Anaerobic Digestion as a Component of Circular Bioeconomy-Case Study Approach

Current and future trends in the world population lead to the continuous growth of municipal waste volumes. Only in the EU-28 approx. 86 million tons of biowaste is produced yearly. On the other hand, the recent energy crisis calls for a fast transition towards more local and renewable energy sources. Most of this stream could be recycled through anaerobic digestion (AD) to produce energy and high-quality fertilizers. This paper presents a balance of dry anaerobic digestion of municipal biowaste based on three years of system monitoring in an industrial-scale AD plant. The results indicate that the average biogas production rate of 120 Nm(3)/ton of fresh waste can be achieved. Biogas utilization in combined heat and power (CHP) units leads to an overall positive energy balance at significantly reduced CO2 emissions. The overall CO2 emission reduction of 25.3-26.6% was achieved, considering that biogas utilization is environmentally neutral. Moreover, biowaste conversion allows digestate production to substitute mineral fertilizers in agriculture and other applications. It is beneficial for soil protection and a broader environmental perspective.

Automated summary

The continuous growth of the world population and the recent energy crisis have led to increasing volumes of municipal waste and the need for more local and renewable energy sources. This paper presents a study on the dry anaerobic digestion of municipal biowaste in an industrial-scale plant. The results show that it is possible to achieve an average biogas production rate of 120 Nm(3)/ton of fresh waste, leading to a positive energy balance and reduced CO2 emissions. Additionally, the conversion of biowaste allows for the production of high-quality fertilizers and has benefits for soil protection and the environment as a whole.