| 1. |
- Olsson, Susanna, et al.
(author)
-
Copper(II) binding to dissolved organic matter fractions in municipal solid waste incinerator bottom ash leachate
- 2007
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:12, s. 4286-4291
-
Journal article (peer-reviewed)abstract
- Information on Cu speciation in municipal solid waste incineration (MSWI) bottom ash leachate is needed for Cu leaching predictions and toxicity estimates. The complexation of Cu with dissolved organic matter (DOM) in leachates from a stored MSWI bottom ash was studied potentiometrically using a Cu-ion selective electrode. More than 95% of the copper was bound to DOM in the hydrophilic fraction of the leachate, indicating that the hydrophilic acids contribute to Cu complex formation. The hydrophilic acids constituted 58% of the dissolved organic carbon in the ash leachate. Comparisons between experimental results and speciation calculations with the NICA-Donnan model and the Stockholm humic model indicated differences between the ash DOM and the natural DOM for which the models have been calibrated. The ratio of carboxylic binding sites to phenolic binding sites was 2 times larger in ash DOM, and the Cu-binding affinity of the former was stronger than accounted for by the generic Cu-binding parameters. The Cu-binding affinity of the phenolic sites, on the other hand, was weaker. When these parameters were adjusted, a good description of the experimental data was obtained.
|
|
| 2. |
|
|
| 3. |
- Arwidsson, Zandra, et al.
(author)
-
Remediation of Metal Contaminated Soil by Organic Metabolites from Fungi I—Production of Organic Acids
- 2008
-
In: Water, Air and Soil Pollution. - Berlin, Germany : Springer. - 0049-6979 .- 1573-2932. ; 205:1-4, s. 215-226
-
Journal article (peer-reviewed)abstract
- Investigations were made on living strains offungi in a bioremediation process of three metal (lead)contaminated soils. Three saprotrophic fungi (Aspergillusniger, Penicillium bilaiae, and a Penicillium sp.) wereexposed to poor and rich nutrient conditions (no carbonavailability or 0.11 M D-glucose, respectively) andmetal stress (25 μM lead or contaminated soils) for5 days. Exudation of low molecular weight organicacids was investigated as a response to the metal andnutrient conditions. Main organic acids identified wereoxalic acid (A. niger) and citric acid (P. bilaiae).Exudation rates of oxalate decreased in response tolead exposure, while exudation rates of citrate were lessaffected. Total production under poor nutrient conditionswas low, except for A. niger, for which nosignificant difference was found between the poor andrich control. Maximum exudation rates were 20 μmoloxalic acid g^−1 biomass h^−1 (A. niger) and 20 μmolcitric acid g^−1 biomass h^−1 (P. bilaiae), in the presenceof the contaminated soil, but only 5 μmol organic acidsg^−1 biomass h^−1, in total, for the Penicillium sp. Therewas a significant mobilization of metals from the soilsin the carbon rich treatments and maximum release ofPb was 12% from the soils after 5 days. This was notsufficient to bring down the remaining concentration tothe target level 300 mg kg^−1 from initial levels of 3,800,1,600, and 370 mg kg^−1in the three soils. Target levelsfor Ni, Zn, and Cu, were 120, 500, and 200 mg kg^−1,respectively, and were prior to the bioremediationalready below these concentrations (except for Cu Soil1). However, maximum release of Ni, Zn, and Cu was28%, 35%, and 90%, respectively. The release of metalswas related to the production of chelating acids, but alsoto the pH-decrease. This illustrates the potential to usefungi exudates in bioremediation of contaminated soil.Nonetheless, the extent of the generation of organicacids is depending on several processes and mechanismsthat need to be further investigated.
|
|
| 4. |
- Arwidsson, Zandra, et al.
