- Title
- Hydrocarbon contaminated subsurface remediation using electrokinetic enhanced bioremediation
- Creator
- Saini, Anish
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2021
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Since the early 1980’s there have been several different approaches identified, designed and used for the remediation of petroleum hydrocarbons (TPHs) in the subsurface environment including physical, chemical or even biological approaches which have had varying remediation efficiencies, risks and intricacies associated with them. Many of these approaches have been difficult to implement, requiring lots of labour mostly by disturbing the site via excavation to reach the contaminated subsurface, costly and time-consuming. Electrokinetics (EK) is an innovative in-situ remediation technology that involves the application of a low voltage current directly to the subsurface contaminated soil as well as groundwater. Bioremediation has been widely used for the remediation of TPH contamination with varying efficiency. Combining EK and bioremediation may help overcome the drawbacks of each of the technology and efficiently remediate the soil economically and in an acceptable time frame. The current applied will not only contribute towards the remediation via the electrically-induced reactions, but it may also activate the indigenous / supplemented microbes capable of degrading TPH to enhance the rate of remediation at the contaminated through different processes like electrolysis, electromigration, electrophoresis and electroosmosis. This study examined the efficiency of an electrokinetic approach coupled with bioremediation for the remediation of TPH from soil obtained from the contaminated subsurface. The study began with a laboratory pilot scale EK remediation study to observe the mineralization of TPH. The study determined remediation of TPH fractions at different depths, which simulate a subsurface soil environment. In the experiment carried out for 7 days, there was a 37% decrease in the concentrations of the C10-C16 fraction, which occurred at all the depths measured. There was no significant change in the concentrations of C17-C34 and the C35-C40 fractions. The first experiment for 7 days showed that the smaller TPH fractions can be mineralized by application of EK. For the next experiment, a new electrode configuration was tested to enhance the efficiency of TPH remediation by EK. This experiment was carried out for 30 days and the new electrode configuration provided for a more rotational effect within the soil. With this test, there was a 68% decrease in the C10-C16 fraction concentrations observed, almost double than the result for 7 days. Further, there was an 18.7% decrease in the C35-C40 fraction concentrations, proving that even the harder to remediate TPH fractions are mineralised via application of EK. Results from the second test led to a final comparative study to select a decisive technology which could be transferred to field trials. The investigations carried out in the final study included: maintenance of soil pH and moisture, use of EK to create optimum conditions and enhance bioremediation and mineralization of TPH fractions from various depths. The EK-PR process demonstrated a 91% decrease in the concentration of the C10-C16 fraction from the initial concentration of 81 ± 5 mg/kg. EK-PR bio cell also resulted in a 98% decrease for the C35-C40 fraction. The results of the study emphasise the use of electrokinetics as an effective enhancement technology for the bioremediation of TPH in soils. Laboratory-scale studies showed the potential of EK to mineralize TPH fractions in the soil at all the depths measured, EK with polarity reversal (PR) to effectively maintain the soil pH and moisture and the combined technology to enhance the mineralization of the heavier TPH fractions. Consequently, it is suggested that EK-PR could be an efficient method of enhancing the bioremediation of TPH in soils. This technology can be developed to be replicated on a field scale level for further observing its efficiency and application in the real world.
- Subject
- subsurface contamination; remediation; total petroleum hydrocarbons (TPH); electrokinetics (EK); bioremediation
- Identifier
- http://hdl.handle.net/1959.13/1514162
- Identifier
- uon:56818
- Rights
- Copyright 2021 Anish Saini
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
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| View Details Download | ATTACHMENT01 | Thesis | 6 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 1 MB | Adobe Acrobat PDF | View Details Download |