Exploring the feasibility of biological hydrogen production using seed sludge pretreated with agro-industrial wastes

The effect of applying agro-industrial waste (AIW), such as potash extract (PE), cassava-steep wastewater (CSWW), and corn-steep liquor (CSTL), as an alternative material to pretreat digested cattle slurry (DCS) for biological hydrogen production was examined. In this study, the pretreated (PT) DCS was employed for H2 fermentation in batch cultures utilising glucose and sucrose as substrates. The result showed that, at 55 degrees C and pH 5.5, the pretreated DCS's daily volumetric hydrogen production (VHP) was higher than the untreated DCS. Although heat-shocked DCS produced a higher daily VHP of 135 NmL H2 g- 1 VS on the second day using glucose as substrates, it is followed by PE-PT DCS, which gave a peak daily VHP of 115 NmL H2 g-1 VS but at a shorter time. When sucrose was the carbon source, the highest peaks were recorded in all the laboratory reactors on day two, with the highest daily VHP of 211 NmL H2 g-1 VS achieved in PE-PT DCS digesters. After the different DCS PT studies, the dominant phylum Firmicutes, represented by the Clostridium and Ruminococcus, were the most abundant bacteria compared to the untreated DCS, which was more diverse. Further research is required to optimise the conditions for AIW DCS pretreatment.

Automated summary

The study examined the use of agro-industrial waste (AIW) as an alternative material to pretreat digested cattle slurry (DCS) for biological hydrogen production. The results showed that the pretreated DCS had higher daily volumetric hydrogen production (VHP) compared to the untreated DCS. When glucose was used as a substrate, heat-shocked DCS had the highest daily VHP, followed by PE-PT DCS. When sucrose was used, PE-PT DCS achieved the highest daily VHP. Further research is needed to optimize AIW DCS pretreatment conditions.