(author)
-
Remediation of soils and sludges containing organic contaminants as well as metals – soil-wash procedures combining biodegradation, chemical complexation and mechanical separation of particulate matter
- 2009
-
Conference paper (peer-reviewed)abstract
- Soil contamination is an urgent issue world wide. More than 83,000 contaminated sites have been identified in Sweden alone, of which approximately some 4,000 require treatment in the near future. Most of the sites carry a mixture of contaminants, metals as well as persistent organics. Most soil remediation efforts are made ex situ, which means that the soil or sludge is dug up and transported to a facility for treatment, or simply for deposition. The aim of the present project is to design a strategy for ex situ treatment of soils with mixed contaminants. A variety of soils and sludges from different sites (around 10), essentially all with organic as well as inorganic (metallic) contaminants, have been selected for experimental studies in laboratory and pilot scale: Military sites (metals, explosives), wood preservation sites (PAHs, As, metals), industrial sites (metals, hydrocarbons, mercury, dioxins and others). Of particular importance in the present study are:Metals – Pb, Cu, Zn, Cr, Hg, as well as As Organics – PAHs, nitro aromatics, dioxinsA number of processes are selected and applied: •Biodegradation - use of commercially available cultures, as well as bacteria cultivated from the contaminated site itself •Mobilisation of organics - use of surface active agents •Mobilisation of metals - use of (1) complexing microbial metabolites produced in the soil (by fungii in paricular), (2) complexing agents generated by degradation of natural organic products (polyhydroxy carboxylic acids), and (3) artificial complexing agents (polyamino carboxylic acids).Biodegradation is performed in batches (anaerobic in most cases), while release and mobilisation of contaminants from soil aggregates are achieved during soil-wash performed in a dynamic system where wash solution is forced through the soil under high pressure (the WTC-process). The efficiency of biodegradation and subsequent soil-wash under various conditions is evaluated from chemical analysis, but also by several ecotoxicological tests. Some results are given that illustrates suitable strategies for treatment of mixed contaminated soil from real sites (soil) as well as for treatment of residues from industrial production (sludges etc).
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Blomqvist, Per, et al.
(author)
-
An experimental study of spontaneous ignition in storages of wood pellets
- 2007
-
In: 10th International Conference - Fire and Materials 2007.
-
Conference paper (other academic/artistic)abstract
- This article focuses on experimental studies of self-heating characteristics of wood pellets. Controlled experiments have been conducted in physical scales from 1 dm3 to 4 m3 with wood pellets. Basket tests have been conducted according to the "crossing-point method" to derive kinetic data on the exothermic reactions responsible for self-heating and eventually spontaneous ignition. The kinetic data was used in the planning of the large-scale experiments for predictions of approximate critical temperatures. The experiments in the 1 m3 scale were set-up basically as an enlargement of the basket tests to obtain validation experiments with controlled boundary conditions in a reasonable large scale. Several experiments were conducted and spontaneous ignition was seen in the centre of the pellet bulk at an ambient temperature of 115C. The close to real-scale experiments with 4 m3 wood pellets filled in a 6 m high silo were not strictly self heating experiments, instead a core shaped heating element was allowed to initiate the pyrolysis in the pellets. Heat and gas production and transportation from the growing pyrolysis zone were mapped with a large number of measurement points in the pellets bulk and in the top of the silo. The experimental work conducted gave kinetic data on the exothermic reactions in wood pellets, insight in self heating processes, a link between different experimental scales and knowledge regarding possibilities for detection of fires in storages of wood pellets.
|
|
| 8. |
- Blomqvist, Per, et al.
(author)
-
Biofuels
- 2005
-
In: 2nd International Symposium on Tunnel Safety & Security..
-
Conference paper (peer-reviewed)
|
|
| 9. |
- Blomqvist, Per, et al.
(author)
-
Fires in storages of biofuels
- 2007
-
In: Fire and Materials 2007 Proceedings.
-
Conference paper (other academic/artistic)
|
|
| 10. |
- Elgh-Dalgren, Kristin, et al.
(author)
-
Anaerobic bioremediation of a soil with mixed contaminants : Explosives degradation and influence on heavy metal distribution, monitored as changes in concentration and toxicity
- 2009
-
In: Water, Air and Soil Pollution. - Dordrecht : Springer Netherlands. - 0049-6979 .- 1573-2932. ; 202:1-4, s. 301-313
-
Journal article (peer-reviewed)abstract
- Two soils with explosives and metals were evaluated for the degradation efficiency of explosives by native microorganisms under anaerobic conditions. The commercially available method Daramend®, amended with zero-valent iron (ZVI), was compared with a horse-manure amended compost and a treatment with ZVI alone. In a moderately contaminated soil, Daramend® and ZVI treatment gave significantly higher removal rates compared to compost and control treatments (Tukey’s test, P<0.05). The largest overall decrease in ecotoxicity, measured with bioluminescent bacteria (Vibrio fischeri), was achieved with ZVI-treatment. In a more contaminated soil no degradation of contaminants and no decline in soil toxicity could be distinguished after the same time period. Problems with establishment of anaerobic conditions during parts of the remediation process and low microbial activity due to acute toxicity of contaminants are plausible explanations. Redistribution that could potentially lead to mobilization of the co-contaminant Pb was not observed in either of the soils during the biological treatments.
|
|
