Search results for "DEGRADATION"
showing 10 items of 1208 documents
Innovative, ecofriendly biosorbent-biodegrading biofilms for bioremediation of oil- contaminated water.
2019
Immobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes. In this study, innovative and ecofriendly biosorbent-biodegrading biofilms have been developed in order to remediate oil-contaminated water. This was achieved by immobilizing hydrocarbon-degrading gammaproteobacteria and actinobacteria on biodegradable oil-adsorbing carriers, based on polylactic acid and polycaprolactone electrospun membranes. High capacities for adhesion and proliferation of bacterial cells were observed by scanning electron microscopy. The bioremediation efficiency of the systems, tested on crude oil and quantified by gas chromatography, showed that…
Biotrickling filter modeling for styrene abatement. Part 1: Model development, calibration and validation on an industrial scale
2017
Abstract A three-phase dynamic mathematical model based on mass balances describing the main processes in biotrickling filtration: convection, mass transfer, diffusion, and biodegradation was calibrated and validated for the simulation of an industrial styrene-degrading biotrickling filter. The model considered the key features of the industrial operation of biotrickling filters: variable conditions of loading and intermittent irrigation. These features were included in the model switching from the mathematical description of periods with and without irrigation. Model equations were based on the mass balances describing the main processes in biotrickling filtration: convection, mass transfe…
Environmental Challenges in the Philippines
2017
The Republic of the Philippines is one of most exposed countries in the world to many “natural” hazards: earthquakes, volcanic eruptions, tsunami, lahar flows, typhoons, flooding, landslides, and sea level rise. Earthquake risks make Metro Manila especially vulnerable, due to the high population density and the poor quality of buildings, partly linked to corruption. This chapter examines the current policies to reduce risk in the metropolis and the scales of vulnerability, both at the national, regional, community and individual levels, focusing on the resilience of people and society when confronted with danger. Their vulnerability is heightened with several forms of environmental degradat…
Co-digestion of harvested microalgae and primary sludge in a mesophilic anaerobic membrane bioreactor (AnMBR): Methane potential and microbial divers…
2020
Abstract Anaerobic co-digestion of primary sludge and raw microalgae (Scenedesmus and Chlorella) was performed in a lab-scale semi-continuous anaerobic membrane bioreactor to assess the biological performance and identify the microbial community involved in the co-digestion process. The reactor was operated at 35 °C for 440 days, working at a solids retention time of 100 days. The system achieved 73% biodegradability and showed high stability in terms of pH and volatile fatty acids. An enriched microbial community was observed. Of the several phyla, Chloroflexi and Proteobacteria were the most abundant. Cellulose-degraders phyla (Bacteroidetes, Chloroflexi and Thermotogae) were detected. Sy…
Anaerobic membrane bioreactors (AnMBR) treating urban wastewater in mild climates
2020
[EN] Feasibility of an AnMBR demonstration plant treating urban wastewater (UWW) at temperatures around 25-30 degrees C was assessed during a 350-day experimental period. The plant was fed with the effluent from the pretreatment of a full-scale municipal WWTP, characterized by high COD and sulfate concentrations. Biodegradability of the UWW reached values up to 87%, although a portion of the biodegradable COD was consumed by sulfate reducing organisms. Effluent COD remained below effluent discharge limits, achieving COD removals above 90%. System operation resulted in a reduction of sludge production of 36-58% compared to theoretical aerobic sludge productions. The membranes were operated a…
Recovery of polyhydroxyalkanoates (PHAs) from wastewater : a review
2020
Abstract Polyhydroxyalkanoates (PHAs) are biopolyesters accumulated as carbon and energy storage materials under unbalanced growth conditions by various microorganisms. They are one of the most promising potential substitutes for conventional non-biodegradable plastics due to their similar physicochemical properties, but most important, its biodegradability. Production cost of PHAs is still a great barrier to extend its application at industrial scale. In order to reduce that cost, research is focusing on the use of several wastes as feedstock (such as agro-industrial and municipal organic waste and wastewater) in a platform based on mixed microbial cultures. This review provides a critical…
Anaerobic degradation of 2-propanol: Laboratory and pilot-scale studies
2017
Abstract The anaerobic degradation of 2-propanol, an important industrial solvent, was scaled-up from batch assays to a pilot expanded granular sludge bed (EGSB) reactor at 25 °C. Batch studies indicated that 2-propanol followed Haldane kinetics, with a maximum rate at 10 g COD L −1 . Concentrations as high as 25 g COD L −1 did not inhibit the degradation of ethanol, a common co-solvent. Similar specific methanogenic activities (SMA) were obtained for water-solvent and water-brewery sludges (88 and 77 ml CH 4 g-VS −1 d −1 at 5 g COD L −1 ). Continuous degradation showed a lag-phase of three weeks with water-brewery sludge. Increases in 2-propanol load from 0.05 to 0.18 kg COD kg-VS −1 d …
Assessment of landfill leachate biodegradability and treatability by means of allochthonous and autochthonous biomasses
2020
Abstract The biodegradability and treatability of a young (3 years old) municipal landfill leachate was evaluated by means of chemical oxygen demand (COD) fractionation tests, based on respirometric techniques. The tests were performed using two different biomasses: one cultivated from the raw leachate (autochthonous biomass) and the other collected from a conventional municipal wastewater treatment plant after its acclimation to leachate (allochthonous biomass). The long term performances of the two biomasses were also studied. The results demonstrated that the amount of biodegradable COD in the leachate was strictly dependent on the biomass that was used to perform the fractionation tests…
Role of Thylakoid ATP/ADP Carrier in Photoinhibition and Photoprotection of Photosystem II in Arabidopsis
2010
L'article original est publié par The American Society of Plant Biologists; International audience; The chloroplast thylakoid ATP/ADP carrier (TAAC) belongs to the mitochondrial carrier superfamily and supplies the thylakoid lumen with stromal ATP in exchange for ADP. Here, we investigate the physiological consequences of TAAC depletion in Arabidopsis (Arabidopsis thaliana). We show that the deficiency of TAAC in two T-DNA insertion lines does not modify the chloroplast ultrastructure, the relative amounts of photosynthetic proteins, the pigment composition, and the photosynthetic activity. Under growth light conditions, the mutants initially displayed similar shoot weight, but lower when r…
Removal of 2-butoxyethanol gaseous emissions by biotrickling filtration packed with polyurethane foam
2016
The removal of 2-butoxyethanol from gaseous emissions was studied using two biotrickling filters (BTF1 and BTF2) packed with polyurethane foam. Two different inoculum sources were used: a pure culture of Pseudomonas sp. BOE200 (BTF1) and activated sludge from a municipal wastewater treatment plant (BTF2). The bioreactors were operated at inlet loads (ILs) of 130 and 195 g m(-3) hour(-1) and at an empty bed residence time (EBRT) of 12.5s. Under an IL of ∼130 g m(-3) hour(-1), BTF1 presented higher elimination capacities (ECs) than BTF2, with average values of 106±7 and 68±8 g m(-3) hour(-1), respectively. However, differences in ECs between BTFs were decreased by reducing the irrigation inte…