of low-level radioactive waste (LLW) from offsite U.S. Department of Energy (DOE) generators, such as the Mound and Rocky Flats Plants. The original WAC was far less prescriptive and rigorous than the current criteria since many of the current DOE order directives, Federal/State laws, and regulations did not exist. The current WAC reflects the results of numerous revisions in order to address the nuances of the varied waste streams and package configurations accepted for disposal at the NNSS. This includes waste streams that exhibit challenges not previously faced or covered by the WAC and therefore, from time to time, require new information and or changes to be made to the WAC. These wastes now represent a growing percentage of the remaining waste at cleanup sites across the DOE Complex. These waste streams present challenges, such as the technical basis for ensuring safe transportation to and disposal at the NNSS. The current WAC (Rev. 10 dated June 2013), is Available online at: http://www.nv.energy.gov/library/publications/Environmental/DOENV{sub 3}25.pdf). Other challenges for the NNSS include incorporating new and emerging technologies and addressing stakeholder concerns. Addressing these challenges sometimes results in changes to the NNSS WAC. Drivers for revising the NNSS WAC over the years have included operating experience improvements, the need to specify waste origin/ownership, and identifying preferred transportation routing. This paper will discuss various aspects of the NNSS WAC, and how it has evolved based upon DOE orders and requirements, acceptance of offsite mixed wastes, acceptance of non-radioactive classified wastes, stakeholder concerns and agreements, and the changing face of the remaining legacy waste at DOE sites across the United States. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Radiological characterization of high Cs-137 waste items at LANL combining Cs-137 NDA results and acceptable process knowledge - 15592

Radiological characterization is an important component to disposition and disposal of radioactive waste at the Los Alamos National Laboratory. Gamma and neutron based non-destructive assay systems are available at LANL's TA-54 Area G for radiological characterization and are generally very effective in quantifying the transuranic radionuclide concentration required for a TRU or low level waste disposition determination. This is routinely performed by scaling some nuclides to direct assay results using acceptable process knowledge scaling from a directly measured key TRU nuclide, e.g., for gamma systems using a standard isotopic distribution to determine the amount of Pu-240 associated with a measured value of Pu-239. However, for two groups of LANL waste items that have high levels of Cs-137, these non-destructive assay systems were unable to make a standard TRU/LLW determination. Therefore, it was necessary to apply an extension of the typical scaling technique that keyed in on the direct Cs-137 gamma assay result to effectively characterize these waste items for TRU processing or LLW disposition. Two basic types of waste packages contained the high Cs-137 waste requiring special scaling: drums and boxes. The drums included 55-gallon, 85-gallon and 110-gallon volume sizes and the boxes included a corrugated metal box, a Standard Waste Box, and several overpack boxes containing oversized waste. All of these items contained radioactive waste generated from operations at the Chemistry and Metallurgical Research facility at LANL that included hot cell, metallographic sectioning and maintenance activities. All of the drums as well as the CMB, SWB and one oversized item in a plywood box were located above-ground at LANL's TA-54 Area G, while five of the oversized items were hot cell liners in metal boxes stored below-ground in shafts. All of the items were measured in the 2013-2014 time period at TA-54 Area G with LANL NDA systems. Most of the items were counted with LLW certified far-field gamma spectroscopy systems employing portable far-field HPGe detectors and carts and some of the items were counted on WIPP certified gamma only or gamma with neutron NDA systems. In all cases Cs-137 was quantified directly with a gamma measurement but the key TRU nuclides were not detectable. Thus, for each waste item AK/PK was studied and scaling factors to Cs-137 were established and applied to provide a comprehensive radiological characterization. A total of 49 waste items were successfully characterized as LLW based on this technique. The above ground waste items were dispositioned and disposed of at an offsite LLW repository and the below ground boxes were left in place as LLW in the TA-54 Area G shafts. This NDA with scaling application has proved effective and defensible in these high Cs-137 cases at LANL and will continue to be used as applicable and appropriate for future waste characterization at LANL. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Developing Waste Characterization Capabilities in Support of the Near Surface Disposal Facility - 19245

