Vermicomposting of gastro waste does not produce high-quality fertilizer

Abstract The production of gastro-waste is an common issue part in all societies, but its disposal, including recycling, is not yet satisfactorily resolved. This research explored whether it is possible to manage this waste directly at its source without special equipment and high initial investments. The study was conducted on a university campus, where a simple three-tier vermicomposter was assembled to process cafeteria leftovers. The vermicomposting process and the quality of the resulting vermicompost were monitored, and a container experiment with a 20% vermicompost concentration was set up.The vermicompost was evaluated from a food perspective and found to attract insects, emite odors, and heat up to over 50 °C within the vermicomposter. The resulting vermicompost parameters were not as favorable for agricultural use as those from thermally untreated waste. The most problematic parameter was the electrical conductivity, which likely caused the early termination of the container experiment due to plant death in the vermicompost-applied variant. Additionally, high concentrations of microorganisms such as Salmonella and E. Coli were found in the vermicompost. In conclusion, using the vermicomposting process for heat-treated food residues is not suitable for regular institutions. Graphical abstract