Experiences with the substrate processing and biogas production from packaged food on such an industrial scale plant in England

To treat such type of organic waste it has to be considered that the amount of non-biodegradable contaminants for example plastic, glass, metals in the organic waste is usually very high. The contaminants have to be separated very early in the process before the biodegradable part of the organic fraction is charged into the digester. The separation of contaminants is important to avoid problems in the process and to assure that the digestate after anaerobic digestion of the organic material is of highest quality. For hygienic reasons this front end processing of the organic waste should be completely automated and in a completely closed system after waste delivery to the reception area of the plant. The front end processing must separate the contaminants efficiently and loss of biodegradable organics must be reduced to the lowest possible level. The quality of separated contaminants should make possible either thermal utilization or material recycling.

Further important process aspects have to be considered by treatment of such type of organic waste as sanitation and production of high quality fertilizer that can be utilized directly after anaerobic digestion without further treatment steps. For economic reasons it is very important to assure the process works very efficient with low energy consumption and with highest possible biogas yield. Industrial organic waste is a very suitable material for biogas production because of its high specific biogas yield. The front end processing of organic waste is the most important part of a biogas plant and must assure that the biogas plant can treat very heterogeneous organic waste fractions also with high a level of contamination of non-biodegradable material.

This article describes a new development of a front end processing technology that is realized in an industrial scale biogas plant in UK. The main targets of the development was a continuous operation, reduction of electricity consumption, increase of biogas production and more efficient separation of biodegradable from foreign nonbiodegradable material. The new front end processing technology is meanwhile since several months in operation in a new biogas plant installed at Cannock, UK. This plant receives different types of organic waste mainly packaged food and has a processing capacity of 120.000 t/y and was already started up in spring 2011. The experiences from the first year of operation confirms that the front end processing is capable to treat organic waste with high amounts of contaminants especially plastics. Contaminants are removed efficiently and there is no need for further digestate treatment after the dewatering process and the digestate can be used directly as fertilizer in agriculture. This should be the preferred and is the simplest way of digestate utilization. As the impact reactor works very selective plastic bags are opened but not crushed to small pieces while the biodegradable waste fraction is disintegrated very efficient. That resulted in a higher biogas production. Continuous operation of the front end processing system and efficient processing of organic waste at very short retention time in the impact reactor results in very low electricity consumption compared to other front end processing technologies. The separated light fraction has very low amounts of biodegradable organic material and that reduces costs for
disposal but also opens further opportunities like plastic recycling to improve the plant economics.

 

 

Hochlauf der Wasserstoffwirtschaft
© Lexxion Verlagsgesellschaft mbH (8/2024)
Überblick über und Diskussion der Maßnahmen zum beschleunigten Ausbau der Wasserstoffinfrastruktur in Deutschland

Die innerstaatliche Umsetzung des Pariser Klimaschutzübereinkommens - ein Rechtsvergleich
© Lexxion Verlagsgesellschaft mbH (8/2024)
Like all public international law treaties, the Paris Climate Accords rely on national law for their implementation. The success of the agreement therefore depends, to a large extent, on the stepstaken or not taken by national governments and legislators as well as on the instruments and mechanisms chosen for this task. Against this background, the present article compares different approaches to the implementation of the Paris Agreement, using court decisions as a means to assess their (legal) effectiveness.

Klimaschutzrecht und Erzeugung erneuerbarer Energien in der Schweiz
© Lexxion Verlagsgesellschaft mbH (8/2024)
Verschachtelte Gesetzgebung unter politischer Ungewissheit

 

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