| 1. |
- Avakian, Maureen D., et al.
(författare)
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The origin, fate, and health effects of combustion by-products : A research framework
- 2002
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Ingår i: Journal of Environmental Health Perspectives. - : National Institute of Environmental Health Sciences. - 0091-6765 .- 1552-9924. ; 110:11, s. 1155-1162
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Tidskriftsartikel (refereegranskat)abstract
- Incomplete combustion processes can emit organic pollutants, metals, and fine particles. Combustion by-products represent global human and environmental health challenges that are relevant not only in heavily industrialized nations, but also in developing nations where up to 90% of rural households rely on unprocessed biomass fuels for cooking, warmth, and light. These issues were addressed at the Seventh International Congress on Combustion BY-Products, which convened 4-6 June 2001 in Research Triangle Park, North Carolina. This congress included a diverse group of multidisciplinary researchers and practitioners who discussed recent developments and future goals in the control of combustion by-products and their effects of exposure on human and ecologic health. Participants recommended that interdisciplinary, coordinated research efforts should be focused to capitalize on the important potential synergisms between efforts to reduce the adverse human health effects linked to exposures to combustion by-products and broader efforts to reduce greenhouse gas emissions and save energy through efficiency. In this article we summarize the principal findings and recommendations for research focus and direction.
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| 2. |
- Broz, J, et al.
(författare)
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The effect of oils on PAH, PCDD, PCDF, and PCB emissions from a spark engine fueled with leaded gasoline
- 2000
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Ingår i: Chemosphere. ; 41:12, s. 1905-11
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Tidskriftsartikel (refereegranskat)abstract
- The effect of synthetic and mineral oils on the formation of polyaromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in emissions from a spark ignition engine was studied on a Skoda Favorit engine fueled with leaded gasoline. The test cycle simulated urban traffic conditions on a chassis dynamometer, in accordance with the ECC 83.00 test. The data for selected PAHs as well as PCDDs, PCDFs, and PCBs congener profiles are presented. PCDD/Fs emissions for an unused oil and the oil after 10000-km operation varied from 300 to 2000 fmol/m3, PCBs emissions from 75 to 178 pmol/m3, and PAHs emissions from 150 to 420 g/m3. The content of PCBs in oils varied from 2 to 920 mg/kg.
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| 3. |
- Börjeson, L, et al.
(författare)
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Characterization of automotive shredder residues from two shredding facilities with different refining processes in Sweden
- 2000
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Ingår i: Waste Management & Research. - : Wiley. - 0734-242X .- 1399-3070. ; 18:4, s. 358-66
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Tidskriftsartikel (refereegranskat)abstract
- Strict legislation imposing producer responsibility on car manufacturers, introduced in 1998 in Sweden, has prompted a search for new alternatives for recycling organic materials In end-of-life vehicles (ELVs), i.e. the automotive shredder residue (ASR). The recovery of materials from ELVs must increase from the present 70 to 75%, to 95% by 2015. The aim of this study was to characterize material other than ferrous components, i.e. the (automotive) shredder residue [(A)SR] and the non-ferrous (NF), material in order to investigate its suitability for energy recovery. The results show that the good heat value of the material gives it potential, but high levels of metals and chlorinated compounds may cause problems. Levels of elements, metals and polychlorinated dibenzodioxins/furans (PCDD/F), polychlorinated biphenyls (PCB) and polychlorinated benzenes (PCBz) in the ASR were also analysed, and the results are described and discussed.
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| 4. |
- Cieplik, Mariusz K, et al.
(författare)
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On Dioxin Formation in Iron Ore Sintering
- 2003
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 37:15, s. 3323-31
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Tidskriftsartikel (refereegranskat)abstract
- Iron ore sintering is an important source of "dioxins", polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This paper reports on attempts to identify materials, conditions, and mechanisms responsible for PCDD/F formation (i) by investigating salient properties of ores (viz., with respect to oxidation, condensation, and chlorination of model organics) and (ii) by mimicking the industrial process on a microscale with real-life materials. Principles of Design of Experiments (DOE) are employed. The reactivities of iron ores differ greatly. Limonite/goethite "soft" ore is a very active oxidation catalyst (e.g., for benzene and phenol), a property that may be useful in cleaning up crude sintering process offgases, whereas hematite/magnetite "hard" ore is not. The latter, however strongly promotes condensation of phenol to dibenzofuran. A newly built lab-microscale sintering facility could satisfactorily imitate the large-scale process, in part or as a whole. Results obtained with realistic feed mixtures point at dioxin formation in the sinter bed at levels significant enough to explain a major part of the outputs observed in the real-life process. With ~8 ppm (wt) of chloride added as NaCl, the PCDD/F output doubled, but with the same proportion of chlorine administered as C2Cl4, the dioxin output was over 2 orders of magnitude larger. The use of process reverts, etc. containing chlorinated organics should therefore be avoided. PCDD/F congener patterns are also reported and compared with those observed in practice.
