Two-phase anaerobic digestion of solid wastes by a multiple liquefaction reactors process

A new solid-waste treatment process was applied ro different vegetable substrates: potato peelings, gr een salad leaves, green pens mixed with carrots, apple pomace. Ir involved at a laboratory scale, several liquefaction digesters, each of them treating one type of waste, coupled to a central methane fixed-film reactor The influence of pH, loan and hydraulic retention time on the process performances was studied at 35 degrees C On average, except for apple pomace, hydrolysis yields were high (up to 80%) during the liquefaction step. Likewise, the mixture of the acidogenic effluents was degraded in a methanation reactor to an extent of 80%. In a final nln with average values near 4 g COD l(-1) day(-1) for loaning rate and 17 days for hydraulic retention rime, over-all organic matter removal reached 87%. (C) 1998 Elsevier Science Ltd. All rights reserved.