Designing a Supply Chain for the Generation of Bioenergy from the Anaerobic Digestion of Citrus Effluents

Abstract

Recently, Mexico was positioned as one of the main countries in citrus production, with approximately 7.6 million tons per year from an area of 550,000 ha. The annual production is equivalent in value to approximately 930 million USD. Although, the supply of citrus in Mexico is about 7.6 million tons per year, this amount is made up of national production and imports. There are three possible routes that contribute to the supply of citrus, i.e., fresh consumption, processing, and export, which correspond to 63, 27, and 10% of the national supply, respectively. Large amounts of liquid residues are generated when the citrus is processed. Inadequate management of these citrus effluents, which have high organic loads and low pH, causes negative environmental impacts as well as social and economic problems. However, anaerobic digestion is a viable and sustainable alternative for the management of citrus effluents because it takes advantage of the physicochemical characteristics of this type of wastewater to generate biogas as a value-added product. The main objective of the study presented in this chapter was to design a supply chain that analyzes and integrates citrus production and processing, the generation and treatment of citrus effluents by anaerobic digestion, and the production of biogas the generation of electricity which can then be used in the citrus processing plants. The results of this analysis indicated that the estimated 2.7 million m3 of citrus effluents that are being generated annually in Mexico could produce 1.6 million m3 of methane (at standard temperature and pressure) and 4.8 GWh of net electricity.