Use this URL to cite or link to this record in EThOS:
Title: Biodegradation of liquid scintillant cocktails
Author: Lubben, Anneke T.
ISNI:       0000 0001 3613 6055
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2001
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
This study considers the use of biodegradation as an alternative means of waste disposal for two common liquid scintillant cocktail types. EcoSafe™ and Gold Star™. 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.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available