Feasibility of a novel use for agroindustrial biogas

• Published in: Journal of cleaner production Vol. 144; pp. 48 - 56
• Main Authors: Moreno, Laura, González, Almudena, Cuadros-Salcedo, Francisco, Cuadros-Blázquez, Francisco
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-02-2017
• Subjects: Anaerobic co-digestion; Economic feasibility; Energetic feasibility; Environmental feasibility; Maize; OMW; OMW; Environmental feasibility; Anaerobic co-digestion; Maize; Economic feasibility; Energetic feasibility
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2016.12.060

Biogas has traditionally been used either for thermal or electric power purposes, or even for injection into the natural gas grid after cleaned of impurities. Its transformation into mechanical power, not to mention its use as energy supply for water-lifting pumps for energy storage or irrigation operations, is far from being a frequent occurrence.
The present paper analyses the technical, economic and environmental viability of a novel use for agroindustrial biogas to feed water-lifting pumps for crop irrigation. In particular, the construction of an Anaerobic Digestion (AD) plant in a maize cultivation area of the Regantes del Canal del Zújar region in Extremadura (located in south-western Spain and bordering Portugal) is proposed. Olive Mill Wastewater (OMW) generated by a nearby olive oil mill and a small portion of maize produced in such region would be treated simultaneously in this plant. Biogas (methane) produced through the anaerobic co-digestion of various OMW and maize kernel flour mixtures was analysed for this study, and the conclusion reached is that the best results are obtained from a mixture of 90% OMW and 10% maize kernel flour.
For this mixture, maximum methane production reached has been 6.58 Nm3 methane/m3 substrate (mixture). According to those results, an AD plant has been designed. Biogas produced from this co-digestion would be used by local farmers to power motor pumps which would pump irrigation water. From the economic analysis we can deduce that the proposed biomethanisation plant is economically feasible, since there is a four year return on the investment if compared with the cost of the electricity consumed each year in the Regantes region.