Anaerobic digestion of stillage to produce bioenergy in the sugarcane-to-ethanol industry

Autor(es)

Fuess, Lucas Tadeu ^[1] ; Garcia, Marcelo Loureiro ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Hydraul & Sanitat, Lab Biol Proc, BR-13563120 Sao Paulo - Brazil

^[2] UNESP Univ Estadual Paulista, Inst Geosci & Exact Sci, Dept Petrol & Metallogeny, BR-13506900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ENVIRONMENTAL TECHNOLOGY; v. 35, n. 3, p. 333-339, FEB 1 2014.
• Citações Web of Science: 14

Resumo

Stillage is the main wastewater from ethanol production, containing a high chemical oxygen demand in addition to acidic and corrosive characteristics. Though stillage may be used as a soil fertilizer, its land application may be considered problematic due its high polluting potential. Anaerobic digestion represents an effective alternative treatment to reduce the pollution load of stillage. In addition, the methane gas produced within the process may be converted to energy, which can be directly applied to the treatment plant. The objective of this paper was to investigate the energetic potential of anaerobic digestion applied to stillage in the sugarcane ethanol industry. An overall analysis of the results indicates energy recovery capacity (ERC) values for methane ranging from 3.5% to 10%, respectively, for sugarcane juice and molasses. The processes employed to obtain the fermentable broth, as well as the distillation step, represent the main limiting factors to the energetic potential feasibility. Considering financial aspects the annual savings could reach up to US\$ 30 million due to anaerobic digestion of stillage in relatively large-scale distilleries (365,000 m(3) of ethanol per year). The best scenarios were verified for the association between anaerobic digestion of stillage and combustion of bagasse. In this case, the fossil fuels consumption in distilleries could be fully ceased, such the ERC of methane could reach values ranging from 140% to 890%. (AU)

• Processo FAPESP: 10/04101-8 - Avaliação da capacidade de recuperação de energia em reatores anaeróbios aplicados ao tratamento de resíduos com alta concentração orgânica
• Beneficiário: Lucas Tadeu Fuess
• Modalidade de apoio: Bolsas no Brasil - Mestrado