Development Of A Methane-Free, Continuous Biohydrogen Production System From Palm Oil Mill Effluent (Pome) In Cstr

This study aimed to develop the start-up experiment for producing biological hydrogen in 2 L continuous stirred tank reactor (CSTR) from palm oil mill effluent (POME) by the use of mixed culture sludge under non-sterile conditions. Besides using different source of starter culture, the effects of acid treated culture and various operating temperature from 35 degrees C to 55 degrees C were studied against the evolved gas in terms of volumetric H-2 production rate (VHPR) and soluble metabolite products (SMPs). The formation of methane was closely observed throughout the run. Within the studied temperature, VHPR was found as low as 0.71 L/L.d and ethanol was the main by-products (70-80% of total soluble metabolites). Attempts were made to produce biohydrogen without methane formation at higher thermophilic temperature (45-55 degrees C) than the previous range. The average of 1.7 L H-2 of 2 L working volume per day was produced at 55 degrees C with VHPR of 1.16 L/L. d. The results of soluble metabolites also are in agreement with the volatile fatty acids (VFAs) which is higher than ethanol. Higher VFAs of 2269 mg/L was obtained with acetic acid being the main by-product. At this time methanogen has been deactivated and no methane was produced. From this study, it can be concluded that thermophilic environment may offer a better option in a way to eliminate methane from the biogas and at the same time improving hydrogen production rate as well.