Anaerobic hydrogen production under different pre-treatment and operating conditions

To determine the effects of different anaerobic sludge pre-treatment techniques and operating conditions on by-product formation during anaerobic wastewater treatment, five conditions were examined using a glucose-fed, laboratory reactor. The conditions tested included: unaltered inoculum sludge operated at pH 7 and pH 6; boiled inoculum operated at pH 7 and pH 6; and an air sparged inoculum. All conditions were operated as sequencing batch systems with sequentially alternating sparging and non-sparging conditions.; Differences in the amounts of gases, volatile fatty acids and alcohols produced were observed between all conditions. Acetic acid, propionic acid and hydrogen production were favoured during sparging, while ethanol and butyric acid production were favoured during non-sparging. The boiled conditions produced the most hydrogen and the least methane, however with a low total gas production. The pH 6.0 condition, although not the most productive in terms of hydrogen, possibly has the greatest potential for full-scale hydrogen production.