Concepedia

Biohydrogen Production as a Function of pH and Substrate Concentration

Steven Van Ginkel, Shihwu Sung, Jiunn‐Jyi Lay

Environmental Science & Technology · 2001 · 728 citations · 8 references

TL;DR

The conversion of organics in wastewater into hydrogen gas could serve the dual role of renewable energy production and waste reduction. The study aimed to recover the chemical energy of a sucrose‑rich synthetic wastewater as hydrogen gas. Using a fractional factorial design, batch experiments varied pH (4.5–7.5) and substrate concentration (1.5–44.8 g COD L⁻¹) with mixed bacterial cultures from compost, potato, and soybean fields that were heat‑treated to suppress methanogens and enrich sporeforming acidogens. The maximum hydrogen production rate was 74.7 mL H₂ (L h)⁻¹ at pH 5.5 and 7.5 g COD L⁻¹, yielding a conversion efficiency of 38.9 mL H₂ (g COD L⁻¹), with the highest observed efficiency reaching 46.6 mL H₂ (g COD L⁻¹).

Abstract

The conversion of organics in wastewaters into hydrogen gas could serve the dual role of renewable energy production and waste reduction. The chemical energy in a sucrose rich synthetic wastewater was recovered as hydrogen gas in this study. Using fractional factorial design batch experiments, the effect of varying pH (4.5−7.5) and substrate concentration (1.5−44.8 g COD/L) and their interaction on hydrogen gas production were tested. Mixed bacterial cultures obtained from a compost pile, a potato field, and a soybean field were heated to inhibit hydrogen-consuming methanogens and to enrich sporeform ing, hydrogen-producing acidogens. It was determined that the highest rate (74.7 mL H2/(L*h)) of hydrogen production occurred at a pH of 5.5 and a substrate concentration of 7.5 g COD/L with a conversion efficiency of 38.9 mL H2/(g COD/L). The highest conversion efficiency was 46.6 mL H2/(g COD/L).