Urban biodegradable waste amount and composition

This report is part of the project "Systems Analysis of Organic Waste", funded by the Swedish Waste Research Council (AFR). In the project a simulation model for analysing different scenarios of organic waste handling systems was constructed, ORWARE (ORganic WAste REsearch model). The results from simulations with ORWARE represent environmental impact and use of resources of the systems studied, i.e. energy and plant nutrients. The environmental impact depends on the contamination level of the waste that is treated. Also the distribution of the major constituents of the waste, such as carbohydrates, protein and fat, are of great importance for the performance of different biological treatments, compost, anaerobic digestion and sewage treatment, and thus of importance for both environmental impact and use of resources. The objective of this report was to present the indata used in the simulation experiments performed in the Uppsala case study. The amount and composition of the organic waste are presented. The method for gaining knowledge on these objects was mainly literature studies but also personal communications. Organic waste from the following sources are investigated; households, parks and gardens, restaurants and caterers, trade, slaughterhouse (Farmek), other industries (Slotts, Pharmacia, Nordmills and three industrialised bakeries) and finally grease separators. The ORWARE model uses a large number of different waste constituents, both major constituents and contaminants such as heavy metals and organic pollutants. In the simulation experiments all input data had to be specified. Thus, when we could not find the data we had to make assumptions The main result from this survey is that data concerning organic wastes are lacking, not only regarding contaminants but also the distribution of the main constituents and plant nutrients. One aspect that is relatively well investigated is the content of heavy metals in household waste and in waste from parks. More research is needed primarily concerning the content of major constituents, the nutritives, such as carbohydrates, fat, protein etc. This is urgent since performance of the biological treatment processes depend on the composition of the feedstock. The content of organic pollutants in waste is not well investigated. However, better input data concerning these pollutants would not much improve the simulation results, since very little is known about the fate of these substances in the treatment processes.