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  • 1.
    Andersson, Fräs Annika
    et al.
    Tekniska Verken.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Tekniska Verken.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Occurrence and abatement of volatile sulfur compounds during biogas production2004In: Journal of the Air & Waste Management Association, ISSN 1047-3289, Vol. 54, no 7, p. 855-861Article in journal (Refereed)
    Abstract [en]

    Volatile sulfur compounds (VSCs) in biogas originating from a biogas production plant and from a municipal sewage water treatment plant were identified. Samples were taken at various stages of the biogas-producing process, including upgrading the gas to vehicle-fuel quality. Solid-phase microextraction was used for preconcentration of the VSCs, which were subsequently analyzed using gas chromatography in combination with mass spectrometry. Other volatile organic compounds present also were identified. The most commonly occurring VSCs in the biogas were hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide, and hydrogen sulfide was not always the most abundant sulfur (S) compound. Besides VSCs, oxygenated organic compounds were commonly present (e.g., ketones, alcohols, and esters). The effect of adding iron chloride to the biogas reactor on the occurrence of VSCs also was investigated. It was found that additions of 500-g/m3 substrate gave an optimal removal of VSCs. Also, the use of a prefermentation step could reduce the amount of VSCs formed in the biogas process. Moreover, in the carbon dioxide scrubber used for upgrading the gas, VSCs were removed efficiently, leaving traces (ppbv levels). The scrubber also removed other organic compounds.

  • 2.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Borgström, Ylva
    Pöyry Sweden AB, Norrköping, Sweden.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Scandinavian Biogas Fuels AB, Stockholm, Sweden.
    Nilsson, Fredrik
    Pöyry Sweden AB, Norrköping, Sweden.
    Svensson, Bo
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Biogasproduktion inom svensk pappers- och massaporduktion : Syntes av möjligheter och begränsningar samt teknisk utvärdering: Bilaga 2 Etablering/effektivisering av biogasproduktion inom svensk pappers- och massaindustri2016Report (Other academic)
    Abstract [sv]

    Linköpings Universitet har tillsammans med Pöyry och Scandinavian Biogas Fuels drivit projektet ”Etablering/effektivisering av  biogasproduktion inom svensk pappers- och massaproduktion”. Potentialen hos det organiska materialet i avloppsvatten från svensk pappers- och massaindustri (PMI) till biogasproduktion skattades vid projektstart till 100 milj. Nm3 metan per år (1 TWh). Denna rapport är en syntes av resultaten från projektet med syfte att ge visa hur de genererade resultaten kan omsättas i teknisk praktik med tillhörande ekonomiska insatser. Syftet är att ge underlag och stöd till PMI-branschen och externa intressenter, som överväger att implementera biogasproduktion inom PMI.

    Substraten för biogasproduktion som återfinns i pappers- och massaindustrins avloppsvatten och slam kännetecknas av stora volymer med låga COD-halter. Detta kräver rötningstekniker, som tillåter mycket korta uppehållstider jämfört med mer traditionellt utformade biogasanläggningar för att inte tankstorleken ska bli för stor. Två tekniker, som utvecklats inom projektet, klarar detta: EGSB (expanded granular sludge bed) och CSTR (completely stirred tank reactor) med slamåterföring. Dessa tekniker har därför utvärderats för tre olika typbruk, ett CTMP-bruk, ett TMP-bruk och ett sulfatmassabruk. Resultaten från dessa experimentella studier är utgångspunkten för i utvärderingen i föreliggande rapport. För varje processkoncept har en grov kostnadsuppskattning (±20 %) gjorts för den investering som krävs för biogasproduktion.

    En EGSB på ett TMP-bruk med ett totalavlopp på 1500 m3/h, där hela blekeriavloppet från peroxidblekningen och en del av det övriga avloppet behandlas i en 4000 m3 reaktor förväntas ge 2,5 milj Nm3 metan/år. Investeringskostnaden för anläggningen uppskattas till 75 milj. SEK (±20 %).

    En EGSB på ett CTMP-bruk med ett totalavlopp på 170 m3/h där hela avloppet behandlas i en 3000 m3 reaktor förväntas ge 1,8 milj Nm3 metan/år. Investeringskostnaden för anläggningen uppskattas till 64 milj. SEK (±20%).

    En CSTR med slamåterföring som körs på bioslam från ett sulfatmassabruk där ett bioslamflöde på 46 m3/h behandlas i en 4000 m3 reaktor förväntas ge 1,0 milj Nm3 metan/år. I denna design är strategin för den aeroba bioreningen ändrad för att producera ett bioslam optimerat för att ge högsta möjliga biogaspotential. Detta innebär produktion av större mängd slam, som i största mån kan rötas till metan, dvs mängd metan per mängd rötat organiskt material samtidigt som COD-reduktionen i vattenreningen bibehålls. Investeringskostnaden för anläggningen uppskattas till 32 milj. SEK (±20%).

