Four main material flows were studied for the Urban Circularity Assessment in the Mikkeli city for year 2019. These main categories of materials were biomass, metal ores, non-metallic minerals, and fossil energy materials/carriers. In addition to collecting data on the extraction, import and export of these materials, the amounts of different waste materials and their treatment were studied.

The main waste materials that the data collection included were chemical and medical wastes, recyclable wastes, equipment, animal and vegetal wastes, mixed ordinary wastes, mineral and solidified wastes, and metallic wastes. The waste was sorted according to the different waste treatment; landfill disposal, releasing into water bodies, incineration disposal and incineration for energy use, and recovery of materials for recycling uses.