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Aerobic Biodegradation of Benzene, Toluene, and Xylene in a Sandy Aquifer—Data Analysis and Computer Modeling (1989)

Chiang, C. Y. ; Salanitro, J. P. ; Chai, E. Y. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Ground water 27 (1989), S. 0

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ISSN: 1745-6584

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences

Notes: 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.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1745-6584.1989.tb01046.x

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Effects of ammonia and phosphate limitation on the activated sludge treatment of calcium-containing chemical waste (1983)

Salanitro, J. P. ; Sun, P. T. ; Thornton, J. B.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 25 (1983), S. 513-523

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ISSN: 0006-3592

Keywords: Chemistry ; Biochemistry and Biotechnology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology

Notes: Laboratory-scale biotreaters were used to study the effects of NH3-N and PO4-P nutrients on the activated sludge treatment of a chemical waste containing soluble calcium (1300 mg/L). Units receiving high or low levels of NH3-N and PO4-P were similar in their ability to remove organic compounds from the waste. Adaptation of sludges to low PO4-P levels (〈0.1 mg/L effluent) resulted in a marked accumulation of CaCO3 in the biosolids, whereas those receiving high PO4-P (2-4 mg/L effluent) had little CaCO3. Microscopic observations of CaCO3 containing sludges showed substantial amounts of CaCO3 crystals imbedded in the biomass. These flocs also appeared to be enriched with nonfilamentous bacterial species in contrast to flocs devoid of CaCO3 which had a floc structure of filamentous and nonfilamentous organisms. Scanning electron micrographs of flocs grown under low NH3-N showed a microbial fibrillar network of exocellular material interconnecting cells in the floc matrix. The sludges adapted to low NH3-N also produced higher amounts of extractable polysaccharide. CaCO3 containing biosolids were more dense, larger, and settled better (low SVI, high ISV) than flocs devoid of the precipitates. It is not known from our experiments whether PO4-P or some inorganic or organic polymer produced by the floc bacteria are involved in inhibiting CaCO3 precipitation in the activated sludge treatment of calcium-containing wastes.

Additional Material: 4 Ill.