Feasibility study of in-situ bioremediation for nitrobenzene-contaminated groundwater

Although many studies have simulated in-situ bioremediation of contaminated groundwater, most of them have not considered hydrochemical conditions and indigenous microorganisms, thus potentially rendering results inapplicable to actual in-situ groundwater bioremediation projects. This study focused on a nitrobenzene-contaminated groundwater site located in Jilin City, China. The actual nitrobenzene-contaminated groundwater was taken from Jilin City to simulate in-situ groundwater bioremediation in the laboratory. The feasibility of in-situ bioremediation for nitrobenzene-contaminated groundwater was studied according to actual site conditions and characteristics of nitrobenzene-degrading microorganisms in groundwater. The results showed that nitrobenzene-degrading bacterium strain NB1 was the dominant species that could effectively and rapidly degrade nitrobenzene by a partial reductive pathway. No negative factors on the growth or degrading function of this strain in groundwater could be detected. During a laboratory simulation experiment, combined in-situ bioremediation technologies, namely air sparging and bioaugmentation, could readily remove approximately 89.56% of nitrobenzene from groundwater without adding nutrients; oxygen was found to be the important growth factor for strain NB1. As the substrate of nitroreductase, encoded by the nitrobenzene nitroreductase (nbzA) gene, nitrobenzene was likely to significantly affect the expression of this gene. In conclusion, in-situ bioremediation is a feasible way to solve the problem of nitrobenzene-contaminated groundwater in Jilin City as long as sufficient oxygen and biomass of strain NB1 is ensured.

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On-site and in situ bioremediation of wood-preservative contaminated groundwater

Water Science & Technology ◽

10.2166/wst.2000.0537 ◽

2000 ◽

Vol 42 (5-6) ◽

pp. 371-376 ◽

Cited By ~ 11

Author(s):

J.A. Puhakka ◽

K.T. Järvinen ◽

J.H. Langwaldt ◽

E.S. Melin ◽

M.K. Männistö ◽

...

Keyword(s):

Iron Oxidation ◽

Wood Preservative ◽

Pilot Scale ◽

High Rate ◽

Contaminated Groundwater ◽

Groundwater Temperature ◽

In Situ Bioremediation ◽

Contaminated Aquifer ◽

Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

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A bioengineering system for in situ bioremediation of contaminated groundwater

Journal of Industrial Microbiology & Biotechnology ◽

10.1038/sj.jim.2900321 ◽

1997 ◽

Vol 18 (2-3) ◽

pp. 189-197 ◽

Cited By ~ 13

Author(s):

R B Knapp ◽

B D Faison

Keyword(s):

Contaminated Groundwater ◽

In Situ Bioremediation

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Degradation of 3-Phenoxybenzoic Acid in Soil byPseudomonas pseudoalcaligenes POB310(pPOB) and Two ModifiedPseudomonas Strains

Applied and Environmental Microbiology ◽

10.1128/aem.65.8.3354-3359.1999 ◽

1999 ◽

Vol 65 (8) ◽

pp. 3354-3359 ◽

Cited By ~ 50

Author(s):

Rolf U. Halden ◽

Sandra M. Tepp ◽

Barbara G. Halden ◽

Daryl F. Dwyer

Keyword(s):

Soil Formation ◽

Dry Weight ◽

Bacterial Survival ◽

In Situ Bioremediation ◽

Soil Microcosms ◽

Genes Encoding ◽

Bacterium Strain ◽

Favorable Conditions ◽

Water Holding

ABSTRACT Pseudomonas pseudoalcaligenes POB310(pPOB) andPseudomonas sp. strains B13-D5(pD30.9) and B13-ST1(pPOB) were introduced into soil microcosms containing 3-phenoxybenzoic acid (3-POB) in order to evaluate and compare bacterial survival, degradation of 3-POB, and transfer of plasmids to a recipient bacterium. Strain POB310 was isolated for its ability to use 3-POB as a growth substrate; degradation is initiated by POB-dioxygenase, an enzyme encoded on pPOB. Strain B13-D5 contains pD30.9, a cloning vector harboring the genes encoding POB-dioxygenase; strain B13-ST1 contains pPOB. Degradation of 3-POB in soil by strain POB310 was incomplete, and bacterial densities decreased even under the most favorable conditions (100 ppm of 3-POB, supplementation with P and N, and soil water-holding capacity of 90%). Strains B13-D5 and B13-ST1 degraded 3-POB (10 to 100 ppm) to concentrations of <50 ppb with concomitant increases in density from 106 to 108 CFU/g (dry weight) of soil. Thus, in contrast to strain POB310, the modified strains had the following two features that are important for in situ bioremediation: survival in soil and growth concurrent with removal of an environmental contaminant. Strains B13-D5 and B13-ST1 also completely degraded 3-POB when the inoculum was only 30 CFU/g (dry weight) of soil. This suggests that in situ bioremediation may be effected, in some cases, with low densities of introduced bacteria. In pure culture, transfer of pPOB from strains POB310 and B13-ST1 to Pseudomonas sp. strain B13 occurred at frequencies of 5 × 10−7 and 10−1 transconjugant per donor, respectively. Transfer of pPOB from strain B13-ST1 to strain B13 was observed in autoclaved soil but not in nonautoclaved soil; formation of transconjugant bacteria was more rapid in soil containing clay and organic matter than in sandy soil. Transfer of pPOB from strain POB310 to strain B13 in soil was never observed.

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