Modeling the impact of feedstock composition and operating temperature on carbon sequestration potential of fecal sludge-derived biochar

Omni Processors (OPs) are community-scale sanitation technologies that can provide decentralized fecal sludge management in areas where sewered sanitation is not feasible. Pyrolytic OPs leverage oxygen-limited thermal treatment to convert fecal sludge into biochar, a graphitic solid which sequesters carbon and improves soil quality. While the general environmental benefits of biochar are known, specific characteristics and carbon sequestration potential of biochar depend on pyrolysis conditions and feedstock composition. It is difficult to accurately assess the benefits of biochar produced in a pyrolytic OP without this context. In this work, a pyrolytic OP was modeled using QSDsan, an open-source quantitative sustainable design tool. Building on an existing process model, additional empirical relations were incorporated to link pyrolysis temperature and feedstock characteristics to biochar yield and carbon sequestration potential. Altogether, the integrated model was used to evaluate system costs, lifecycle environmental impacts, and the fate of carbon and nutrients. By simulating the performance of the system across feedstock ash content from 15% to 75% and at temperatures from 300°C to 900°C, the relative importance of these parameters for yield and carbon sequestration was characterized. Simulations revealed positive correlations between pyrolysis temperature and biochar yield, feedstock ash content and biochar yield. The trends identified in this study can be used to generate insight to optimize biochar production and carbon sequestration potential, and according to context-specific needs.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• To, Lane

Contributors dc:contributor

• Cusick, Ro D
• Guest, Jeremy S

• Biochar
• Carbon Sequestration
• Pyrolysis
• Fecal Sludge Management
• Non-sewered Sanitation
• Decentralized Sanitation

Statement dc:rights

• Copyright 2023 Lane To

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/120468

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F120468