Search results for "MEDIATION"
showing 10 items of 783 documents
Heavy metal remediation technologies in Latvia: possible applications and preliminary case study results / Technologie remediacji obszarów zanieczysz…
2012
Abstract Environmental contamination with heavy metals as a result of anthropogenic activities is not a recent phenomenon. Contaminated sites with heavy metals can be found in functioning as well as abandoned industrial (brownfield) territories, landfills, residential areas with historical contamination, road sides and rarely in polluted sites by natural activities. Pollution data on its amount and concentrations is known from historical studies and monitoring nowadays, but it should be periodically updated for the use of territorial planning or in case of a change of the land use. A special attention should be paid to heavy metal contamination, because in many cases this contamination is m…
Stabilization and Solidification Technology Implementation in Latvia: First Studies
2012
Soil and groundwater are environmental compartments that are primarily affected by industrial development with increasing amount of industrial wastes and inadequate dumping of them. A special attention should be paid to heavy metal contamination at least 56 contaminated territories of National priority are known as contaminated with heavy metals in different amount and concentration in Latvia. The stabilization / solidification technology refers to binding of waste contaminants to a more chemically stable form and thus diminishing leaching of contamination. In order to choose the remediation method the pre-investigation in industrial case study area was done in stages: data analysis of prev…
Small business and entrepreneurship in Africa : the nexus of entrepreneurial ecosystems and productive entrepreneurship
2020
The impact of entrepreneurship and small business activities in Africa has habitually been lower and receives less attention in research. This study aims at investigating the mediation role of innovations on the relationship between entrepreneurial ecosystem approach and productive entrepreneurship. Using panel dataset of 35 African countries, the study contributes to the existing literature in two ways. First, the panel regression findings contribute to the theoretical debate and fill the empirical gap, recent research has been dominated by conceptual works. The findings reveal mixed (positive and negative) and weak insignificant direct influence of eco-factors such as finance, government …
Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.
2006
Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10–20 °C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 °C. Removal of total chemical oxygen demand (CODt) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperatu…
Assessment of flushing methods for the removal of heavy chlorinated compounds DNAPL in an alluvial aquifer.
2017
International audience; Immiscible mobilization and foam flushing were assessed as low surfactant consuming technologies, for the enhanced recovery of dense non-aqueous phase liquid (DNAPL) residual at a site contaminated by heavy chlorinated compounds. Preliminary experiments in well-controlled conditions demonstrated the phenomena involved in these remediation technologies and their limitations. Furthermore, we characterized the technologies according to by their surfactant consumption (per kg of DNAPL recovered) and the final DNAPL saturation reached. Surfactant foam flushing (SFF) produced lower DNAPL saturation than immiscible mobilization, thanks to its higher viscosity. However, its …
Functionalization of ultrasound enhanced sewage sludge-derived biochar: Physicochemical improvement and its effects on soil enzyme activities and hea…
2020
Abstract Poor physicochemical characteristics and high heavy metals content are main limitations of applying sludge-based biochars in remediation studies. The present study attempts to combine two practical approaches of ultrasound pre-treatment with low-time and low-frequency and chemical functionalization using citric acid. The aims of this study are enhancement physicochemical characteristics and environmental applicability of sludge-derived biochar. The characteristics of obtained ultrasound-treated functionalized biochar (UFB), sludge-derived biochar (SDB) and sewage sludge (SS) were evaluated. Then, the effects of these additives on soil heavy metals availability, soil enzyme activiti…
The use of anthracene as a model compound in a comparative study of hydrous pyrolysis methods for industrial waste remediation
2011
Author's version of an article published in Chemosphere, 84 (4), 403-408. Also available from the publisher: http://dx.doi.org/10.1016/j.chemosphere.2011.03.061 Polycyclic aromatic hydrocarbons are very stable compounds and tend to bioaccumulate in the environment due to their high degree of conjugation and aromaticity. Hydrous pyrolysis is explored as a technique for the treatment of industrial water containing PAH, using anthracene as a model compound. The reactivity of anthracene under a range of temperatures and durations are studied in this paper. Aliquots of 1.0-10.0mg of anthracene in a range of 1.0-5.0 mL of H(2)O are subjected to hydrous pyrolysis under varied conditions of tempera…
Spontaneous ecological recovery of vegetation in a red gypsum landfill: Betula pendula dominates after 10 years of inactivity
2019
International audience; Red gypsum is the product of the neutralization of titanium dioxide (TiO 2) extraction residue from ilmenite and anatase. The disposal of red gypsum creates heterogeneous plots with layers that may include Fe, Ca, Al, Mg, Mn, S, and other elements and an alkaline pH that makes revegetation complicated and slow. The vertical and horizontal dispersion of the sediment particles are the main concern. Therefore, the establishment of precise vegetation cover is needed to address this issue. One of the aims of this study was (1) to explore the distribution of the spontaneous vegetation found along a red gypsum-formed landfill located at the Ochsenfeld site in eastern France…
Comparative assessment of a foam-based oxidative treatment of hydrocarbon-contaminated unsaturated and anisotropic soils.
2019
Abstract In situ delivery of liquid reagents in vadose zone is limited by soil anisotropy and gravity. The enhanced delivery of persulfate (PS) as oxidant, using a new foam-based method (F-PS) was compared at bench-scale to traditional water-based (W-PS) and surfactant solution-based (S-PS) deliveries. The goal was to distribute PS uniformly in coal tar-contaminated unsaturated and anisotropic soils, both in terms of permeability and contamination. Water was the less efficiently delivered fluid because of the hydrophobicity of the contaminated soils. Surfactant enhanced PS-distribution into contaminated zones by reducing interfacial tension and inverting soil wettability. Regardless of coal…
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…