Abstract:

Students being able to develop research in the future is one of the most important achievements in Higher Education. At CITES (Science and Technology of Sustainability) research group at Universitat Politecnica de Catalunya (Spain), this education is endured mostly with the final master thesis. In this context, as part of the master's program in Environmental Engineering, an academic research project has been developed by a master’s student. It is related to circular economy applied to the pork industry, especially in the process developed in slaughterhouses. The project sought to understand the environmental burden of pork production and at the same time create a proposal for the complete valorization of each waste and the use of each part of the pig, in a way that allows improving the use of animal by-products in the slaughterhouse phase, within the framework of the circular economy. To this end, the environmental performance of pork production in Catalonia was evaluated, using the life cycle analysis (LCA) methodology with real data from a slaughterhouse, taking into account a functional unit of 1 kg of pork outgoing.

Visits were made to slaughterhouses and waste assessment facilities in Catalonia. A flow chart and the diagram of existing synergies of the pig slaughterhouse was then drawn. Finally, some proposals were considered to close the material cycle in this system, so some new synergies were proposed.

The results of the environmental assessment showed an impact on climate change (CC) of 8.38 kg CO2-eq per kg of pork. Freshwater Eutrophication (EA) and Marine Eutrophication were estimated at 1.79 g P-eq and 9.59 g N-eq per kg of pork respectively, while Terrestrial Acidification (TA) showed a value of 87 .4 g SO2-eq per kg of pork. The analysis of the results showed the supply of raw materials (pork for slaughter) as the process with the greatest contribution to the environmental load in almost all the impact categories evaluated. This was mainly associated with the food requirements (feed) and the implications of pig farming on farms, given that, according to the literature, the main impacts derived from meat production, regardless of the type of meat, are related to the activities agricultural.

The electrical supply brings the second bigger impact with a contribution greater than 11% in the ionizing radiation (IR) category, as well as an important contribution in the DC impact categories (0 ,5%). Followed by emissions derived from the requirement of cleaning agents, which gave a notable contribution to freshwater eutrophication. These results were found in line with other European pork production studies. On the other hand, the contributions related to slaughterhouse waste were less significant in relation to the total environmental impacts, being 0.3% in terms of total Climate Change (CC) and insignificant in the other categories analyzed, where bones and fat, Blood and manure were the wastes with the greatest contribution to the result.

In response to these results, cycle closing strategies were proposed based on the principles of the circular economy and industrial ecology, which allow the sector to optimize material flows.

This academic research experience highlights the importance of educational projects that are committed to sustainability, since it allows the researcher to experiment and put into practice some of the new proposals of the circular economy.

Keywords:

Research experience, Industrial Ecology, LCA, circular economy, education for sustainability, pig slaughterhouses.