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- André, Erik, et al.
(författare)
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Dagsljus i ledningarna
- 2003
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Ingår i: Energi och miljö. - 1101-0568. ; :2, s. 60-62
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Hemmingsson, Carl, 1964-, et al.
(författare)
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Deep-Level Defects in Electron-irradiated 4H SiC Epitaxial Layers
- 1997
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 81:9, s. 6155-6159
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Tidskriftsartikel (refereegranskat)abstract
- Deep level defects in electron-irradiated 4H SiC epitaxial layers grown by chemical vapor deposition were studied using deep level transient spectroscopy. The measurements performed on electron-irradiated p+n junctions in the temperature range 100–750 K revealed several electron traps and one hole trap with thermal ionization energies ranging from 0.35 to 1.65 eV. Most of these defects were already observed at a dose of irradiation as low as ≈5×1013 cm-2. Dose dependence and annealing behavior of the defects were investigated. For two of these electron traps, the electron capture cross section was measured. From the temperature dependence studies, the capture cross section of these two defects are shown to be temperature independent. © 1997 American Institute of Physics.
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| 10. |
- Nordell, Erik
(författare)
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Karlfeldts patriotism
- 1941
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Ingår i: Samlaren. - Uppsala : Svenska Litteratursällskapet. - 0348-6133 .- 2002-3871. ; N.F. 22, s. 80-96
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 11. |
- Nordell, Erik, et al.
(författare)
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Post digestion of biogas production residues at mid-range mesophilic temperature
- 2011
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Ingår i: International IWA-Symposium on Anaerobic Digestion of Solid Waste and Energy Crops 2011 Vienna, Austria, August 28th – September 1st. - : IWA Publishing.
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Konferensbidrag (refereegranskat)abstract
- A common way to store digestate from anaerobic digesters is in open air lagoons. The aim of this study was to investigate whether cooling of digestate before transfer to the storage prevents methane production. Furthermore, if methanogenesis is not prevented, to determine the potential maximum methane slip from an open air lagoon, supplied with heat exchanged digestate from a mesophilic co-digestion plant such as Linköping biogas plant. Results indicate that methane production is not terminated by cooling and that a high methane production can occur in open air lagoons if the conditions are advantageous. Furthermore, the results suggest that it can be worthwhile, from both an economical and an environmental point, to replace open air lagoons with closed post-digesting units. At 25 oC, the methane slip from an open air lagoon could reach as high as 2.6% of the total methane production of a biogas plant, even when the volume of the open air lagoon is only one third of the digesters volume. The combination of low additional cost of production, with significant decrease in release of green house gases to the atmosphere, makes the implementation of post-digestion units at larger biogas plants attractive.
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| 12. |
- Nordell, Erik, et al.
(författare)
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Post-treatment of dewatered digested sewage sludge by thermophilic high-solid digestion for pasteurization with positive energy output
- 2021
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 119, s. 11-21
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the possibility to use thermophilic anaerobic high solid digestion of dewatered digested sewage sludge (DDS) at a wastewater treatment plant (WWTP) as a measure to increase total methane yield, achieve pasteurization and reduce risk for methane emissions during storage of the digestate. A pilot-scale plug-flow reactor was used to mimic thermophilic post-treatment of DDS from a WWTP in Linköping, Sweden. Process operation was evaluated with respect to biogas process performance, using both chemical and microbiological parameters. Initially, the process showed disturbance, with low methane yields and high volatile fatty acid (VFA) accumulation. However, after initiation of digestate recirculation performance improved and the specific methane production reached 46 mL CH4/g VS. Plug flow conditions were assessed with lithium chloride and the hydraulic retention time (HRT) was determined to be 19–29 days, sufficient to reach successful pasteurization. Degradation rate of raw protein was high and resulted in ammonia-nitrogen levels of up to 2.0 g/L and a 30% lower protein content in the digestate as compared to DDS. Microbial analysis suggested a shift in the methane producing pathway, with dominance of syntrophic acetate oxidation and the candidate methanogen family WSA2 by the end of the experiment. Energy balance calculations based on annual DDS production of 10 000 ton/year showed that introduction of high-solid digestion as a post-treatment and pasteurization method would result in a positive energy output of 340 MWh/year. Post-digestion of DDS also decreased residual methane potential (RMP) by>96% compared with fresh DDS.
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| 13. |
- Nordell, Erik, et al.
(författare)
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The Diverse Response on Degradation Rate of Different Substrates Upon Addition of Zeolites
- 2010
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Ingår i: 3rd International Symposium on Energy from Biomass and Waste. Venice, Italy, Nov 8-11, 2010..
