The influence of enzyme and surfactant on biohydrogen production and electricity generation using Palm Oil Mill Effluent

Batch production experiments on biohydrogen from Palm Oil Mill Effluent (POME) pretreated with (i) OPTIMASH BG® (enzyme) and (ii) Tween 80® (surfactant) were carried out using anaerobic seed sludge subjected to heat pretreatment at 105 °C for 90 min. Batch experiments were also conducted in a double chamber microbial fuel cell separated by a Proton Exchange Membrane (PEM) to study the amount of electricity produced. Results from a pretreatment with OPTIMASH BG® at 0.20% and pH 7 showed a hydrogen yield of 1.88 mol H2/g COD. Better results were obtained when the wastewater was pretreated with Tween 80® at the same concentration and pH, where the hydrogen yield was 2.76 mol H2/g COD. In all pretreatments, no methane production was observed when using the heat-treated sludge as seed inoculum. The percentage COD removal was found to be 58% using Tween 80® as pretreatment whereas the OPTIMASH BG® pretreatment resulted in a 52% reduction in COD. The maximum power output was obtained from POME after pretreatment with Tween 80® (15,066 mW). On the other hand, the average maximum power output with POME pretreated with OPTIMASH BG® and untreated POME was 12,434 mW and 10,926 mW, respectively. Higher COD removal rates and power outputs were seen for both pretreatment methods as compared to the control. The conditions that enhanced hydrogen production also enhanced electricity generation. The results indicate that POME can be used as a source of renewable biomass to produce hydrogen. Pretreatment with Tween 80® and OPTIMASH BG® considerably enhances the H2 production, with the former showing better results than the latter.

► Palm Oil Mill Effluent can be potential source of hydrogen production.
► Heat-treated anaerobic inoculum increases hydrogen production and eliminates methane.
► All pretreatment methods showed positive influence on overall H2 production rate.
► Hydrogen production was highest for Tween 80® followed by OPTIMASH BG®.
► COD removal rate and power output obtained using pretreated Palm Oil Mill Effluent were higher than the control.