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Your search keyword '"nutrient recycling"' showing total 2 results
2 results on '"nutrient recycling"'

1. Assessment of biomethane production from maritime common reed.

Author

Risén, Emma, Gregeby, Erik, Tatarchenko, Olena, Blidberg, Eva, Malmström, Maria E., Welander, Ulrika, and Gröndahl, Fredrik

Subjects
*METHANE, *EUTROPHICATION, *BIOMASS, *PHRAGMITES australis, *GREENHOUSE gases
Abstract

Abstract: Several ongoing projects are harvesting maritime biomass from the Baltic Sea for eutrophication mitigation and utilisation of the recovered biomass. Some of this biomass comprises common reed (Phragmites australis), one of the most widespread vascular plants on Earth. Reed utilisation from eutrophied coastal areas needs to be evaluated. Therefore, a system analysis was performed of reed harvesting for biofuel and biofertiliser production. The specific objectives of the analysis were to: investigate the methane yield associated with anaerobic co-digestion of reed; make a primary energy assessment of the system; quantify Greenhouse Gas (GHG) savings when a fossil reference system is replaced; and estimate the nutrient recycling potential of the system. The results from energy and GHG calculations are highly dependent on conditions such as system boundaries, system design, allocation methods and selected indicators. Therefore a pilot project taking place in Kalmar County, Sweden, was used as a case study system. Laboratory experiments using continuously stirred tank reactor digesters indicated an increased methane yield of about 220 m3 CH4/t volatile solids from co-digestion of reed. The energy balance for the case study system was positive, with energy requirements amounting to about 40% of the energy content in the biomethane produced and with the non-renewable energy input comprising about 50% of the total energy requirements of the system. The net energy value proved to be equivalent to about 40 L of petrol/t reed wet weight. The potential to save GHG emissions compared with a fossil reference system was considerable (about 80%). Furthermore an estimated 60% of the nitrogen and almost all the phosphorus in the biomass could be re-circulated to arable land as biofertiliser. Considering the combined benefits from all factors investigated in this study, harvesting of common reed from coastal zones has the potential to be beneficial, assuming an appropriate system design, and is worthy of further investigations regarding other sustainability aspects. [Copyright &y& Elsevier]

Published
2013
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2. Carbon footprint and energy use of recycled fertilizers in arable farming

Author

Hanna Tuomisto, Venla Vilhelmiina Kyttä, Juha Helenius, Department of Agricultural Sciences, Future Sustainable Food Systems, Ruralia Institute, Mikkeli, Helsinki Institute of Sustainability Science (HELSUS), Juha Helenius / Principal Investigator, and Plant Production Sciences

Subjects
Biogas digestate, 020209 energy, Strategy and Management, Allocation, Biomass, 02 engineering and technology, 7. Clean energy, Industrial and Manufacturing Engineering, 4111 Agronomy, 12. Responsible consumption, Life cycle assessment, Biogas, ANAEROBIC-DIGESTION, BONE MEAL, BENEFITS, 0202 electrical engineering, electronic engineering, information engineering, Climate change, Ammonium sulfate, Life-cycle assessment, 1172 Environmental sciences, EMISSIONS, CEREALS, 0505 law, General Environmental Science, 2. Zero hunger, Waste management, Nutrient recycling, Renewable Energy, Sustainability and the Environment, business.industry, LCA, 05 social sciences, 6. Clean water, NITROGEN, Meat and bone meal, LIFE-CYCLE ASSESSMENT, 13. Climate action, Agriculture, Greenhouse gas, Digestate, 050501 criminology, Carbon footprint, Food systems, Environmental science, business, Agroecology
Abstract

The globally growing demand to produce more food with fewer inputs, less energy, and lower greenhouse gas (GHG) emissions challenges current agricultural practices. Recycled fertilizers made of various side streams and types of biomass have been developed mainly to improve nutrient recycling in food systems. However, the knowledge of the impacts of different recycled fertilizers on GHG emissions and energy use is lacking. There is also a need for developing environmental assessment methods for quantifying the impacts of recycling processes, particularly in terms of choosing reasonable methods for co-product allocation. The aims of this study were to address the above mentioned research gaps by i) assessing energy use and GHG emissions of various recycled fertilizers, ii) comparing the recycled fertilizers with mineral fertilizers, and iii) comparing the impacts of using different co-product allocation methods for the recycled fertilizers. Attributional Life Cycle Assessment (LCA) was used for estimating energy use and GHG emissions of recycled fertilizers, including ammonium sulfate, biogas digestate, and meat and bone meal, using kg of nitrogen in the fertilizers as a functional unit. In addition, the energy use and GHG emissions of oat production when using the recycled and mineral fertilizers were quantified. The data were obtained from field experiments, LCA databases, published literature, and fertilizer companies. The life-cycle energy consumption and GHG emissions of recycled fertilizers were found to be lower than that of mineral fertilizer, but also differences between recycled fertilizer products were notable. The biggest differences between fertilizers occurred in manufacturing and transportation. However, this conclusion is highly sensitive to several decisions, such as data sources and LCA methods used. Handling the raw materials of recycled fertilizers as by-products instead of residues adds burdens from primary production to fertilizers. Also handling the materials as waste increases the impacts due to burdens from the recycling process. Since the raw materials of fertilizers have only little economic value, applying economic allocation results to significantly lower impacts than mass allocation. Consequential LCA studies would be needed to improve the understanding of the wider impacts of recycled fertilizers, e.g. considering the benefits of avoided waste management processes. (C) 2020 Elsevier Ltd. All rights reserved.

Published
2021

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