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| 5. |
- Liljelind, Per, et al.
(författare)
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Method for Multiresidue Determination of Halogenated Aromatics and PAHs in Combustion-Related Samples
- 2003
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 37:16, s. 3680-6
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Tidskriftsartikel (refereegranskat)abstract
- Flue gas and fly ash samples have a complex composition. Thus, thorough extraction and selective cleanup prior to analysis are essential. This paper presents an evaluated method for determining halogenated dibenzo-p-dioxins (PXDD), halogenated dibenzofurans (PXDF), chlorinated biphenyls (PCB), chlorobenzenes (CBz), -phenols (CPh), dibenzo-p-dioxins (DD), dibenzofurans (DF), and polycyclic aromatic hydrocarbons (PAH) in a single sample. Since these combustion byproducts are ubiquitous, harmful environmental contaminants it is very important to obtain reliable assessments of them: especially specific PCDD/F and PCB congeners with Ah-receptor mediated toxicity. The reported method for this purpose includes techniques such as solid-phase extraction, Soxhlet-Dean-Stark extraction, cleanup using open liquid chromatographic columns, and finally GC/MS analysis/determination with quantification by the isotope dilution technique. The validation results presented here show good reproducibility for PXDD/F and PCB and are satisfactory for CPh, CBz, and PAH. An extraction efficiency test revealed that a nonpolar solvent did not completely extract a few analytes, i.e., diCPh and fluorene, which appear to require a more polar extraction agent. To pinpoint and minimize the loss of analytes, specific studies on reductions of their amounts during sample concentration were performed, showing that traditional rotary evaporation and nitrogen blow-down produce equally good results as a novel technique.
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| 6. |
- Liljelind, Per, et al.
(författare)
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Removal of dioxins and related aromatic hydrocarbons from flue gas streams by adsorption and catalytic destruction
- 2001
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Ingår i: Chemosphere. ; 42:5-7, s. 615-23
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Tidskriftsartikel (refereegranskat)abstract
- The dioxin removing capacity of the shell dedioxin system (SDDS – a Ti/V oxidative type catalyst) has been tested using the Umeå lab-scale incinerator over the temperature range 100–230°C and at space velocities of 8000 and 40,000 h−1. Other analogous organic compounds, such as PCBs, PAHs, chlorobenzenes and chlorophenols have also been investigated. Results show a high degree of dioxin removal already at 100°C (82%), which occurs mainly by adsorption. When the temperature is raised a transition towards destruction is seen and at 150°C, gas hour space velocity (GHSV) 8000 and at 230°C, GHSV 40,000 virtually all removal is by destruction. High PCDD/F destruction efficiencies are reported (>99.9%, based on I-TEQ); the other dioxin-related species and PAHs are also removed and destroyed to a significant extent. The SDDS has proved to be an effective means of destroying organic compounds in the gas phase, particularly dioxins, at temperatures as low as 150°C.
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| 7. |
- Lundin, Lisa, et al.
(författare)
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Distribution of mono- to octa-chlorinated PCDD/F in fly ashes from a municipal solid waste incinerator
- 2004
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Ingår i: Environmental Science and Technology. - Washington : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 42:4, s. 1245-1250
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Tidskriftsartikel (refereegranskat)abstract
- We have estimated the concentration and distribution of the mono to octa-chlorinated congeners of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) in fly ashes at various sampling points in a large-scale municipal solid waste incinerator at Umeå, Sweden, as they cooled from 700 to 170 °C. Differences between the ashes were observed, the PCDD homologue profile was found to vary with temperature. The total amount of PCDD and PCDF increased as the temperature decreased in the postcombustion zone. The increase was due to both adsorption to the fly ash and formation of PCDD and PCDF. Mono- to trichlorinated PCDD predominated at high temperatures, whereas hepta- and octachlorinated PCDD predominated at temperatures below 400 °C. PCDF predominated over PCDD in the whole temperature range. However, the changes in homologue profile for PCDF were minor. The isomer distribution within the homologue groups was not changed as the temperature decreased in the postcombustion zone.
