Microbial degradation of low-level radioactive waste. Final report

Rogers, Robert D.; Hamilton,; Veeh, R.H.; McConnell, J.W.

doi:10.2172/261095

Cited by 8 publications

(4 citation statements)

References 9 publications

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“…Such problems could include corrosion of cement by sulphuric acid produced by sulphur‐oxidising bacteria, as well as other organic and mineral acids. Others are formation of active biofilm on the surface of cement‐solidified wastes, and gas formation within cementitious systems leading to cracks and loss of homogeneity …”

Section: Biodegradation and Cements: Brief Historical Perspectivementioning

confidence: 99%

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Encouraging microbial activity in cementitious systems: an emerging frontier in contaminated soil treatment

Kogbara

2013

J of Chemical Tech & Biotech

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Bioremediation is widely accepted as the most effective remediation technology for organic contamination. Nevertheless, it is ineffective for heavy metals, which cannot be degraded, and their immobilisation through pH control achieved with high‐pH cementitious materials is one of very few feasible means of treatment available. However, progress is being made in encouraging microbial activity in cementitious systems, which could provide a single technology that is effective and can be used for simultaneous treatment of organic and metallic contaminants in contaminated soils. This work considers efforts in this direction; the successes achieved and the challenges encountered are described. The utility of relatively low‐pH magnesium phosphate cement(s) and compost in providing a favourable environment for microbes, as well as the capacity of microbes like Saccharomyces cerevisiae and Rhodococcus ruber immobilised in the cement in degrading organics is highlighted. Overall, the findings are promising and are likely to expand the frontiers of bioremediation and stabilisation/solidification technologies for sustainable treatment of contaminated soils and may be extended to other applicable hazardous waste streams. © 2012 Society of Chemical Industry

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Section: Biodegradation and Cements: Brief Historical Perspectivementioning

confidence: 99%

“…There are reports of work on microbial influenced degradation of concrete employed in the immobilisation of radioactive wastes . Three different genera of bacteria involved in cement degradation have been identified.…”

Section: Biodegradation and Cements: Brief Historical Perspectivementioning

confidence: 99%

Encouraging microbial activity in cementitious systems: an emerging frontier in contaminated soil treatment

Kogbara

2013

J of Chemical Tech & Biotech

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“…The Nuclear Regulatory Commission in their Low-Level Waste Management Branch Technical Position on Waste Form (1991) requires a biodegration test if the waste form contains carbon. However, a recent contract report (NUREG/CR-6641, June 1996) 14 recommends that a sulfur-oxidizing bacteria be used since this bacteria is common in landfill soils. Thus, this experiment follows the more recent recommended test procedure.…”

Section: Microbial Degradation Of Grout Studymentioning

confidence: 99%

Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-99 Status Report

Herbst¹,

McCray²,

Kirkham³

et al. 1999

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The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to nearsurface disposal. During fiscal year 1999, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed on radionuclide leaching, microbial degradation, waste neutralization, and a small mockup for grouting the INTEC underground storage tank residual heels. iv SUMMARYThe general purpose of the Low-Activity Waste Process Technology Program is to solidify and stabilize the liquid low-activity wastes (LAW) generated at the Idaho Nuclear Technology and Engineering Center (formerly the Idaho Chemical Processing Plant). It is anticipated that LAW will be produced from the following: (1) chemical separation of the tank farm liquid sodiumbearing waste, (2) chemical separation of dissolved aluminum and zirconium calcines, and (3) facility decontamination and process equipment wastes. Grout formulation studies included cesium separated sodium-bearing waste and newly generated liquid wastes. Additional studies were completed in radionuclide leaching, microbial degradation, and pH adjustment. A small scale mockup test was completed for grouting the tank farm vessel residual heels.Initial grout formulations were developed for the cesium separated sodium-bearing waste and the projected newly generated liquid waste. The cesium separated waste would be a tranurance waste that could be sent to the Waste Isolation Pilot Plant. A waste loading of up to 70% weight percent was successfully prepared. Grout formulations of up to 47% weight percent can be prepared for one projected newly generated liquid waste. Both of these formulations utilize the waste as the liquid for the cement powders. The small lab-scale mockup test for the closure of the underground storage tank residual heels demonstrated that Savannah River reducing grout will work with the acidic heels.

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“…It is required that the immobilized radioactive elements not be leached out of the concrete for a period equivalent to 10 half-lives (i.e., about 300 years for the isotopes of strontium and cesium). Isolation of Thiobacillus thiooxidans and other sulfur-oxidizing bacteria from soils at disposal sites for low-level radioactive wastes (18) has increased awareness of possible environmental pollution by leakage of radioactive isotopes from the buried cement. Biodegradation of cement in natural environments due to exposure to microbially generated sulfuric acid is a very slow process, which may take many years, and it may therefore be difficult to evaluate the resistance of various cementitious materials to microbial corrosion.…”

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confidence: 99%

Accelerated Biodegradation of Cement by Sulfur-Oxidizing Bacteria as a Bioassay for Evaluating Immobilization of Low-Level Radioactive Waste

Aviam

Bar-Nes²,

Zeiri³

et al. 2004

Appl Environ Microbiol

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Disposal of low-level radioactive waste by immobilization in cement is being evaluated worldwide. The stability of cement in the environment may be impaired by sulfur-oxidizing bacteria that corrode the cement by producing sulfuric acid. Since this process is so slow that it is not possible to perform studies of the degradation kinetics and to test cement mixtures with increased durability, procedures that accelerate the biodegradation are required. Semicontinuous cultures of Halothiobacillus neapolitanus and Thiomonas intermedia containing thiosulfate as the sole energy source were employed to accelerate the biodegradation of cement samples. This resulted in a weight loss of up to 16% after 39 days, compared with a weight loss of 0.8% in noninoculated controls. Scanning electron microscopy of the degraded cement samples revealed deep cracks, which could be associated with the formation of low-density corrosion products in the interior of the cement. Accelerated biodegradation was also evident from the leaching rates of Ca 2؉ and Si 2؉ , the major constituents of the cement matrix, and Ca exhibited the highest rate (up to 20 times greater than the control rate) due to the reaction between free lime and the biogenic sulfuric acid. Leaching of Sr 2؉ and Cs ؉ , which were added to the cement to simulate immobilization of the corresponding radioisotopes, was also monitored. In contrast to the linear leaching kinetics of calcium, silicon, and strontium, the leaching pattern of cesium produced a saturation curve similar to the control curve. Presumably, the leaching of cesium is governed by the diffusion process, whereas the leaching kinetics of the other three ions seems to governed by dissolution of the cement.

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Microbial degradation of low-level radioactive waste. Final report

Cited by 8 publications

References 9 publications

Encouraging microbial activity in cementitious systems: an emerging frontier in contaminated soil treatment

Encouraging microbial activity in cementitious systems: an emerging frontier in contaminated soil treatment

Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-99 Status Report

Accelerated Biodegradation of Cement by Sulfur-Oxidizing Bacteria as a Bioassay for Evaluating Immobilization of Low-Level Radioactive Waste

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