Our recent technological advancements are placing large burden on the energy sector. The fast developing trends have higher energy requirements too. The global energy provider, fossil fuels being non-renewable & eco-destructive cannot be relied on a long term basis. This realization cast light on the pathway of renewable and sustainable sources. Hydrogen is an eco-friendly fuel with an energy yield nearly 2.75 times that of hydrocarbon fuels. The current production techniques of hydrogen are energy intensive and expensive. This book provides an insight into biological hydrogen production through fermentation of dairy wastewater. It provides environmental benefits in the form of sustainable biofuel generation along with wastewater treatment. A novel approach of using a substrate mixture of dairy wastewater and coir pith in biohydrogen reactor is included in this study. This aspect has reportedly enhanced the biohydrogen production. The analysis shall introduce some new hopes in the field of hydrogen energy research.