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Konferensbidrag (refereegranskat)abstract
- SUMMARY: This study evaluates the effects of addition of the natural zeolite clinoptilolite to anaerobic digesters treating different materials in both batch and continuous lab-scale setups. Zeolite addition to a CSTR with high ammonium levels (5 g NH4+/L) was performed with the purpose to investigate the effects on the amount of free ammonium. We also investigated non ammonium related effects of zeolite addition in dosage between 0-10 g zeolite/L to distinguish any beneficial properties effects. The concentration that was found to be most suitable for slaughterhouse waste (5 g zeolite/L) was subsequently tested and compared in batch conditions for slaughterhouse waste, thin stillage from ethanol production and sewage sludge. Batch experiments with slaughterhouse waste with 5 g zeolite/L significantly decreased the lag phase and in effect increased the degradation rate; no similar effect could be identified for the other substrates tested. We suggest that the increase of degradation rate when adding zeolites in low concentrations is unrelated to the ammonium reduction caused by the zeolite.
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| 15. |
- Nordell, Erik, et al.
(författare)
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Thermal post-treatment of digestate in order to increase biogas production with simultaneous pasteurization
- 2022
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Ingår i: Journal of Biotechnology. - : Elsevier. - 0168-1656 .- 1873-4863. ; :344, s. 32-39
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Tidskriftsartikel (refereegranskat)abstract
- Biogas production by anaerobic digestion (AD) of organic wastes is important for the transition to fossil free fuelsin both the transport sector, industries and shipping. The aim of this study was to target the residual organicmatter in the outgoing residue from the AD process, so called digestate, with different thermal treatmentmethods in order to improve digestate degradability and biogas potential upon post-digestion. The thermaltreatment was performed at 55 ◦C in 24 h, 70 ◦C in 1 h and by thermal hydrolysis process (THP; 165 ◦C, 8 bar in0.33 h), and were carefully selected to offer a simultaneous possibility for pasteurization of the digestate accordingto the regulations in Sweden. Digestates from ten full-scale biogas plants were collected, with differentsubstrate profiles including wastewater treatment plant (WWTP), food waste digestion, agriculture digestion andmanure digestion. The results showed that all thermal treatment methods caused increased dissolved organiccarbon concentration (DOC). Four of the thermal treated digestates with the highest increase in DOC weresubsequently tested for the bio-methane potential. Thermal treatments at 70 ◦C and THP, respectively, resulted inthe highest increase in bio-methane potentials, with an increase of 15–39% for one WWTP, 38 – 40% fordigestate from an agriculture digestion plant and 20 – 22% for digestate from a co-digestion plant treating foodwaste. Interestingly, the bio-methane potential from digestate treated with the energy-intense THP method, didnot show any significant difference compared to thermal treatment at 70 ◦C for 1 h. The outcomes of this studysuggest that placing a pasteurization unit between a main digester and a post digester, when applying two-stepdigestion allows for a combined pasteurization and increased biogas production.
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| 16. |
- Nordell, Erik, et al.
(författare)
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Zeolites relieves inhibitory stress from high concentrations of long chain fatty acids
- 2013
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 33:12, s. 2659-2663
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Tidskriftsartikel (refereegranskat)abstract
- Protein and fat rich slaughterhouse waste is a very attractive waste stream for the production of biogas because of the high biochemical methane potential of the substrate. The material has however some drawbacks as the sole material for biogas production due to the production of several process disturbing metabolites such as ammonia, sulfides and long chain fatty acids. We can in this work present results that show that zeolites have the potential to relieve inhibitory stress from the presence of long chain fatty acids. Moreover, the results strongly indicate that it is mainly acetic acid consumers that are most negatively affected by long chain fatty acids and that the mechanism of stress relief is an adsorption of long chain fatty acids to the zeolites. In addition to this, it is shown that the effect is immediate and that only a small amount of zeolites is necessary to cancel the inhibitory effect of long chain fatty acids.
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| 17. |
- Nordell, Pär, 1978, et al.
(författare)
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Supercoil-Accelerated DNA Threading Intercalation
- 2009
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Ingår i: Biochemistry. - 1520-4995 .- 0006-2960. ; 48:7, s. 1442-1444
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Tidskriftsartikel (refereegranskat)abstract
- The effect of DNA supercoiling on a sterically very demanding threading intercalation process is here investigated. We find that the threading rate of a dimeric ruthenium complex into a negatively supercoiled plasmid at low binding density is two orders of magnitude higher than into the cleaved linear form. Further saturation is however, in comparison to the linear DNA, kinetically hampered. We also observe that threading kinetics correlates with the inhibition of luciferase expression from the plasmid construct. The results show how the target torsional strain can function as control of DNA threading kinetics and gene expression efficiency.
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