An integrated approach to explore UASB reactors for energy recycling in pulp and paper industry: a case study in Brazil

Document Type: Research Paper


1 Faculty of Food Engineering, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, 13083-862, Campinas, São Paulo, Brazil.

2 Interdisciplinary Center of Energy Planning (NIPE), University of Campinas (UNICAMP), Rua Cora Coralina, 13083-970, Campinas, São Paulo, Brazil.


Brazil is currently focused on its energy matrix transition in favor of increasing of the share of renewable energy carriers for both enhanced energy security and mitigation of greenhouse gas emissions. In this context, the country`s pulp and paper industry whose different wastes teams are not generally exploited, could play a critical role. Accordingly, the main objective of this work is to develop a conceptual ‘systemic’ biorefinery framework integrating the treatment of pulp and paper mill wastewater using upflow anaerobic sludge blanket (UASB) reactor with energy recovery through biogas production and its conversion into heat and power in stationary engines and boilers, respectively. Based on the results obtained through the present case study, it was revealed that the adoption of UASB reactors by the paper mill industry could properly addresses the environmental concerns faced while could contribute to the national agenda favoring an increasing share of renewable energies in the country`s energy matrix. The financial analysis showed that the investment required for the implementation of UASB reactors within a biorefinery platform would be minor vs. the investment in the whole mill and would be returned in 6.4 yr with a high return on investment even when operated at half of operational capacity. Moreover, through the developed UASB reactor-based biorefinery, the Brazilian pulp and paper industry as a whole could avoid 1.06 ×105 CO2eq tons, effectively contributing to the decarbonization of the country`s economy.

Graphical Abstract

An integrated approach to explore UASB reactors for energy recycling in pulp and paper industry: a case study in Brazil


  • Conceptual ‘systemic’ biorefinery framework for simultaneous wastewater treatment and bioenergy/biomaterail recovery was developed.
  • UASB reactor-based biorefinery was found efficient in addressing the environmental concerns faced by the pulp and paper industry. 
  • Investment required for UASB reactors would be minor accounting for only 6.8% of the mill`s annual sales.
  • Nationwide implementation of the proposed biorefinery could avoid national GHG emissions by 1.06 ×105 CO2eq tons.
  • Biogas burning in stationary engines can avoid USD 2.89 Millions in electric energy charge. 


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