Upon approval from the Canadian Nuclear Safety Commission, Canadian Nuclear Laboratories (CNL) Proposed Near Surface Disposal Facility (NSDF) to be constructed at CNL's Chalk River Laboratories will be the first permanent disposal facility in Canada for the disposal of low level radioactive waste. The NSDF is currently in the approval process and as such, a preliminary Waste Acceptance Criteria (WAC) has been implemented for the proposed facility. Waste currently generated at CNL is being characterized to verify that it meets the WAC and will be 'disposal ready' once the NSDF is operational. A robust waste characterization program is required for the following reasons: 1. Improved waste segregation to support waste minimization and recycling to ensure non-radioactive waste is reliably segregated and removed from radioactive waste streams destined for the NSDF. This includes characterization and discrimination of Naturally Occurring Radioactive Material (NORM) and anthropogenic radioactive material. 2. To ensure low level waste (LLW) is properly characterized as per the limits stipulated within the WAC to ensure criteria is met for NSDF packaging requirements 3. To ensure intermediate level waste is reliably segregated from NSDF destined wastes streams The purpose of this paper is to provide a review of the development of a waste characterization program strategy at Chalk River Laboratories and applicability of various waste streams; including consideration of important factors such as measurement methods, techniques, and the management of data. Emphasis is necessarily placed on non-destructive gamma spectrometry systems which are central to CNL's approach. A review of near-term developments is also provided. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

33 Shafts Category of Transuranic Waste Stored Below Ground within Area G

This report compiles information to support the evaluation of alternatives and analysis of regulatory paths forward for the 33 shafts. The historical information includes a form completed by waste generators for each waste package (Reference 6) that included a waste description, estimates of Pu-239 and uranium-235 (U-235) based on an accounting technique, and calculations of mixed fission products (MFP) based on radiation measurements. A 1979 letter and questionnaire (Reference 7) provides information on waste packaging of hot cell waste and the configuration of disposal shafts as storage in the 33 Shafts was initiated. Tables of data by waste package were developed during a review of historical documents that was performed in 2005 (Reference 8). Radiological data was coupled with material-type data to estimate the initial isotopic content of each waste package and an Oak Ridge National Laboratory computer code was used to calculate 2009 decay levels. Other sources of information include a waste disposal logbook for the 33 shafts (Reference 9), reports that summarize remote-handled waste generated at the CMR facility (Reference 10) and placement of waste in the 33 shafts (Reference 11), a report on decommissioning of the LAMPRE reactor (Reference 12), interviews with an employee and manager involved in placing waste in the 33 shafts (References 13 and 14), an interview with a long-time LANL employee involved in waste operations (Reference 15), a 2002 plan for disposition of remote-handled TRU waste (Reference 16), and photographs obtained during field surveys of several shafts in 2007. The WIPP Central Characterization Project (CCP) completed an Acceptable Knowledge (AK) summary report for 16 canisters of remote-handled waste from the CMR Facility that contains information relevant to the 33 Shafts on hot-cell operations and timeline (Reference 17).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Conversion of Coal Wastes and Coal Plus Other Opportunity Fuel Mixtures, Such as Coal Plus Municipal Solids, to Produce Electricity and/or Liquid Fuels

For the foreseeable future, the Nation’s energy demand will continue to come largely from indigenous fossil energy resources and hydrocarbon fuels. Specifically waste coal plus other opportunity fuels need to be utilized as a feedstock to eliminate a waste stream and optimized to maximize energy yield and cleanly minimize pollutant emissions. Modular equipment is needed for installation in coal preparation locations, military installations, and research park facilities. Thermal decomposition of coal, biomass, and mixed solid waste (MSW) have been shown to reduce a waste stream while providing liquid and gaseous fuel products with low pollutant emissions. However, thermal decomposition processes have several challenges associated with preprocessing biomass and MSW, feeding and conveying material into the reactor, and post processing of syngas to remove undesirable products while upgrading to increase yield of high value products. Increasing total energy output from power plants by utilizing biomass and mixed wastes ultimately lowers energy costs, harmful environmental impacts of emissions, and has significant impacts on the energy security and sustainability of the U.S. economy. Entrained flow gasifiers (EFGs) produce very little CH4 and a wide range of H2/CO ratios (0.5–2.0) but are limited in their ability to effectively feed large biomass or MSW particles into the reactor. A solution to the feeding problems is to use pyrolysis torrefaction (PT) for conversion of waste materials to create a feedstock similar to coal and capable of grinding down and mixing with the coal feed. Mainstream experimentally explored reaction pathways for the conversion of coal waste plus municipal solids (CWPMS) and demonstrated a bench-scale reactor used for torrefaction of the municipal solid waste (MSW) to create a coal-like feed for blending with the coal waste. The material was processed in a pilot-scale EFG to determine product yield and emissions with CWPMS fuels, as well as the ash content and slagging properties of these feedstocks. The PT-EFG system was experimentally validated, where emissions and yield data were used to develop a high-fidelity process model and economic analysis. The following was accomplished in the Phase I: Determined optimal torrefaction process conditions for MSW and biomass through TGA; maximized heating value of fuel while maximizing final mass of torrefied product Demonstrated torrefaction of MSW and biomass feedstocks at 334°C, pulverized to uniform 74 µm particle size, and processed into coal-like feedstocks Demonstrated 8 lb/h pilot-scale EFG using MSW and biomass blends with waste coal; demonstrated 100% biomass in EFG Determined major effects of MSW torrefaction and co-gasifying high-ash coal waste-MSW blends have on pilot-scale EFG Demonstrated blending low-ash, low-sulfur torrefied biomass with high-ash waste bituminous and anthracite refuse coals generates a higher quality syngas compared to syngas from high-ash waste coals Demonstrated a high carbon conversion (> 99.5%) and syngas with 29.47% H2 content, and 0% CH4 content; greater water–gas shift occurs in EFG than predicted by equilibrium ASPEN Plus model Blended lower-ash, high-alkali biomass MSW to lower slag viscosities of the high-ash coal refuse sufficiently for better slag flow compared to feeding the high-ash coal Used low-sulfur biomass to greatly reduce the EFG syngas H2S concentrations and produce non-leachable slag and quench water with very little organic and trace metal contamination Developed a process model and TEA showing the modular PT EFG is cost competitive to existing power plants with the advantage of using low- or negative-value feedstocks such as waste coal stockpiles and non-landfilled MSW; providing a large incentive to implement an economical PT-EFG process

