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At least 73 records · Page 4

Evaluation of Glass Density to Support the Estimation of Fissile Mass Loadings in Sludge Batch 10 Glasses

Per a directive from the Department of Energy Savannah River Operations Office (DOE-SR) in 2008, the fissile mass loading concentration must remain below 897 g/m 3 in each high-level waste (HLW) glass canister produced by the Defense Waste Processing Facility (DWPF). To support Sludge Batch 5 (SB5) processing, the Savannah River National Laboratory (SRNL) developed a technical basis that facilitates the evaluation of fissile mass loading of the glass product. The calculation is based on the iron (Fe) concentration in the glass as determined by measurements from the Slurry Mix Evaporator acceptability analysis as well as the glass density. In April 2022, a subsequent DOE-SR directive increased the fissile mass loading limit to 2500 g/m 3 beginning with Sludge Batch 11. Thus, the 897 g/m 3 limit still applies to Sludge Batch 10 (SB10) processing.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Evaluation of the 0.65 Weight Percent Sulfate Solubility Limit for Sludge Batch 10 Based on November 2022 Projections

The Defense Waste Processing Facility (DWPF) is currently preparing to initiate processing of Sludge Batch 10 (SB10), which is comprised of material from Tanks 11H, 13H, 15H, 26F, 40H (heel only), and Alternate Feed Stock-2 and Sodium Reactor Experiment material from H-Canyon. Frit 473 was recommended for sludge-only (SO) and coupled processing with the Salt Waste Processing Facility (SWPF) based on previous assessments of SB10 projections with the DWPF Product Composition Control System glass property models and their associated Measurement Acceptance Region constraints. Savannah River Mission Completion (SRMC) subsequently pursued Wash Cycle Y to further reduce the total sulfur in the sludge batch and increase processing flexibility at DWPF. In October 2022, SRMC System Planning provided an updated SB10 Tank 40H blend baseline projection based on the Tank 51 confirmation sample results. Due to the reduced Na concentration relative to previous SB10 projections, two additional projections based on the addition of 7,000 gallons of caustic were provided in November 2022.

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Updating the Default Anaerobic Digester Technology for Wastewater Sludge Anaerobic Digestion Pathways in R&D GREET 2025 Rev.1

The Greenhouse Gases, Regulated Emissions and Energy Use in Technologies model (R&D GREET) evaluates the life cycle impacts of renewable fuels and materials, including renewable natural gas (RNG) produced from wastewater (WW) sludge. In the sludge-to-RNG pathway, the assumed anaerobic digestion (AD) technology impacts results, such as energy use, greenhouse gases (GHG), and air pollutant emissions. Prior versions assumed sludge was fed through a thermal hydrolysis stage preceding the mesophilic AD (Thermohydrolysis). Such a process is expected to yield biosolids with sufficiently reduced pathogens to qualify for U.S Environmental Protection Agency (EPA) Class A designation. Other technologies, such as mesophilic AD without any advanced pretreatments, typically produce lower quality Class B biosolids but requires a lower energy burden and infrastructure investment. Table 1 displays the available AD technologies and the assumed resulting EPA biosolids class type from each technology. Full descriptions of each technology and their performance differences can be found in previous work.

09 BIOMASS FUELS↗

Investigation of effects of background water on upwelled reflectance spectra and techniques for analysis of dilute primary-treated sewage sludge

In an effort to improve understanding of the effects of variations in background water on reflectance spectra, laboratory tests were conducted with various concentrations of sewage sludge diluted with several types of background water. The results from these tests indicate that reflectance spectra for sewage-sludge mixtures are dependent upon the reflectance of the background water. Both the ratio of sewage-sludge reflectance to background-water reflectance and the ratio of the difference in reflectance to background-water reflectance show spectral variations for different turbid background waters. The difference in reflectance is the only parameter considered.

Whitlock, C. H.↗

Bacterial degradation of polychlorinted biphenyls in sludge from an industrial sewer lagoon

A laboratory experiment was conducted to determine if polychlorinated biphenyls (PCB's) found in an industrial sewer sludge can be effectively degraded by mutant bacteria. The aerated sludge was inoculated daily with mutant bacteria in order to augment the existing bacteria with bacteria that were considered to be capable of degrading PCB's. The pH, nitrogen, and phosphorus levels were monitored daily to maintain an optimum growing medium for the bacteria. A gas chromatographic method was used to determine the PCB concentrations of the sludge initially and also throughout the experiment. Results and discussion of the bacterial treatment of polychlorinated biphenyls are presented.

