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At least 1,513 records · Page 84
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Summary of Calcine Disposal Development Using Hot Isostatic Pressing

Battelle Energy Alliance, LLC, has demonstrated the effectiveness of the hot isostatic press (HIP) process for treatment of hazardous high-level waste known as calcine that is stored at the Idaho Nuclear Technology and Engineering Center (INTEC) at Idaho National Laboratory. HIP trials performed with simulated calcines at Idaho National Laboratory’s Materials and Fuels Complex and an Australian Nuclear Science and Technology Organization facility from 2007 to 2010 produced a dense, monolithic waste form with increased chemical durability and effective (storage) volume reductions of ~10 to ~70% compared to granular calcine forms. In December 2009, the U.S. Department of Energy signed an amended Record of Decision selecting HIP technology as the treatment method for the 4,400 m3 of granular zirconia and alumina calcine stored at INTEC. Testing showed that HIP treatment reduces the risks associated with radioactive and hazardous constituent release, post-production handling, and long-term (repository) storage of calcines and would result in estimated storage cost savings in the billions of dollars. Battelle Energy Alliance has the ability to complete pilot-scale HIP processing of INTEC calcine, which is the next necessary step in implementing HIP processing as a calcine treatment method.

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DOE OSTI2017

A framework for evaluating the accessibility of raw materials from end-of-life products and the Earth’s crust

Highlights: • Defined and conceptualised raw material accessibility. • Applied concept extraction in raw material management. • Developed a framework for evaluating raw material accessibility. •Carried out an evaluation with End-of-Life products and natural deposits. • Developed an early project stage evaluation for accessing raw materials. - Abstract: An increasing number of geochemically scarce metallic raw materials are entering into our lives via new technologies. A reversal of this trend is not foreseeable, leading to concerns regarding the security of their supply. However, the evaluation of raw material supply is currently hampered by inconsistent use of fundamental terminologies and incomplete assessment criteria. In this paper, we aim to establish a consistent framework for evaluating raw material supply from both anthropogenic and geological sources. A method for concept extraction was applied to evaluate systematically the use of fundamental terms in the evaluation of raw material supply. The results have shown that ‘availability’ is commonly used in raw material supply evaluations, whilst other researchers suggest that raw material supply should be evaluated based on ‘accessibility’. It was revealed that ‘accessibility’ actually comprises two aspects: ‘availability’ and ‘approachability’. Raw material ‘approachability’ has not previously been explicitly addressed at a system level. A novel, consistent framework for evaluating raw material supply was therefore developed. To demonstrate the application of the established framework, we evaluated the raw material supply of four rare earth element case studies. Three case studies are End-of-Life products (the anthroposphere) from Switzerland: (i) phosphors in fluorescent lamps, (i) permanent magnets in the drive motors of electric cars and (iii) fibre optic cable. The fourth case study source is the Earth’s crust (the geosphere): Mount Weld deposit in Australia. The framework comprises a comprehensive evaluation of six components relating to raw material mining and processing: their geological knowledge, eligibility, technology, economic, societal and environmental impacts. Our results show that metals are not considered to be fully accessible in any of the case studies due to a lack of necessary technologies and potential societal and environmental impacts. The framework presented here can serve as a starting point for the development of an evaluation framework for raw material accessibility at an early project development stage.

