TREATMENT PERFORMANCE AND MICROBIAL STRUCTURE OF A GRANULAR CONSORTIUM HANDLING METHANOLIC WASTE

Granular sludge cultivated on brewery waste was subjected to the treatment of methanolic waste in an UASB reactor at mesophilic temperatures. More than 80% of methanol could be converted at an average volumetric loading rate of 15 g methanol/l.d. A maximum volumetric loading rate of 32 g methanol/l.d was applied with conversion efficiency of 70%. The granules were stable after 120 d of operational period although they underwent certain changes. The conversion of methanol has been shown to occur through the intermediate formation of volatile fatty acids which is indicated to be the rate-limiting step. After the substrate shift, there was alteration in the methanogenic population. The scanning electron microscopy of the interior of the granules revealed that the granules consisted of heterogeneous population in the core and the exterior layer but a single morphology in the layer in between. The treatment results manifest good potential of applicability of anaerobic treatment to methanolic wastes.