Kim, W. S.↗

Role of redox-active biochar with distinctive electrochemical properties to promote methane production in anaerobic digestion of waste activated sludge

Biochar has been reported as an effective additive to improve methane production during anaerobic digestion (AD). However, the mechanism for such a stimulatory impact remains unclear. Here we investigated the capability of three pyrolytic biochars with distinctive electrochemical properties (BC300, BC500, BC700) to promote methanogenic performance of anaerobic digesters treating waste activated sludge (WAS). The cumulative methane production and the maximum methane production rate were increased by 46.9% and 181.6%, respectively, with BC300 amendment. By characterizing the electrochemical properties of biochar, our research team found out that methane production in AD of sludge was positively correlated to biochar’s electron-donating capacity (EDC) rather than its bulk electrical conductivity. These results indicate that the electron transfer mediated by the redox-active functional groups may prevail over the direct electron migration as the predominant mechanism to facilitate interspecies electron transfer in syntrophic communities for enhanced methanogenesis. Microbial community analysis suggests that biochar enriched Methanosarcina and Methanobacterium. Overall, this study shows that functional groups-mediated electron transfer contributes greatly to the improved methane production in WAS digester with biochar amendment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Analysis of the Sludge Batch 7b (Macrobatch 9) DWPF Pour Stream Glass Sample

The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 7b (SB7b), also referred to as Macrobatch 9 (MB9), in January 2012. SB7b is a blend of the heel of Tank 40 from Sludge Batch 7a (SB7a) and the SB7b material that was transferred to Tank 40 from Tank 51. SB7b was processed using Frit 418.

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Summary Report for the Analysis of the Sludge Batch 7b (Macrobatch 9) DWPF Pour Stream Glass Sample for Canister S04023

In order to comply with the Defense Waste Processing Facility (DWPF) Waste Form Compliance Plan for Sludge Batch 7b, Savannah River National Laboratory (SRNL) personnel characterized the Defense Waste Processing Facility (DWPF) pour stream (PS) glass sample collected while filling canister S04023. This report summarizes the results of the compositional analysis for reportable oxides and radionuclides and the normalized Product Consistency Test (PCT) results. The PCT responses indicate that the DWPF produced glass that is significantly more durable than the Environmental Assessment glass. Results and further details are documented in SRNL-STI-2013-00462, Revision 1 “Analysis of the DWPF Sludge Batch 7b (Macrobatch 9) Pour Stream Glass Sample.”

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Characterization of the SRNL-Washed Tank 51 Sludge Batch 10 Qualification Sample

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 10 – SB10) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) sent SRNL two 3-L samples of Tank 51H slurry to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet. Sample HTF-51-19-114 was received on January 28, 2020, and HTF-51-20-15 was received on February 4, 2020. SRNL washed the Tank 51H sample per the Tank Farm washing strategy. During washing, material from H Canyon Tanks 16.3 and 16.4 was also added to the Tank 51 samples to simulate canyon discharges subsequent to sampling. A part of the qualification process is extensive radionuclide and chemical characterization of the SRNL-washed Tank 51H slurry. This report documents the chemical characterization of the washed slurry; radiological characterization will be documented in a separate report. The major supernatant components, elements on a weight percent calcined basis, and the weight percent solids of the SRNL-washed sample were comparable to the Tank Farm projections, with the exception of free hydroxide and carbonate. Therefore, this SRNL-washed sample is suitable for further SB10 qualification activities and SRR planning for SB10.

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Sludge Batch 11 Assembly: Tank 15

Savannah River Mission Completion Nuclear Safety and Engineering Integration (SRMC-E) has requested that Savannah River National Laboratory (SRNL) perform Tank 15 characterization analyses in support of Sludge Batch 11 (SB11) assembly. This report provides important characterization of the slurry in Tank 15 prior to transfer from Tank 15 to Tank 13 (prior to sending to Tank 51) in order to demonstrate that the transfer is "Low Rem" and ensure the sludge concurs with the estimated transfer mass for the SB11 recipe. A total of 3 sets of Tank 15 samples were delivered to SRNL from December 2022 to August 2023. The individual sets of composite samples were analyzed for density, weight percent solids, chemical composition, radionuclides, and/or supernate corrosion control tests.