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| 8. |
- Rahm, Sara, 1972-
(författare)
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Hydrolysis and photolysis of brominated flame retardants and some traditional persistent organic pollutants : Reactivity as a tool in fate assessement of chemicals
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An organic compound that remains in the environment for a long time is regarded as a persistent organic pollutant (POP). Still, persistency is not a well defined property with a firm definition. Instead it is a conceptual property of chemicals for which DDT and PCB are typical representatives. No organic chemicals in the environment are inert and are thus subjected to chemical transformation reactions in air, water, soil sediments and in biota. Environmental pollutants are distributed in the environment based on their physicochemical properties and their reactivity. While the former properties have been thoroughly studied and used in modelling of the fate of chemicals in the environment, the latter property – reactivity – has been investigated poorly. The far-reaching objective with the present thesis is to introduce the reactivity of chemicals into the concept of persistency. More specifically the aim is to develop methodologies for defining chemical reactivity by determination of disappearance reaction constants for hydrolysis and photolysis of actual or potential environmental contaminants. Other transformation reactions in the environment such as oxidations reductions and radical reactions are not included at this stage. In this thesis, hydrolysis include both substitution and elimination reactions. The developmental work is performed largely by comparing the reactivity of brominated flame retardants but also include several traditional contaminants for comparative reasons. A new method for determination of the rate of hydrolysis of chemicals is developed using methoxide in methanol and DMF, which is done by using hexachlorobenzene (HCB) as the test chemical. The method is applied to several other chemicals, particularly polybrominated diphenyl ethers (PBDEs) but also traditional POPs. Chemicals such as DDT,TBBPA 2,3-dibromopropyl ether react very fast and the perbrominated diphenyl ether (BDE-209) is shown to undergo nucleophilic aromatic substitution faster than HCB. Compounds that can undergo elimination are rapidly degraded while the rates of substitution reactions of aromatic chemicals depend on the degree of halogenation. A new method is used for studying photolytic reactions based on irradiation of UV light at environmentally relevant wavelengths and with the study compounds dissolved in methanol/water (4:1). Disappearance constants and quantum yields are determined for several traditional and potential environmental contaminants. Halogenated phenols are rapidly transformed under these conditions. Polybrominated aromatics are indicated to react faster than the corresponding chlorinated compounds. The two methods for studying reactivity of chemicals have the potential of being useful to predict the persistency of chemicals in the environment. Such predictions must however also include the compound’s susceptibility to oxidation, reduction and radical reactions in all major environmental compartments and knowledge of their physicochemical characteristics.
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| 9. |
- Redin, LA, et al.
(författare)
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Co-combustion of shredder residues and municipal solid waste in a Swedish municipal solid waste incinerator
- 2001
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Ingår i: WASTE MANAGEMENT & RESEARCH. - 0734-242X. ; 19:6, s. 518-25
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Tidskriftsartikel (refereegranskat)abstract
- Incinerating automotive shredder residue (ASR) in order to increase the recovery from end of life vehicles (ELVs) is an attractive option when recycling this material. In this study, incineration combined with energy recovery, was investigated. The incineration experiments, where 20% shredder residue (SR) was burnt with conventional municipal solid waste (MSW), were conducted in a full-scale MSW horizontal grate incinerator. Measurements were made before, during and after the incineration. The results showed some minor increases in the emission levels of raw gases sampled after an electrostatic filter, but almost no significant differences when sampled after a wet scrubber. An increased level of 'non-toxic' metals was detected within the bottom ash. It was concluded that refined SR, in small quantities, is suitable to add to MSW.
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| 10. |
- Söderström, Gunilla, et al.
(författare)
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Formation of PBCDD and PBCDF during flue gas cooling
- 2004
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Ingår i: Environmental Science and Technology. - Washington : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 38:3, s. 825-830
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Tidskriftsartikel (refereegranskat)abstract
- The presence of bromine and chlorine in combustion, particularly in waste combustion, results in the formation of PBCDD and PBCDF. Formation pathways of PCDD/F are not fully understood, although much is known about them, and they are currently being further investigated. PBCDD/F is likely to be formed in reactions similar to those leading to PCDD/F, but the processes involved have been less intensively studied. In this study a fuel with bromine and chlorine in equal molar amounts was combusted in a pilot-scale fluid bed reactor and the cooling flue gas was sampled at 800, 350, and 250 C. Analysis revealed that levels of PBCDD and PBCDF increased between all sampling ports. The chlorine/bromine ratio also increased with reductions in temperature and increases in residence time for both PBCDD and PBCDF. However, the formation of PBCDD and PBCDF seems to follow different routes with respect to the level and pattern of halogenation.
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