| 1. |
- Björn (Fredriksson), Annika, 1972-, et al.
(författare)
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Interimreport 1 for the project on natural formation, degradation and occurrence of methyltins in different habitats. : Common project between Rohm and Haas, former Morton Plastics Additive (MPA), Cincinnati, Ohio, USA and the Department of Water and Environmental Studies (DWES), Linköping Univeristy, Sweden
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Ejlertsson, Jörgen, et al.
(författare)
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Anaerobic Degradation of Nonylphenol Mono- and Diethoxylates in Digestor Sludge, Landfilled Municipal Solid Waste, and Landfilled Sludge
- 1999
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 1086-931X .- 1520-6912 .- 0013-936X .- 1520-5851. ; 33:2, s. 301-306
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the extent to which anaerobic digestor sludge, landfilled sludge, and landfilled municipal solid waste (MSW) degrade NPEOs under methanogenic conditions. NPEO1 and NPEO2 (NPEO1-2), used in a mixture, were chosen as model compounds. Anaerobic experimental bottles were amended with 100% digestor sludge at three different concentrations of NPEO1-2: 2, 60, and 308 mg L-1. [U-14C]-NPEO1-2 was used to detect any possible decomposition of the aromatic moiety of the NPEO1-2. All inoculates used degraded NPEO1-2 at 2 mg L-1, with nonylphenol (NP) forming the ultimate degradation product. The NP formed was not further degraded, and the incubations with labeled NPEO showed that the aromatic structure remained intact. Both landfill inoculates also transformed NPEO1-2 at 60 mg L-1. CH4 production was temporarily hampered in bottles with MSW landfill inoculum at 60 and 308 mg L-1. With 2 mg L-1 of NPEO, CH4 production closely followed that in the controls. Both NP and NPEO1-2 interacted with the organic matter which resulted in sorption to the solid phase.
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| 3. |
- Ejlertsson, Jörgen, et al.
(författare)
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Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions
- 1995
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Ingår i: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology. - 0003-6072 .- 1572-9699. ; 69:1, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- The potential for biological transformation of 23 xenobiotic compounds by microorganisms in municipal solid waste (MSW) samples from a laboratory scale landfill reactor was studied. In addition the influence of these xenobiotic compounds on methanogenesis was investigated. All R11, 1,1 dichloroethylene, 2,4,6 trichlorophenol, dimethyl phthalate, phenol, benzoate and phthalic acid added were completely transformed during the period of incubation (> 100 days). Parts of the initially added perchloroethylene, trichloroethylene, R12, R114, diethyl phthalate, dibutyl phthalate and benzylbutyl phthalate were transformed. Methanogenesis from acetate was completely inhibited in the presence of 2,5 dichlorophenol, whereas 2,4,6 trichlorophenol and R11 showed an initial inhibition, whenafter methane formation recovered. No transformation or effect on the anaerobic microflora occurred for R13, R22, R114, 3 chlorobenzoate, 2,4,6 trichlorobenzoate, bis(2 ethyl)hexyl phthalate, diisodecyl phthalate and dinonyl phthalate. The results indicate a limited potential for degradation, of the compounds tested, by microorganisms developing in a methanogenic landfill environment as compared with other anaerobic habitats such as sewage digestor sludge and sediments.
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| 4. |
- Ejlertsson, Jörgen
(författare)
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Fate of phthalic acid esters during digestion of municipal solid waste under landfill conditions
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this thesis has been to investigate whether anaerobic microorganisms developing in acidogenic and methanogenic landfill environments have the potential to degrade phthalic acid esters (PAEs) and what kinds of intermediates may be formed, assuming PAE degradation. PAEs form a group of compounds widely used in huge amounts worldwide, mainly as plasticiser in PVC-plastics. PAEs are presently entering Swedish landfills, mostly via PVC-plastics deposited as refuse, but also via other products. At landfills they are subjected to an anaerobic environment and may be stored for several decades and centuries under such conditions. Diluted and homogenised municipal solid waste (MSW) samples from different landfill environments were used as inocula in an assay developed for the purpose to determine the potential of microbial PAE degradation. The results showed that the microorganisms present in the MSW-samples were able to transform almost all PAEs investigated. However, the degradation of PAEs may give rise to compounds which are more chemically inert than the parental compounds. As an example bis(2-ethylhexyl) phthalate (DEHP) was observed to be degraded to mono(2-ethylhexyl) phthalate during 300 days of incubation. Monoesters of PAEs were observed in leachate from methanogenic landfill lysimeters in concentrations up to 12 mg per litre during MSW degradation. Ten fold amounts of PVC-plastic were also added to landfill lysimeters to investigate whether PAEs or degradation intermediates could be detected in the lysimeter leachate above the indigenous concentrations of PAEs. This was shown not to be the case for methanogenic conditions. However, the PVC-plastics subjected to methanogenic conditions were shown to be leached of PAEs, which did not occur for samples under acidogenic conditions. The results imply that microbial degradation enhanced the loss of PAEs from the PVC-plastics incubated under methanogenic conditions
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| 5. |
- Karlsson, Anna, 1969-, et al.
(författare)
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Degradation of phenol under meso- and thermophilic, anaerobic conditions
- 1998
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Ingår i: Anaerobe. - : Elsevier BV. - 1075-9964 .- 1095-8274. ; 5:1, s. 25-35
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Tidskriftsartikel (refereegranskat)abstract
- Based on the results of preliminary studies on phenol degradation under mesophilic conditions with a mixed methanogenic culture, we proposed a degradation pathway in which phenol is fermented to acetate: Part of the phenol is reductively transformed to benzoate while the rest is oxidised, forming acetate as end product. According to our calculations, this should result in three moles of phenol being converted to two moles of benzoate and three moles of acetate (3phenol+2CO2+3H2O→3acetate+2benzoate): To assess the validity of our hypothesis concerning the metabolic pathway, we studied the transformation of phenol under mesophilic and thermophilic conditions in relation to the availability of hydrogen. Hence, methanogenic meso- and thermophilic cultures amended with phenol were run with or without an added over-pressure of hydrogen under methanogenic and non-methanogenic conditions. Bromoethanesulfonic acid (BES) was used to inhibit methanogenic activity. In the mesophilic treatments amended with only BES, about 70% of the carbon in the products found was benzoate. During the course of phenol transformation in these BES-amended cultures, the formation pattern of the degradation products changed: Initially nearly 90% of the carbon from phenol degradation was recovered as benzoate, whereas later in the incubation, in addition to benzoate formation, the aromatic nucleus degraded completely to acetate. Thus, the initial reduction of phenol to benzoate resulted in a lowering of H2levels, giving rise to conditions allowing the degradation of phenol to acetate as the end product. Product formation in bottles amended with BES and phenol occurred in accordance with the hypothesised pathway; however, the overall results indicate that the degradation of phenol in this system is more complex. During phenol transformation under thermophilic conditions, no benzoate was observed and no phenol was transformed in the BES-amended cultures. This suggests that the sensitivity of phenol transformation to an elevated partial pressure of H2is higher under thermophilic conditions than under mesophilic ones. The lack of benzoate formation could have been due to a high turnover of benzoate or to a difference in the phenol degradation pathway between the thermophilic and mesophilic cultures.
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