    Baserat på de COD-kvantiteter som når de luftade dammarna inom PMIs vattenreningssystem förbrukas årligen ca 0,8 TWh el. Införande av biogasproduktion i massaindustrins spillvattenrening skulle reducera mängden COD med mellan 30-50%, vilket får till följd att den årliga elförbrukningen i samband med den aeroba reningen går ner med ca 0,2-0,4 TWh. Detta innebär alltså ett energitillskott av 0,9 – 1,1 TWh givet att hela den tillgängliga biogaspotentialen skulle byggas ut. Till detta kommer eventuella vinster relaterade till slamhanteringen.

  • 3.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ekstrand, Eva-Maria
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Larsson, Madeleine
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Truong, Xu-Bin
    Cardell, Lina
    Borgström, Ylva
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Nilsson, Fredrik
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    The methane potential of Swedish pulp and paper industry - A screening of wastewater effluents2012In: International Conference on Applied Energy 2012, 2012Conference paper (Other academic)
  • 4.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Hörsing, Maritha
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Mersiowsky, Ivo
    Hamburg, Germany.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Impacts of temperature on the leaching of organotin compounds from poly(vinyl chloride) plastics – A study conducted under simulated landfill conditions. Journal of Vinyl and Additive Technology 2007In: Journal of Vinyl & Additive Technology, ISSN 0193-7197, E-ISSN 1548-0577, Vol. 13, no 4, p. 176-188Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate whether organotin-stabilized poly(vinyl chloride) (PVC) products could contribute to the pool of organotins observed in landfill leachates, and if the possible release could be related to different temperatures and landfill degradation phases. Small-scale anaerobic reactors filled with generic household waste, a mixture of inocula, and different PVC plastics were used in the study and incubated at 20, 37, 55, and 70°C. The reactor units incubated at temperatures of 20–55°C underwent the anaerobic degradation phases that are characteristic for the aging of landfilled waste material. There were, however, differences in the duration of the phases as well as in the total biogas production among the units. Under methanogenic conditions greater losses of organotin compounds were observed as compared to acidogenic conditions. It was shown that the release of organotin stabilizers increases considerably at temperatures above the glass transition of the PVC products. A dealkylation from di- into monoalkyltin species was observed, as well as a possible methylation of inorganic tin. However, the main part of the organotins was adsorbed into the solid waste matrix. J. VINYL ADDIT. TECHNOL., 13:176–188, 2007. © 2007 Society of Plastics Engineers

  • 5.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Shakeri Yekta, Sepehr
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Danielsson, Åsa
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Rheological characteristics of reactor liquid from 12 full-scale biogas reactors2012In: International Conference on Applied Energy, ICAE 2012, 2012Conference paper (Other academic)
    Abstract [en]

    Rheological properties of reactor liquids are important for the construction and intensity mixing systems in biogas reactors. Most frequently the total solids content (TS) is used as a proxy to guide in these matters. In order to establish a more comprehensive basis the rheology of twelve full-scale continuously stirred tank biogas reactors was characterized and related to differences in substrate composition and operational conditions. Reactor material from eight mesophilic (36−38°C) and four thermophilic (52−55°C) reactors were sampled at two occasions. The feedstocks of nine of these reactors were included in the analysis. Two of the mesophilic and one of the thermophilic digesters were fed sewage sludge (SS), while the others digested mixtures of organic matter including slaughterhouse waste (SHW), food industry waste (FIW), fat, manure, fodder residues and the organic fraction of municipal solid waste (OFMSW). The organic loading rates ranged 2.4−3.6 kg VS m-3 d-1 and the TS of the reactor materials were at 1.8−5.3% . The rheological characteristics of the reactor liquids were interpreted from flow- and viscosity curves as well as from determination of dynamic viscosity, limit viscosity, yield stress, flow behavior and consistency index.

    The fluid dynamic- and limit viscosities of the fluids ranged 5−600 mPa*s and 4−40 mPa*s, respectively. All reactor fluids except one from a thermohilic CD-reactor showed pseudoplastic behavior, since they became thinner with increasing shear stress until the viscosity reached a plateau of limit viscosity. In addition the mesophilic CD reactors were strongly thixothropic, i.e. they exhibited partial structure recovery. The results from the analysis of the thermophilic CD-reactors indicated a weak dilatant behavior, i.e. shear thickening behavior.

    The results showed differences in viscosity despite similar TS-content for several reactor liquids. From this survey it is clear that the TS content of biogas reactor fluids is not a good estimator of the fluid viscosity and that the fluid characteristics vary as a result of substrate composition and process operation conditions.

