Title page for ETD etd-0708103-181831


Type of Document Master's Thesis
Author Iqbal, Javed
Author's Email Address jiqbal1@lsu.edu
URN etd-0708103-181831
Title Effect of Temperature on Efficiency of in Situ Bioremediation Technology: A Laboratory Microcosm and Field Study
Degree Master of Science (M.S.)
Department Environmental Studies
Advisory Committee
Advisor Name Title
Ralph J. Portier Committee Chair
Edward B. Overton Committee Member
Vincent L. Wilson Committee Member
Keywords
  • superfund
  • hazardous waste
  • bioremediation
  • microcosm
Date of Defense 2003-06-27
Availability unrestricted
Abstract
Laboratory microcosm experiment and parallel ex situ bioremediation studies were conducted to study the effect of temperature on in situ bioremediation systems installed at Superfund site in southeast Georgia. Laboratory microcosms, inoculated with PAHs/phenols specific microorganisms, at high temperatures (422C; 1073F) demonstrated a significant reduction of residual polycyclic aromatic hydrocarbons (PAHs) and selected phenols from 49271356ng/g dry weight soil to 1158530ng/g with a kinetic rate of 76.116.8ng/g/day (84% reduction; p≤0.01) in 49days. High temperature non-inoculated microcosms were reduced of residual PAHs and phenols from 1117436ng/g to 341116ng/g with a kinetic rate of 15.86.5ng/g/day (65% reduction; p≤0.01) in 49days. Low temperature inoculated treatment (211C; 692F), was reduced from 3048200ng/g to 1,094240ng/g PAHs/phenols with kinetic rate of 39.81ng/g/day (66% reduction, p≤0.01) in 49days; A 50% reduction in low temperature non-inoculated treatment from 813189ng/g to 36779ng/g (p≤0.1794) was also observed with kinetic rate of 9.12.2ng/g/day. The laboratory study demonstrated that efficiency of bioremediation could be enhanced by maintaining an elevated temperature using amended and/or indigenous microflora. Amended populations were also proved to be more effective at lower temperatures. Field biopile data sets presented somewhat different findings. Minimal reduction at high ambient temperature range of 70-79F from 93491420 to 93001017mg/kg (kinetic rate: 0.403.3ng/g/day) was seen in the first 120days of the field study. Evaluations of the pile indicated significant desiccation occurred due to black polypropylene cover used to entrain heat. By correcting moisture level using trickling spray under the plastic sheeting, significant reductions of ≥35% (139122054 -90211660mg/kg PAHs/phenols) with a kinetic rate of 40.73.3ng/g/day, despite lower air temperatures of 48-58F in the last 120days. The results showed the efficacy of correctly using immobilized bed bioreactors (bioplugs) under plastic sheeting coupled with proper soil moisture management during colder winter months. These studies show that optimizing temperature for in situ bioremediation technologies at Superfund sites can reduce time required for treatment of hazardous wastes; hence reduction in operational time and effort to ensure smooth running of the remediation process year round (especially in cold regions and cold weather) can be realized.
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