Elements of post-fermentation slurry vermicomposting technology and its impact on fertilizer value

The intensification of biogas production leads to increased production of digestate -a by product of anaerobic digestion -whose management poses a significant environmental and economic challenge.In the context of the transition toward a circular economy, there is a growing need to develop technologies that enable the transformation of this material into a product with greater utility.One promising solution is vermicomposting, which enables biological stabilization of digestate and improves its fertilizing properties.In the conducted studies, Dendrobaena veneta earthworms were used in various substrate compositions containing digestate, enabling both an assessment of the process's effectiveness and an evaluation of changes in the digestate's physicochemical properties and the dynamics of the earthworm population's development.The resulting vermicompost was subjected to agronomic analysis by evaluating its effect on the germination and growth of common corn (Zea mays L.) seedlings as an indicator plant.The results indicate that appropriately selected proportions of substrates with digestate intensify organic matter transformation within them and increase the fertilizing value of the final product.From an economic perspective, this technology can help reduce digestate management costs, increase its market value, and improve the environmental efficiency of biogas plant operations, aligning with the principles of the circular economy.