Valorization of organic waste fractions: a theoretical study on biomethane production potential and the recovery of N and P in Austria

Due to climate change and the rising world population, sustainable energy and fertilizer production faces many challenges. The utilization of organic waste fractions is one possible solution for promoting sustainability. Organic waste fractions have a high potential for biomethane production, which could positively contribute to the current energy mix. Furthermore, organic waste fractions could be used for nutrient recovery (i.e., the recovery of N and P) concurrently to their use in biomethane production. This study examined the theoretical potential of organic waste fractions for valorization in Austria. Further, it provides a theoretical overview of biomethane production and nutrient-recovery potential. This analysis revealed a total substrate potential of 13 Mt per year in Austria, with the highest contribution from manure. Over 900 million Nm3 of biomethane could potentially be produced from organic waste fractions. Furthermore, developing organic waste fractions as an energy source could improve the impact of the natural gas consuming sectors on climate, reducing 2.4 Mt of CO2 emissions annually. Regarding nutrient recovery, more than 60 kt of N and 20 kt of P could potentially be recovered per year. The study shows a high potential for producing biomethane from organic waste fractions in Austria. The overall production potential could substitute up to 11% of the Austrian natural gas demand, which could highly decrease the CO2 emissions from fossil energy carriers. Furthermore, a high nutrient recovery potential was identified for an inclusive implementation of an efficient recovery.