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

A Composition-Based Approach for Predicting Hanford Tank Waste Liquid Viscosity

Liquid viscosity is an important Hanford waste physical property that governs, in part, the performance of key Hanford flowsheet unit operations and processes, including waste filtration, ion exchange, pumping and transport, and mixing. Evaluation and optimization of these processes rely on liquid viscosity correlations subject to substantial error (at least ±60%) that can lead to overly conservative, and sometimes physically unachievable, limits for validation and operation of these unit operations. The current liquid viscosity correlations used for the Hanford flowsheet attempt to capture the effects of specific waste chemistry (namely, the speciation of various salts) on liquid viscosity using liquid density alone. It is postulated that the ±60% or greater error associated with these “density-based” liquid viscosity predictions is driven in part by the inability of waste density to capture the full impact of waste chemistry on liquid viscosity, and that improved prediction accuracy could be achieved by implementing a composition-based approach to evaluating liquid viscosity for Hanford wastes. Recent publications, namely those of Lencka et al. (1998), Hu (2004), and Laliberté (2007a), provide correlations and comprehensive, consolidated databases of single-salt solution viscosity that enable composition-based predictions for Hanford-type liquids (i.e., concentrated multi-component aqueous electrolyte solutions). In the current study, the viscosities of Hanford wastes and waste simulants were predicted using a composition-based model developed by Laliberté (2007a) (hereafter referred to as the “Laliberté viscosity model”) to evaluate its accuracy relative to the current density-based models used to predict waste viscosity for engineering applications at the Hanford Site. A viscosity database that captured the composition and viscosity of wastes and waste simulants was developed to support this evaluation. To facilitate application of the Laliberté viscosity model, waste and waste simulant compositions were converted to an equivalent salt recipe composed of salts with known viscosity coefficients using a number of simplifying assumptions that have the potential to impact the fidelity of the model prediction. Despite these simplifications, the Laliberté viscosity model was able to predict viscosity more accurately than the density-based correlations currently available for Hanford flowsheet use, such as that proposed in RPP-RPT- 51652. The use of composition-based viscosity models, like that proposed by Laliberté (2007a), shows promise for leading to improved prediction of liquid waste viscosity. As implemented in this study, application of the Laliberté viscosity model could lead to a decrease in the uncertainty associated with liquid viscosity prediction by as much as a factor of two, allowing for reduction in unit operation design conservatism and for the more realistic selection of test simulants for flowsheet process evaluation and optimization, all of which could potentially reduce flowsheet design margins, lower costs and reduce duration of the Hanford mission, and reduce Hanford flowsheet risks.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

An application of the theory of planned behaviour to study the influencing factors of participation in source separation of food waste

