IFAT 2008: Production of Gas from Waste

The raw material for this fermentation process is organic waste from a range of sources. The technology and services associated with biogas are a new focus at IFAT 2008. From 5 to 9 May 2008, this long-standing environmental trade fair held in Munich brings together around 80 systems manufacturers, full-service suppliers, manufacturers and wholesalers of individual components as well as service specialists in the area of biogas.

There has been much discussion in agricultural circles in recent months about the downside of generating energy from biomass. When land is given over to producing maize and grain for generating heat and energy, doesn´t this have a negative impact on food production? Will more fertilisers and pesticides be needed if we grow more renewable raw materials? And if we import these raw materials instead, aren´t we just contributing to further erosion of endangered tropical eco-systems? There is, however, one form of biomass that is not subject to these criticisms, and still produces energy-rich, climate-neutral gas through a process of fermentation - bio-waste.

Ordinary household waste - organic waste and food remains that people put in a bin designated for this purpose - is ideal for use in fermentation processes to produce biogas. At the moment in Germany a large part of the 8.4 million tonnes (2006) of organic waste separately collected from households is still being composed, but the debate on climate change, high energy prices, government funding through the Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz - EEG) and advances in biogas technology are raising interest in fermenting this waste.

The decision to compost or ferment is dependent primarily on the type of initial substrate. If the material is easily broken down, liquid or paste-like, fermentation is recommended. Wood and therefore lignin-rich, difficult-to-break-down materials, however, are more suited to composting. While with pure composting, only the end product - the finished compost - is utilised, with fermentation, both the end product and also the energy generated are exploited, because when generating biogas it´s also possible to use the residues from the process as fertilisers. Fermentation processes are generally more expensive than composting systems, so investment is only sensible when the revenue from selling the heat and power compensates for the additional expenses.

Biogas can also be generated from unsorted general household waste. The key term here is mechanical-biological treatment or MBT. This technology supports the European-wide environmental goal of reducing landfill volumes in favour of a modern, ecologically oriented waste economy. In Germany, since 1 June 2005, no more untreated waste can be dumped in landfills. MBT systems sorts the waste, initially mechanically via sifting and segregation processes, into different streams according to material type.

The biological portion is either composted or fermented to biogas. In Germany, the forerunner in MBT technology, there are currently 48 MBT systems, says the Arbeitsgemeinschaft Stoffspezifische Abfallbehandlung (ASA, Ennigerloh), eight of them producing biogas. As such the market is more or less saturated in this country. Not so elsewhere in Europe and in Asia. At present, for example, the Greater Manchester Waste Disposal Authority in the UK is currently planning the construction of five new MBT systems.

In addition to end consumers and local authorities, industry and trade also produces waste that can be utilised for energy generation. For example, a new biogas plant in the Höchst Industrial Park in Frankfurt am Main which goes into production this summer will be consuming 310,000 tonnes of industrial sludge per year, supplemented by up to 90,000 tonnes of foodstuffs, waste from abattoirs, used oils and fats, and residues from the pharmaceuticals industry. This 15-million euro project will be turning it into around four megawatts of electricity and two megawatts of heat, and feeding this into the supply grids for the industrial park. Many of the 90 or so chemicals, pharmaceuticals and biotechnology companies located here thus have an environmentally friendly disposal solution for their organic waste. The operators of this unique system are also confident that it will contribute to stabilising energy prices in the industrial park.

TheBioenergySite News Desk

Sign up for our
regular news updates

Latest Bioenergy Industry News

•   Cooperation Agreements for Brazil and Canada
•   NTR in Algae Joint Venture
•   Symposium on Future of Biodiesel
•   Consumers Energy Wind Farm Plan
•   Commissioner at International Conference on Biofuels
•   Daewoo Logistics Biofuel Project for Madagascar
•   Biodiesel from Urban Waste
•   Wind Farm Plan for Brazil
•   Egypt Wants Brazilian know-how in Biofuels
•   Inland Empire Oilseeds Starts Biodiesel Production