The production of nitrogen (N) and phosphorus (P) mineral fertilizers currently requires non-renewable resources and the use of natural gas but significant amounts of N and P could be recovered from waste streams.
Recovery of nitrogen (N) from biowaste is the most effective way to reduce GHG emissions from N-fertilizer production is to recover nitrogen directly from biowaste. The production of synthetic N fertilizers from N2 gas is an energy-demanding process, responsible for 1,2% of world energy consumption. Next, biowaste is an important source of phosphorus (P), which an essential and non-renewable element.
The EC has decided to place P on the list of Critical Raw Materials and actively stimulates the recovery and recycling of P from biowaste by the implementation of its circular economy package. Recycling of P from sewage sludge and food waste from households could cover 70% of Europe’s demand for mineral P fertilizers showing the enormous potential of organic waste as a resource for mineral phosphorus.
Paradoxically, the excessive production and use of N and P also causes severe environmental problems, especially in regions with intensive livestock husbandry which has led to leaching of nutrients to groundwater and eutrophication of waterbodies. Due to restrictions on manure application rates, large amounts of manure have to be transported over large distances (>500 km) to regions with a demand for nutrients. The transport of manure leads to high CO2 emissions, high manure disposal costs for farmers. Meanwhile, arable farmers need to buy synthetic N fertilizers because the available biowaste – mainly manure – does not meet the NP requirements of the plant.
Additionally, transport of biowaste leads to a regional loss of valuable organic matter which plays a crucial role in maintaining soil quality and soil fertility. The storage of organic carbon in agricultural soils is an important pathway to reduce soil degradation and mitigate GHG emissions contributing to achieving the long-term objective of limiting the temperature increase to +1,5-2°C. In many regions in the EU, there is a concern about decreasing organic carbon contents in agricultural.
SYSTEMIC’s solution: biowaste as a resource for mineral nutrients and organic fertilizers
The solution to the above described pressing environmental and economic problems lies in the implementation of circular economy solutions, leading to reuse of nutrient in the nearby region. This can be realised by processing biowaste into mineral nutrients and organic fertilizers that meet regional market demands in terms of nutrient composition and are up are to standard in terms of nutrient uptake efficiency. The processing of biowaste – consisting of a mixture of components – into user-specific fertilizers with a predefined nutrient composition – requires the use of separation and recovery technologies that enable to separate the mineral nutrients from the organic fraction. In recent years, multiple NRR technologies have been developed and tested in pilot facilities and proven to be ready for implementation at large scale. SYSTEMIC has selected the most promising NRR technologies and aspires to implement these on five state-of-the-art AD demonstration plants in order to demonstrate that the combination of anaerobic digestion and nutrient recovery forms a prerequisite for the valorisation of biowaste in an economically viable manner.