Technical insights on various routes of hydrogen production from pharmaceutical, hydrothermal, sewage and textile wastewaters: Cost comparison and challenges

[Display omitted] •Industrial wastewater treatment-based hydrogen production is hot research area.•Light dependent and independent are the common techniques for hydrogen production.•Microbial electrolysis is the most cost economical way for hydrogen production.•Future research needed in hydrogen safe storage, transport and distribution. Wastewater generation and its complex nature paves way for the need of sustainable treatment regime for effective treatment and safer discharge. This review mainly focuses on clean and sustainable approaches for achieving simultaneous goals of hydrogen and wastewater treatment. Different hydrogen production routes, challenges, opportunities and futuristic research directions are investigated. Photocatalysis, microbial electrolysis, photocatalysis, dark fermentation, super critical water gasification and photoelectrochemical methods are the most common methods investigated for hydrogen production from wastewater in both lab-scale and pilot scale. However, the success of the method depends upon the environmental, economic, exergetic and energetic analysis. It was found that microbial electrolysis and photocatalysis method will serve for lowest global warming potential (GWP). This review will serve in achieving sustainable development goals (SDGs) like good health and well-being (SDG 3), clean water and sanitation (SDG 6), affordable and clean energy (SDG 7), economic growth (SDG 8) and climate action (SDG 13) respectively.