Alternative Fuel : Dried food waste as alternative fuel for cement industry

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In Greece household fermentable waste (HFW) is usually disposed as part of mixed waste in landfills, the least sustainable option. The HORIZON 2020 project Waste4think developed an alternative approach to deal with the masses of food waste produced each day. Within this project source separated HFW is taken to a drying and shredding plant that is located in the municipality where it ist turned into a high quality biomass product called FORBI. Researchers around Konstantina Papadopoulou from the School of Chemical Engineering at the National Technical University of Athens looked at the use of FORBI as an alternative to coal fuel for the cement industry using life cycle assessment (LCA) and life cycle costing (LCC) tools.

"As far as the environmental performance of the alternative scenarios is concerned, it has been proved that the alternative scenario performs significantly better in most of the impact categories selected (climate change, ozone depletion, etc.). It is impressive that in terms of climate change, which is probably of the highest importance for policy makers, the decrease in the environmental footprint reaches 100%", the scientists write. "Furthermore, considering the economic performance of the scenarios, an important parameter is the selling price of FORBI. This study adopted a straightforward methodology for the estimation of this price. Specifically, the potential economic benefit for the cement plant from the avoidance of buying coal was used as the basis for pricing FORBI. In this best case of Scenario 1 the decrease in the HFW management costs rises from 12% decrease in HFW management costs in worst case of Scenario 1) to 35% (corresponding decrease in best case of Scenario 1)."

But one point, according to Papadopoulou and Co, needs improving: The optimisation of the drying/shredding process in order to reduce its energy intensity and environmental loadings.

The study was published in the Special Issue for the ISWA Conference of Waste Management & Research and is publicly available till the end of October.