1. Effect of anaerobic digestion of vinasse on mitigation of greenhouse gas emission (GEE) Moraes BS 1 ; Triolo JM 2 ; Zaiat M 3 ; Petersen SO 4 ; Sommer SG 2 1 Brazilian Bioethanol Science and Technology Laboratory (CTBE), CNPEM, Brazil 2 Department of Chemical Engineering, Biotechnology and Environmental Technology, SDU, Denmark 3 CPDI-EA, São Carlos Engineering School (EESC), USP, Brazil 4 Department Agroecology, Research Centre Foulum, Denmark bruna.moraes@bioetanol.org.br Results Anaerobic digestion (AD) concept in a biorefinery concept Material and methods Conclusion  Anaerobic digestion of vinasse: effective to reduce GHG emissions from its application in the soil as fertilizer → use of digestate could result in carbon credits generation, being an opportunity to provide extra income for the bioethanol production plants and to stimulate the carbon credits market. www.ctbe.cnpem.br Acknowledgments  This work has financial supported of FAPESP process no. 2013/03578-3. ABSTRACT: Vinasse is generated during ethanol distillation in a ratio between 10 to 15 liters per liter of ethanol produced, depending on the raw material and production process. In Brazil, the most common destination of vinasse is its application to the soil as fertilizer for sugarcane cultivation (fertirrigation), but some environmental impacts are associated with this practice, especially regarding GHG emissions. The possibility to produce biogas from the anaerobic digestion of vinasse arises as a sustainable way to dispose of such waste because it promotes its environmental suitability and bioenergy generation through the use of biogas. This work evaluated the GHG emissions from application of vinasse and digestate (biodigested vinasse) in the soil. The results showed that the reduction and stabilization of organic matter in the digestate, as well as its amoniacal nitrogen content, provided lower partial denitrification reactions in the soil, resulting in lower N 2 O emissions when compared to vinasse.  Soil sampling: from grazed pasture near Research Centre Foulum in Denmark.  Vinasse: from sugar beet ethanol production (Nordic Sugar, Denmark).  Digestate: from biogas production performed in CSTR treating the same vinasse (Moraes et al., 2014) a.  Inorganic fertilizer: NH 4 NO 3 applied in the soil at a rate of 100 kg N ha -1. a Moraes BS, Triolo JM, Lecona VP, Sommer SG, Zaiat M (2014). Biogas production from vinasse: Effects of by-products of livestock and sugar-beet production as co-substrates. In: Proceedings of 22th EUBCE, Hamburg, German. F: Gas flux (mg gas m -2 h -1 ); dC/dt: rate of change in gas (CO 2, CH 4 or N 2 O) concentration inside the glass jar (ppm h -1 ); ρ: density of the gas (CO 2, CH 4 or N 2 O) at the incubation temperature (mg m -3 ); V: glass jar volume (m 3 ); A: surface area circumscribed by the glass jar (m 2 ).  N 2 O fluxes: the most expressive for comparison Vinasse Anaerobic digestion (AD) concept in a biorefinery ADAD Digestate Ethanol Biogas GHG Digestate: stable organic matter and nutrients = lower emissions Fertirrigation S UPPOSITION Objective: Comparison between GHG emissions from application of vinasse and digestate, reproducing the fertirrigation in bench scale. ParameterUnitVinasseDigestate Dry Matterg kg -1 114.0446.39 Volatile Solidsg kg -1 83.5324.75 Total Amonia Nitrogeng L -1 0.842.76 Total Kjedahl Nitrogeng L -1 4.903.56 pHn.a.4.967.97 Chemical Oxygen Demandg L -1 77.4133.16 C/N ration.a.5.923.5 Total Volatile fatty acidsmg L -1 2379.644882.28  Fluxes of CO 2, CH 4 and N 2 O: calculated using linear regression from the concentration as a function of the incubation time (t 0, t 1, t 2 and t 3 ) in the glass jars. (a) (b) Figure 1. Average daily fluxes of N 2 O measured in the experiments with (a) vinasse and (b) digestate application. (a) (b) Figure. Average daily nitrogen content in the soil after application of (a) vinasse and (b) digestate: (○) NH 4 + -N and ( ■ ) NO 3 -N. ↓57%↓57%  Nitrogen content in the soil → possible explanations: Microsites anaerobiosis: conversion of organic nitrogen to NH 4 + Aerated microsites: nitrate increase due nitrification reactions Stable N content and low available organic matter: occurrence of biological reactions was minimized, preventing higher N 2 O emissions Decrease in NO 3 -N → highest N 2 O emissions: partial heterotrophic denitrification