Anaerobic co-digestion of sugarcane press mud with vinasse on methane yield

• Published in: Waste management (Elmsford) 2017-10, Vol.68, p.139-145
• Main Authors: López González, Lisbet Mailin, Pereda Reyes, Ileana, Romero Romero, Osvaldo
• Format: Article
• Language: English
• Subjects: Anaerobic co-digestion; ANAEROBIC DIGESTION; Anaerobiosis; Biofuels; Bioreactors; Filter cake; LIQUID WASTES; MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; METHANE; MIXTURES; Press mud; Saccharum; SOLID WASTES; SUGAR CANE; Vinasse; YIELDS
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2017.07.016

•Press mud and vinasse co-digestion was investigated.•Methane yield during co-digestion was 64% higher to mono-digestion.•Press mud and vinasse co-digestion increased process stability. The conversion efficiency of high solids waste digestion as sugarcane press mud (P) may be limited due to hydrolysis step. The option of co-digestion with vinasse, main liquid waste generated from ethanol production, was investigated under batch regime at mesophilic conditions (37.5±1°C) and the best mixture was evaluated under semicontinuous regime in stirred-tank reactors. The maximum values for methane yield in batch tests were for V75/P25 and V50/P50 mixtures (on basis of the chemical oxygen demand (COD) percentage added in the mixture), with an average value of 246NmL CH4g−1 CODfed, which was 13% higher than that of press mud alone. A highest methane production rate of 69.6NmL CH4g−1 CODfed−1d−1 was obtained for the mixtureV75/P25. During the experiment carried out in CSTR reactors, the organic loading rate (OLR) was increased from 0.5 up to 2.2gVSL−1d−1. Methane yields of 365L CH4 kg−1VS and biogas productivities of 1.6LL−1 were obtained in co-digestion, which was 64% higher in comparison to mono-digestion. The performance of the process in mono-digestion was less stable than in co-digestion, with a significant fall of methane yield to 1.8kgVSm−3d−1, and a partial inhibition of the methanogenic archaeas when the OLR was increased up to 2.2kgVSm−3d−1. The co-digestion of vinasse with press mud is a good option for the treatment of streams at the alcohol-sugar industry.