  • 6.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Segura de La Monja, Paula
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Differences and shifts in the rheological characteristics of fluids in controlled stirred tank reactors for biogas production.2010In: World Conference in Anaerobic Digestion (AD12): in Guadalajara, Mexico, den 31 oktober – 4 november 2010., 2010Conference paper (Refereed)
  • 7.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Segura de la Monja, Paula
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Rheological characterization2012In: Biogas / [ed] Sunil Kumar, Rijeka, Croatia: INTECH, 2012, p. 63-76Chapter in book (Refereed)
    Abstract [en]

    This book contains research on the chemistry of each step of biogas generation, along with engineering principles and practices, feasibility of biogas production in processing technologies, especially anaerobic digestion of waste and gas production system, its modeling, kinetics along with other associated aspects, utilization and purification of biogas, economy and energy issues, pipe design for biogas energy, microbiological aspects, phyto-fermentation, biogas plant constructions, assessment of ecological potential, biogas generation from sludge, rheological characterization, etc.

  • 8.
    Björn (Fredriksson), Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Hörsing, Maritha
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Mersiowsky, Ivo
    Department of Waste Management, Technical University of Hamburg-Harburg, D-21079 Hamburg, Germany.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Impacts of Temperature on the Leaching of Organotin Compounds From Poly(vinyl chloride) Plastics: A Study Conducted Under Simulated Landfill Conditions2007In: Journal of Vinyl and Additive Technology, ISSN 1083-5601, Vol. 13, no 4, p. 176-188Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate whether organotin-stabilized poly(vinyl chloride) (PVC) products could contribute to the pool of organotins observed in landfill leachates, and if the possible release could be related to different temperatures and landfill degradation phases. Small-scale anaerobic reactors filled with generic household waste, a mixture of inocula, and different PVC plastics were used in the study and incubated at 20, 37, 55, and 70°C. The reactor units incubated at temperatures of 20-55°C underwent the anaerobic degradation phases that are characteristic for the aging of landfilled waste material. There were, however, differences in the duration of the phases as well as in the total biogas production among the units. Under methanogenic conditions greater losses of organotin compounds were observed as compared to acidogenic conditions. It was shown that the release of organotin stabilizers increases considerably at temperatures above the glass transition of the PVC products. A dealkylation from di- into monoalkyltin species was observed, as well as a possible methylation of inorganic tin. However, the main part of the organotins was adsorbed into the solid waste matrix.

  • 9.
    Ejlertsson, Jörgen
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Johansson, Elisabeth
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Meyerson, Ulrika
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions1995In: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology, ISSN 0003-6072, E-ISSN 1572-9699, Vol. 69, no 1, p. 67-74Article in journal (Refereed)
    Abstract [en]

    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.

  • 10. Ejlertsson, Jörgen
    et al.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Lagerkvist, Anders
    Hjertberg, Thomas
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Effects of co-disposal of wastes containing organic pollutants with municipal solid waste - A landfill simulation reactor study2003In: Advances in Environmental Research, ISSN 1093-0191, E-ISSN 1093-7927, Vol. 7, no 4, p. 949-960Article in journal (Refereed)
    Abstract [en]

    Different phases of the life cycle of a landfill receiving municipal solid waste (MSW) were monitored in landfill simulation reactors (LSRs) with the aim of investigating the effects of co-disposal of wastes containing organic pollutants (OPs) with MSW. Two LSRs out of four filled with well-characterised MSW received waste materials containing OPs. These included two types of plasticised PVC flooring materials, freon-blown insulation and phosphorus- and nitrogen-based flame-protected materials. Each of the two LSRs was operated under acid fermentative and neutral methanogenic conditions, respectively as were their corresponding controls, i.e. without extra OP. The methanogenic consortia degrading MSW were hampered by the addition of wastes containing OPs, probably due to the presence of Freon R11 and its degradation product, R21. The concentrations of R11 and R21 ranged between 0.1 and 1800 mg m-3 depending on the biogas production rate in the OP-amended LSRs. Losses of butylbenzyl- (26%) and bis(2-ethylhexyl)phthalate (15%) from one of two flooring materials was observed, whereas the other remained unaffected. Methanogenic conditions favoured the loss of plasticisers as compared to acidogenic conditions. Total phosphorus was significantly higher in the OP-spiked LSRs, which indicated a transformation of the non-halogenated flame-retardants. ⌐ 2002 Elsevier Science Ltd. All rights reserved.

  • 11.
    Feng, Xinmei
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bertilsson, Stefan
    Uppsala University.
    Impact of trace element addition on biogas production from food industrial waste - linking process to microbial communities2010In: FEMS MICROBIOLOGY ECOLOGY, ISSN 0168-6496, Vol. 74, no 1, p. 226-240Article in journal (Refereed)
    Abstract [en]

    Laboratory-scale reactors treating food industry waste were used to investigate the effects of additions of cobalt (Co), nickel/molybdenum/boron (Ni/Mo/B) and selenium/tungsten (Se/W) on the biogas process and the associated microbial community. The highest methane production (predicted value: 860 mL g-1 VS) was linked to high Se/W concentrations in combination with a low level of Co. A combination of quantitative real-time PCR of 16S rRNA genes, terminal restriction fragment length polymorphism (T-RFLP) and clone library sequencing was used for the community analysis. The T-RFLP data show a higher diversity for bacteria than for archaea in all the treatments. The most abundant bacterial population (31-55% of the total T-RFLP fragments intensity) was most closely related to Actinomyces europaeus (94% homology). Two dominant archaeal populations shared 98-99% sequence homology with Methanosarcina siciliae and Methanoculleus bourgensis, respectively. Only limited influence of the trace metal additions was found on the bacterial community composition, with two bacterial populations responding to the addition of a combination of Ni/Mo/B, while the dominant archaeal populations were influenced by the addition of Ni/Mo/B and/or Se/W. The maintenance of methanogenic activity was largely independent of archaeal community composition, suggesting a high degree of functional redundancy in the methanogens of the biogas reactors.

