Produção de biogás utilizando matéria orgânica proveniente da criação de tilápia do Nilo em sistema aquapônico

Abstract

The increase in demand for food and the availability of natural resources has led to a growing demand for more intensive and sustainable production systems. In aquaponics, we have the association of fish farming with hydroponic vegetable production, with water constantly circulating between the two systems. Although plants utilize some of the residual nutrients, the remaining portion is discarded, generating a considerable amount of organic matter that can be utilized for biogas production. Therefore, in this experiment, the production of biogas from the settled organic matter in the decanters of an NFT (Nutrient Film Technique) aquaponic system was evaluated. In this system, Nile tilapia (Oreochromis niloticus) were stocked at a density of 10 fish per m³, totaling 120 fish, in association with the production of 200 heads of butterhead lettuce (Lactuca sativa). Two batch-type digesters with a capacity of 50 liters each were built and connected to a gas meter to measure biogas production. The organic material was collected from the system over a period of 20 days and added to the digesters after two settling phases (pre-settling and settling). The quantification of biogas production was conducted over a period of 10 days. The results obtained demonstrate a productive potential of 13.74 cm³ per liter of organic material deposited in the digesters, with an average biogas production of 562.515 cm³ per kilogram of feed consumed by the fish. The production of biogas from organic matter derived from Nile tilapia farming in aquaponic systems is viable, adding value to the activity.