PHYSICOTHERMOCHEMICAL PRETREATMENTS OF FOOD-PROCESSING WASTE FOR ENHANCING ANAEROBIC-DIGESTION AND BIOGAS GENERATION

The bioconversion of Lignocellulosic biomass to organic acids and eventually to methane gas, is hindered by their relative resistance to enzymatic hydrolysis. This paper was conducted to evaluate the effect of milling and alkali lime cooking pretreatments on the rate and extent of methane generation from sugar Cane bagasse. The effect of pretreatment process variables (Particle size 8-0.003 mm, tempetature between 100 and 250-degrees-C and alkaline dosage between 0 and 8 g CaO/kg VS) on the biogas generation from Sugar Cane bagasse has been investigated. Methane generation from tho pretreated cane bagasse was studied using serum bottle technique and an upflow anaerobic filter bioreactor. The optimum condition involves alkali-cooking of cane bagasse (0.5 mm) with 4% CaO at 200-degrees-C, dissolving most of the cellulose and converting it in a mixture of organic acids, including formic, acetic, lactic, and succinic acids. About 80% of the COD content of the cellulose was retained in the cooked liquor. A very rapid biogas were observed in the first three days of 70% methane content from the pretreated cane bagasse and the digestion was completed within 8 days. It has been concluded, that the lime-cooking of CB could produce methane as much as 70% of that from glucose. Inhibition did not seems to be serious problem in the biogas generation from the alkali-cooking cane bagasse.