ISSN:0262-6667    

DOI:10.1080/02626669309492672

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Most organic materials that contaminate soil and the subsurface environment are readily degraded by natural biological processes. To this degree, in situ bioremediation can be thought of as a highly successful purification process. However, some organic molecules are naturally refractory to biodegradation, or other environmental factors induce molecular recalcitrance such as the absence of a proper microbial population or the presence of unsuitable environmental conditions. Examples of recalcitrant groundwater contaminants are soluble components of petroleum hydrocarbons (BTEX) and chlorinated aliphatic hydrocarbons (CAHs). Organic recalcitrance may be changed through introduction of degrading populations of microorganisms or by changing the environmental conditions through introduction of nutrients or other chemicals. The most significant engineering deficiency in in situ bioremediation is the absence of proven methods to introduce such materials into the subsurface environment for efficient mixing with microorganisms and the contaminants of concern.

ISSN:0262-6667    

DOI:10.1080/02626669309492673

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The availability of oxygen generally controls the rate at which aerobic in situ bioremediation proceeds. Bioventing, which couples soil venting with bioremediation, is often the most effective means of supplying oxygen to unsaturated zone soil. Laboratory treatability studies were conducted which showed that bioventing could be successfully applied to compounds ranging from light hydrocarbons, such as gasoline or diesel, to heavier hydrocarbons, such as fuel oils, as well as other volatile and semivolatile compounds. In many cases, the promotion of biological activity through the addition of nutrients and moisture, and optimization of the bioventing flow rates, may achieve greater contaminant reductions than venting alone.

ISSN:0262-6667    

DOI:10.1080/02626669309492674

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper describes a bioventing study design and initial activities applied to a JP-4 jet fuel spill at Eielson Air Force Base, Alaska. The primary objectives of the project were to investigate the feasibility of using bioventing technology to remediate JP-4 jet fuel contamination in a sub-arctic environment and to determine to what degree the biodegradation rate of JP-4 soil contaminants could be enhanced by increasing soil temperature, both actively by circulating heated groundwater and passively by utilizing solar energy. Biodegradation rates at the bioventing site remained relatively high during the winter months in the active-warming test plot and were consistently higher than those observed in the passive-warming and control test plots. These studies suggest that an active-warming system operated in conjunction with bioventing is a useful method for remediating fuel-contaminated areas in cold climates.

ISSN:0262-6667    

DOI:10.1080/02626669309492675

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An estimated 50 000 1 of diesel fuel contaminated soil over a depth of 1.5 to 3.5 m (approximately 1.5% by weight in the soil) following fuel recovery operations at the site of a diesel spill. Laboratory treatability identified oxygen supply treatment as having significant potential to enhance bioremediation of the soil in situ. A bioventing system was designed and tested on a quarter of the site. Venting alone over a period of six months reduced total hydrocarbon concentrations by 10 to 30% to a depth of 3 m. Venting with nutrient addition resulted in a further reduction of 30% over a subsequent 6 month period to the full depth of 3.5 m.

ISSN:0262-6667    

DOI:10.1080/02626669309492676

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Field and laboratory evidence show natural degradation of toluene, ethylbenzene, m-, p- and o-xylenes, 1,3,5-trimethylbenzene and naphthalene in sulphate reducing groundwater conditions of the Bassendean Sands in the Perth basin, Western Australia. Natural degradation rates were obtained from a groundwater tracer test with deuterated organic compounds injected into a dissolved hydrocarbon plume, down-gradient of a leaking underground storage tank at an urban service station. These were compared with similar data obtained from modelling of the whole contaminant plume itself and also with data obtained from large-scale laboratory column experiments with groundwater spiked with BTEX compounds. Toluene degradation rate was 200 to 500 times higher in the anaerobic laboratory columns than in the field. Degradation rates in the tracer test compared well with model-derived field estimates.

ISSN:0262-6667    

DOI:10.1080/02626669309492677

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An in situ microbial filter technology is being tested and developed for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). The current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. This microbial filter strategy has been successfully demonstrated using emplaced, attached resting cells (no methane additions) in a 1.1 m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 15 mm h−1; no TCE (< 0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 21 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph is a result of the laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1 m test bed yielded a high resting-cell finite TCE biotransformation capacity of about 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site.

ISSN:0262-6667    

DOI:10.1080/02626669309492678

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Porphyrins are the molecules which are at the heart of most biochemical reactions involved in bioremediation. This review paper discusses the chemical structures, the biosynthetic pathways and the occurrence of porphyrins in the environment. The parallel between the mammalian and bacterial cytochrome P-450 enzyme systems and the similarity of the reactions at the molecular level is brought to the attention of the reader. Experiments where porphyrins and corrinoids are used as catalysts in the absence of the enzymes or the bacterial cells are opening the field of biochemical remediation, somewhere midway between biological and abiotic reactions.

ISSN:0262-6667    

DOI:10.1080/02626669309492679

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492680

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492681

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor