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Mohammadi, A., Sandberg, M., Govindarajan, V., Eskandari, S., Dalgaard, T. & Granström, K. (2019). Environmental analysis of producing biochar and energyrecovery from pulp and papermill biosludge. Journal of Industrial Ecology
Open this publication in new window or tab >>Environmental analysis of producing biochar and energyrecovery from pulp and papermill biosludge
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2019 (English)In: Journal of Industrial Ecology, ISSN 1088-1980, E-ISSN 1530-9290Article in journal (Refereed) Epub ahead of print
Abstract [en]

Sweden is one of the largest exporters of pulp and paper products in the world. It follows that huge quantities of sludge rich in carbonaceous organic material and containing heavy metals are generated. This paper carried out a comparative environmental analysis of three different technologies, which can be adopted to produce biochar and recover energy from the biosludge, using landfilling as the reference case. These three thermochemical biosludge management systems—using incineration, pyrolysis, and hydrothermal carbonization (HTC)—were modeled using life cycle assessment (LCA). Heat generated in the incineration process (System A) was considered to be for captive consumption within the kraft pulp mills. It was assumed that the biochars—pyrochar and hydrochar—produced from pyrolysis (System B) and HTC (System C), respectively, were added to the forest soils. The LCA results show that all the alternative systems considerably improve the environmental performance of biosludge management, relative to landfilling. For all systems, there are net reductions in greenhouse gas emissions (–0.89, –1.43, and –1.13 tonnes CO2‐equivalent per tonne dry matter biosludge in Systems A, B, and C, respectively). System B resulted in the lowest potential eutrophication and terrestrial ecotoxicity impacts, whereas System C had the least acidification potential. The results of this analysis show that, from an environmental point of view, biochar soil amendment as an alternative method for handling pulp and paper mill biosludge is preferable to energy recovery. However, an optimal biochar system needs to factor in the social and economic contexts as well.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
acidification, carbonsequestration, forestry, heavymetals, lifecycleassessment, soilfertility
National Category
Environmental Engineering
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-70488 (URN)10.1111/jiec.12838 (DOI)
Note

Funding information: 

This study was financially supported by the European Regional Development fund through the Swedish Agency for Economic and Regional Growth, and the NitroPortugal, H2020‐TWINN‐2015, EU coordination and support action no. 692331.

Available from: 2018-12-14 Created: 2018-12-14 Last updated: 2019-07-12Bibliographically approved
Mohammadi, A., Sandberg, M., Govindarajan, V., Eskandari, S., Dalgaard, T., Joseph, S. & Granström, K. (2019). Environmental performance of end-of-life handling alternatives for paper-and-pulp-mill sludge: Using digestate as a source of energy or for biochar production. Energy, 182, 594-605
Open this publication in new window or tab >>Environmental performance of end-of-life handling alternatives for paper-and-pulp-mill sludge: Using digestate as a source of energy or for biochar production
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2019 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 182, p. 594-605Article in journal (Refereed) Published
Abstract [en]

This paper evaluates the environmental impacts of different alternatives for handling of sludge from paper and pulp mills in Sweden, using Life Cycle Assessment (LCA). The common practice of incineration of biosludge with energy recovery followed by landfilling of ash (System A) was compared with the alternative of digesting sludge anaerobically to produce biogas using different digestate residue management options. The digestate produced from anaerobic digestion (AD) was assumed to be incinerated for heat energy recovery in System B or pyrolyzed for biochar production in System C to be mixed with forest soils. The impact categories considered in this work are climate change, non-renewable energy use, mineral extraction, aquatic ecotoxicity, carcinogens and non-carcinogens. The LCA results demonstrate that the two proposed systems significantly reduce the environmental impacts of biosludge management relative to incineration. An 85% reduction in the aquatic ecotoxicity impact is achieved in System C, due to the reduced mobility of heavy metals in biochar relative to ash. System C, on the whole, outperformed the other two, leading the authors to the recommendation that the use of pulp and paper mill biosludge in biogas-biochar production systems is preferable to merely recovering energy from it.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Anaerobic digestion, Ash, Biochar, Forest soils, Heavy metals
National Category
Environmental Sciences
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-73061 (URN)10.1016/j.energy.2019.06.065 (DOI)000479021700048 ()2-s2.0-85067679125 (Scopus ID)
Projects
FOSBE
Funder
Swedish Agency for Economic and Regional Growth, 20201239
Note

Funding text

The authors declare that there are no conflicts of interest. This study was funded by a grant from the Swedish Agency for Economic and Regional Growth , grant number 20201239 , project name Fosbe, and by a European Union grant through the Interreg Sweden-Norway program , grant number 20200023 , project name IMTRIS. Appendix A

Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-08-29Bibliographically approved
Eskandari, S., Mohammadi, A., Sandberg, M., Eckstein, R. L., Hedberg, K. & Granström, K. (2019). Hydrochar-Amended Substrates for Production of Containerized Pine Tree Seedlings under Different Fertilization Regimes. Agronomy, 9(7), 1-17
Open this publication in new window or tab >>Hydrochar-Amended Substrates for Production of Containerized Pine Tree Seedlings under Different Fertilization Regimes
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2019 (English)In: Agronomy, E-ISSN 2073-4395, Vol. 9, no 7, p. 1-17Article in journal (Refereed) Published
Abstract [en]

There is a growing body of research that recognizes the potentials of biochar application in agricultural production systems. However, little is known about the effects of biochar, especially hydrochar, on production of containerized seedlings under nursery conditions. This study aimed to test the effects of hydrochar application on growth, quality, nutrient and heavy metal contents, and mycorrhizal association of containerized pine seedlings. The hydrochar used in this study was produced through hydrothermal carbonization of paper mill biosludge at 200 °C. Two forms of hydrochar (powder and pellet) were mixed with peat at ratios of 10% and 20% (v/v) under three levels of applied commercial fertilizer (nil, half and full rates). Application of hydrochar had positive or neutral effects on shoot biomass and stem diameter compared with control seedlings (without hydrochar) under tested fertilizer levels. Analysis of the natural logarithmic response ratios (LnRR) of quality index and nutrient and heavy metal uptake revealed that application of 20% (v/v) hydrochar powder or pellet with 50% fertilizer resulted in same quality pine seedlings with similar heavy metal (Cu, Ni, Pb, Zn and Cr) and nutrient (P, K, Ca and Mg) contents as untreated seedlings supplied with 100% fertilizer. Colonization percentage by ectomycorrhizae significantly increased when either forms of hydrochar were applied at a rate of 20% under unfertilized condition. The results of this study implied that application of proper rates of hydrochar from biosludge with adjusted levels of liquid fertilizer may reduce fertilizer requirements in pine nurseries.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
containerized production systems, heavy metals, paper mill sludge, biochar-ash pellet, quality index
National Category
Environmental Sciences
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-73516 (URN)10.3390/agronomy9070350 (DOI)000478660500044 ()
Projects
FOSBE
Available from: 2019-07-07 Created: 2019-07-07 Last updated: 2019-08-29Bibliographically approved
Mohammadi, A., Govindarajan, V., Sandberg, M., Eskandari, S. & Granström, K. (2019). Life cycle assessment of combination of anaerobic digestion andpyrolysis: focusing on different options for biogas use. Advances in Geosciences, 49, 57-66
Open this publication in new window or tab >>Life cycle assessment of combination of anaerobic digestion andpyrolysis: focusing on different options for biogas use
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2019 (English)In: Advances in Geosciences, ISSN 1680-7340, Vol. 49, p. 57-66Article in journal (Refereed) Published
Abstract [en]

The combination of anaerobic digestion and pyrolysistechnologies could be a novel energy-biochar productionsystem to maximize energy and nutrient recovery frompulp and paper mill sludge. Herein, the life-cycle energy productionand emissions reduction of sludge treatment from atypical pulp and paper mill were investigated, in which alternativeuses of biogas for industrial or household application,in different regions of the world, were assessed. Thethree scenarios considered for different end-uses of biogasare: (A) biogas for vehicle fuel in the transportation sectorin Sweden, (B) biogas for heat and electricity in the powersector in Brazil, and (C) biogas for cooking in households inChina. The results of Environmental Life-Cycle Assessment(E-LCA) show that for all these three scenarios, the use ofbiogas and pyrolysis gas contributes most to emissions mitigation,while the dewatering and drying processes carriedout on the sludge, contribute the most to the environmentalemissions. Addition of biochar to the soil, contributes significantlyto a reduction in global warming by sequesteringcarbon in the soil. Compared to scenarios B and C, ScenarioA, in which biogas substitutes gasoline in transportation, andheat from combusted pyrolysis gases is used for district heatingin Sweden, demonstrates the highest environmental performancefor all the evaluated impact categories.

