Based on the experimental results obtained in WP5 and WP6, this WP aims at optimizing both the HTC process and the hydroponic system. As far as the former is concerned, the optimal conditions for obtaining products with the most suitable characteristics for soilless application will be identified. Furthermore, the combined exploitation of the HTC process liquid (fertirrigation solution) and the hydrochar as a growth substrate in an integrated system will be evaluated. For this purpose, the expertise of the Industrial Technical Physics group of the Free University of Bolzano will be used, regarding in particular process simulation, using open-source and commercial software for the development of thermodynamic, kinetic and system models.
Once the model will be calibrated with the experimental data, it will be possible to evaluate the optimal process conditions according to the characteristics of the initial digestate, both in terms of energy efficiency and to maximize the most interesting features for the application of products in soilless systems. As far as the latter is concerned, an optimized and innovative system for the fertirrigation solution recirculation will be developed in order to reduce the loss of water resources and to increase the efficiency on nutrients usage.