D. Duca

Mitigation strategies in the agro-food sector: the anaerobic digestion of tomato purée by-products. An Italian case study.

Tomato processing involves a significant production of residues, mainly constituted by discarded tomatoes, skins, seeds and pulp. Often, these residues are not valorized and represent an added cost for manufacturing companies because of disposal processes, with environmental issues due to the difficult management. The exploitation of these residual materials results complex as their availability is mainly concentrated in few months. A possible solution is the production of biogas employed in a Combine Heat and Power engine for energy production, in line with the 2020 targets of European Union in terms of promotion of energy from renewable resources and greenhouse gas emission reduction. The tomato by-product utilization for energy production as a strategy to reduce the environmental load of tomato purée was evaluated by means of Life Cycle Assessment. Two scenarios were considered: Baseline Scenario - tomato by-products are sent back to the tomato fields as organic fertilizers; Alternative Scenario - tomato by-products are employed in a nearby biogas plant for energy production. Methane production of tomato by-products was assessed by means of specific laboratory tests. The comparison between the two scenarios highlighted reductions for all the impact categories with the Alternative Scenario. The most important reductions are related to particulate matter (-5.3%), climate change (-6.4%) and ozone depletion (-13.4%). Although small, the reduction of the environmental impact cannot be neglected; for example for climate change, the anaerobic digestion of by-products allows a saving of GHG emissions that, over the whole year, is equal to 1.567 tons of CO2 eq. The results of this study could be up-scaled to the food industries with high heat demand producing considerable amounts of fermentable by-products employable as feedstock for biogas production.

Energy Value Stream Mapping, Development and Application of a Tool to Reduce Energy Inefficiencies of the Production Processes

Over the last years, the industrial energy consumption has become a critical issue and several energy management systems have been developed. At the same time, the lean philosophy has been used to evaluate the critical points of the production processes. One of the main tools used by lean champions is the Value Stream Mapping (VSM) to identify “bottlenecks” and also to provide graphically areas of interest for improvement within the shop floor. Current VSM models do not include information about energy as a fundamental content. To overcome this lack, the present work is focused on the development of a new extended VSM tool able to map the energy consumption. Energy value Stream mapping (EVSM) is a tool to evaluate issues related to the energy consumption. Through it, the energy manager can pursue the minimum energy consumption. The proposed tool has been applied and tested in a real case study.Copyright