Biodegradation of liquid scintillant cocktails
Biodegradation of liquid scintillant cocktails
This study considers the use of biodegradation as an alternative means of waste disposal for two common liquid scintillant cocktail types. EcoSafeTM and Gold StarTM.
Sequencing batch reactors were used containing activated sewage sludge (ASS) as a biomass source, a standard nutrient medium and a carbon source in the form of LS cocktail or one of its components. Compounds of interest were butoxyethoxy ethanol (BEE), di-isopropyl naphthalene (DIPN), branched alkyl benzenes (BABs), 2,5-diphenyl oxazole (PPO), bis-(o-methylstyryl benzene (bis-MSB) and nonylphenol ethoxylates (NPEs). All experiments were conducted under laboratory conditions with no temperature, pressure or light controls. Aeration was used to ensure aerobic conditions and mixing.
Due to analytical limitations, compound concentrations were only determined for BEE, DIPN, BABs and PPO. Bis-MSB and NPEs were not assessed. Both biotic and abiotic losses were quantified at a compound concentration level equal to that present in a 1 % LS cocktail solution. Losses were found for BEE and PPO, which were primarily attributable to biomass increases and therefore biodegradation. Some abiotic losses were also evident. DIPN showed no biotic or abiotic losses under the conditions used. This contradicts the outcomes of other studies which showed that biodegradation did occur, albeit at much lower levels (0.005 %). The sixteen BAB isomers were grouped according to the length of their shorter alkyl chain. It was evident that selective losses were occurring as a function of this chain length. Those with one or two atoms in their aliphatic chain showed large abiotic and biotic losses. With increased chain length compound losses were reduced, particularly regarding biotic losses. Degradation rates were calculated by first order rate equations. Both lag time and degradation rate were directly related to compound recalcitrance. The experimental technique did not allow for the detection of degradation products. Despite limited control of degradation conditions, and the use of fresh activated sewage sludge for each experiment, the extent of compound loss was shown to be reproducible.
A commercial viability investigation and the basis for an environmental impact assessment were included in this study.
University of Southampton
Lubben, Anneke T
d182d22d-abf7-438c-8aba-abdb35836693
2001
Lubben, Anneke T
d182d22d-abf7-438c-8aba-abdb35836693
Lubben, Anneke T
(2001)
Biodegradation of liquid scintillant cocktails.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This study considers the use of biodegradation as an alternative means of waste disposal for two common liquid scintillant cocktail types. EcoSafeTM and Gold StarTM.
Sequencing batch reactors were used containing activated sewage sludge (ASS) as a biomass source, a standard nutrient medium and a carbon source in the form of LS cocktail or one of its components. Compounds of interest were butoxyethoxy ethanol (BEE), di-isopropyl naphthalene (DIPN), branched alkyl benzenes (BABs), 2,5-diphenyl oxazole (PPO), bis-(o-methylstyryl benzene (bis-MSB) and nonylphenol ethoxylates (NPEs). All experiments were conducted under laboratory conditions with no temperature, pressure or light controls. Aeration was used to ensure aerobic conditions and mixing.
Due to analytical limitations, compound concentrations were only determined for BEE, DIPN, BABs and PPO. Bis-MSB and NPEs were not assessed. Both biotic and abiotic losses were quantified at a compound concentration level equal to that present in a 1 % LS cocktail solution. Losses were found for BEE and PPO, which were primarily attributable to biomass increases and therefore biodegradation. Some abiotic losses were also evident. DIPN showed no biotic or abiotic losses under the conditions used. This contradicts the outcomes of other studies which showed that biodegradation did occur, albeit at much lower levels (0.005 %). The sixteen BAB isomers were grouped according to the length of their shorter alkyl chain. It was evident that selective losses were occurring as a function of this chain length. Those with one or two atoms in their aliphatic chain showed large abiotic and biotic losses. With increased chain length compound losses were reduced, particularly regarding biotic losses. Degradation rates were calculated by first order rate equations. Both lag time and degradation rate were directly related to compound recalcitrance. The experimental technique did not allow for the detection of degradation products. Despite limited control of degradation conditions, and the use of fresh activated sewage sludge for each experiment, the extent of compound loss was shown to be reproducible.
A commercial viability investigation and the basis for an environmental impact assessment were included in this study.
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Published date: 2001
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Local EPrints ID: 464640
URI: http://eprints.soton.ac.uk/id/eprint/464640
PURE UUID: 2a26f73e-b2df-4f36-859a-38aa7e5d4da0
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Date deposited: 04 Jul 2022 23:53
Last modified: 16 Mar 2024 19:40
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Author:
Anneke T Lubben
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