Keywords
Biochar, paper mill sludge, forest soil, LCA
National Category
Natural Sciences
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-74802 (URN)10.5194/adgeo-49-57-2019 (DOI)
Projects
FOSBE
Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-09-19
Frodeson, S., Berghel, J., Ståhl, M., Granström, K., Romlin, C. & Thelander, A. (2019). The Potential for a Pellet Plant to Become a Biorefinery. Processes, 7(4), 1-11, Article ID 233.
Open this publication in new window or tab >>The Potential for a Pellet Plant to Become a Biorefinery
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2019 (English)In: Processes, ISSN 2227-9717, E-ISSN 1099-5862, Vol. 7, no 4, p. 1-11, article id 233Article in journal (Refereed) Published
Abstract [en]

The use of bioenergy has increased globally in recent years, as has the utilization of biomaterials for various new product solutions through various biorefinery concepts. In this study, we introduce the concept of using a mechanical dewatering press in combination with thermal drying in a pellet plant. The purpose of the study is to increase the understanding of the effects a mechanical dewatering press has in a pellet production chain and investigate whether a pellet plant could thus become a biorefinery. The evaluations in this study are based on industrial data and initial tests at the university. The results show that the concept of using the mechanical dewatering press together with a packed moving bed dryer reduces energy use by 50%, compared to using only a packed moving bed dryer. The press water could be used as a raw material for biogas, bioplastics, and biohydrogen. Hence, this study points out the possibilities of a pellet plant increasing the efficiency of the drying step, while moving towards becoming a biorefinery.

Place, publisher, year, edition, pages
Basel: MDPI, 2019
Keywords
Energy efficiency, wood pellet production, drying, biorefinery, bioplastics, mechanical dewatering
National Category
Energy Systems
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-72418 (URN)10.3390/pr7040233 (DOI)000467771400056 ()2-s2.0-85067518721 (Scopus ID)
Note

Funding: Swedish Agency for Economic and Regional Growth through the project FOSBE

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-07-10Bibliographically approved
Sandberg, M., Govindarajan, V. & Granström, K. (2018). Experimental study and analysis of the functional and life-cycle global warming effect of low-dose chemical pre-treatment of effluent from pulp and paper mills. Journal of Cleaner Production, 174, 701-709
Open this publication in new window or tab >>Experimental study and analysis of the functional and life-cycle global warming effect of low-dose chemical pre-treatment of effluent from pulp and paper mills
2018 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 174, p. 701-709Article in journal (Refereed) Published
Abstract [en]

Aeration, as a process in pulp and paper wastewater treatment, uses the greatest share of the energy. Therefore, if the energy efficiency of the treatment has to be improved, the focus must be on aeration. A Ivey finding from the trials conducted for this paper, with effluent from a paper and pulp mill, was that the oxygen transfer coefficient could be doubled and the chemical oxygen demand could be decreased by 25%, if the effluent was pre-treated with 30 mg/I of aluminium coagulant (equivalent to 9.4 tonnes per day of AVR to 20000 cubic metres of effluent). Decrease in oxygen requirement implies decreases in aeration energy use. Pulp and paper mill effluents are not as biodegradable as municipal sewage, and the improvement in oxygen transfer properties of the effluent will have a positive influence over a longer period of time in the biological treatment. If the sludge is digested anaerobically, pre-treatment will also result in doubling the potential for methane generation. A holistic analysis of modifications to processes entails a study of the economic and environmental consequences as well. While the economic aspect is beyond the scope of this paper, only the net global warming as an environmental impact category has been studied, by taking recourse to specific emission coefficients. Of the four dosages of ferric aluminium sulphate considered in this analysis, the net greenhouse gas emissions are the least - 426 kg carbon dioxide equivalent per day when the daily consumption is 9.4 tonnes.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Chemical Sciences
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-66538 (URN)10.1016/j.jclepro.2017.10.214 (DOI)000424727100063 ()
Available from: 2018-03-02 Created: 2018-03-02 Last updated: 2018-06-12Bibliographically approved
From-Aldaron, M., Sandberg, M. & Granström, K. (2018). Low Dosage Chemical Treatment for Improved Oxygenation of Pulp Mill Effluents. Journal of environmental engineering, 144(3), Article ID 06017012.
Open this publication in new window or tab >>Low Dosage Chemical Treatment for Improved Oxygenation of Pulp Mill Effluents
2018 (English)In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 144, no 3, article id 06017012Article in journal (Refereed) Published
Abstract [en]

