Ozonation aided mesophilic biohydrogen production from palm oil mill effluent

Abstract

Ozone pretreatment of palm oil mill effluent (POME) was employed to improve sustrate biodegradability prior to biological H2 production. The H2 production was conducted at varing pHs from 4.0 to 6.0 to examine the impact of pH on the H2 mesophilic production (37 °C). The optimal pH for H2 production was 6.0 for both raw and ozonated POME. The POME concentrations were greatly influenced the yields and rates of H2 production. At the optimal pH, the maximum H2 production yield of 182 ± 7.2 mL.g−1 COD (7.96 mmoL.g−1 COD) was achieved at the ozonated POME concentration of 30,000 mg COD.L−1. The maximum H2 production rate (Rmax) of 43.1 ± 2.5 mL.h−1 was obtained at the ozonated POME concentration of 25,000 mg COD.L−1. The highest total COD removal was 44% at of 15,000 mg COD.L−1 ozonated POME. Acetic and butyric acids were dominant products during H2 fermentation and tended to increase with the increased POME concentrations. Ozonation as a pretreatment process showed significant enhancement of the POME biodegradability , and subsequently improved the H2 production H2.