Valorising spent coffee grounds : An assessment of possibilities in the municipality of Stockholm

Sammanfattning: Circular economy is an economic model that is gaining more and more attention, themodel aims to close production chains by recirculate waste into the system as newraw material. Spent coffee grounds are a waste that has great potential to becomenew products since the spent coffee ground contains many valuable substances suchas polysaccharides, polyphenols, and lipids. Swedes are the sixth largest coffeeconsumers per capita in the world, which means that large quantities of coffeegrounds are produced in the country. Therefore, the purpose of this report is toinvestigate possible ways to valorize spent coffee grounds in the municipality ofStockholm, as an alternative to the treatment processes that exist today. Toinvestigate this, the main methods have been a literature review, a field study andeconomic analyses based on existing data. The results show that from 5 large coffee-shop chains in the municipality of Stockholm, approximately 138,477 kg of coffeegrounds can be collected each year. Furthermore, it shows that five differentmethods for extracting polysaccharides, polyphenols, biochar, oil, and protein fromspent coffee grounds have been effective and that these substances and products canbe used in, for example, the food industry, in cosmetics, as plastics and asadsorbents. The economic assessment shows that biochar, polyphenols, and oil arethe compounds and products that are economically profitable to extract, and theycan give a maximum profit of SEK 482.28/kg of spent coffee grounds. The resultsare consistent with previous research on the subject, but there are someuncertainties in the exact figures as there is a lack of economic analyses for spentcoffee grounds in the previous research. However, the results show great potentialfor spent coffee grounds in a circular economy, but further research is required toensure the economic gain. In addition, analyses need to be done on the ecologicalsustainability and more studies need to be done on coffee grounds in Sweden tovalidate the results.