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Analytical Results of the Tank 51H Sludge Batch 11 As-Received Qualification Sample

Savannah River National Laboratory (SRNL) has been requested by Savannah River Mission Completion (SRMC) to qualify the next sludge batch, Sludge Batch 11 (SB11), for processing at the Defense Waste Processing Facility (DWPF). This report documents the first steps of the qualification process, characterization of the Tank 51H as-received qualification material. SRMC sent SRNL two 200 mL samples received from Tank 51H on the 12th of August 2024. The combined sample, HTF-51-24-85/86, was analyzed for the following: supernate and slurry density, weight percent solids, settling, chemical composition, and radionuclides.

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High-Throughput Microbial Community Analyses to Establish a Natural Fungal and Bacterial Consortium from Sewage Sludge Enriched with Three Pharmaceutical Compounds

Emerging and unregulated contaminants end up in soils via stabilized/composted sewage sludges, paired with possible risks associated with the development of microbial resistance to antimicrobial agents or an imbalance in the microbial communities. An enrichment experiment was performed, fortifying the sewage sludge with carbamazepine, ketoprofen and diclofenac as model compounds, with the aim to obtain strains with the capability to transform these pollutants. Culturable microorganisms were obtained at the end of the experiment. Among fungi, Cladosporium cladosporioides, Alternaria alternata and Penicillium raistrickii showed remarkable degradation rates. Population shifts in bacterial and fungal communities were also studied during the selective pressure using Illumina MiSeq. These analyses showed a predominance of Ascomycota (Dothideomycetes and Aspergillaceae) and Actinobacteria and Proteobacteria, suggesting the possibility of selecting native microorganisms to carry out bioremediation processes using tailored techniques.

59 BASIC BIOLOGICAL SCIENCES↗

Technoeconomic Assessment of Phosphoric Acid and Rare Earth Element Recovery from Phosphoric Acid Sludge

Sustainability faces many challenges, including the availability of materials necessary for technological advancement. Rare earth elements (REEs), for example, are key materials for several manufacturing industries that can unlock renewable energy and sustainable development. In this study, a decanter centrifuge has been employed to successfully separated phosphoric acid and REE-containing particles from phosphoric acid sludge with concentrations ranging from 1000 to 2200 ppm REEs. Operating efficiently with up to 35 wt.% solids, the centrifuge was demonstrated to achieve approximately 95% phosphoric acid recovery and 90% REE recovery in a single pass, eliminating the need for additional processing steps. This breakthrough supports a proposed rare earth oxide (REO) recovery process integrating phosphoric acid (PA), elemental phosphorus (P4), and REO into two potential pathways: PA-REO and PA-P4-REO. These processes aim to reintroduce recovered phosphoric acid into the main product to significantly increase output and revenue. Post-separation, phosphorus-rich particles can be converted to P4, while REE-containing solids undergo further treatment including acid leaching, extraction/stripping, precipitation, and calcination to produce a marketable REO material. Technoeconomic analysis indicates promising profitability, with the PA-REO process showing a delta net present value (ΔNPV) of USD 441.8 million over a 12-year period and expected return within a year of construction, while the PA-P4-REO process yields a ΔNPV of USD 178.7 million over a 12-year return period. Both pathways offer robust financial prospects and demonstrate the feasibility of commercial-scale REO recovery from phosphoric acid sludge, offering an economically feasible approach to produce REEs for future sustainable development challenges related to sustainability.

36 MATERIALS SCIENCE↗

Development of Acoustic Backscatter for In Situ Monitoring of Nuclear Sludge Wastes During Transfer - 20117

This paper presents an overview into the use of acoustic backscatter systems (ABS) for the in situ characterization of nuclear waste sludge concentration, size and aggregation, highlighting key achievements from the University of Leeds. Previous projects funded through the Engineering and Physical Sciences Research Council (EPSRC) UK and Innovate UK are firstly reviewed and linked to current research within the new TRANSCEND consortium. Detailed are a number of developments at various stages of technology readiness level, from the use of ABS to monitor small-scale sludge settling in columns, to large-scale jet-mixing and waste transfer operations. Current work with Sellafield Ltd will see new technology and world leading analysis methods deployed to measure the consolidation of complex wastes currently undergoing containment, the first time full industrial utilization of these systems has been achieved. (authors)

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Longitudinal Multi-omics Reveal Phase-Dependent Viral Adaptive Strategies and Functional Potential During Formation of Algal-bacterial Granular Sludge