Most pulp and paper mills use aerobic biological treatment for their effluents. Aeration is the single most energy intensive process of a treatment plant. Surfactants, commonly occurring in pulping wastewaters, have been shown to decrease the oxygen transfer rate. The aim of this study was to decrease the surface activity of surfactants and thereby increase the oxygen transfer rate in pulp mill effluents by the use of chemical pretreatment in very low doses. Trials using 5 g/m(3) ferric iron showed statistically significant improvement on both k(L)a(@20) and surface tension. No sludge was precipitated owing to the very low ferric iron dosage. The novel use of chemical pretreatment, in very low doses, aiming specifically at improving oxygen transfer rate, is a promising concept for reducing the need for aeration in wastewater treatment and thus lower the electricity requirement of the wastewater treatment plant. (c) 2017 American Society of Civil Engineers.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2018
National Category
Energy Systems
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-66051 (URN)10.1061/(ASCE)EE.1943-7870.0001320 (DOI)000422803400005 ()
Available from: 2018-02-01 Created: 2018-02-01 Last updated: 2018-06-25Bibliographically approved
Granström, K. & Sandberg, M. (2017). Characterization of Wood-Dryer Condensate with Assessment of Toxicity to Microorganisms. Journal of environmental engineering, 143(7), Article ID 04017019.
Open this publication in new window or tab >>Characterization of Wood-Dryer Condensate with Assessment of Toxicity to Microorganisms
2017 (English)In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 143, no 7, article id 04017019Article in journal (Refereed) Published
Abstract [en]

Drying of wood causes airborne emissions that can be reduced by recirculating all or part of the drying medium. This favors both emission control and energy efficiency, but results in a condensate that contains significant amounts of organic compounds. Drying operations have been requested by municipal regulatory bodies to clean the condensate before release. The industry has tested biological treatment of condensate from biomass dryers, but maintaining the viability of microorganisms has been a challenge. In this study, the effect of drying gas temperature and the final wood moisture content on the chemical composition and acute toxicity of the condensate was tested. Results showed that whereas the condensate from wood drying was extremely toxic to Vibrio fischeri employed in Microtox assays, the undefined mixed culture present in biosludge from a pulp and paper mill treatment plant were considerably less affected. (C) 2017 American Society of Civil Engineers.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2017
National Category
Energy Systems
Identifiers
urn:nbn:se:kau:diva-65476 (URN)10.1061/(ASCE)EE.1943-7870.0001200 (DOI)000399912100002 ()
Available from: 2017-12-29 Created: 2017-12-29 Last updated: 2018-06-26Bibliographically approved
Hagelqvist, A. & Granström, K. (2016). Co-digestion of manure with grass silage and pulp and paper mill sludge using nutrient additions. Environmental technology, 37(16), 2113-2123
Open this publication in new window or tab >>Co-digestion of manure with grass silage and pulp and paper mill sludge using nutrient additions
2016 (English)In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 37, no 16, p. 2113-2123Article in journal (Refereed) Published
Abstract [en]

The purpose of this research is to evaluate how methane production is affected by the co-digestion of pig and dairy manure with grass silage and pulp and paper mill sludge at mesophilic conditions, and to assess whether methane production is affected by other factors than the now known ones, i.e., nutrient deficiency, low buffering capacity, inadequate dilution, and an insufficient activity and amount of microorganism culture. The season of grass silage and manure collection proved to be an important, previously unreported, factor affecting short-term (20 days) methane production.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2016
Keywords
agricultural waste, anaerobic digestion, biomethane potential, co-digestion
National Category
Energy Engineering
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-26120 (URN)10.1080/09593330.2016.1142000 (DOI)000379772100011 ()
Note

Titel i avhandling:Co-digestion of manure with grass silage and pulp and paper mill sludge using the BMP methodology

Available from: 2013-02-01 Created: 2013-02-01 Last updated: 2017-07-04Bibliographically approved
Granstrom, K. & Javeed, A. (2016). Emissions from sawdust in packed moving bed dryers and subsequent pellet production. Drying Technology, 34(3), 258-266
Open this publication in new window or tab >>Emissions from sawdust in packed moving bed dryers and subsequent pellet production
2016 (English)In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 34, no 3, p. 258-266Article in journal (Refereed) Published
Abstract [en]

This study quantifies emissions of hydrocarbon terpenes from the drying of sawdust in packed moving bed dryers, through the production chain to the finished pellets, and determines the parameters suitable for emission control. The terpene content in softwood sawdust and pellets was analyzed using gas chromatography. The distribution of VOC emissions over the bed was measured with a flame ionization detector. After drying, 30-40% of the initial terpenes remain in the wood, 20-30% remain after grinding, and 10-15% remain after pelleting. Dryer emissions correlate with residence time and final sawdust moisture content. Pellet press emissions correlate with pellet moisture content.

Keywords
Dryer, pellets, sawdust, terpene, VOC
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-40997 (URN)10.1080/07373937.2015.1043555 (DOI)000367606500002 ()
Available from: 2016-03-09 Created: 2016-03-09 Last updated: 2019-07-11Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0380-3533

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