13-25: Anaerobic biodegradability of the waste from the biofuels industry: the palm kernel bagasse

Monday, April 29, 2013
Exhibit Hall
Adriana G. Costa1, Gleyciara C. Pinheiro2, Gleycielle C. Pinheiro1, Alexsandro F. Viana1, Sandra T. Santaella2, André B. Dos Santos3, Morsyleide F. Rosa4 and Renato C. Leitão4, (1)Enviromental Management Technology Department, Instituto Federal de Educação, Ciência e Tecnologia do Ceará, Fortaleza - CE, Brazil, (2)Sea Science Institute, Federal University of Ceará, Fortaleza - CE, Brazil, (3)Enviromental and Hydraulics Engineering Department, Federal University of Ceará, Fortaleza - CE, Brazil, (4)Biomass Technology Laboratory, Brazilian Agricultural Research Corporation, Fortaleza - CE, Brazil
Brazil generates a huge amount of lignocellulosic waste from biofuel production chains, which can be exploited for production of second generation biofuels via ethanol or methane. However, the use of this biomass as energy source via fermentation usually requires pretreatment of the lignocellulosic material, in order to solubilize the sugars or to remove the lignin. This study aimed to evaluate the anaerobic biodegradability and methane production potential (MPP) of the palm mesocarp fiber. Three different types of physical-chemical pretreatments were used, varying the reaction time, temperature, ratio mass:volume and concentration of acid or alkali in order to get the best system that facilitate the anaerobic digestion of the material. Pretreatments were evaluated using central composite design 23. The hydrolyzed material that had the higher concentration of fermentable sugars or lower lignin content was subjected to anaerobic biodegradability tests. The results showed that the values of biodegradability and MPP of the hydrothermally or chemically pretreated fibers (based on the dry crude fiber) were similar to those fibers that were just milled, between 16 and 19%, and between 96 and 114 L CH4/kg dry fiber, respectively. This is an indication that it is not economically feasible to use pretreatments on the palm mesocarp fiber if the goal is only to produce energy via methane. However, if there is an use for the extracted lignin, the hydrolyzed palm mesocarp fiber using alkali pretreatment will generate 305.7 L CH4/kg of dry fiber, which will allow energy production of 10.9 MJ/kg of dry fiber.