Modeling the national potential of pyrolytic biochar production from publicly owned treatment works

Biochar production through pyrolysis of wastewater biosolids was modeled across major Publicly Owned Treatment Works (POTWs) in the United States. The model system boundary considered the deployment of a Biogenic Refinery (a commercially available pyrolysis omni-processor) at the end of current POTW solids handling pretreatment trains. An improved pyrolysis biochar yield model was developed to quantify the impact of sequesterable carbon and drying energy requirements based on reported biosolids pretreatment methods for each POTW. These improved metrics allow for a more holistic techno-economic analysis (TEA) and lifecycle assessment (LCA). Results show that pyrolysis could be a carbon negative solution to handling biosolids and producing biochar, especially when modeled with POTWs that are already air or heat drying biosolids. Global warming potential for the biogenic refinery system was modeled across four pretreatment methods that could impact biochar yield: anaerobic digestion, aerobic digestion, combined digestion, and no digestion, and we found that the biogenic refinery could operate with net negative emissions [-55.8 – -78.0 kg CO2eq/ton-biosolids-treated, varying across 2617 facilities]. The TEA showed that the lifecycle cost of biosolids pyrolysis [$145 – $2260 per ton of biochar produced] was sensitive to facility size and biosolids pretreatment methods, with larger facilities being significantly more cost-effective until economy of scale plateaued near 4,000 dry tons/biosolids-yr. No external energy would be needed for drying if facilities already are heat drying biosolids, and facilities that air dry were found to have a mean drying requirement of [3.7, 4.3] GJ/ton-dry-biosolids which is within the range of thermal energy that would be available to the system by considering the difference in biochar output energy and biosolids input energy.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Marszewski, Aaron

Contributors dc:contributor

• Cusick, Roland D.

• Pyrolysis
• Biochar
• Potw
• Biosolids
• Carbon Sequestration
• Tea
• Lca
• Wrrf
• Biogenic Refinery
• Pfas
• Drying Energy

Statement dc:rights

• Copyright 2025 Aaron Marszewski

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129971

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129971