HOUSEHOLD AND GARDEN WASTE IN THE CITY OF HAMBURG –THEIR ENERGETIC POTENTIAL AND INTEGRATION POSSIBILITIES INTO A BIOREFINERY APPROACH

摘要

This paper focus on the inventory of the private household and garden wastes as well as street leaf in the district Bergedorf and their suitability for an energetic use in biogas plants. The inventory covers quantity and quality of the wastes by 1) evaluating data provided by the City Cleaning Company, 2) Interviewing people delivering waste to a buyback centre, 3) distributing questionnaires to households and doing waste bin sorting analyses in two selected roads. The organic waste led to an approximate amount of 90 kilograms per inhabitant an year. This amount can be divided into 4 fractions: kitchen waste, herbaceous waste, leaf, lignocellulosic waste. The chemical composition of this fractions varies and is important for the conversion processes into energy. The values for actual electricity consumption and the theoretical energetic potential calculated show that energetic utilization of organic waste can not solve the energy provision problem of the future, but it can be a very important part in the energy mix. All the considered wastes are more or less wet, what makes them more feasible for anaerobic digestion compared to incineration. To come to a maximum energetic efficiency into the future, new collection systems have to be introduced to allow fraction-adapted treatments. E.g. lignocellulosic waste fractions are not suitable for biogas generation due to their chemical structure, but can made ready by a steam-refining pre-treatment.