Pretreatment of cheese whey for hydrogen production using a simple hydrodynamic cavitation system under alkaline condition

• Hydrodynamic cavitation (HC) system gives heating and sonication effects.
• HC satisfies the commercialization requirements such as low energy and scale-up.
• Combination of HC with alkaline makes more advantages including production rate.

A simple hydrodynamic cavitation (HC) system was newly employed as a pretreatment method for H2 production from cheese whey. This system offered not only the sonication effect but also an increase in the temperature of the solution. With HC pretreatment for 15 min, a higher H2 production yield (1.89 mol H2/mol lactose) was obtained than with other conventional pretreatment methods such as heating and sonication. HC pretreatment efficiency was synergistically increased when combined with alkaline conditions. In this way, the amount of solubilized nutrient was greatly increased and methanogens were completely removed, leading to H2 gas of higher purity (48%) and a yield of 3.30 mol H2/mol lactose. HC pretreatment under alkaline conditions can be used to efficiently pretreat organic-rich wastewater, including cheese whey, without any scale-up problem, and is an excellent pretreatment option for H2 production.