Abstract
In pursuit of establishing a circular economy, a waste-to-energy approach is gaining increasing attention. Valorization of sewage sludge constitutes a critical importance due to generation in high quantities, difficulties in disposal, and associating environmental impacts. Hydrothermal carbonization (HTC) is a relatively recent yet an acclaimed method for sewage sludge management and valorization due to process compliance with sludge characteristics. In this review, research studies are evaluated via categorization of application fields of sludge-derived HTC products such as solid fuel production, gas production, soil remediation, nutrient recovery, water treatment, and energy storage. Research findings are compiled and a network mapping is employed for the visualization of the current situation and correlation in respective fields. The potential of HTC for sewage sludge valorization and future projections concerning available techniques are assessed within the context of circular economy.
Highlights
Industrialization and population growth led to increasing quantities of sewage sludge raising environmental concerns [1, 2] due to contaminants, pathogens, and toxic elements in its composition [3]
A methane yield of 248 ml C H4 g COD−1 and a chemical oxygen demand (COD) reduction of 86% was achieved. These results suggest that Hydrothermal carbonization (HTC) of activated sludge might be a probable addition to wastewater treatment plants
Available publications on HTC of sewage sludge are assessed in relation to feedstock, method, end product, and application field
Summary
Industrialization and population growth led to increasing quantities of sewage sludge raising environmental concerns [1, 2] due to contaminants, pathogens, and toxic elements in its composition [3]. The applications of products obtained from HTC of sewage sludge are evaluated in detail under the following categories: (i) solid fuel production; (ii) gas production by HTC integrated processes; (iii) soil remediation; (iv) nutrient recovery; (v) pollutant adsorption; and (vi) energy storage. Combustion properties of hydrochar produced from the HTC of sewage sludge at 200 °C are investigated in the study by He et al [34].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
