Energy Management Research Journal (EMRJ)

Research Article

Characterization of A Low-Cost Biodigester of Dairy Cattle Manure Installed in Southern Brazil

Fábio Nuernberg, Kátia Cilene Rodrigues Madruga and Elaine Virmond

Federal University of Santa Catarina, Center of Sciences, Technologies and Health, Department of Energy and Sustainability, Campus Araranguá, Rodovia Governador Jorge Lacerda, 3201, Jardim das Avenidas, 88906-072, Araranguá, SC, Brasil.

Submitted: April 1, 2020; Accepted: September 16, 2020.

Abstract

The southern region of Brazil is currently one of the largest milk producers, an activity that contains great diversification in terms of its production system. The problem associated with the creation of dairy cattle is the high production of manure, which requires special care not to negatively affect the environment. One of the alternatives for the treatment of such waste is biodigestion, which promotes the reduction of the organic load present in the substrate, produces biogas and organic fertilizer. Biogas consists of a gas mixture (CH₄, CO₂, NH₃, H₂S, others) that can be used in different ways depending on the composition. The present work evaluated a low-cost biodigester of dairy cattle manure installed in a rural property located in Southern Brazil. For this, the substrate, organic fertilizer and biogas were characterized. In the substrate and in the organic fertilizer, the contents of total, volatile and fixed solids were evaluated to quantify the reduction of the content of volatile solids, which represents the decrease of the organic load present in the substrate. In the substrate the content of volatile solids found was 83.07±5.41%. After the biodigestion process, a concentration of 74.29±2.06% in the organic fertilizer was obtained, totaling a reduction of 10.28% of the organic load. The biogas chemical composition, energy content and the influence of temperature on its production were evaluated. The biogas produced had an average concentration of CH₄ of 72.9±8.6%, a LHV of 26.10 MJ/m³ and Wobbe Index of 25.72 MJ/m³, demonstrating that there is potential for replacement of LPG. The analysis carried out with the biogas showed a significant difference in the production during the spring when compared to the winter. In addition to these factors, it was estimated the amount of waste produced and the daily production of CH₄ within the property. The amount of waste treated nowadays is only 11% of the total available according to the estimative, what indicates that nine more biodigesters of the same model would be needed to treat all the waste produced and, as consequence, CH₄ production could be at least nine times higher.

Keywords

Low-Cost Biodigester; Dairy Cattle Manure; Southern Brazil.

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