Wastewater as a resource: Evaluating light dependent and light independent methods, challenges, and future directions for sustainable hydrogen generation

The increasing need for environmentally friendly energy sources has contributed to the development of innovative technologies that also resolve environmental issues. Hydrogen can be produced in a number of ways, including using fossil fuels, biomass, and renewable energy sources like wind and sun. Using renewable energy for water-based production is the most sustainable method of producing hydrogen. However, since fresh water is scarce, the main way to address this issue is to use wastewater. Although wastewater is frequently seen as an issue it could additionally be seen as a valuable source of energy as it has the potential to produce bio-hydrogen. The current review emphasizes the key conclusion of studies examining the viability of the generation of hydrogen from wastewater by applying a variety of technologies in order to investigate each method’s potential, which effectively removes pollutants from wastewater addressing both environmental challenges of wastewater treatment as well as clean energy production. Hydrogen production from wastewater using sustainable, low-energy methods enhances energy recovery in treatment plants and promotes a circular economy. This low-carbon hydrogen supports global decarbonization, and simultaneously achieving pollutant degradation with advanced systems offers dual benefits over traditional wastewater treatment methods. The essential details of 7 emerging technologies, their working mechanisms, affecting parameters, work advances, advantages and disadvantages, and their future prospects are taken into consideration in 2 distinct classes- light-independent and light-dependent technologies.