  • 12.
    Gustavsson, Jenny
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, The Institute of Technology.
    Shakeri Yekta, Sepehr
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Skyllberg, Ulf
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bioavailability and chemical forms of Co and Ni in the biogasprocess: an evaluation based on sequential and acid volatile sulfide extractionsManuscript (preprint) (Other academic)
    Abstract [en]

    Several previous studies report stimulatory effects on biogas process performance after trace element supplementation. However, the regulation of the bioavailability in relation to chemical speciation (e.g. the role of sulfide) is not fully understood. The objective of the present study was to determine the effect of sulfide on the chemical speciation and bioavailability of Co and Ni in lab-scale semi-continuously fed biogas tank reactors, digesting grain stillage. The chemical forms and potential bioavailability of Co and Ni in the reactors were determined by sequential extraction (SE), and analysis of acid volatile sulfide (AVS) together with simultaneously extracted metals (AVS-Me). The results for metal speciation analysis demonstrated that Ni was completely associated to the organic  matter/sulfide fraction and AVS, suggesting low potential Ni-bioavailability. Cobalt was predominantly associated to organic matter/sulfide and AVS, but also to more soluble fractions which are considered to be more bioavailable. Process performance data showed that both Co and Ni were available for microbial uptake. Although the actual bioavailability of Co could be explained by association to more bioavailable chemical fractions as determined by SE, AVS and AVS-Me analysis, the complete association of Ni with organic matter/sulfides and AVS shows that Ni was taken up despite its expected low bioavailability. Thus, the results of the present study imply that Ni-sulfide precipitation does not prevent microbial uptake in the studied biogas reactors.

  • 13.
    Gustavsson, Jenny
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    The feasibility of trace element supplementation for stable operation of wheat stillage-fed biogas tank reactors2011In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 64, no 2, p. 320-325Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the effect of trace element supplementation on operation of wheat stillage-fed biogas tank reactors. The stillage used was a residue from bio-ethanol production, containing high levels of sulfate. In biogas production, high sulfate content has been associated with poor process stability in terms of low methane production and accumulation of process intermediates. However, the results of the present study show that this problem can be overcome by trace element supplementations. Four lab-scale wheat stillage-fed biogas tank reactors were operated for 345 days at a hydraulic retention time of 20 days (37 degrees C). It was concluded that daily supplementation with Co (0.5 mg L(-1)), Ni (0.2 mg L(-1)) and Fe (0.5 g L(-1)) were required for maintaining process stability at the organic loading rate of 4.0 g volatile solids L(-1) day(-1).

  • 14.
    Hörsing, Maritha
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Jonsson, Susanne
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Leaching of Flame Retardants from products deposited in LandfillsManuscript (Other academic)
    Abstract [en]

    Materials in many products in daily use are amended with chemicals to give them desired properties, e.g. flame retardants (FRs) used to reduce the risks of products catching fire. However, potential risks posed by some of these chemicals, including FRs, to the environment and human health have raised concerns. Hence, there is a need for more knowledge regarding the fate of FRs, notably in landfills, where many FR-containing products are deposited. This article presents analyses of FRs and derivatives in leachates sampled during laboratory-scale simulations of landfills containing various FR-containing products progressing through typical landfill ageing phases. The FRs represented substances used both reactively, i.e. bound to the flame-protected material and additively, i.e. without any covalent bonding to the product.The phosphorus-based Pyrovatex-FR and the brominated tetrabromobisphenol A (TBBPA) were used to represent the reactive FRs, and the nitrogen-based melamine and phosphorus-based FR of Proban the additive FRs. Residual FRs from the treatment of the materials were probably the main contributors to the leachates from all products. Their durability, i.e. ability to withstand laundry washes, was reflected in their leaching abilities, while the different landfill conditions were of minor importance, except for melamine (of which approximately 10% of the amount present in the test product leached and mineralised to carbon dioxide and ammonia, mainly during the period when the landfill models passed from acidogenic to methanogenic conditions). The other additively applied FR in Proban leached first during the later part of the incubation (between 80 and 112 weeks), in accordance with its laundry resistance. Substantial proportions of the residual chemicals in Pyrovatex-treated materials are generally lost during the first washing. Accordingly, early losses of the chemicals used in this treatment were detected during the landfill simulation. Elevated phosphate concentrations were also detected in simulations with the Pyrovatex- and Proban-treated products, suggesting that the FRs generated in these treatments were degraded during or after release to the leachate. Small amounts of TBBPA were observed at the end of the incubation, and no TBBPA degradation products were observed, but debromination (which is likely to occur during anoxic stages) would lead to the formation of bisphenol A.

