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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, 23(5), 1039-1051
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 1530-9290, Vol. 23, no 5, p. 1039-1051Article in journal (Refereed) Published
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
Hoboken: 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)000488924100004 ()
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: 2019-11-14Bibliographically 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.

Place, publisher, year, edition, pages
Copernicus GmbH, 2019
Keywords
Biochar, paper mill sludge, forest soil, LCA
National Category
Earth and Related Environmental 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: 2020-04-14Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9655-9682

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