Transport and fate of benzene in a saturated groundwater environment - laboratory column study | |
| Author | Misra, Girish Chandra |
| Call Number | AIT Thesis no.EV-93-28 |
| Subject(s) | Water, Underground--Microbiology Benzene--Biodegradation |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Petroleum hydrocarbons from leaking underground storage tanks, accidental spillage or leachate from waste-dump sites have tremendous potential to contaminate the underground water bodies which serve as the primary source of drinking water for the majority of human population around the world. These chemicals, while traversing through the vadose zone, undergo physical, chemical and biological changes with significant depletion of concentration before finally reaching the aquifer. Microbial activity occurs to a varying degree within the aquifer too, although in most cases it is limited by either substrate deficiency, low nutrient availability or lack of electron acceptors. In this study mixed aerobic culture obtained from an activated sludge plant and later enriched with benzene degrading bacteria, was tested under batch condition (in serum bottle) and continuous flow soil columns for determining the extent of benzene biodegradation. Pure benzene as well as benzene present in gasoline were tested as carbon source. Results indicated a zero order rate of 0.9 mg/l.d for pure benzene and about 0.76 mg/l.d for gasoline. The effect of cosubstrate (glucose) on benzene biodegradation and toxicity of benzene on microbes were also studied. Presence of cosubstrate did not effect benzene degradation rate significantly. At concentration ranges tested (32.3-167.18 mg/I) benzene completely inhibited biomass growth. Results of column test indicated that benzene can be degraded in groundwater environment provided sufficient time is given for microbial acclimation and the presence of dissolved oxygen is ensured. Transport parameters estimated included the coefficient of dispersion and adsorption. Adsorption is found to be an important phenomenon which can significantly retard movement of benzene contaminated plume. The presence of fine soil particles such as clay and silt is pivotal in determining the extent of adsorption occurring in subsurface. The study provided valuable information for use in groundwater models to predict vertical penetration of aqueous phase benzene in aquifers. |
| Year | 1993 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Chongrak Polprasert;Gupta, Ashim Das; |
| Examination Committee(s) | Lee, Seong-Key; |
| Scholarship Donor(s) | Royal Thai Government (King's Scholarship); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1993 |