  • 15.
    Hörsing, Maritha
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Mersiowsky, Ivo
    Department of Waste Management, Technical University of Hamburg-Harburg , Germany.
    Svensson, Bo H
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Effects of Temperature and Landfill Ageing on leaching and Degradation of Phtalates from a Poly(vinyl chloride) Carpet under Simulated Landfill ConditionsManuscript (Other academic)
    Abstract [en]

     

    Phthalic ether esters are a group of chemicals used in the manufacture of PVC plastics, often as plasticizing additives, hence they may leach from the material and/or finished products before, during and after their use. This article presents results from laboratory-scale investigations of the fates of di-2-ethylhexyl phthalate (DEHP) and benzyl-butyl phthalate (BBP) under simulated landfill conditions, in custom-designed incubation units filled with model municipal solid waste. More specifically, the effects of temperature and landfill degradation phase on both the leaching and degradation potential of the two phthalates from a PVC carpet were examined, by measuring them in samples from units maintained at 20, 37, 55 and 70°C as they progressed through anaerobic acidogenic and methanogenic landfill phases. The results show that both BBP and DEHP leached from the carpet. For DEHP there was a clear temperature effect, and the highest losses were observed at 70°C, while for BBP slight increases in losses with temperature were observed from 20 to 55°C, and from 55 to 70°C, but the largest losses were seen at 37°C, probably due to biodegradation. Further degradation of the leached phthalates occured at all temperatures. Apparent degradation products observed included phthalic acid (PA) and mono (2-ethylhexyl)-, monobutyl- and monobenzyl-phthalate. In all cases the biological degradation of the phthalates occurred mainly after the systems switched to methanogenic conditions. The rate-limiting step of degradation in the 20 and 37°C units seemed to be the transformation of the monoesters, which tended to accumulate more than PA, while at 55 and 70°C PA accumulated to a higher extent.

  • 16.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Anaerobic degradation of phenol and related aromatics2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Phenol and other simple aromatic compounds have been found in water leached from landfills, showing that these types of compounds could be either present in disposed waste, or released from it via transformation and degradation processes. Hence, the fate anddegradation potential of such compounds under landfilling conditions is of great concern. Therefore, using micro-organisms from landfills, I have investigated the anaerobic biodegradation of phenol, dimethyl phthalate, 3-chlorobenzoate, 2,4,6-trichlorophenol, tetrabromophthalic acid and aniline. The compounds were chosen to represent substrates of potentially important reactions in the transformation and degradation of aromatic compounds. 24 waste samples from landfills and a time series of samples taken over five years from fourlandfill simulation reactors (in all 20 waste samples) were used as sources of microorganisms. The capacity of these waste samples to degrade the halogenated aromatics was poor or completely absent, indicating that halogenated compounds could be more persistent inlandfills than in other previously investigated anaerobic environments. Phenol and dimethyl phthalate were more readily transformed by most landfill samples, but the degradation capacity was poorer in the landfill simulation experiments. Here the unique sampling series showed an increase in degradation capacity with time, indicating that one to two years is needed to allow a micro-flora capable of degrading aromatic compounds to develop. However, the landfill samples showed higher degradation potentials than the simulation reactor samples, even from the later stages.

    A more extensive study designed to elucidate the phenol degradation pathway under anaerobic, fermenting conditions is also presented. Here, phenol was for the first time shown to be degraded to non-aromatic products in a non-methanogenic fermenting culture. The endproductsformed were benzoate, acetate and butyrate. The conversion of phenol to benzoate was proved to be an electron sink reaction, used during processes such as degradation of glucose and is a new example of the diversity of compounds that can used as electronsinks/ acceptors in anaerobic environments. The degradation pathway in the studied cultureproceeds via fom1ation of 4-hydroxybenzoate, 4-hydroxybenzoyl-CoA and benzoyl-CoA, and the activity of a CoA-transferase which activates 4-hydroxybenzoate was measured.

    List of papers
    1. Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions
    Open this publication in new window or tab >>Anaerobic degradation of xenobiotics by organisms from munical solid waste under landfilling conditions
    Show others...
    1995 (English)In: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology, ISSN 0003-6072, E-ISSN 1572-9699, Vol. 69, no 1, p. 67-74Article in journal (Refereed) Published
    Abstract [en]

    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.