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DOE OSTI2017

Dounreay Shaft Intervention Platform - 17346

In early 2013, Oxford Technologies Ltd, part of Kurion-Veolia, was awarded a contract by Dounreay Site Restoration Ltd (DSRL) to design, build, install and commission a remotely controlled Intervention Platform which will facilitate the retrieval of waste from the Dounreay Shaft and Stub tunnel complex. Removing 1,500 tonnes of waste from Dounreay's 65-metre shaft is the world's deepest nuclear clean-up job and one of the site's most challenging tasks. The shaft was originally sunk to allow a tunnel to be built for the discharge of low-activity radioactive effluent. In 1958, the shaft was licensed to take radioactive waste from Britain's post war nuclear power research programme and was routinely used over almost 20 years for the disposal of unconditioned Intermediate Level Waste (ILW). To enable decommissioning, the waste must now be retrieved so it can be safely packaged for long term disposal. With radiation levels too high for workers to operate in the shaft, remote handling is the only option for retrieving the material. A specialised platform has been developed, with telescopic mechanical arms attached to the underside which will reach down, grab the waste and bring it back to the platform. The technology has been adapted from conventional hydraulic and electrical equipment, brought together and re-engineered to use in the shaft, with the additional requirement to operate remotely. The highly flexible system can tackle a range of activities including the grab becoming stuck and the cutting up in the shaft of items too large or heavy to be retrieved in one piece. Recent trials involved the use of high pressure water cannon that is able to wash out the sludge left behind in the 18 m long stub tunnel after larger items have been retrieved by the telescopic arms fitted with grab tools. Several different kinds of replica sludge were used to demonstrate the process would be successfully deployed. (authors)

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DOE OSTI2013

R and D Programs and Policy within the CEA-AREVA Joint Vitrification Lab (LCV) - 13592

Waste management is a key issue for the reprocessing industry; furthermore, vitrification is considered as the reference for nuclear waste management. In order to further improve and strengthen their historical cooperation in high temperature waste management, the CEA, R and D organization, and AREVA, Industrial Operator, decided, in September 2010, to create a Joint Vitrification Laboratory within the framework of a strategic partnership. The main objectives of the CEA-AREVA Joint Vitrification Laboratory (LCV) are (i) support AREVA's activities, notably in its La Hague plants and for new projects, (ii) strengthen the CEA's lead as a reference laboratory in the field of waste conditioning. The LCV is mandated to provide strong, innovative solutions through the performance of R and D on processes and materials for vitrification, fusion and incineration, for high, intermediate and low level waste. The activities carried out in the LCV include academic research on containment matrices (formulation, long-term behaviour), and the improvement of current technologies/development of new ones in lab-scale to full-scale pilot facilities, in non-radioactive and radioactive conditions, including modelling and experimental tools. This paper focuses on the programs and policy managed within the LCV, as well as the means employed by the CEA and AREVA to meet common short-,mid- and long-term challenges, from a scientific and industrial point of view. Among other things, we discuss the technical support provided for the La Hague vitrification facilities on hot melter and CCIM technologies, the start-up of new processes (decommissioning effluents, UMo FP) with CCIM, the preparation of future processes by means of an assessment of new technologies and containment matrices (improved glasses, ceramics, etc.), as well as incineration/vitrification for organic and metallic mixed waste or metallic fusion. The close relationship between the R and D teams and industrial operators enables the LCV to propose attractive waste management solutions, with appropriate schedules and optimized development costs, making allowance for R and D constraints, engineering requirements and the industrial environment. (authors)

