Influence of reactor configuration on fermentative hydrogen production during wastewater treatment

Influence of reactor configuration [biofilm/suspended growth] on fermentative hydrogen (H2) production and substrate degradation was evaluated employing anaerobic mixed consortia. Reactors were operated at acidophilic (pH 6.0) condition employing designed synthetic wastewater as substrate at an organic loading rate of 3.4 Kg COD/m3-day with a retention time of 24 h at 28 ± 2 °C. Experimental data enumerated the influence of reactor configuration on both H2 production and wastewater treatment. Biofilm reactor (28.98 mmol H2/day; 1.25 Kg COD/m3-day) showed relatively efficient performance over the corresponding suspended growth configuration (20.93 mmol H2/day; 1.08 Kg COD/m3-day). Specific H2 yields of 6.96 mmol H2/g-CODL-day (19.32 mmol H2/g-CODR-day) and 5.03 mmol H2/g-CODL-day (16.10 mmol H2/g-CODR-day) were observed during stabilized phase of operation of biofilm and suspended growth reactors respectively. Higher concentration of VFA generation was observed in the biofilm reactor. Both the configurations recorded higher acetate concentration over other soluble metabolites indicating the dominance of acid-forming metabolic pathway during the H2 production process.