Search results for "DEGRADATION"
showing 10 items of 1208 documents
Contribution of bacterial biodiversity on the operational performance of a styrene biotrickling filter.
2020
Abstract Long-term operational stability of biotrickling filters (BTFs) degrading volatile organic compounds (VOCs) is dependent on both physicochemical as well as biological properties. Effects of increasingly stressful levels of air pollutants on the microbial structure of biofilms within BTFs are not well understood, especially for VOCs such as styrene. To investigate the relationship between biofilm biodiversity and operational stability, the temporal dynamics of a biofilm from a biotrickling filter subjected to stepwise increasing levels of air polluted with styrene was investigated using 16S rDNA pyrosequencing and PCR-denaturing gradient gel electrophoresis (PCR-DGGE). As styrene con…
Insight into metal immobilization and microbial community structure in soil from a steel disposal dump phytostabilized with composted, pyrolyzed or g…
2021
Abstract The soil system is a key component of the environment that can serve as a sink of pollutants. Using processed waste for aided phytostabilization of metals (HMs) in contaminated soils is an attractive phytoremediation technique that integrates waste utilization and recycling. In this study, we evaluated the effect of biologically and thermally processed wastes, i.e. sewage sludge compost (CSS), poultry feather ash (AGF) and willow chip biochar (BWC), on phytostabilization of contaminated soil from a steel disposal dump. Greenhouse experiments with Lupinus luteus L. and amendments (dosage: 3.0%, w/w) were conducted for 58 days. Soil toxicity was evaluated with Ostracodtoxkit and Phyt…
Evaluation of biodegradation of nonylphenol ethoxylate and lignin by combining toxicity assessment and chemical characterization.
2009
Abstract The aerobic biodegradation of commercial nonylphenol ethoxylate (NPE) mixture and alkali lignin was studied using the OECD headspace test accompanied by the simultaneous measurement of ecotoxicity directly from the biodegradation liquors and by the follow-up of the chemical composition of the studied chemicals. NPE degradation was dependent on the inoculum source: approximately 40% of NPE was mineralized into CO2 during the 4-week experiment when inoculum from Helsinki City wastewater treatment plant (WWTP) was used, and only 12% was mineralized when inoculum from Jyvaskyla City WWTP was used. Chemical analyses revealed a shift in the ethoxylate chain length from longer to shorter …
Performance evaluation of a biotrickling filter treating a mixture of oxygenated VOCs during intermittent loading
2008
Laboratory scale-studies on the biodegradation of a 1:1:1 weight mixture of three oxygenated volatile organic compounds (VOCs), ethanol, ethyl acetate, and methyl-ethyl ketone (MEK) in a biotrickling filter (BTF) were carried out using two identically sized columns, filled with different polypropylene rings. The performance of the BTFs was examined for a period of 10 months applying several operational strategies. Similar performance was obtained for both supports. Intermittent flow rate of trickling liquid was shown beneficial to improve the removal efficiency (RE). Continuous feeding of VOC resulted in an excessive accumulation of biomass so high pressure drop was developed in less than 2…
An engineered plant that accumulates higher levels of heavy metals than Thlaspi caerulescens, with yields of 100 times more biomass in mine soils
2006
8 pages, 3 figures, 2 tables.
A model for the formation and degradation of bound residues of the herbicide 14C-isoproturon in soil
1999
Abstract The humic monomer catechol was reacted with 14 C-isoproturon and some of its metabolites, including 14 C-4-isopropylaniline, in aqueous solution under a stream of oxygen. Only in the case of 14 C-4-isopropylaniline, incorporation in oligomers, in fulvic acid-like polymers, and in humic acid-like polymers was observed. The main oligomer was identified by mass spectrometry as 4,5-bis-(4-isopropylphenylamino)-3,5-cyclohexadiene-1,2-dione. Oligomers and polymers containing bound 14 C-4-isopropylaniline were subjected to biodegradation studies in a loamy agricultural soil during 55 days by quantifying 14 CO 2 evolved. In all cases, significant mineralization rates could be determined, w…
Behaviour of EDTA in marine microcosms
2000
Laboratory-scale microcosm tests were carried out in sea water with and without sediment to investigate the importance of ultraviolet (UV) light and microbes in the temperature-dependent degradation of metal complexes of ethylenediaminetetraacetic acid (EDTA). After 17 weeks, 44% and 48% of the original EDTA (initial concentration 385 microg/L) were converted at 10 degrees C and 22 degrees C, respectively. The degradation was more influenced by UV light than by sediment microbes, although the latter were very important. At both temperatures, absorption of EDTA to the sediment phase reached a maximum in the initial stage of the experiments (4 weeks): at 10 degrees C about 4% and at 22 degree…
A new foam-based method for the (bio)degradation of hydrocarbons in contaminated vadose zone
2020
International audience; An innovative foam-based method for Fenton reagents (FR) and bacteria delivery was assessed for the in situ remediation of a petroleum hydrocarbon-contaminated unsaturated zone. The surfactant foam was first injected, then reagent solutions were delivered and propagated through the network of foam lamellae with a piston-like effect. Bench-scale experiments demonstrated the feasibility of the various treatments with hydrocarbon (HC) removal efficiencies as high as 96 %. Compared to the direct injection of FR solutions, the foam-based method led to larger radii of influence and more isotropic reagents delivery, whereas it did not show any detrimental effect regarding H…
Concentrations of monosaccharides in humic substances in the early stages of humification.
2001
Deteriorated liquid packaging board (LPB) and biowaste compost are matrices, mainly consisting of cellulose, in the early stages of humification. Degradative studies on these matrices allow an examination of the role of carbohydrates in the synthesis of humic substances. Samples of different age were collected and divided by extraction into hot water extract (HWE), bitumen, humic acid (HA), fulvic acid (FA) and humin or residual fibre fractions. The following monosaccharides were identified in these fractions: L-arabinose, D-ribose, D-xylose, L-fucose, D-mannose, D-fructose, D-galactose, D-glucose, L-rhamnose and xylitol. The main component in all fractions was glucose. The concentrations o…
Effect of additives on process stability of mesophilic anaerobic monodigestion of pig slaughterhouse waste
2012
The effect of two additives on anaerobic monodigestion of pig slaughterhouse waste was studied in three laboratory scale continuously stirred tank reactors (CSTRs) operated for 242-284 days at 35°C. A higher organic loading rate (OLR), namely 2.25 kg volatile solids (VS)/m(3)d with a hydraulic retention time (HRT) of 30 d was feasible with an additive containing Fe, HCl and trace elements while an OLR of 1.5 kg VS/m(3)d (HRT 30 d) led to instabilities in CSTR with an additive consisting of Fe and HCl and in CSTR without additives. Methane yields of ca. 700 dm(3) CH(4)/kg VS(fed) were obtained in all reactors under stable conditions. Both additives decreased H(2)S concentration of the biogas…