Biodigestion of vinasse in Brazil

Historically, vinasse has been considered an undesirable by-product of ethanol distillation, and it is still a major concern in most sugarcane producing countries since between 10 to 15 litres of stillage are produced for each litre of ethanol. Even prior to the creation of Brazil's National Alcohol Programme (NAP) in 1975, although stillage was produced on a small scale, it generated undesirable secondary effects such as river pollution near the distilleries. On-site disposal of vinasse by biodigestion (and consequent biogas production) is still associated with a number of technical, economic and environmental problems. Currently, most of the disposal involves a technique called "ferti-irrigation". Although this method produces good results, including increasing the overall agricultural yield, it does not solve all the associated problems, particularly at distilleries where large amounts of surplus vinasse are produced. Further improvements are needed to make the process more cost-effective, but biodigestion remains a promising alternative process for the large-scale treatment of vinasse, particularly in Brazil.1001196403