Aerobic Biodegradation of Benzene, Toluene, and Xylene in a Sandy Aquifer—Data Analysis and Computer Modeling

Soluble hydrocarbon and dissolved oxygen (DO) in a shallow aquifer beneath a field site were characterized by sampling ground water at 42 monitoring wells. Results from 10 sampling periods over three years showed a significant reduction in total benzene mass with time in ground water. These reduction and leakage rates from sources were determined from material balance and nonlinear least-squares analyses. The natural attenuation rate was calculated to be 0.95%/day. Spatial relationships between DO and total benzene, toluene, and xylene (BTX) were shown to be strongly correlated by statistical analyses and solute transport modeling. In addition, laboratory microcosm biodegradation experiments were performed to determine possible threshold limits for aromatic hydrocarbon oxidation under varying levels of dissolved oxygen. The results were remarkably consistent with field data on the presence of high or low levels of BTX and DO in several monitoring well-water samples.

[1]  S. Karickhoff,et al.  Semi-empirical estimation of sorption of hydrophobic pollutants on natural sediments and soils , 1981 .

[2]  R. Rhodes Trussell,et al.  Design of aeration towers to strip volatile contaminants from drinking water , 1980 .

[3]  Jorge J. Moré,et al.  The Levenberg-Marquardt algo-rithm: Implementation and theory , 1977 .

[4]  E. Geldreich,et al.  A new medium for the enumeration and subculture of bacteria from potable water , 1985, Applied and environmental microbiology.

[5]  G. C. Patrick,et al.  Natural Attenuation of Aromatic Hydrocarbons in a Shallow Sand Aquifer , 1987 .

[6]  D. Ronen,et al.  Anthropogenic anoxification (“eutrophication”) of the water table region of a deep phreatic aquifer , 1987 .

[7]  Jorge J. Moré,et al.  User guide for MINPACK-1. [In FORTRAN] , 1980 .

[8]  H. Gvirtzman,et al.  Microscale chemical heterogeneity in groundwater , 1987 .

[9]  Fred J. Molz,et al.  Performance, Analysis, and Simulation of a Two‐Well Tracer Test at the Mobile Site , 1986 .

[10]  T. A. Bellar,et al.  Determining volatile organics at microgram-per-litre levels by gas chromatography , 1974 .

[11]  F. Molz,et al.  Internal inconsistencies in dispersion-dominated models that incorporate chemical and microbial kinetics , 1988 .

[12]  P. Bedient,et al.  BIOPLUME II computer model of two-dimensional contaminant transport under the influence of oxygen limited biodegradation in ground water. Documentation. Final report , 1988 .

[13]  John A. Cherry,et al.  Migration of contaminants in groundwater at a landfill: A case study: 4. A natural-gradient dispersion test , 1983 .

[14]  J. Bredehoeft,et al.  Computer model of two-dimensional solute transport and dispersion in ground water , 1978 .