Case Story Brazil

BIOMETHANE DEMONSTRATION

Innovation in urban waste treatment and in biomethane vehicle fuel production in Brazil

November 2017

Mission and Vision

ITAIPU Binacional and the International Center on Renewable Energies – Biogás / CIBiogás are active in renewable energy initiatives contributing to emissions reduction. Together they have established a partnership to develop a biogas plant to digest grass cuttings, food waste and sewage effluent generated at the Itaipu Binational complex. The demonstration facility will allow research to assess continual improvements of the process for replication elsewhere.

The Concept

Urban residues have particular characteristics including for seasonality, consistency and volume; these offer different challenges to rural and agricultural substrates. The residues digested here include for: 600kg of food waste per day; 1,200kg per day of grass cuttings from 400 hectares of grass (Figure 1); and 10m3 / day of sewage. The grass is ensiled after shredding. The food waste is screened to remove nonorganic components. The sewage offers dilution to the substrate mix. To reduce costs the digester was pre-fabricated with light material, produced in separate sections and assembled on site (Figure 2). The bioreactors are maintained at 37°C, have a useful volume of 700m3 , which provide a hydraulic retention time of 60 days. Analysis carried out in the first accredited biogas laboratory in Brazil operated by CIBiogas suggested a biogas production of 519m3 per day. The biogas had a typical consistency of about 60% methane (Figure 3), The biogas is refined to biomethane with a patented process developed in Brazil, that integrates water scrubbing and pressure swing adsorption. The biomethane produced (Figure 4) satisfies required standards and is supplied to over 60 ITAIPU Binacional vehicles (Figure 5).