Greenhouse gas emissions from sugarcane vinasse transportation by open channel: a case study in Brazil

Sugarcane ethanol has been proposed to be one of the best options to substitute fossil fuels. However, despite its benefits, ethanol production generates large amounts of residues, especially vinasse, a liquid residue that may result in environmental problems, such as greenhouse gas emissions (GHG). The aim of this study was to quantify the CH4 and N2O emissions during vinasse transportation by open channel in a sugarcane Mill in Brazil. Additionally, we estimated the contribution of vinasse emission to total sugarcane ethanol emissions. We set up six points to collect gas samples and quantify the emissions of CH4 and N2O along the main vinasse transportation channel. The emissions of CH4 accounted for over 98% of the total emissions, while the N2O fluxes represented, on average, less than 2%. We estimated an emission factor of 1.43 kg CO2 eq m−3 of transported vinasse. Improvements in vinasse storage and transportation methods, either by coating the open channels or by use of coated tanks and pipes should significantly reduce GHG emissions. The reduction of GHG emissions in ethanol production can make a significant contribution toward a cleaner production of biofuels.