    Keywords
    biodegradation, chlorinated compounds, freons, methane formation, phthalic acid esters, phenol
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-31281 (URN)10.1007/BF00641613 (DOI)17042 (Local ID)17042 (Archive number)17042 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-01-13Bibliographically approved
    2. Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactors
    Open this publication in new window or tab >>Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactors
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The ability by micro-organisms developed in landfilled waste totransform phenol, dimethyl phthalate (DMP), aniline, tetrabromophthalic acid (TBPA), 3-chlorobenzoate (CB) and 2,4,6-trichlorophenol (TCP) was investigated using a method modified after ISO 17334. Forty-four solid waste samples from landfills and landfill simulation reactors (LSRs) were used. The LSRs were run over a five-year period and simulated acid and methanogenic landfill conditions. The biodegradability of each aromatic compound (0.5-0. 7 mM) was assayed over 100-200 days. The degradation capacity was monitored both by quantification of the aromatic compounds and by methane analysis

    The degradation capacity for the halogenated aromatics was poor or completely lacking by the landfill inocula investigated showing that this kind of compounds might persist in landfill. TCP inhibited both the methanogenic and fermentative micro-flora present in the waste samples, however, in early LSR assays no inhibition was observed. Phenol and DMP was transformed to non aromatic products in most assays. The biodegradation capacity towards these compounds increased over time in the LSR studies i.e. the acid and early methanogenic land fill phases had no or poor degradation capacity. These results indicates that the earlymethanogcnic tlora developing in landfills and landfill simulation reactors is different from the one later established by being less efficient in transformation of aromatic compounds but also less sensitive to aryl halides.

    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-79139 (URN)
    Available from: 2012-06-29 Created: 2012-06-29 Last updated: 2018-01-12Bibliographically approved
    3. Degradation of phenol under meso- and thermophilic, anaerobic conditions
    Open this publication in new window or tab >>Degradation of phenol under meso- and thermophilic, anaerobic conditions
    1998 (English)In: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 5, no 1, p. 25-35Article in journal (Refereed) Published
    Abstract [en]

    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.

    Keywords
    phenol degradation, electronacceptor, acetate formation, meso and thermophilic conditions, methane formation
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-31040 (URN)10.1006/anae.1998.0187 (DOI)16748 (Local ID)16748 (Archive number)16748 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-01-13Bibliographically approved
    4. CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture
    Open this publication in new window or tab >>CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture
    2000 (English)In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 173, no 5-6, p. 398-402Article in journal (Refereed) Published
    Abstract [en]

    Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of P(H2) on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578 was observed, compared to controls, as a consequence of phenol degradation, however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.

    Keywords
    Phenol fermentation, Reductive dehydroxylation, Hydrogen partial pressure, Ring cleavage
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-32080 (URN)10.1007/s002030000160 (DOI)17935 (Local ID)17935 (Archive number)17935 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-01-13Bibliographically approved
    5. Reduction of phenol to benzoate: an electron sink reaction used by a highly enriched anaerobic culture
    Open this publication in new window or tab >>Reduction of phenol to benzoate: an electron sink reaction used by a highly enriched anaerobic culture
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A non-methanogenic pasteurised enrichment culture fermenting phenolto benzoate, butyrate and acetate was studied, focusing on the effects of adding yeast extract (0.1, 0.2 or I g!l) or glucose (1.5 mM) together with the phenol (5 mM). The results showed that the reductive formation of benzoate from phenol increased when either yeast extract (1 g 1-') or glucose was added to the medium. The culture also transformed phenol at a higher rate when glucose was added as a "co-substrate" than when it was grown on phenol alone. Furthermore, higher growth rates occurred in cultures grown on both substrates rather than on glucose or phenol alone.

    Keywords
    phenol fermentation, electron sink, glucose
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-79144 (URN)
    Available from: 2012-06-29 Created: 2012-06-29 Last updated: 2018-01-12Bibliographically approved
  • 17.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Einarsson, Peter
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Schnurer, Anna
    Swedish University of Agriculture Science, Sweden .
    Sundberg, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Impact of trace element addition on degradation efficiency of volatile fatty acids, oleic acid and phenyl acetate and on microbial populations in a biogas digester2012In: Journal of Bioscience and Bioengineering, ISSN 1389-1723, E-ISSN 1347-4421, Vol. 114, no 4, p. 446-452Article in journal (Refereed)
    Abstract [en]

    The effect of trace element addition on anaerobic digestion of food industry- and household waste was studied using two semi-continuous lab-scale reactors, one (R30+) was supplied with Fe, Co and Ni, while the other (R30) acted as a control. Tracer analysis illustrated that methane production from acetate proceeded through syntrophic acetate oxidation (SAO) in both digesters. The effect of the trace elements was also evaluated in batch assays to determine the capacity of the microorganisms of the two digesters to degrade acetate, phenyl acetate, oleic acid or propionate, butyrate and valerate provided as a cocktail. The trace elements addition improved the performance of the process giving higher methane yields during start-up and early operation and lower levels of mainly acetate and propionate in the R30+ reactor. The batch assay showed that material from R30+ gave effects on methane production from all substrates tested. Phenyl acetate was observed to inhibit methane formation in the R30 but not in the R30+ assay. A real-time PCR analysis targeting methanogens on the order level as well as three SAO bacteria showed an increase in Methanosarcinales in the R30+ reactor over time, even though SAO continuously was the dominating pathway for methane production. Possibly, this increase explains the low VFA-levels and higher degradation rates observed in the R30+ batch incubations. These results show that the added trace elements affected the ability of the microflora to degrade VFAs as well as oleic acid and phenyl acetate in a community, where acetate utilization is dominated by SAO.

