Hydrogen production from sulfate- and ferrous-enriched wastewater

The quantitative relationship between sulfate reducing bacteria (SRB) and hydrogen (H 2) production from sulfate (SO 4 2−) and ferrous [Fe(II)] enriched wastewater was investigated. Both Fe(II) (0–11,600 mg/L) and SO 4 2− (0–20,000 mg/L) improved the H 2 production efficiency from wastewater. The H 2 yields were increased up to 1.9 mol H 2/mol glucose in 580–1750 mg Fe(II)/L and 1000–3000 mg SO 4 2−/L enriched wastewater at pH 5.8–6.2. Quantitative Fluorescence In Situ Hybridization (FISH) analyses revealed that the specific sulfate reducing activities (SSRA) were increased from 0.08 and 0.06 to 0.16 and 0.21 g TS/g SRB h in response to variations in sulfate concentration from 300–20,000 mg/L at pH 5.8 and 6.2, respectively. H 2 production was not influenced by low SSRA (≤0.1 g TS/g SRB h), which was independent of pH variation. The results demonstrated that the SSRA and Fe(II) concentration can significantly influence on the biological H 2 production from SO 4 2− and Fe(II) containing wastewater. ► High Fe(II) and SO 4 2− concentration improved the biological H 2 production from wastewater. ► Fermentative H 2 production was not influenced by low specific sulfate reducing activities (SSRA). ► FISH analysis showed that the SSRA were also increased.