Gasification of Sewage Sludge for Hydrogen Production

Sewage sludge production has increased severely in recent years and is predicted to grow multifold in the upcoming years. Sustainable treatment technologies for sewage sludge with efficient utilization of its energy potential are the need of the hour. Energy production from sewage sludge in the form of clean hydrogen has enough potential to meet the forthcoming energy requirement. This chapter discusses the biological and thermochemical treatment technologies for sewage sludge for hydrogen production. The advantages of thermochemical and biological methods have been discussed. Especially, gasification technology and distinct amendments in the gasification process employed for intensifying and improving results have been mentioned. In particular, co-gasification, catalytic gasification, and the role of reactor configuration for sewage sludge have been discussed comprehensively. The review of past studies suggested that gasification is advantageous for hydrogen production rather than other thermochemical techniques. Moreover, the mechanisms of pyrolysis, gasification, and supercritical water gasification (SCWG) have been discussed. Applying supercritical water as a gasifying agent positively impacts hydrogen yield during sewage sludge gasification. The chapter summarizes the scope of future research as the development of new catalysts and innovative reactor configurations for improved efficacy of sewage sludge thermochemical conversion.