Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor

Abstract

BackgroundA modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses.ResultsThe study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate.ConclusionsThe modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production.Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.

Sequential fermentative and phototrophic system for hydrogen production: An approach for Brazilian alcohol distillery wastewater

“…that used a pure culture (Rhodobacter ZX-5) for hydrogen production from acid-rich residues (i.e., acetic, butyric and succinic acids). COD removal observed in the present study was also comparable to that measured in a study that evaluated methane production from vinasse (69%) [62].…”

Treatment of sugarcane vinasse by combination of coagulation/flocculation and Fenton’s oxidation

“…In general, anaerobic digestion (AD) is the technique commonly adopted for sugarcane vinasse treatment (Harada et al, 1996;Wilkie et al, 2000;España-Gamboa et al, 2012;Mota et al, 2013;Nogueira et al, 2015) because the high organic content of vinasse permits to generate energy from methane produced. Moreover, AD yields low amounts of sludge, making the process economically and environmentally advantageous (Wilkie et al, 2000).…”

Influence of alkalinity and VFAs on the performance of an UASB reactor with recirculation for the treatment of Tequila vinasses

“…azul) in Tequila production. Tequila vinasse is a dark brown liquid; it presents a pH of 3.5 and a high chemical oxygen demand (COD), which ranges from 60 to 100 g l -1 ; generating potential risks to the environment if it is discharged without treatment to water bodies [1][2][3][4]. Between the different treatments of vinasses, the anaerobic process stands out as the most viable; it has been used for the treatment of Tequila vinasse [2,[5][6][7] and for other distilled spirits [3,[8][9][10].…”