  • 18.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Addition of HCl as a means to improve biogas production from protein-rich food industry waste2012In: Biochemical engineering journal, ISSN 1369-703X, E-ISSN 1873-295X, Vol. 61, p. 43-48Article in journal (Refereed)
    Abstract [en]

    The effect of pH on the production of biogas during anaerobic digestion of a protein-rich substrate, containing mainly slaughter house waste, was investigated. Four laboratory scale reactors (4 L liquid volume) with an organic load of 3.5 g volatile solids (VS) L-1 reactor volume day(-1), and a hydraulic retention time 24 days were run under mesophilic conditions in semi-continuous mode for 64 days. Two of the reactors were pH-regulated (target pH was 7.6 and 7.8, respectively) by adding HCl, while the other two reactors were operated as controls (pH 8.0). By the end of the experiment the pH-controlled reactors produced 0.6 L of methane g VSadded-1 day(-1), while the controls produced 0.4 L. The gas produced did in all cases have a CH4 - content of about 65%. The improvement in process performance in the pH-regulated reactors, compared to the controls, was also reflected in lower final levels of acetate, propionate, isobutyrate and 2-metylbutyrate. The laboratory-scale study showed that lowering the pH by 0.2-0.4 units by adding HCl to the reactors increased the methane yield with about 50%, indicating a considerable increase of the microbial ability to utilise the organic material for biogas production.

  • 19.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Nezirevic, Dzeneta
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Degradation of phenol under meso- and thermophilic, anaerobic conditions1998In: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 5, no 1, p. 25-35Article in journal (Refereed)
    Abstract [en]

    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.

  • 20.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Nezirevic, Dzeneta
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactorsManuscript (preprint) (Other academic)
    Abstract [en]

    The ability by micro-organisms developed in landfilled waste totransform phenol, dimethyl phthalate (DMP), aniline, tetrabromophthalic acid (TBPA), 3-chlorobenzoate (CB) and 2,4,6-trichlorophenol (TCP) was investigated using a method modified after ISO 17334. Forty-four solid waste samples from landfills and landfill simulation reactors (LSRs) were used. The LSRs were run over a five-year period and simulated acid and methanogenic landfill conditions. The biodegradability of each aromatic compound (0.5-0. 7 mM) was assayed over 100-200 days. The degradation capacity was monitored both by quantification of the aromatic compounds and by methane analysis

    The degradation capacity for the halogenated aromatics was poor or completely lacking by the landfill inocula investigated showing that this kind of compounds might persist in landfill. TCP inhibited both the methanogenic and fermentative micro-flora present in the waste samples, however, in early LSR assays no inhibition was observed. Phenol and DMP was transformed to non aromatic products in most assays. The biodegradation capacity towards these compounds increased over time in the LSR studies i.e. the acid and early methanogenic land fill phases had no or poor degradation capacity. These results indicates that the earlymethanogcnic tlora developing in landfills and landfill simulation reactors is different from the one later established by being less efficient in transformation of aromatic compounds but also less sensitive to aryl halides.

  • 21.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Nezirevic, Dzeneta
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo H.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Reduction of phenol to benzoate: an electron sink reaction used by a highly enriched anaerobic cultureManuscript (preprint) (Other academic)
    Abstract [en]

    A non-methanogenic pasteurised enrichment culture fermenting phenolto benzoate, butyrate and acetate was studied, focusing on the effects of adding yeast extract (0.1, 0.2 or I g!l) or glucose (1.5 mM) together with the phenol (5 mM). The results showed that the reductive formation of benzoate from phenol increased when either yeast extract (1 g 1-') or glucose was added to the medium. The culture also transformed phenol at a higher rate when glucose was added as a "co-substrate" than when it was grown on phenol alone. Furthermore, higher growth rates occurred in cultures grown on both substrates rather than on glucose or phenol alone.

  • 22.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture2000In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 173, no 5-6, p. 398-402Article in journal (Refereed)
    Abstract [en]

    Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of P(H2) on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578 was observed, compared to controls, as a consequence of phenol degradation, however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.

  • 23.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Johansson, Elisabeth
    Transformation of tetrabromo phthalic acid under anaerobic landfill conditions.1997In: 6th Int. Landfill Symposium,1997, 1997, p. 245-249Conference paper (Other academic)
  • 24.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Truong, Xu-Bin
    Scandinavian Biogas Fuels AB.
    Gustavsson, Jenny
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Nilsson, Fredrik
    Poyry Sweden AB.
    Ejlertsson, Jorgen
    Scandinavian Biogas Fuels AB.
    Anaerobic treatment of activated sludge from Swedish pulp and paper mills - biogas production potential and limitations2011In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 32, no 14, p. 1559-1571Article in journal (Refereed)
    Abstract [en]

