A review on evaluation of applied pretreatment methods of wastewater towards sustainable H₂ generation: Energy efficiency analysis

This study reviewed the recent updates on the pretreatment methods employed towards the enhancement of hydrogen production. Low hydrogen yield was considered to be a current obstacle for hydrogen utility on the industrial scale. On pretreating, the wastewater, the structure of the macromolecule gets dissipated and destroyed which reduces the polymerization potency. It favors the availability of monomers for the fermentation process. Various pretreatment methods with operating conditions and parameters were documented along with their pros and cons. Mainly, the pretreatment methods adopted for reducing the toxicity levels of wastewater to enhance biohydrogen production are dealt with in detail. Pretreatment methods have shown a positive impact on most of the cases studied. It acts on various components of wastewater and makes it amenable for the hydrogen-producing microbiome. Energy balance methodologies have also been provided towards the selection of a cost-effective and sustainable approach. Perspectives and recommendations on pretreatment systems were directed towards the development of a successful hydrogen economy. Overall documentation details the significance of pretreatment in the fermentation process for higher hydrogen yield.