Municipal wastewater sludge as a renewable, cost-effective feedstock for transportation biofuels using hydrothermal liquefaction

Hydrochar derived from municipal sludge through hydrothermal processing: A critical review on its formation, characterization, and valorization

“…Using HTL, where C is maximized to biocrude and P is enriched in hydrochar to allow its recovery, represents a justifiable operation for MS treatment. Through several techno-economic analyses, Pacific Northwest National Laboratory in the US has concluded that HTL of MPS (20-25% TS) is very promising in producing economically competitive and environmentally sustainable biocrude, while significantly reducing management costs and environmental risks associated to sludge solids Seiple et al, 2020Seiple et al, , 2017Snowden-Swan et al, 2017. However, HTL aqueous still contains a large portion of solubilized C (e.g., 20% of total input), which could contribute 9% BOD and 18% ammonia load to the WWTP (Snowden-Swan et al, 2017).…”

Phosphorus recovery from municipal sludge-derived ash and hydrochar through wet-chemical technology: A review towards sustainable waste management

“…Although incineration facilities are well-established and reliable, HTL has attracted extensive interest from academics and industries recently for several advantages. First, it converts wet sludge (5-20% total solids) into energy-dense biocrude for fuel production by processing at a moderate temperature (250-374 • C) and autogenous pressure (4-22 MPa) within a short period (1-60 min) [27]. Second, without drying feedstocks, it is able to generate net-positive energy recovery due to significantly reduced energy inputs and high performance of heat exchanger (up to 80% heat recovery) [28,29].…”

Analysis of operational issues in hydrothermal liquefaction and supercritical water gasification processes: a review

“…The optimum dry content usually has the range of 10-20% by weight for high hydrogen yields in SCWG processes, depending on the biomass type [161]. Meanwhile, HTL processes have feedstocks with higher solid contents at the optimum conditions, e.g., up to 35% [162,163].…”