Livestock Manure dIgestate Treatments to reduce GHGs and NH3 emissions and meet crop nutrients requirement - (LiMIT DGGAS)

The European Green Deal aims to get climate neutrality through a modern, resource-efficient and competitive economy where there are no net emissions of greenhouse gases within 2050. A specific challenge is posed for agriculture, that is responsible for 10.3% of the EU’s GHG emissions and about 94% of NH3 emissions, with nitrogen and phosphorous losses exceeding the European limit by a factor of 3.3, and 2.0, respectively, thus threatening terrestrial, aquatic, and atmospheric ecosystems. One cause can be found in the management of animal manure in livestock and crop production, which is one of the major causes of pollution due to nitrogen, phosphorus and carbon losses. In this sense, anaerobic digestion is a consolidated process that can provide an effective support in livestock manure management, ensuring the production of biomethane and more stabilized effluents for agricultural uses. Nevertheless, some constraints are still reported in the application of anaerobic digestion in livestock farming since it is a process that does not affect the total N and P content of fed animal manure. Given the importance of the implementation of such a process devoted to producing methane and organic fertilizers, further treatments are strategic to ensure the achievement of Eu Green Deal’s targets.Specifically, great attention has to be posed to the valorization of the field agronomic utilization of digestate while avoiding the release of gases (NH3, N2O, CH4, and CO2) in the atmosphere.Based on these premises, this project is aimed to test two promising treatment strategies based on the recovery of nutrients in digestate, in order to produce new types of fertilizers or amendments. Moreover, the project is aimed to assess the fertilization efficiency of effluents and to monitor gaseous emissions from various phases of the treatment plants, and after the application of treated digested to the soil. With specific regards to soil application of digestate and ammonia emissions, data will be collected according to dataset provided by ALFAM2 model, to improve results for digestate use in Mediterranean climate. For the project’s purpose, two existing treatment plants will be tested in order to overcome the existing gap in the technology and to reduce their environmental impact or enhance their cost-effectiveness. Expected results of the projects are 1) reducing constraints of treatment strategies for valorizing nutrients from digestate; 2) Evaluating fertilization efficiency of treated digestate; 3) Estimation of NH3 e GHGs emissions from relevant phase of livestock manure digestate chain; 4) Providing dataset for ALFAM2 model; 5) Techno-economic analysis and territorial assessment of treatment strategies adopted. Accordingly, the project will trace the road for a control on by-products quality, valorization of agronomic utilization of digestate, reduction of environmental effects due to the release of pollutant gases, as required from policy-makers and stakeholders.