Waste bio-refineries for the cassava starch industry: New trends and review of alternatives

The cassava starch industrial process generates very pollutant effluents that need to be treated before discharge. A series of successful experiences concerning the transformation of treatment ponds into covered lagoons have been conducted in the last years in Brazil, proving that the use of anaerobic digesters could make the worldwide cassava industry more profitable. The circular economy approach is used to add the balance of greenhouse gases, water and land use to the assessment of a set of waste-to-resource alternatives for this particular industrial process. The results point out to the convenience of upgrading the covered lagoon solution to a more complete waste bio-refinery that not only focus in electric power generation but also recovers process heat and biofertilizers as byproducts. Co-generation is very attractive for the resource recovery of this agricultural residue. It was also found that the higher efficiency that characterizes co-generation leads to the lowest level of greenhouse gases emissions.