American Society of Civil Engineers


Microbial Decontamination of Polluted Soil in a Slurry Process


by M. J. Geerdink, (Res., Kluyver Lab. for Biochemical Technol., Delft Univ. of Technol., Julianalaan 67, 2628 BC Delft, The Netherlands.), R. H. Kleijntjens, (Res., Kluyver Lab. for Biochemical Technol., Delft Univ. of Technol., Julianalaan 67, 2628 BC Delft, The Netherlands.), M. C. M. van Loosdrecht, (Assoc. Prof. of Envir. Biotechnol., Kluyver Lab. for Biochemical Technol., Delft Univ. of Technol., Julianalaan 67, 2628 BC Delft, The Netherlands.), and K. C. A. M. Luyben, (Prof. of Biochemical Engrg., Kluyver Lab. for Biochemical Technol., Delft Univ. of Technol., Julianalaan 67, 2628 BC Delft, The Netherlands.)

Journal of Environmental Engineering, Vol. 122, No. 11, November 1996, pp. 975-982, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9372(1996)122:11(975))

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Document type: Journal Paper
Abstract: Oil-contaminated soil (2.3–17 g/kg), even soil with high clay and silt content, was remediated microbiologically in a slurry reactor. The presence of soil, however, limits the degradation rate of oil. In contrast with results from experiments using oil dispersed in water, the relative composition of the oil components in a soil slurry after degradation was about the same as that of the original oil. Thus the composition of the degraded oil is the same as that of the original oil, which is indicative for a physical, rather than a (bio)chemical, limitation on the oil degradation rate. About 70% of the contaminant was readily available and was degraded in less than eight days. The dual injected turbulent suspension (DITS) reactor is able to combine remediation of part of the contaminated (polydisperse) soil with separation of the soil into a heavily and a lightly polluted fraction. In continuous operation, lowering the overall soil residence time from 200 to 100 h did not significantly increase the oil concentration in the effluent soil. Therefore a soil residence time of less than 100 h is feasible. With a residence time of 100 h, overall oil degradation rates at the steady state were more than 70 times faster than in a comparable land farm. After treatment in a DITS reactor, the remaining oil in the contaminated soil fraction is slowly released from the soil. From a batch experiment it was found that another 10 weeks were needed to reach the Dutch reference level of 50 mg/kg. This can be done in a process with a low energy input, such as a land farm.


ASCE Subject Headings:
Biological processes
Fuels
Microbes
Remediation
Slurries
Soil pollution
Soils