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Title: In-vessel composting bioremediation of electrical insulating oil-contaminated soil
Author: Warner, Lucinda Alice Rose
ISNI:       0000 0004 2671 7798
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2009
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Electrical insulating oils are used to insulate electrical transmission devices. The oils consist of saturated and aromatic hydrocarbons and are released into the environment through leaks and accidental releases. Electrical insulating oils in soil can be measured as total petroleum hydrocarbons (TPH). Contaminated soils are disposed of to landfill, but this is unsustainable. Therefore, in-vessel composting bioremediation is an attractive alternative treatment. The aims of this study were to optimize in-vessel composting bioremediation of electrical insulating oil-contaminated soils, to achieve efficient removal of TPH contamination and to examine the effects of soil properties, contaminant ageing and compound physico-chemical properties on TPH removal during composting. For identification and quantification of TPH, samples were extracted using ASE® and analyzed by GC-MS. A preliminary pilot-scale composting study was evaluated to determine the effectiveness of composting on TPH losses that were 14.3 to 61.5%. Composting process optimization at bench-scale found optimal operating conditions of 0.8:1 soil to green waste ratio, 38°C operating temperature and 60% moisture content, which resulted in enhanced TPH removal of 75.6 to 86.1%. By composting two contrasting oil-contaminated soils, it was shown that differing soil characteristics had no significant effect on TPH biodegradation during composting. Contaminated soils were aged for 3 months to examine contaminant ageing effects on composting, but no significant difference in TPH losses from aged soils and freshly contaminated soils was found. Loss of some contaminants was influenced by their physico-chemical properties, more hydrophobic compounds being less susceptible to degradation. The microbial community involved in composting was dominated by bacteria; Gram-positive bacteria and actinomycetes were more abundant than Gram-negative bacteria, fungi were less numerous. This study demonstrates that composting bioremediation has potential for the clean-up of electrical insulating oil-contaminated soils.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available