Vinasse is the final by-product of the biomass distillation, mainly for the production of ethanol, from sugar crops (beet and sugarcane), starch crops (corn, wheat, rice, and cassava), or cellulosic material (harvesting crop residues, sugarcane bagasse, and wood).
Because of the large quantities of vinasse produced, alternative treatments and uses have been developed, such as recycling of vinasse in fermentation, fertirrigation, concentration by evaporation, and yeast and energy production.
The characteristics of vinasses depend mainly on the rawmaterial used for bio-ethanol production. Vinasses with high concentrations of sol-uble solids can be obtained when sugar cane, sugar beet, grape, agaves or sweet sorghum are used. From these feed-stocks, 9 to 14 L of wastewater can be obtained per litre ofalcohol. These wastewaters are acidic (pH: 3.5–5), dark brownin colour and have a high organic content with chemicaloxygen demand (COD) values from 50,000–150,000 mg/L.These vinasses can be used as fertilizer due to their nutrientcontent, mainly calcium and potassium and their high organicmaterial content.
However, due to their origin they contain a great amounts of biomass, organic matter, nitrogen, sugars, among other nutrients[3,4], able to produce biogas by anaerobic digestion in covered lagoon digester, which they have a low cost of implementation and maintenance, reduced excess sludge production, low energy consumption and simplicity in operation.