Hydrothermal Liquefaction and Carbonization for Sustainable Treatment of Sewage Sludge

Abstract

Sewage sludge is an emerging concern for the urban population and directly impacts public health. The volume of sludge is increasing with the load on the existing wastewater systems, and it is a serious time to consider its sustainable management. Sludge, an organic and nutrient-rich feedstock, is suitable for multiple conversion processes. But the generated quantity requires approaches that can withstand the required conversion rate. With this scope, the present chapter focuses on sewage sludge hydrothermal treatment, covering liquefaction, and carbonization. The significance of hydrothermal processing due to high moisture and sludge heterogeneity is discussed in detail. The considerations for process specifications are also underlined to indicate the potential utilization of products. In the end, pathway-based resources and energy recovery potential have been discussed for the sustainable conversion of sewage sludge through hydrothermal processing.