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DOE OSTI2019

Path of Disposal for Hazardous and Non-hazardous Waste from Cradle to Grave

Hazardous waste is a threat to human health and the environment and must be managed and disposed of properly. A Solid Waste is defined as any material (solid, liquid, containerized gas) which has been discarded, abandoned (no longer needed), or recycled. The Resource Conservation Recovery Act (RCRA) is a law that creates the framework for the proper management of solid waste. Under RCRA, EPA has developed a program which ensures hazardous waste is managed safely from the moment it is generated to its final disposal (cradle-to-grave)2. To educate about how waste is handled at the Savannah River Research Campus (SRRC) under RCRA, the path it takes from point of generation (cradle) to disposal (grave), and the responsibilities of every person involved in the process. Researcher or other laboratory personnel that generates waste as a result of their work Responsibilities: - Fill out inventory log sheet and corresponding container sheet which includes the constituents of the waste; - Properly label waste container with SAA/WSA ID no., generator's name, what it is, the hazards, and date; - Place waste in designated waste storage area. Laboratory Custodian Responsibilities: - Ensures waste is handled and stored properly; - Ensures inventory is updated; - Ensures all container sheets are completed; - Ensures only authorized personal have access to waste storage areas. Environmental Compliance Authority Responsibilities: - Develops waste procedures; - Provide waste training; - Inspects for improperly handled waste; - Establishes or closes waste storage areas as needed; - Determines if waste can be recycled; - Determines if waste is RCRA hazardous: Is it U or P listed? - Unused commercial chemical products; Is it F listed - Spent solvents; Is it characteristic? - Flammable/Oxidizer, Corrosive, Reactive, Toxic; - Weighs waste to ensure laboratory has not exceeded its monthly or total storage limits; - Maintains waste records; - Determines how waste should be disposed: Trash - Nonhazardous solids; Drain - Nonhazardous Liquids; Labpack; - Prepares waste for shipment with Vendor and Department of Transportation (DOT) personnel. Packages, Transports, and Treats Hazardous Waste Responsibilities: - Must be EPA permitted and approved by the Department of Energy - Picks up hazardous waste for transport to a treatment, storage or disposal facility depending on waste disposal requirements - Must meet all Department of Transportation regulations for transporting hazardous waste - Dispose of waste according to RCRA regulations. Due to the potential risks to human health and the environment, waste must be handled safely through the chain of possession from cradle to grave. To ensure proper handling, there are many safety checks as required by RCRA and DOT regulations. This includes proper labeling, inventory, and characterization to ensure all hazards are known, inspections by the Custodian, ECA, and the state regulator (SCDHEC), and transportation verifications and manifesting. One of the best ways to reduce the risks that waste presents is to minimize or eliminate the creation of waste. This can be accomplished through source reduction which includes: Inventory control, material substitution, process modification, improved housekeeping, and preventative maintenance and recycling.

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DOE OSTI2012

Volatilisation and oxidation of aluminium scraps fed into incineration furnaces

Highlights: Black-Right-Pointing-Pointer Aluminium packaging partitioning in MSW incineration residues is evaluated. Black-Right-Pointing-Pointer The amount of aluminium packaging recoverable from the bottom ashes is evaluated. Black-Right-Pointing-Pointer Aluminium packaging oxidation rate in the residues of MSW incineration is evaluated. Black-Right-Pointing-Pointer 80% of aluminium cans, 51% of trays and 27% of foils can be recovered from bottom ashes. - Abstract: Ferrous and non-ferrous metal scraps are increasingly recovered from municipal solid waste incineration bottom ash and used in the production of secondary steel and aluminium. However, during the incineration process, metal scraps contained in the waste undergo volatilisation and oxidation processes, which determine a loss of their recoverable mass. The present paper evaluates the behaviour of different types of aluminium packaging materials in a full-scale waste to energy plant during standard operation. Their partitioning and oxidation level in the residues of the incineration process are evaluated, together with the amount of potentially recoverable aluminium. About 80% of post-consumer cans, 51% of trays and 27% of foils can be recovered through an advanced treatment of bottom ash combined with a melting process in the saline furnace for the production of secondary aluminium. The residual amount of aluminium concentrates in the fly ash or in the fine fraction of the bottom ash and its recovery is virtually impossible using the current eddy current separation technology. The average oxidation levels of the aluminium in the residues of the incineration process is equal to 9.2% for cans, 17.4% for trays and 58.8% for foils. The differences between the tested packaging materials are related to their thickness, mechanical strength and to the alloy.

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DOE OSTI2020

Compilation of Site Names and Spatial Extents for Sites in the Hanford Site Disposition Database

Several analyses that will be completed as part of the Hanford Composite Analysis (CA) and Cumulative Impact Evaluation (CIE) require the extents of facilities, waste sites, and other locations on the Hanford Site. The purpose of this calculation is to provide spatial extents and consistent naming convention for those locations used as part of the analyses in a single dataset. This calculation documents the process used to develop the dataset.

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DOE OSTI2019

Analysis of the Sludge Batch 8 (Macrobatch 10) DWPF Pour Stream Glass Sample

To meet the objectives of the Defense Waste Processing Facility (DWPF) Glass Product Control Program, DWPF and Saltstone Facility Engineering (D&S-FE) requested that Savannah River National Laboratory (SRNL) analyze a radioactive glass pour stream (PS) sample collected during the processing of Sludge Batch 8 (SB8), also known as Macrobatch 10 (MB10). The analyses requested by D&S-FE (listed as tasks one through five in the Technical Task Request (TTR) included determination of the chemical and radionuclide composition, performance of the Product Consistency Test (PCT), and measurement of glass density and REDOX state. The tasks associated with accomplishing these analyses were controlled under a Task Technical and Quality Assurance Plan (TTQAP) and Analytical Study Plan. This report provides results from the requested analyses and satisfies deliverable number five of the TTR.

