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World Student Environnement Summit 2010 in Tübingen, Germany Switzerland

Florent Michaud and Wladyslaw Senn

1st Assignment – An original project on sustainability

Biomethanisation of organic food waste July 2010

Introduction Every university is directly involved in a particular local landscape and its community. At the same time, its impact is much larger. Its core missions are indeed to create knowledge and especially to train future citizens of the world. The entailing responsibility towards society is therefore significant. Five years ago, the University of Lausanne initiated a programme to reduce its own direct impact on the environment. By taking concrete measures, and increasing the awareness of the inhabitants of the campus through campaigns under the label Campus Plus, the objective was and still is to improve the environment and the quality of life of these inhabitants, as well as set an example of attitude for all of them to eventually perpetuate after leaving the campus. Different projects were set into course with various impacts on the energy and material consumption, the waste management and recycling, and the mobility. Among them, a new strategy of organic food waste management was successfully implemented. A project on food and food waste… On the shore of the Geneva lake, the University of Lausanne welcomes indeed every year over 11'000 students. With around 2’550 regular employees (full-time equivalent), the total population working and studying on the site reached last year over 13’000 people every week. A part of them remains on the campus for meals at one of the five cafeterias or at the restaurant. Statistics show that over 2’500 meals are served every day in all these catering outlets, with an output in 2009 of 46 tonnes of collected food refuses. Next to the 644 tonnes of the total quantity of waste produced that year on the campus, this number appears small at first sight. However, compared to the other 24 different types of collected waste, the organic food waste represents clearly an important sector in terms of volume; and like any other waste, it has to be disposed of, with the entailing costs and impacts on the environment. …a new disposal method Until recently, the usual disposal method has been to feed pigs with the refuse and to incinerate the coffee grounds. In April 2009, the University of Lausanne decided to value this waste and joined a new pilot project initiated in 2007 by the Lausanne city services. Since 1st April 2009, indeed, all organic food waste and coffee grounds from the University are sent to the farm of Saugealles, above the city of Lausanne, to generate biogas. …chemical processes At the farm, the refuses and the coffee grounds are mixed with the farm’s ordinary organic waste in a digestor. The content is heated at 40°C for 40 days and regularly mixed. During the process, bacteria degrade the organic waste, generating natural gas (60% methane and the rest of CO2, approx.) and substance matter. This matter is then automatically separated into a liquid (manure) and a solid part (digestate – over 2’000 tons a year). Both serve as organic fertilizers for the 1


Florent Michaud, Wladyslaw Senn

July 2010

University of Lausanne, Switzerland

farm’s cultures. As for the gas, it is burned in a specific engine to produce heat (2/3) and electricity (1/3). This provides the farmhouse biogas installation and some surrounding houses with a cheap heating system. The biogas installation also covers the farm’s electricity consumption. The surplus of electricity is then reinjected back on the local grid as green power for 80 surrounding households (of 4 people). …and multiple benefits The benefits of this new disposal option of the biomethanisation are multiple. On one hand, the impacts on the environment are reduced. The organic waste is, indeed, regularly sent to the digesting installation limiting therefore the risk of water pollution from leachate in landfill, for instance. The reduction of other energy supplies and the improvement of the disposal’s environmental footprint contribute also to this positive outcome. In addition, this solution also lowers the costs of waste disposal. After a year, the benefits for the University and the local community are increasing with the raising awareness of the students, the professors and the staff, and the following improvement of the refuse collection. …an example useful to others !

Sources: - Management report 2009 of the University of Lausanne http://www.unil.ch/webdav/site/central/shared/docs/rapport_gestion_09.pdf - Campus Plus campaign website - http://www.unil.ch/campus-plus - Press release on the biomethanisation method on the University’s website (16.4.09) http://www.unil.ch/getactu/actunil:wwwcampusplus_1239861666903/actunil:displayBDef/display - Description of the biogas installation on the City of Lausanne’s website http://www.lausanne.ch/view.asp?docId=29528&domId=64635&Language=E - Picture : http://www.biomasseenergie.ch/Portals/0/2_fr/01_produire/Pdf/IB_Saugealles_04-0507_fr_Druck_Var2.pdf

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