Co-digestion of corn (nejayote) and brewery wastewater at different ratios and pH conditions for biohydrogen production

The capacity of a heat-treated sludge (HTS) to produce hydrogen from the mono-and co digestion of corn (NW, pH 13.1) and brewery (BW, pH 3.8) wastewater was evaluated. The co-digestion of NW and BW was conducted with ratios (NW/BW) from 40/60 to 80/20 (vol/ vol) at pH 6 and under different initial pH values (from 5.8 to 12.3) according to the substrates mixtures. With the initial pH adjusted to 6, the highest production (302 mL) occurred for the mono-digestion of NW, but hydrogen was produced in all incubations. For incubations under variable pH values, the highest hydrogen production was obtained with the ratio 60/40 (270 mL), followed by the ratio 65/35 (260 mL) with pH values of 10.8 and 10.4, respectively. The initial pH influenced the kinetic parameters, especially on maximum production and lag phase. For the ratio 60/40, with an alkaline pH value (10.4), the lag phase was delayed up to 122 h, but the highest volume of hydrogen was obtained with this condition. The Clostridium genus, present in all samples, could be associated as the main responsible for hydrogen production. Besides, the presence of Burkholderia genus, previously related to hydrogen production, was identified as the main involved in the culture at pH 10.8. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study evaluated the capacity of heat-treated sludge to produce hydrogen through mono-and co-digestion of corn and brewery wastewater. Different initial pH values significantly influenced hydrogen production, with alkaline conditions potentially enhancing the production. The Clostridium genus played a key role in hydrogen production, especially under alkaline pH conditions.