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DOE OSTI2014

Selective Gaseous Extraction: Research, Development and Training for Isotope Production, Final Technical Report

General Atomics and the University of Missouri Research Reactor (MURR) completed research and development of selective gaseous extraction of fission products from irradiated fuel, which included training and education of MURR students. The process used porous fuel and after irradiation flowed product gases through the fuel to selectively removed desired fission products with the primary goal of demonstrating the removal of rhodium 105. High removal rates for the ruthenium/rhodium (Ru/Rh), tellurium/iodine (Te/I) and molybdenum/technetium (Mo/Tc) series were demonstrated. The success of this research provides for the reuse of the target for further production, significantly reducing the production of actinide wastes relative to processes that dissolve the target. This effort was conducted under DOE funding (DE-SC0007772). General Atomics objective of the project was to conduct R&D on alternative methods to produce a number of radioactive isotopes currently needed for medical and industry applications to include rhodium-105 and other useful isotopes. Selective gaseous extraction was shown to be effective at removing radioisotopes of the ruthenium/rhodium, tellurium/iodine and molybdenum/technetium decay chains while having trace to no quantities of other fission products or actinides. This adds a new, credible method to the area of certain commercial isotope production beyond current techniques, while providing significant potential reduction of process wastes. Waste reduction, along with reduced processing time/cost provides for superior economic feasibility which may allow domestic production under full cost recovery practices. This provides the potential for improved access to domestically produced isotopes for medical diagnostics and treatment at reduced cost, providing for the public good.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

Impacts of constraints and uncertainties on projected amount of Hanford low-activity waste glasses

A systematic evaluation of Hanford low-activity waste (LAW) loading in alkali-aluminoborosilicate glasses was performed. A set of 22 waste compositions were selected to represent the range of wastes anticipated across the Hanford mission. Glass composition was formulated for each waste to simultaneously satisfy a full cadre of property and composition constraints while maximizing waste loading. Glass properties were estimated using property models recently developed for Hanford LAW Facility operation. The impacts from the property and composition constraints on the glass mass to be produced were calculated and compared. Electrical conductivity, Vapor Hydration Test and SO 3 melter tolerance, and canister-centerline cooling crystal constraints have a large effect on reducing total glass mass, while the impact from Product Consistency Test, viscosity, and isothermal crystal constraints is relatively small. Additionally, effects of model prediction and process/composition uncertainties were quantified. The results identified areas of future research that could be useful to improve the efficiency of plant operation.

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DOE OSTI2013

Conjugates of Magnetic Nanoparticle -- Actinide Specific Chelator for Radioactive Waste Separation

A novel nanotechnology for the separation of radioactive waste that uses magnetic nanoparticles (MNPs) conjugated with actinide specific chelators (MNP-Che) is reviewed with a focus on design and process development. The MNP-Che separation process is an effective way of separating heat generating minor actinides (Np, Am, Cm) from spent nuclear fuel solution to reduce the radiological hazard. It utilizes coated MNPs to selectively adsorb the contaminants onto their surfaces, after which the loaded particles are collected using a magnetic field. The MNP-Che conjugates can be recycled by stripping contaminates into a separate, smaller volume of solution, and then become the final waste form for disposal after reusing number of times. Due to the highly selective chelators, this remediation method could be both simple and versatile while allowing the valuable actinides to be recovered and recycled. Key issues standing in the way of large-scale application are stability of the conjugates and their dispersion in solution to maintain their unique properties, especially large surface area, of MNPs. With substantial research progress made on MNPs and their surface functionalization, as well as development of environmentally benign chelators, this method could become very flexible and cost-effective for recycling used fuel. Finally, the development of this nanotechnology is summarized and its future direction is discussed.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2015

