Improvement of Mesophilic Biohydrogen Production from Palm Oil Mill Effluent Using Ozonation Process

Biological fermentative production of hydrogen from the ozonated palm oil mill effluent (POME) was conducted in batch reactors using an anaerobic sludge as a microbial seed. Fermentation was setup at pH 4.0-6.0, varying POME concentration range of 5,000-37,000 mg L-1 under mesophilic condition (37 °C). The results showed that pH 6.0 is an optimum pH and the maximum hydrogen yield of 28.3 mL g-1 COD was obtained. Comparative results of hydrogen production from the raw POME versus the ozonated POME indicated that the ozone pretreatment of POME (mg COD: mg ozone = 102.8) elevated the biodegradability of the POME constituents and significantly enhanced yield and rate of the hydrogen production. Hydrogen production using ozonated POME concentration of 30,000 mg L-1 displayed the maximum yield of 182.3 mL g-1 COD, which is 49% higher than that from raw POME. Meanwhile the maximum production rate of 43.1 mL h-1 was observed at COD concentration of 25,000 mg L-1 ozonated POME. Maximum COD removal was 44% at COD concentration of 15,000 mg L-1 ozonated POME. This work demonstrated ozonation of POME significant improved performance of hydrogen production.