Biogas production via anaerobic codigestion of rice parboiling effluent and organic waste

Abstract

The urgency of innovation in the Brazilian energy matrix, coupled with the high generation of agro-industrial waste and effluents on the national scene, drives the use of anaerobic digestion technique as a promising technology for treating such environmental liabilities and biogas production. Anaerobic codigestion, simultaneous digestion of two or more substrates, allows operational advantages and better environmental conditions for the bacteria responsible for biofuel production. Thus, the objective of this work was to evaluate the biogas production potential through the effluent (substrate) and sludge (inoculum) codigestation of the Upflow Anaerobic Sludge Blanket from the Effluent Treatment Station of a parboiled rice industry in southern Brazil with two different organic solid residues (cosubstrate), orange peel and banana peel separately. A 2³ factorial arrangement was performed using orange peel as cosubstrate and another using banana peel. The digesters used in the study were developed from the reuse o Polyethylene Terephthalate bottles and operated for 168 hours at 35°C. Biogas quantification was performed using the fluid displacement principle. The highest similar biogas production in both factor arrangements was with 40% effluent, 20% solid waste solution and 30% sludge, 8.49E-03m³ produced with banana peel and 1.17E-02m³ with orange peel, with COD removals of 4686.87mgL-1 and 6809.92mgL-1, respectively.