Conference article

Ola Eriksson
University of Gävle, Gävle, Sweden \ Profu AB, Mölndal, Sweden

Mattias Bisaillon
Profu AB, Mölndal, Sweden

Mårten Haraldsson
Profu AB, Mölndal, Sweden

Johan Sundberg
Profu AB, Mölndal, Sweden

Download articlehttp://dx.doi.org/10.3384/ecp110573193

Published in: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden

Linköping Electronic Conference Proceedings 57:25, p. 3193-3200

Published: 2011-11-03

ISBN: 978-91-7393-070-3

ISSN: 1650-3686 (print), 1650-3740 (online)

Management of municipal solid waste is an efficient method to increase resource efficiency as well as to replace fossil fuels with renewable energy sources. This is due to that (1) waste to a large extent is renewable in itself as it contains food waste; paper; wood etc. and (2) when energy and materials are recovered from waste treatment; fossil fuels can be substituted. In this paper some of the results from a comprehensive system study of future waste management in the Gothenburg and Borås regions are presented. Emphasis is put on biological treatment of easy degradable waste such as food waste; by-products from food industry and sewage sludge. The project has been performed in cooperation between Kretsloppskontoret (The municipal office for waste and water management); Göteborg Energi (The energy company in the city of Gothenburg); Renova (The waste management company in the Gothenburg region); Gryaab (A water management company in Gothenburg) and researchers from Profu (Environmental and Energy Consultancy).

Several treatment options for the organic waste have been investigated. Different collection and separation systems for food waste in households have been applied as well as technical improvements of the biogas process as to reduce environmental impact. The biogas replaces fossil fuels and the solid residue is pelletised and either used as fertiliser or as fuel. The method used is computer modelling with the ORWARE (Organic Waste Research) model for the waste management system. Deliverables from the model are environmental impact categories as developed within life cycle assessment and financial costs and revenues.

The results show that central sorting of a mixed fraction into recyclables; combustibles; biowaste and inert is a competitive option compared to source separation. The result is however based on several crucial assumptions. Separation and utilisation of nitrogen in the wet part of the digestion residue is made possible with a number of technologies which decreases environmental impact drastically; however to a substantial cost in some cases. There are several advantages with pelletisation of the solid digestion reside. Use of pellets is beneficial compared to direct spreading as fertiliser. Fuel pellets seem to be the most favourable option; which to a large extent depends on the circumstances in the energy system. Waste management integrated with local energy supply; wastewater treatment; agriculture and vehicle fuel supply is thus a cost efficient method to decrease greenhouse gases and promote the use of waste as a renewable fuel.

[1] Swedish Biogas Association; Biogas – renewable energy from organic waste; 2004; broschure

[2] Energimyndigheten (Swedish Energy Agency); Produktion och användning av biogas år 2009 (Production and use of biogas in 2009); 2010; ES 2010:05; ISSN 1654-7543

[3] AvfallSverige (Swedish Waste Management); Energi från avfall ur ett internationellt perspektiv (Energy from waste in an international perspective); 2008; report 2008:13; ISSN 1103-4092

[4] BFE; Schweizerische Statistik der erneuerbaren Energien –Ausgabe 2005; 2006; Bundesamt für Energie

[5] Energimyndigheten (Swedish Energy Agency); Produktion och användning av biogas 2005 (Production and use of biogas in 2005); 2007; ER 2007:05; ISSN 1403-1892

[6] Eurobserver; Biogas barometer; 2007; SYSTÈMES SOLAIRES le journal des énergies renouvelables No 179

[7] AvfallSverige (Swedish Waste Management); Den svenska biogaspotentialen från inhemska råvaror (The Swedish biogas potential from domestic raw material); 2008; report 2008:02; ISSN 1103-4092

[8] P. Börjesson; M. Berglund; Environmental systems analysis of biogas systems – Part I: Fuel-cycle emissions; Biomass and Bioenergy 30; 2006; pp. 469-485 doi: 10.1016/j.biombioe.2005.11.014.

[9] P. Börjesson; M. Berglund; Environmental systems analysis of biogas systems – Part II: The environmental impact of replacing various reference systems; Biomass and Bioenergy 31; 2007; pp. 326-344 doi: 10.1016/j.biombioe.2007.01.004.

[10] O. Eriksson; Environmental technology assessment of natural gas compared to biogas; Chapter 6 in the book “Natural Gas”; 2010; SCIYO; ISBN 978-953-307-112-1

[11] ISO 14040 International Standard; Environmental management – Life cycle assessment - Principles and framework; International Organisation for Standardization; 2006; Geneva; Switzerland

[12] O. Eriksson; B. Frostell; A. Björklund; G. Assefa; J. -O. Sundqvist; J. Granath; M. Carlsson; A. Baky; L. Thyselius; ORWARE - A simulation tool for waste management; Resources; Conservation & Recycling 36/4; 2002; pp. 287-307. doi: 10.1016/S0921-3449(02)00031-9.

[13] M. Bisaillon; J. Sundberg; M. Haraldsson; O. Eriksson; Systemstudie Avfall i Göteborg (A systems study of the waste management system in Gothenburg) (In Swedish with English summary); project report WR 21; WASTE REFINERY; SP Sveriges Tekniska Forskningsinstitut; 2010; ISSN 1654-4706

[14] P. Aarsrud; M. Bisaillon; H. Hellström; G. Henriksson; E. Jakobsson; T. Jarlsvik; U. Martinsson; C. Jensen; L-G. Johansson; M. Kanerot; D. Ling; Förädling av rötrest från storskaliga biogasanläggningar (Refinement of digestate from large scale biogas plants); (In Swedish); project report WR 20; WASTE REFINERY; SP Sveriges Tekniska Forskningsinstitut; 2010; ISSN 1654-4706

[15] Guinée J.B.(final editor); M. Gorrée; R. Heijungs; G. Huppes; R. Kleijn; L. van Oers; A. Wegener Sleeswijk; S. Suh; H. A. Udo de Haes; H. de Bruij; R. van Duin; M.A.J. Huijbregts; Life Cycle Assessment An operational guide to the ISO standards; Volume 1; 2 en 3; 2001; Centre of Environmental Science Leiden University; Leiden; the Netherlands