Produção de biogás a partir de resíduos de alimentos: uma proposta para um restaurante em Recife, PE

Abstract

Several researches have been extended to the use of food waste for the production of biogas as a source of clean energy and its reuse as fuel and energy generation. All organic matter decomposition processes occur in the anaerobic environment, for which reactors are used (aka biodigesters). For the present study, a prototype was proposed with a modern technology for the food waste of the Federal Institute of Pernambuco Employee Association’s restaurant – ASSIFPE organic residues treatment. After the literary review, the methodology consisted in the collection of food waste samples, separation, and weighing as well as their respective qualitative and quantitative laboratory analysis. The following parameters were evaluated: pH, total alkalinity, total solids, chemical oxygen demand, fatty acid, ammoniacal nitrogen and total nitrogen. For the sizing of the proposed biodigester, the characterization of the study area (restaurant) was carried out, together with the study of the volume and the biogas generation. The next step was the evaluation of the potential biogas generation and the biodigester sizing. With the results obtained of the food waste residues it was possible to size the biodigester with digestion capacity of 140 kg of food waste produced by the restaurant in the sampling period of 5 (five) days and with the daily production of 14 m3 of biogas. With the purpose of bringing to the study a more current technology and a lower cost of implantation, a prototype composed of a tubular biodigestor and an aerobic pond with a volume of 9m3, called Mini Biodigestor 6000, was proposed. It presents in its biogas production the equivalent of 1 day on the stove burning of 2 hours and 10 minutes for food cooking. The assumptions were that monthly the restaurante will function for 22 days during the business hours (Monday to Friday) with total of 48 cooking hours which the daily gas consumption is 8 hours (2 hours using biogas and 6 hours using GLP), this will bring savings to the restaurant and return on investment in 2 years and 3 months.