An Integrated Approach to the Hydrothermal Carbonization of Sewage Sludge: Simulation, Modeling, and Life Cycle Assessment

Sewage sludge management at wastewater treatment plants is becoming a more and challenging task. Here, an innovative integrated modeling approach developed to investigate the optimization of municipal plant (MWWTP) by inclusion hydrothermal carbonization (HTC). To this aim, two alternative layouts have been considered: (i) conventional activated sludge-based plant, i.e., based on thickening, stabilization, conditioning, dewatering; (ii) additional spent liquor in line. An Italian MWWTP has selected as case study, three different scenarios implemented process simulation software World Wide Engine for Simulation Training Automation (WEST) considering effect digestion times aerobic reactor. Then, according Design Experiment (DoE) methodology applied both simulated experimental data, use Python code, desired models compared. Finally, Life Cycle Assessment (LCA) study carried out estimate impacts human health, ecosystems, resources. The integration HTC corresponds generation valuable product (the hydrochar), whereas layout associated with high disposal costs sewage sludge. According LCA results, age 40 days recommended due lowest estimated, without section. This ascribed mainly electricity demand line, which increases excess flow rate, decreases.