Highlights: ► Theory of planned behaviour (TPB) has been conducted to identify the influencing factors for participation in source separation of food waste using self administered questionnaires. ► The findings suggested several implications for the development and implementation of waste separation at home programme. ► The analysis indicates that the attitude towards waste separation is determined as the main predictors where this in turn could be a significant predictor of the repondent’s actual food waste separation behaviour. ► To date, none of similar have been reported elsewhere and this finding will be beneficial to local Authorities as indicator in designing campaigns to promote the use of waste separation programmes to reinforce the positive attitudes. - Abstract: Tremendous increases in biodegradable (food waste) generation significantly impact the local authorities, who are responsible to manage, treat and dispose of this waste. The process of separation of food waste at its generation source is identified as effective means in reducing the amount food waste sent to landfill and can be reused as feedstock to downstream treatment processes namely composting or anaerobic digestion. However, these efforts will only succeed with positive attitudes and highly participations rate by the public towards the scheme. Thus, the social survey (using questionnaires) to analyse public’s view and influencing factors towards participation in source separation of food waste in households based on the theory of planned behaviour technique (TPB) was performed in June and July 2011 among selected staff in Universiti Putra Malaysia, Serdang, Selangor. The survey demonstrates that the public has positive intention in participating provided the opportunities, facilities and knowledge on waste separation at source are adequately prepared by the respective local authorities. Furthermore, good moral values and situational factors such as storage convenience and collection times are also encouraged public’s involvement and consequently, the participations rate. The findings from this study may provide useful indicator to the waste management authorities in Malaysia in identifying mechanisms for future development and implementation of food waste source separation activities in household programmes and communication campaign which advocate the use of these programmes.

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DOE OSTI2014

Review of LCA studies of solid waste management systems – Part I: Lessons learned and perspectives

Highlights: • We perform a critical review of 222 LCA studies of solid waste management systems. • Studies mainly concentrated in Europe with little application in developing countries. • Assessments of relevant waste types apart from household waste have been overlooked. • Local specificities of systems prevent a meaningful generalisation of the LCA results. • LCA should support recommendations representative of the local conditions. - Abstract: The continuously increasing solid waste generation worldwide calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, life cycle assessment (LCA) is a tool, which can contribute to answer that call. But how, where and to which extent has it been applied to solid waste management systems (SWMSs) until now, and which lessons can be learnt from the findings of these LCA applications? To address these questions, we performed a critical review of 222 published LCA studies of SWMS. We first analysed the geographic distribution and found that the published studies have primarily been concentrated in Europe with little application in developing countries. In terms of technological coverage, they have largely overlooked application of LCA to waste prevention activities and to relevant waste types apart from household waste, e.g. construction and demolition waste. Waste management practitioners are thus encouraged to abridge these gaps in future applications of LCA. In addition to this contextual analysis, we also evaluated the findings of selected studies of good quality and found that there is little agreement in the conclusions among them. The strong dependence of each SWMS on local conditions, such as waste composition or energy system, prevents a meaningful generalisation of the LCA results as we find it in the waste hierarchy. We therefore recommend stakeholders in solid waste management to regard LCA as a tool, which, by its ability of capturing the local specific conditions in the modelling of environmental impacts and benefits of a SWMS, allows identifying critical problems and proposing improvement options adapted to the local specificities.

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DOE OSTI2013

Westinghouse waste simulation and optimization software tool

Applications for dynamic simulation can be found in virtually all areas of process engineering. The tangible benefits of using dynamic simulation can be seen in tighter design, smoother start-ups and optimized operation. Thus, proper implementation of dynamic simulation can deliver substantial benefits. These benefits are typically derived from improved process understanding. Simulation gives confidence in evidence based decisions and enables users to try out lots of 'what if' scenarios until one is sure that a decision is the right one. In radioactive waste treatment tasks different kinds of waste with different volumes and properties have to be treated, e.g. from NPP operation or D and D activities. Finding a commercially and technically optimized waste treatment concept is a time consuming and difficult task. The Westinghouse Waste Simulation and Optimization Software Tool will enable the user to quickly generate reliable simulation models of various process applications based on equipment modules. These modules can be built with ease and be integrated into the simulation model. This capability ensures that this tool is applicable to typical waste treatment tasks. The identified waste streams and the selected treatment methods are the basis of the simulation and optimization software. After implementing suitable equipment data into the model, process requirements and waste treatment data are fed into the simulation to finally generate primary simulation results. A sensitivity analysis of automated optimization features of the software generates the lowest possible lifecycle cost for the simulated waste stream. In combination with proven waste management equipments and integrated waste management solutions, this tool provides reliable qualitative results that lead to an effective planning and minimizes the total project planning risk of any waste management activity. It is thus the ideal tool for designing a waste treatment facility in an optimum manner, taking account of the detailed waste stream and specific requirements. (authors)

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