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Dario Frascari, Giulio Zanaroli, Anthony S Danko
The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere...
2015: Journal of Hazardous Materials
Patrick Höhener, Violaine Ponsin
Contamination of the vadose zone with various pollutants is a world-wide problem, and often technical or economic constraints impose remediation without excavation. In situ bioremediation in the vadose zone by bioventing has become a standard remediation technology for light spilled petroleum products. In this review, focus is given on new in situ bioremediation strategies in the vadose zone targeting a variety of other pollutants such as perchlorate, nitrate, uranium, chromium, halogenated solvents, explosives and pesticides...
June 2014: Current Opinion in Biotechnology
Mohammad Mehdi Amin, Mohammad Sadegh Hatamipour, Fariborz Momenbeik, Heshmatollah Nourmoradi, Marzieh Farhadkhani, Fazel Mohammadi-Moghadam
The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE...
2014: TheScientificWorldJournal
J P Okx, L Hordijk, A Stein
Soil remediation has only a short history but the problem addressed is a significant one. Cost estimates for the clean-up of contaminated sites in the European Union and the United States are in the order of magnitude of 1,400 billion ECU. Such an enormous operation deserves the best management it can get. Reliable cost estimations per contaminated site are an important prerequisite. This paper addresses the problems related to site-wise estimations.When solving soil remediation problems, we have to deal with a large number of scientific disciplines...
December 1996: Environmental Science and Pollution Research International
F Javier García Frutos, Olga Escolano, Susana García, Mar Babín, M Dolores Fernández
The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5...
November 15, 2010: Journal of Hazardous Materials
S M C Magalhães, R M Ferreira Jorge, P M L Castro
Bioventing has emerged as one of the most cost-effective in situ technologies available to address petroleum light-hydrocarbon spills, one of the most common sources of soil pollution. However, the major drawback associated with this technology is the extended treatment time often required. The present study aimed to illustrate how an intended air-injection bioventing technology can be transformed into a soil vapour extraction effort when the air flow rates are pushed to a stripping mode, thus leading to the treatment of the off-gas resulting from volatilisation...
October 30, 2009: Journal of Hazardous Materials
Nadja Kabelitz, Jirina Machackova, Gwenaël Imfeld, Maria Brennerova, Dietmar H Pieper, Hermann J Heipieper, Howard Junca
In order to obtain insights in complexity shifts taking place in natural microbial communities under strong selective pressure, soils from a former air force base in the Czech Republic, highly contaminated with jet fuel and at different stages of a bioremediation air sparging treatment, were analyzed. By tracking phospholipid fatty acids and 16S rRNA genes, a detailed monitoring of the changes in quantities and composition of the microbial communities developed at different stages of the bioventing treatment progress was performed...
March 2009: Applied Microbiology and Biotechnology
Patrick J Evans, Mary M Trute
When present in the vadose zone, potentially toxic nitrate and perchlorate anions can be persistent sources of groundwater contamination. Gaseous electron donor injection technology (GEDIT), an anaerobic variation of petroleum hydrocarbon bioventing, involves injecting electron donor gases, such as hydrogen or ethyl acetate, into the vadose zone, to stimulate biodegradation of nitrate and perchlorate. Laboratory microcosm studies demonstrated that hydrogen and ethanol promoted nitrate and perchlorate reduction in vadose zone soil and that moisture content was an important factor...
December 2006: Water Environment Research: a Research Publication of the Water Environment Federation
T H Lee, I G Byun, Y O Kim, I S Hwang, T J Park
An in situ measuring system of respiration rate was applied for monitoring biodegradation of diesel fuel in a bioventing process for bioremediation of diesel contaminated soil. Two laboratory-scale soil columns were packed with 5 kg of soil that was artificially contaminated by diesel fuel as final TPH (total petroleum hydrocarbon) concentration of 8,000 mg/kg soil. Nutrient was added to make a relative concentration of C:N:P = 100:10:1. One soil column was operated with continuous venting mode, and the other one with intermittent (6 h venting/6 h rest) venting mode...
2006: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Hong Sui, Xingang Li, Guoqiang Huang, Bin Jiang
Cometabolic bioventing for removal of TCE in the unsaturated zone was studied in a soil column study using methane as growth substrate. A numerical model was developed for simulating the behavior of TCE during cometabolic bioventing. The model parameters were estimated independently through laboratory batch experiments or from the literature. Simulations were found to provide reasonable agreement with the experimental data. The experimental data show that a total TCE remediation efficiency of over 95% was obtained...
February 2006: Environmental Geochemistry and Health
H Aichberger, Marion Hasinger, Rudolf Braun, Andreas P Loibner
Preliminary tests at different scales such as degradation experiments (laboratory) in shaking flasks, soil columns and lysimeters as well as in situ respiration tests (field) were performed with soil from two hydrocarbon contaminated sites. Tests have been evaluated in terms of their potential to provide information on feasibility, degradation rates and residual concentration of bioremediation in the vadose zone. Sample size, costs and duration increased with experimental scale in the order shaking flasks - soil columns - lysimeter - in situ respiration tests, only time demand of respiration tests was relatively low...
March 2005: Biodegradation
P Di Gennaro, E Collina, A Franzetti, M Lasagni, A Luridiana, D Pitea, G Bestetti
The aim of the research was to verify the possibility of applying bioremediation as a treatment strategy on a poly(vinyl chloride) (PVC) manufacturing site in the north of Italy contaminated by diethylhexyl phthalate (DEHP) at a concentration of 5.51 mg/g of dry soil. Biodegradation kinetic experiments with DEHP contaminated soil samples were performed in both slurry- and solid-phase systems. The slurry-phase results showed that the cultural conditions, such as N and P concentrations and the addition of a selected DEHP degrading strain, increased the natural DEHP degradation rate...
