Eva-Maria EkstrandLinköping University | LiU · Department of Thematic Studies (TEMA)
Eva-Maria Ekstrand
Doctor of Philosophy in Environmental Science
About
9
Publications
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Introduction
Eva-Maria Ekstrand currently works at the Department of Thematic Studies (TEMA), Linköping University. Eva-Maria does research in Bioengineering and Biosystems Engineering. Their current project is 'Establishment/optimization of biogas production in the pulp and paper industry.'
Publications
Publications (9)
With the final aim of reducing the energy consumption and increase the methane production at Swedish pulp and paper mills, the methane potential of 62 wastewater effluents from 10 processes at seven pulp and/or paper mills (A–G) was determined in anaerobic batch digestion assays. This mapping is a first step towards an energy efficient and more sus...
Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for the biogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibre sludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation. Two lab-scale reactors (4L) were run...
The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate...
The pulp and paper industry is a large producer of wastewater and sludge, putting high pressure on waste treatment. In addition, more rigorous environmental legislation for pollution control and demands to increase the use of renewable energy have put further pressure on the pulp and paper industry’s waste treatment, where anaerobic digestion (AD)...
The production processes of the pulp and paper industry often run in campaigns, leading to large variations in the composition of wastewaters and waste sludges. During anaerobic digestion (AD) of these wastes, the viscosity or the production of extracellular polymeric substances (EPS) and soluble microbial products (SMP) may be affected, with the r...
Background
This study examines the destiny of macromolecules in different full-scale biogas processes. From previous studies it is clear that the residual organic matter in outgoing digestates can have significant biogas potential, but the factors dictating the size and composition of this residual fraction and how they correlate with the residual...
This study analysed to what extent biogas solutions can improve the nutrient recovery of biobased industrial clusters in different sectors. Three cases representing the agricultural, marine and forest sectors were analysed quantitatively using mass flow analysis. Adding a biogas plant facilitated production expansion and development of collaborativ...
During the process of pulp-and papermaking, large volumes of fibre-rich primary sludge are generated. Anaerobic digestion of primary sludge offers a substantial potential for methane production as an alternative approach to the inefficient energy recoveries by commonly used incineration techniques. However, a systematic study of the importance of u...
Type 2 diabetes originates in an expanding adipose tissue that for unknown reasons becomes insulin resistant. Insulin resistance reflects impairments in insulin signaling, but mechanisms involved are unclear because current research is fragmented. We report a systems-level mechanistic understanding of insulin resistance, using systems wide and inte...
Questions
Questions (2)
We are measuring the rheology of a biological sludge over time. On some occasions, we observe a drastic increase in viscosity (to 100-600 mPa*s), and the fluid behavior of the sludge appears rheopectic. Since this is a rare property of a liquid, we are concerned that maybe the measuring protocol is not suitable. Can this be the case? Or can the liquid be truly rheopectic?
We are using a rotational rheometer ((RheolabQC SN80609650)
equipped with a CC27‐SN19237 measuring system and a C‐ LTD80/QC cell. The measuring protocol is as follows:
- Interval 1: Shear rates are increased linearly from 0-800/s during 800s
- Interval 2: Shear rate is maintained at 800/s for 30s
- Shear rate is decreased linearly from 800-0/s during 800s.
We are using a rotational rheometer ((RheolabQC SN80609650)
equipped with a CC27‐SN19237 measuring system and a C‐ LTD80/QC cell, coupled with Rheoplus software (Anton Paar, Ostfildern, Germany). The sample volume is 17 ml and the temperature 37 degrees. Shear rates are increased linearly from 0-800/s.
For some reason many of my samples give negative shear stresses for the first shear rates (up to about 100-200/s). I'm now trying to model the flow behaviour using R, but I don't know if it makes sense to include the negative shear stresses in the parameter estimation.