    The methane potential of activated sludge from six Swedish pulp and paper mills was evaluated. The methane production potential of sludge samples ranged from 100-200 NmL CH(4) g(-1) volatile solids (VS) and for four of the six sludge samples the potential exceeded 170 NmL CH(4) g(-1) VS. The effects of sludge age and dewatering on the methane production potential were evaluated. The effects of enzymatic and ultrasonic pre-treatment on the digestibility of sludge were also investigated, but energy or enzyme inputs in viable ranges did not exert a detectable, positive effect. Long-term, semi-continuous trials with sludge from two of the mills were also conducted in attempts to develop stable biogas production at loading rates up to 4 g VS L(-1). Cobalt addition (0.5 mg L(-1)) was here found to positively affect the turnover of acetate. High viscosity was a problem in all the experimental reactors and this limited the organic loading rate.

  • 25.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Vallin, Lina
    Ejlertsson, Jörgen
    Effects of temperature, hydraulic retention time and hydrogen extraction rate on hydrogen production from the fermentation of food industry residues and manure2008In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 33, no 3, p. 953-962Article in journal (Refereed)
    Abstract [en]

    The production of H2 from food residues and manure has been optimised using a central composite face-centred (CCF) design. In all 17 assays were run, varying the temperature (20, 37 and 55 {ring operator} C), hydraulic retention time (2, 5 and 8 days) and N2-flow rates (5, 25 or 125 mL/min). Completely stirred tank reactors (2 L) were operated for three hydraulic retention times and hydrogen production was determined during the course of a 24-h period before termination. The concentrations of H2, CH4 and volatile fatty acids were measured, together with pH, throughout the experiment. A temperature of 55 {ring operator} C, combined with a sparging rate of 125 mL/min, and a hydraulic retention time of 2 days resulted in the highest hydrogen formation. The maximal production experimentally obtained was 16.5 mL H2/g VS. A model was calculated from the data with a squared correlation coefficient (R2) of 0.97 and a predictive power of 0.64 (Q2). © 2007 International Association for Hydrogen Energy.

  • 26.
    Sundberg, Carina
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Al-Soud, Waleed A.
    University of Copenhagen, Denmark .
    Larsson, Madeleine
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Alm, Erik
    SMI, Sweden .
    Shakeri Yekta, Sepehr
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sorensen, Soren J.
    University of Copenhagen, Denmark .
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    454 pyrosequencing analyses of bacterial and archaeal richness in 21 full-scale biogas digesters2013In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 85, no 3, p. 612-626Article in journal (Refereed)
    Abstract [en]

    The microbial community of 21 full-scale biogas reactors was examined using 454 pyrosequencing of 16S rRNA gene sequences. These reactors included seven (six mesophilic and one thermophilic) digesting sewage sludge (SS) and 14 (ten mesophilic and four thermophilic) codigesting (CD) various combinations of wastes from slaughterhouses, restaurants, households, etc. The pyrosequencing generated more than 160 000 sequences representing 11 phyla, 23 classes, and 95 genera of Bacteria and Archaea. The bacterial community was always both more abundant and more diverse than the archaeal community. At the phylum level, the foremost populations in the SS reactors included Actinobacteria, Proteobacteria, Chloroflexi, Spirochetes, and Euryarchaeota, while Firmicutes was the most prevalent in the CD reactors. The main bacterial class in all reactors was Clostridia. Acetoclastic methanogens were detected in the SS, but not in the CD reactors. Their absence suggests that methane formation from acetate takes place mainly via syntrophic acetate oxidation in the CD reactors. A principal component analysis of the communities at genus level revealed three clusters: SS reactors, mesophilic CD reactors (including one thermophilic CD and one SS), and thermophilic CD reactors. Thus, the microbial composition was mainly governed by the substrate differences and the process temperature.

  • 27.
    Svensson, Bo
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Anna
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Dark fermentation for hydrogen production from organic wastes2005In: Biofuels for fuel cells: renewable energy from biomass fermentation / [ed] Lens, Piet, London: IWA Publishing , 2005, p. 209-220Chapter in book (Other academic)
    Abstract [en]

    The increasing demand for energy and the related environmental concerns are the main drivers for the strong interest in Biomass Fermentation towards usage in Fuel Cells. The integration of Biomass Fermentation (BF) and Fuel Cells (FC) technology creates a new and interdisciplinary research area. Due to their high efficiency Fuel Cells are therefore considered as a strategic technology for future energy supply systems. The fact that biomass is a renewable source of energy in combination with the most efficient energy conversion system (FC) makes this combination unique and advantageous. This book has a clear orientation towards making products of our waste. Biofuels for Fuel Cells comes at a time when this field is rapidly developing and there is a need for a synthetising book. The holistic and multidisciplinary description of this topic, including discussion of technological, socio-economic, system analysis and policy and regulatory aspects, make this book the definitive work for this market. Biofuels for Fuel Cells will cross-link scientists of all fields concerned with Biomass Fermentation, Fuel Upgrading and Fuel Cells at European and World level.

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