Virus-host interactions within microbial aggregates critically influence microbiome function and stability, yet how physicochemical stresses shape the interactive dynamics remains largely unexplored. Here, we investigated virus–host dynamics during the transition of algal-bacterial granular sludge (ABGS) from activated sludge under continuous hydraulic shear using integrated metagenomics and metatranscriptomics. Hydraulic stress initially reduced host a-diversity, which coincided with a marked increase in viral lysogenicity. During this host diversity bottleneck, viral microdiversity increased, and genes related to virion structure and DNA packaging were under positive selection (pN/pS >1). As host diversity recovered, viral microdiversity declined, while viral anti-defense systems (ADS) significantly increased in abundance. Lagged correlation analysis revealed a significant positive correlation between viral ADS and host defense systems (DS), suggesting an evolutionary arms race. Furthermore, active lysogenic infections were accompanied by enrichment of DS and auxiliary viral genes (AVGs) involved in genetic information processing and amino acid metabolism, potentially enhancing host fitness. Overall, our study unveils a phase-dependent co-evolutionary interplay between viruses and hosts during ABGS formation, providing insights into the development and maintenance of microbial structural and functional resilience in engineered ecosystems.

Qi, Huiyuan↗

Radioactive waste immobilization of Hanford sludge in magnesium potassium phosphate ceramic forms

Here, this paper evaluates immobilization of Hanford K-Basin tank sludge in magnesium potassium phosphate ceramic forms. The waste forms were produced using two simulated non-radioactive sludge streams, each with distinct characteristics and composition. Ceramicrete with wollastonite as filler was used as the matrix for this purpose. The resulting waste forms were tested for their mechanical properties, radiation stability, and leaching resistance. In another series of tests, the samples were vitrified in borosilicate glass and glass waste forms were produced. The Product Consistency Test, the American Nuclear Society's ANS 16.1 test, and the Toxicity Characteristic Leaching Procedure, which are used to develop waste acceptance criteria in the United States for permanent storage of treated waste, were used for evaluation of the leaching resistance of all waste forms.

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Solubility Testing to Support the Addition of Sodium Reactor Experiment Material to Sludge Batch 10

The Savannah River Site H-Canyon Facility is planning to discard dissolved Sodium Reactor Experiment (SRE) material into Tank 51 prior to Sludge Batch 10 (SB10). SB10 with the SRE material will be processed in the Defense Waste Processing Facility (DWPF) using the Nitric-Glycolic Acid (NGA) flowsheet. The DWPF Nuclear Criticality Safety Evaluation (NCSE) protects a 14:1 mass ratio of manganese to equivalent uranium-235 in both the solid and liquid phases during processing by requiring a 70:1 mass ratio in the feed. A concern was raised that freshly precipitated manganese in the SRE material will behave differently from the manganese in sludge during DWPF processing and potentially invalidate the criticality control. To mitigate risks to the DWPF criticality controls, the Savannah River National Laboratory (SRNL) performed a metals solubility test applicable to recently precipitated manganese and uranium, as would be expected with SRE transfers to SB10. The objective of this analysis is the tracking of partitioning of the primary fissile component (uranium-235) with the credited poison (manganese) between the aqueous and insoluble phases.

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Alternative Liquid DSA Containers for Sludge Slurry Storage in the SRNL Shielded Cells

A pending revision of the Documented Safety Analysis (DSA) for the Savannah River National Laboratory (SRNL) defines “DSA containers” for liquid sludge slurries as containers not susceptible to a flashing spray release in a fire and requires that a list of DSA containers be maintained. High Level Waste (HLW) samples are typically received from the Savannah River Site (SRS) tank farm after retrieval from the storage tanks. Glass bottles are preferred for long-term storage of radioactive liquid sludge slurry samples but are not on the DSA container list. An evaluation has been conducted to identify vessel lids for the glass bottles that would vent prior to pressurization and liquid superheating in a fire event. Low melting Field’s Metal eutectic alloy with a melting point of 62 °C has been identified as a preferred material of construction for vessel lids for this application because the material is resistant to puncture and is expected to have good chemical compatibility and radiation stability in the shielded cells environment. A test vessel was designed to evaluate the alloy and confirm that it would melt before the water in the vessel reaches the boiling point. The tests confirmed: 1) that the reported melting point of the alloy was accurate, 2) that a top fashioned from this material will melt creating an open atmosphere in the vessel headspace prior to sample boiling under moderate and fast heating rates, and 3) that nonuniform heating of the bottle from the bottom also results in melting of the alloy prior to boiling. Based on the results, neither an engulfing fire with standing or toppled bottles or a fire producing localized heat at the vessel bottom would result in flashing spray conditions.

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