MIRAI 2.0 R&I Week 2023 

Utilization of Digestate for Sustainable Cycle Systems of Carbon, Nitrogen and Phosphorus

Iryna Ablieieva
Biogas solutions, anaerobic digestate, biofertilizer, nutrient cycles, sustainable development
Short workshop abstract:
The digestate is a by-product of the anaerobic digestation process that has been successfully used as biofertilizer and a valuable source of major plant nutrients, which are essential for plant growth, soil fertility and therefore sustainable crop production. Strategies that improve the availability of nutrients in soils, in particular, C, N, P can help meet targets for nutrition security, soil conservation, and reinforce a multidisciplinary approach. A well-designed waste management strategy along with the concept of circular economy presents a restorative and regenerative option for sustainable digestate management in Hokkaido and Linköping. System analysis of biogas plants in the region of Hokkaido shows the potential for digestate application in nutrient recycling. Existing problems on biogas plants can be solved through such steps: biogas plants should be operated without feed-in tariff; new business should be launched, like Shikaoi town; re-recognition of value of digestate as fertilizer is needed.
In the case of Japan, due to the fact that the land is small, and the mixture of urban and rural areas is progressing, there is a lot of composting and purification treatment that is not common in Europe and Sweden. This strategy will be compared with the Nordic model for biogas production. The results of carbon accumulation in the soil after long-term digestate application will be presented. One of the most perspective substrate and option for biogas production is digestate utilization for algae cultivation. Therefore, innovative technology related to diffusion-driven nutrient extraction systems with no energy will be discussed.