Search results for "Remediation"
showing 10 items of 278 documents
EVALUATION OF AEROBIC AND ANAEROBIC BACTERIAL DECHLORINATION POTENTIAL OF A 1,2-DICHLOROETHANE CONTAMINATED AQUIFER
2023
Chlorinated solvents, belonging to the class of chlorinated aliphatic hydrocarbons (CAHs), are synthetic organohalide chemicals frequently found as contaminants of groundwater and soil, due to their widespread use in several industrial processes and improper disposal methods. These compounds pose serious health threats because of their toxic and sometimes carcinogenic effects. Among these compounds, 1,2-dichloroethane (1,2-DCA) is one of the most common aquifer contaminants, considered toxic and classified as a possible human carcinogen. Remediation approaches toward these contaminants include conventional cleanup technologies based on physical/chemical methods, and bioremediation, consider…
A battery of toxicity tests as indicators of decontamination in composting oily waste.
2000
Heterogeneous oily waste from an old dumping site was composted in three windrows constructed from different proportions of waste, sewage sludge, and bark. The objectives of this pilot study were to examine the usefulness of composting as a treatment method for this particular waste and to study decontamination in the composting process by using a battery of toxicity tests. Five samples from the windrow having intermediate oil concentrations were tested with toxicity tests based on microbes (Pseudomonas putida growth inhibition test, ToxiChromotest, MetPLATE, and three different modifications of a luminescent bacterial test), enzyme inhibition (reverse electron transport), plants (duckweed …
Genetic methods to improve Cr(VI) bioremediation in groundwater
2009
Cr(VI) contamination of groundwater and soils is a primary public health. Bioremediation is an environmental-friendly alternative for Cr(VI) removal from groundwater and soils, but Cr(VI) toxicity limits the efficiency of the process. We use the genome shuffling technique in order to improve Cr(VI) tolerance and Cr(VI) reduction capability of the strict anaerobic bacterium Geobacter metallireducens. We will investigate the mechanism of Cr(VI) reduction in the resulting G. metallireducens mutants through an innovative electrochemical approach. Finally, we will test the best performing mutants in a bench-scale Cr(VI) bioremediation process.
GEOBACTER METALLIREDUCENS MUTANTS FOR CHROMIUM BIOREMEDIATION
2011
Geobacter metallireducens is known to use oxidized metals such as Fe(III) and Mn(IV) as terminal extracellular electron acceptors. G. metallireducens can reduce the highly soluble and toxic Cr(VI) to its insoluble form Cr(III), thus enabling chromium removal from contaminated water and soil. This process is limited by the low toxicity resistance of G. metallireducens to Cr(VI). Genome shuffling can generate mutants with improved phenotype. In our work we are carrying out G. metallireducens genome shuffling, in order to increase its resistance to Cr(VI). In Geobacter species, metal toxicity resistance is correlated to the respiration rate, hence to the reduction rate of the metallic electron…
GEOBACTER METALLIREDUCENS MUTANTS FOR CHROMIUM BIOREMEDIATION
2011
Genetic technology to improve biofilms electroactivity for bioremediation applications
Genetic technology to improve biofilms electroactivity for bioremediation applications
2010
Hexavalent chromium bioremediation occurs through its reduction to Cr(III) and its following precipitation. Geobacter metallireducens is a dissimilatory metal reducing bacteria known to reduce Cr(VI) to Cr(III) through extracellular electron transfer. However, the effectiveness of this bioreduction process is limited by the low toxicity resistance of G. metallireducens to Cr(VI). G. metallireducens mutants with improved Cr(VI) toxicity resistance can be obtained by genome shuffling method. Here we present the experimental setup for genome shuffling of G. metallireducens, including the optimization of mutagenesis procedure and the respiration rate measure for G. metallireducens in potentiost…
NEMATODE COLONIZATION OF PYRITE CINDER-POLLUTED SOIL
2020
The nematofauna was studied in the early stages of a remediation trial at an industrial site where pyrite cinders had accumulated for 40 years in a large area and were then covered with mineral soil. The cinders were contaminated with several metals and metalloids. The soil of the experimental plots was derived from the mixture of cinders with the covering soil in a 1:1 ratio. Plots were amended with manure and sown with 3 metal resistant plants: Sorghum bicolor L., Helianthus annuus L., and Arundo donax L. Samples were taken : a) at the beginning of the trial on the pyrite cinders and covering soil, separately; b) from the mixture before the application of manure; c) from cultivated plots.…
The effect of peatland drainage and restoration on Odonata species richness and abundance
2015
Background Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration efforts. Results Here, we studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration. We sampled larvae in three sites (restored, drained, pristine) on each o…
Fighting carbon loss of degraded peatlands by jump-starting ecosystem functioning with ecological restoration
2015
Degradation of ecosystems is a great concern on the maintenance of biodiversity and ecosystem services. Ecological restoration fights degradation aiming at the recovery of ecosystem functions such as carbon (C) sequestration and ecosystem structures like plant communities responsible for the C sequestration function. We selected 38 pristine, drained and restored boreal peatland sites in Finland and asked i) what is the long-term effect of drainage on the peatland surface layer C storage, ii) can restoration recover ecosystem functioning (surface layer growth) and structure (plant community composition) and iii) is the recovery of the original structure needed for the recovery of ecosystem f…
Effect of river restoration on life-history strategies in fish communities
2019
Assessments of river restoration outcomes are mostly based on taxonomic identities of species, which may not be optimal because a direct relationship to river functions remains obscure and results are hardly comparable across biogeographic borders. The use of ecological species trait information instead of taxonomic units may help to overcome these challenges. Abundance data for fish communities were gathered from 134 river restoration projects conducted in Switzerland, Germany and Finland, monitored for up to 15 years. These data were related to a dataset of 22 categories of ecological traits describing fish life-history strategies to assess the outcome of the restoration projects. Restora…