Responding climate change and ensuring high-quality water resources are two of the greatest challenges of our time. Most of greenhouse gas (GHG) emissions originate from energy production and use and, in addition to industry, other important sources are agriculture and waste management. In Europe, around a third of GHG emissions and more than half of eutrophication are related to food chains. Policy goals and measures are set to respond to these environmental challenges and responsible consumers increasingly use their voice on the market. Enterprises face these challenges through new rules and incentives, which also offer new options. One such option is utilisation of untapped waste and by-product biomasses of food chains to produce renewable energy and recycling fertilisers. Or is it? How could it be technically feasible and profitable, support regional economy and meet the environmental expectations? And in what kind of activity would the enterprises like to participate? These questions were answered by the present study through considering alternative ways of arranging such biorefinery activity in the context of real regions which differ from each others by biomasses, distances and markets. Despite many unanswered questions, pioneering enterprises have already emerged. By studying them and future visions of other practitioners we got more material for the answers. Our target region was South Savo, and for biomasses and their locations it was compared with Satakunta. This selection was based on our attempt to provide solutions with national relevance. The detailed goals and solutions were identified in an interaction among enterprise actors from different areas of biorefinery activity and researchers representing different disciplines. Decision analytical approach to problem solving with multiple goals was used and scenario techniques were applied. Biomass potentials were assessed based on primary data collected from actors and utilising available data bases and GIS techniques. Transportation distances along roads were estimated by applying linear optimisation. For assessing energy, nutrient and product outputs a model for mass, energy and nutrient balances was created. Based on these results and on identified business options, contrasting biorefinery scenarios were constructed to reflect alternative optimisation goals as jointly selected with the actors. Also the elements of biorefinery activity and their contrasting features in the alternative scenarios were identified together with the actors. An economic evaluation including input-output analysis of the regional impacts, and a life cycle assessment were performed. The various criteria of the overall sustainability of biorefinery activity were weighed by the actors. The dependence of the results on various assumptions and choices was studied through sensitivity analyses. Waste and by-product biomasses of food chains turned out to have a significant potential in mitigation of climate change and water eutrophication. The theoretical potential through utilisation of all the biomass of the studied regions represents 3 to 5% of electricity and 14 to 45% of heat, or 10% of traffic fuels, used in the regions. The nutrient content of the processed biomass corresponds to the total phosphorus or more, and half or three fourths of the nitrogen harvested in the crop yields in the regions. In practice only part of the biomasses can be utilised, however, and the share depends on many choices. Most important seem to be agricultural biomasses, especially farmyard manure, and depending on the region also by-products of food processing. The full benefits for climate and water protection require biorefineries which utilise both nutrients and energy. Therefore anaerobic digestion is a key process. Benefits for climate are highest, if replacement of non-renewable energy is maximised. Eutrophication is best hindered through utilisation of the nutrient contents of all the biomasses and adapting the application on fields according to the nutrients in the harvested biomass and in field soil, for replacing mineral fertilisers. Combustion of dry biomasses increases energy output with minor losses in the nutrient output. Composting can be used for enhancing sequestration of carbon from biomass in soil. Profitability of the activity is most affected by energy output and utilisation degree of heat, as well as by the opportunity to charge for waste management services. Biorefinery activity offers new business opportunities also in logistic and expert services, technology and construction, emission trade and through commercialisation of corporate social responsibility. Extensive initiation of business activity requires, however, new thinking and action patterns and further societal interventions. In South Savo, immediate potential is offered by large- scale joined processing of all the waste and by-product biomass types in one or two of the biggest population centres. Also small or middle-sized processing plants close to heat demand have potential if waste management income can be generated for part of the processed biomass.