LBNF 1.2 MW TARGET: CONCEPTUAL DESIGN & FABRICATION

Fermilab’s Long-Baseline Neutrino Facility (LBNF) will utilize a modified design based on the NuMI low energy target that is reconfigured to accommodate beam operation at 1.2 MW. Achieving this power with a graphite target material and ancillary systems originally rated for 400 kW requires several design changes and R&D efforts related to material bonding and electrical isolation. Target cooling, structural design, and fabrication techniques must address higher stresses and heat loads that will be present during 1.2 MW operation, as the assembly will be subject to cyclic loads and thermal expansion. Mitigations must be balanced against compromises in neutrino yield. Beam monitoring and subsystem instrumentation will be updated and added to ensure confidence in target positioning and monitoring. Remote connection to the target hall support structure must provide for the eventual upgrade to a 2.4 MW target design, without producing excessive radioactive waste or unreasonable exposure to technicians during reconfiguration. Current designs and assembly layouts will be presented, in addition to current findings on processes and possibilities for prototype and final assembly fabrication.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

LBNF 1.2 MW Target: Conceptual Design & Fabrication

Fermilab’s Long-Baseline Neutrino Facility (LBNF) will utilize a modified design based on the NuMI low energy target that is reconfigured to accommodate beam operation at 1.2 MW. Achieving this power with a graphite target material and ancillary systems originally rated for 400 kW requires several design changes and R&D efforts related to material bonding and electrical isolation. Target cooling, structural design, and fabrication techniques must address higher stresses and heat loads that will be present during 1.2 MW operation, as the assembly will be subject to cyclic loads and thermal expansion. Mitigations must be balanced against compromises in neutrino yield. Beam monitoring and subsystem instrumentation will be updated and added to ensure confidence in target positioning and monitoring. Remote connection to the target hall support structure must provide for the eventual upgrade to a 2.4 MW target design, without producing excessive radioactive waste or unreasonable exposure to technicians during reconfiguration. Current designs and assembly layouts will be presented, in addition to current findings on processes and possibilities for prototype and final assembly fabrication.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Geo-polymer Solidification of Intermediate Level Waste - 17078

To reduce the amount of hydrogen generated due to water radiolysis in stored intermediate-level waste, geo-polymer solidification, followed by drying, was studied. From the viewpoints of high thermal stability and low processing cost, geo-polymer solidification is an excellent method for conditioning intermediate level waste. In this study, in order to determine if radioactive waste could be treated using geo-polymer solidification, tests were conducted by using a simulated slurry generated from contaminated water treatment. The uniaxial compressive strength of the geo-polymer solidified waste containing 50 wt.% of the slurry was more than 10 MPa. To reduce the amount of hydrogen generated, the geo-polymer-solidified waste was dehydrated, and the water content of the remaining solid was less than 1 wt.%. Moreover, the value of the uniaxial compressive strength of dehydrated geo-polymer-solidified waste was similar to that of the untreated one. The volume reduction rate of the slurry solidification was obtained at the applicability limit. (authors)

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DOE OSTI2019

Performance Assessment Results for the Hanford Integrated Disposal Facility - 19134

