An anaerobic maifanite-immobilized sludge reactor was used to investigate continuous hydrogen production for treatment of pharmaceutical intermediate wastewater at different organic loading rates according to changes in the hydraulic retention time.

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The feasibility and performance of continuous hydrogen production from herbal wastewater via anaerobic fermentation was investigated at different organic loading rates (OLRs) (from 12 to 96 kg chemical oxygen demand [COD]·L−1·day−1) in diatomite‐immobilized sludge reactor and suspended sludge reactor. Results indicated that the diatomite‐immobilized sludge reactor presented more efficient and stable performance than suspended sludge reactor in terms of hydrogen production rate. In diatomite‐immobilized sludge reactor, the highest hydrogen production rate of 11.17 ± 0.45 mmol·L−1·h−1 was achieved at the optimum OLR of 72‐kg COD·L−1·day−1. The metabolic route of acetate acid and butyrate acid production at low OLR (from 12‐ to 40‐kg COD·L−1·day−1) was modified to be ethanol production by an increase in OLR to 56 and 72‐kg COD·L−1·day−1, which was reflected by the distribution of bacterial community. The maximum energy recovery efficiency by dual production of hydrogen and ethanol was determined to be 31.2 kJ·L−1·h−1 at OLR of 72‐kg COD·L−1·day−1.

Anaerobic continuous stirring tank reactor (CSTR) was employed for biohydrogen production by anaerobic co-digestion from the mixture of herbal wastewater (HW) and monosodium glutamate wastewater (MGW). A series of blend volumetric proportions (MGW/HW), organic loading rates (OLR) were used as control strategy and evaluated for optimal biohydrogen production. The highest biohydrogen production of 7260±7.7 mL L-1 d-1 was attained at blend proportion of 15%, OLR of 41 g COD L-1 d-1 while the highest biohydrogen yield of 508.9±7.2 mL g CODremoved-1 was observed at same conditions. This study demonstrated the feasibility and effectiveness of enhanced biohydrogen production by adding MGW to compensate the low nitrogen content of HW.