January 1, 2005: Environmental Science & Technology
Patricia Osterreicher-Cunha, Eurípedes do Amaral Vargas, Jean Rémy Davée Guimarães, Tácio Mauro Pereira de Campos, Cassiane Maria Ferreira Nunes, Ariovaldo Costa, Franklin dos Santos Antunes, Maria Isabel Pais da Silva, Denise Maria Mano
Remediation methods for environmental contamination problems based on physical or chemical processes frequently present low efficiency and/or high costs. On the other hand, biological treatment is being proved to be an accessible alternative for soil and water remediation. Bioventing is commonly used for petroleum hydrocarbon (PHC) spills. This process provides better subsurface oxygenation, thus stimulating degradation by indigenous microorganisms. In Brazil, gasoline and ethanol are routinely mixed; some authors suggest that despite gasoline high degradability, its degradation in the aquifer is hindered by the presence of much rapidly degrading ethanol...
July 5, 2004: Journal of Hazardous Materials
Philip G Mihopoulos, Makram T Suidan, Gregory D Sayles, Sebastien Kaskassian
A numerical and experimental study of transport phenomena underlying anaerobic bioventing (ABV) is presented. Understanding oxygen exclusion patterns in vadose zone environments is important in designing an ABV process for bioremediation of soil contaminated with chlorinated solvents. In particular, the establishment of an anaerobic zone of influence by nitrogen injection in the vadose zone is investigated. Oxygen exclusion experiments are performed in a pilot scale flow cell (2 x 1.1 x 0.1 m) using different venting flows and two different outflow boundary conditions (open and partially covered)...
October 2002: Journal of Contaminant Hydrology
Edgard S El Chaar, Ziad N Jalbout
This case report concerns the loss of osseous tissue around two hydroxyapatite (HA) Biovent implants, placed in 1993, at sites #30 and #31. The implant in site #31 was positioned with a distal angle, resulting in an ill-fitting prosthesis. This permitted bacterial colonization to set up a periimplantitis. The rough HA coating on the implants further exacerbated the resultant bone loss. In an attempt to rectify the pathology, surgical debridement, antibiotic therapy, bone grafting, and guided tissue regeneration with a barrier membrane were utilized...
2002: Periodontal Clinical Investigations: Official Publication of the Northeastern Society of Periodontists
B Vallejo, A Izquierdo, R Blasco, P Pérez del Campo, M D Luque de Castro
In order to decontaminate a large area of restricted access contaminated by a fuel spill, laboratory and field studies were developed in two steps: (a) monitoring of the laboratory experiment on bacterial growth under aerobic and anaerobic conditions with and without addition of nutrients; and (b) use of the best conditions obtained in (a) for the decontamination of the soil. A hydraulic barrier was installed both to clean the aquifer and to avoid migration of hydrocarbons as a consequence of their solution in the groundwater and subsequent displacement...
June 2001: Journal of Environmental Monitoring: JEM
J Bachman, S M Kanan, H H Patterson
Bioventing is an improved method of soil remediation that is being used with increasing frequency. In this paper, we refine techniques to measure the progress of petroleum hydrocarbon decomposition by monitoring vapor phase composition with synchronous scan fluorescence spectroscopy (SSFS). Analysis of the vapor phase has advantages compared to standard extraction techniques that require extensive sample handling and clean up. For comparison, hydrocarbon contamination in the soil was measured by analysis of Soxhlet extractions with gas chromatography-mass spectrometry (GC-MS)...
2001: Environmental Pollution
J K Shah, G D Sayles, M T Suidan, P Mihopoulos, S Kaskassian
Initial degradation of highly chlorinated compounds and nitroaromatic compounds found in munition waste streams is accelerated under anaerobic conditions followed by aerobic treatment of the degradation products. The establishment of anaerobic environment in a vadose zone can be accomplished by feeding appropriate anaerobic gas mixture, i.e., "anaerobic bioventing". The gas mixture contains an electron donor for the reduction of these compounds. Lab scale study was conducted to evaluate potential of anaerobic bioventing for the treatment of an unsaturated zone contaminated with 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and 2,4-dinitrotoluene (DNT)...
2001: Water Science and Technology: a Journal of the International Association on Water Pollution Research
P G Mihopoulos, M T Suidan, G D Sayles
Bioventing principles have been applied to completely dechlorinate tetrachloroethylene vapors in the unsaturated zone in a sequential anaerobic-aerobic pattern. The aerobic step yields trans-DCE and VC as PCE reductive dechlorination byproducts, while TCE and cis-DCE are observed as intermediates. The aerobic step results in rapid oxidation of the VC and trans-DCE to carbon dioxide. Hydrogen was delivered in the gas phase as a reducing agent for the anaerobic step at levels of 1%, and oxygen at 4.2% was used as an electron acceptor in the aerobic step...
2001: Water Science and Technology: a Journal of the International Association on Water Pollution Research
G Brunel, S Armand, N Miller, J Rue
This study presents the histologic analysis of an implant retrieved 14 months after loading because of a fracture in the collar region. The implant (Biovent) was removed with part of the periimplant tissues, and the block was prepared using cutting and grinding equipment to obtain 3 sections approximately 30 microns thick. The examination evidenced a high degree of osseointegration, with a bone-to-implant contact of 74% +/- 13%. The lamellar bone was dense and in close relation with the hydroxyapatite coating of the implant...
October 2000: International Journal of Periodontics & Restorative Dentistry
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