Bioprocessing of Domestic Wastewater and Sewage Sludge for Biohydrogen Production: Different Routes and Pretreatment Strategies

Hydrogen is a clean and non-polluting source of energy, which has received a lot of interest in the recent times. However, for its sustainable production and positive impact on the environment, it is necessary to utilize renewable feedstock as substrate. Municipal wastewater is one such alternative substrate that can be utilized for production of hydrogen through biological route. Large quantities of municipal wastewater are generated worldwide which require treatment. Combining municipal wastewater treatment process with biohydrogen production will help in recovering energy and value addition to the treatment process. Municipal wastewater is a mixture of domestic grey water from kitchen, wastewater from toilets, and sometimes can include industrial wastewater as well. The organic content of the municipal wastewater is generally lower than many other industrial wastewaters and it ranges in between 250 and 100 mg/L of COD. Municipal wastewater is also characterized by low dissolved and suspended solids, making it ideal for easy microbial degradation without any pre-treatment. There are many previous studies that explored biohydrogen production from municipal wastewater, including up scaling the process to industrial level. This chapter aims to provide information from the literature and case studies on biohydrogen production from municipal wastewater including bioreactor designs. Further, it describes the potential use of microbial electrolysis cell (MEC) for biohydrogen production from sewage. It also provides a holistic view on the effect of important process parameters, challenges for its commercialization and future research directions in the field.