Climate changes are nowadays reality and affect all aspects of everyday life. One of the places where these changes influence the society the most is the Brazilian Ceará region and Jaguaribara basin that suffer long-lasting, devastating drought cycles. They have a dramatic negative impact on local economy, forcing change in business models. This work presents the valorisation of wastes and residues from local fish, prawns, and the vegetable-cultivation industry via biogas production forced to adapt to these new circumstances. Along a single year, as much as 189.74 tonnes of wastes and residues can be processed by the biogas production facility, producing as much as 94 GJ of cooling energy and 1 tonne of biofertiliser monthly. Even for such a small biogas production facility, the NPV is positive already after 11 years; its IRR is 6.2%, and accumulated ROI for 20 years of operation is as high as 77.8%. This work demonstrates that a valorisation of industrial wastes and residues via biogas production is a feasible solution for a specific industrial scenario addressing new socio-economic challenges for the particular enterprise.

-The objective of this work was to determine the nutrient digestibility and metabolizable energy (ME) of fish silage, as well as to evaluate the effect of the dietary inclusion of fish silage meal (FSM) in diets on the performance, carcass characteristics, meat quality, sensory analysis of meat and mortadella, and economic viability of growing and finishing pigs. In the digestibility assay, 16 barrows (33.20±4.93 kg) received diets with and without FSM. The fish silage had 39.01% crude protein and 4,032 kcal kg -1 ME. In the performance assay, 32 barrows (26.00±1.68 kg) were fed diets containing different inclusion levels of FSM (0, 25, 50, and 75%). FSM, obtained from the mixture (1:1) of fish silage with corn, showed a quadratic effect on average daily gain, and the best result was obtained with the inclusion level of 25.83%. The results for feed conversion and economic viability indicate that up to 25% FSM, corresponding to 5.87% of fish silage based on dry matter, can be used in the pig growing and finishing phases.