In 2014, the US DOE Office of River Protection and its contractors began to develop a performance assessment for the near-surface disposal of low-level and mixed low-level waste at the Hanford Integrated Disposal Facility. The Hanford Integrated Disposal Facility is a doubly-lined landfill that was constructed between 2004 and 2006 to be the disposal facility for the vitrified low-activity waste containers that will be produced at the Hanford Waste Treatment and Immobilization Plant. The disposal facility is also expected to receive solid secondary waste produced at the Hanford Waste Treatment and Immobilization Plant and other solid wastes from site activities. The constructed facility is awaiting authorization to receive waste. Although no waste destined for the facility is currently being generated, operations cannot begin until the facility has received a Disposal Authorization Statement from US DOE and a permit modification from the State of Washington Department of Ecology. Both the Disposal Authorization Statement and permit modification require a demonstration that the system of engineered and natural features of the disposal facility will limit releases from the facility and be protective of human health and the environment for the next 1,000 to 10,000 years. Based on the analyses presented in the Integrated Disposal Facility Performance Assessment, US DOE issued a conditional Disposal Authorization Statement for the facility in June 2018. Demonstrating the long-term performance of the facility to be protective of human health and the environment was evaluated under the requirements of US DOE Order 435.1, Radioactive Waste Management. Computer simulations were performed to evaluate whether or not the disposal facility would comply with the performance objectives specified in the order. The evaluation was performed using numerical models to simulate source term releases from vitrified and cement-based waste forms. Source term releases were subsequently transported through an air pathway and a groundwater pathway to a point of compliance 100 meters from the disposed of waste. In addition, an analysis evaluating the consequences of an inadvertent intrusion into the waste was also performed. In accordance with US DoE's technical standard for performance assessments, deterministic and probabilistic analyses were performed to demonstrate that the Hanford Integrated Disposal Facility, together with the engineered features of the waste forms and natural features of the selected site, provides a reasonable expectation that the low-level waste and mixed low-level waste disposal will meet the radiological performance objectives established by US DOE. Post-closure doses to future members of the public were evaluated after the time of closure and included a 100-year period of institutional controls that limited exposure immediately following closure of the facility. Calculated doses to a future member of the public from the air pathway were below the 100 μSv/yr dose performance objective. Calculated doses to a future member of the public from all exposure pathways, including the air pathway and the groundwater pathway, were below the 250 μSv/yr dose performance objective. Doses following an inadvertent intrusion into the facility after the institutional control period were below the 5 mSv acute dose performance measure and the 1 mSv/yr chronic dose performance measure. (authors)

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DOE OSTI2015

Grout testing to support tank closure at the Savannah River Site - 15370

Final operational closure of the Savannah River Site (SRS) waste tanks is performed by filling the voids inside the tanks with a series of tailored grout formulas thereby stabilizing the remaining residuals. These tailored grout formulas were each developed to meet the demands of the closure process. The needs identified for the closure process include (1) a flowable, self-consolidating, reducing grout for tank fill, (2) a highly flowable grout capable of filling the 7-1/4 kilometers (4-1/2 miles) of 5-centimeter (2-inch) diameter cooling coils inside the tank, and (3) a highly flowable grout capable of filling equipment remaining in the tank. The specific characteristics of each of the grout formulations were tested to ensure they would function as required during implementation. Performance testing was also done on some of the grout formulations to confirm mix effectiveness and improve worker handling proficiency and conducted additional testing on the bulk fill grout to expand the placement capabilities of the grout. This paper focuses on the evolution of the closure process' identified needs, formulation development, and the subsequent testing of the tailored grout formulations utilized in the past tank closure processes at SRS. (authors)

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DOE OSTI2012

Development of an Integrated Leachate Treatment Solution for the Port Granby Waste Management Facility - 12429

The Port Granby Project (the Project) is located near the north shore of Lake Ontario in the Municipality of Clarington, Ontario, Canada. The Project consists of relocating approximately 450,000 m{sup 3} of historic Low-Level Radioactive Waste (LLRW) and contaminated soil from the existing Port Granby Waste Management Facility (WMF) to a proposed Long-Term Waste Management Facility (LTWMF) located adjacent to the WMF. The LTWMF will include an engineered waste containment facility, a Wastewater Treatment Plant (WTP), and other ancillary facilities. A series of bench- and pilot-scale test programs have been conducted to identify preferred treatment processes to be incorporated into the WTP to treat wastewater generated during the construction, closure and post-closure periods at the WMF/LTWMF. (authors)

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DOE OSTI2011

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions

Highlights: > High-solids (dry) anaerobic digestion is attracting a lot of attention these days. > One reactor was fed with food waste (FW) and paper waste. > Maximum biogas production rate of 5.0 m{sup 3}/m{sup 3}/d was achieved at HRT 40 d and 40% TS. > The other reactor was fed with FW and livestock waste (LW). > Until a 40% LW content increase, the reactor exhibited a stable performance. - Abstract: With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO{sub 2} emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH{sub 4} production yield (MPY) and VS reduction achieved in this condition were 5.0 m{sup 3}/m{sup 3}/d, 0.25 m{sup 3} CH{sub 4}/g COD{sub added}, and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m{sup 3}/m{sup 3}/d, MPY of 0.26 m{sup 3} CH{sub 4}/g COD{sub added}, and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.

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