Search results for "Pollutant"
showing 10 items of 1389 documents
Calcium effect on enhanced biological phosphorus removal.
2006
The role of calcium (Ca) in enhanced biological phosphorus removal and its possible implications on the metabolic pathway have been studied. The experience has been carried out in an SBR under anaerobic–aerobic conditions for biological phosphorus removal during 8 months. The variations of influent Ca concentration showed a clear influence on the EBPR process, detecting significant changes in YPO4. These YPO4 variations were not due to influent P/COD ratio, pH, denitrification and calcium phosphate formation. The YPO4 has been found to be highly dependent on the Ca concentration, increasing as Ca concentration decreases. The results suggest that high Ca concentrations produce “inert” granul…
Copper Isotope Fractionation during Complexation with Insolubilized Humic Acid
2010
The bioavailability, mobility, and toxicity of Cu depend on Cu speciation in solution. In natural systems like soils, sediments, lakes, and river waters, organo-Cu complexes are the dominating species. Organo-complexation of Cu may cause a fractionation of stable Cu isotopes. The knowledge of Cu isotope fractionation during sorption on humic acid may help to better understand Cu isotope fractionation in natural environments and thus facilitate the use of Cu stable isotope ratios (delta(65)Cu) as tracer of the fate of Cu in the environment. We therefore studied Cu isotope fractionation during complexation with insolubilized humic acid (IHA) as a surrogate of humic acid in soil organic matter…
MODIFICATION OF HUMIC SUBSTANCES FOR DEVELOPMENT OF MATERIALS FOR ENVIRONMENTAL TECHNOLOGIES
2019
Humic substances are high molecular weight refractory polycationites formed during decay of living organic matter and through biosynthesis of low molecular weight organic substances (metabolites or decay products of living organisms). Presence of many functional groups in the structure of humic substances determines their ability to interact with metal ions forming stable complexes and influencing metal ion speciation in the environment and mobility, behaviour and speciation forms in the environment. Presently humic substances are a product of industrial scale and quantities in amounts of hundreds of tons are produced. The aim of this study is to analyse derivatization possibilities of humi…
Effects of Pentachlorophenol and Biotic Interactions on Soil Fauna and Decomposition in Humus Soil
1995
In a laboratory experiment, effects of chemical stress (pentachlorophenol, PCP, at concentrations of 0, 50, and 500 mg/kg) and biotic interactions (nematodes in the presence or absence of collembolas and enchytraeids) on the community structure of soil animals and decomposition processes were studied. PCP was strongly adsorbed to humus that contained 65% organic matter. Numbers of fungal-feeding nematodes decreased significantly at the highest PCP concentration, while no effects were found in bacterial feeders. There were differences in the numbers of nematodes between different animal combinations, but at the highest PCP concentration, collembolas and enchytraeids had no effect on them. Nu…
Contamination from polycyclic aromatic hydrocarbons (PAHs) in the soil of a botanic garden localized next to a former manufacturing gas plant in Pale…
2010
The Botanical Garden lies within the city of Palermo, a few meters away from one of the largest unused Manufacturing Gas Plant in Sicily. The total concentrations of PAHs (23 compounds) in the soil of Botanical Garden ranged from 947 to 18,072 microg/kg. The wide range of PAH concentrations (RSD=84%) found in the soil samples indicates heterogeneous levels of contamination in the area and this can be explained by considering the different tree distributions which prevents the homogeneous deposition of pollutants on the soil. Soils collected in the Botanical Garden generally showed the highest PAH concentrations, being almost 2-3 times higher than the concentration samples obtained in the ur…
Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) in urban soils of Bratislava, Slovakia: patterns, relation to PAHs and vertical distributi…
2011
Abstract We determined concentrations, sources, and vertical distribution of OPAHs and PAHs in soils of Bratislava. The ∑14 OPAHs concentrations in surface soil horizons ranged 88–2692 ng g−1 and those of ∑34 PAHs 842–244,870 ng g−1. The concentrations of the ∑9 carbonyl-OPAHs (r = 0.92, p = 0.0001) and the ∑5 hydroxyl-OPAHs (r = 0.73, p = 0.01) correlated significantly with ∑34 PAHs concentrations indicating the close association of OPAHs with parent-PAHs. OPAHs were quantitatively dominated by 9-fluorenone, 9,10-anthraquinone, 1-indanone and benzo[a]anthracene-7,12-dione. At several sites, individual carbonyl-OPAHs had higher concentrations than parent PAHs. The concentration ratios of se…
Removal of TEX vapours from air in a peat biofilter: influence of inlet concentration and inlet load
2006
This paper presents the results of the study of the removal of toluene, ethylbenzene, and o-xylene (TEX) by biofiltration using a commercial peat as filter-bed material. Runs with a single organic compound in air, and with the mixture of TEX in air, were carried out for at least 55 days in laboratory-scale reactors inoculated with a conditioned culture. The influence of organic compound inlet load and of gas flow rate on the biofilter's performance was studied, including relatively high values of pollutant inlet concentration (up to 4.3 gC m−3 for ethylbenzene, 3.2 gC m−3 for toluene, and 2.7 gC m−3 for o-xylene). Results obtained show maximum elimination capacities of 65 gC m−3 h−1 for o-x…
Heavy metals in sewage sludges contribute to their adverse effects on the arbuscular mycorrhizal fungusGlomus mosseae
2003
Applying sewage sludges to agricultural land is a widespread practice because of the sludges’ agronomic value as a source of plant nutrients and organic matter. Nevertheless, sludges often contain micropollutants that can constitute a menace for health and the environment. Arbuscular mycorrhizal fungi are sensitive to sewage sludges that have been spiked, or not, with metallic trace elements (MTE). Here we have investigated if MTE in sewage sludges could be responsible for effects on mycorrhizal development betweenGlomus mosseae andMedicago truncatula. The impact of a dehydrated or composted urban sewage sludge spiked or not with MTE, was tested on spore germination and root colonization by…
Remediation of Soil Contamination with Heavy Metals by Using Zeolite and Humic Acid Additives
2012
- Soil remediation at contaminated sites very often needs customized approach, because of the different content of pollutants. Various technologies from simple soil excavation and transporting to hazardous waste landfills to different kinds of remediation by vitrification and the use of additives can be used for the treatment of soil. A series of remediation experiments using zeolites and humic acids were applied to soil contaminated with copper. Remediation can be performed with easily available additive materials of natural origin found near the place of application, in order to diminish the leaching of contaminants. Soils contaminated and spiked with copper were mixed with additives, and…
Pollutant Adsorbtion and Detection: Methyl-Substituted α-Cyclodextrin as Affinity Material for Storage, Separation, and Detection of Trichlorofluorom…
2018
The cover image depicts the hazard caused by chlorofluorocarbons such as CFC‐11, which are used, for example, as blowing agents for polyurethane foams, and the protective effect of the oligosaccharide, hexakis‐(2,3,6‐tri‐O‐methyl)‐α‐cyclodextrin, which is capable of binding CFC‐11 by supramolecular complexation and thus protecting the stratospheric ozone layer from the harmful trichlorofluoromethane. Further details can be found in article number 1800057 by Ralf Hellmann, Siegfried R. Waldvogel, and co‐workers.