Activated carbon (AC) is one of the best adsorbents for removing trace contaminants from air, soil and water due to its adsorption properties. It is produced from carbon-rich materials, mainly fossil raw materials. However, the price of hard coals has increased significantly in recent years due to the COVID-19 pandemic and the war in Ukraine. The existing eastern markets became blocked for carbon-raw-material sourcing. It is therefore important to find alternative materials or plant-based products. This study investigated the possibility of manufacturing activated carbon from waste biomass such as sugar beet fibers (SBSF), mixed vegetable processing waste (mainly corn) (MVW) and cherry stones (ChS). The raw material was subjected to pyrolysis, milling, granulation, carbonisation and activation at different times and temperatures. However, of the biomass materials tested, only SBSF in the form of marc can be processed into valuable activated carbon in further production steps. MVW and ChS as carbon substrates showed, in addition to high moisture and ash, low efficiency in decolourising molasses and methylene blue MB and also had a lower specific surface area.