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

Marszewski, Aaron

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

Description

Title

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

Author(s)

Marszewski, Aaron

Issue Date

2025-07-22

Director of Research (if dissertation) or Advisor (if thesis)

Cusick, Roland D

Department of Study

Civil & Environmental Eng

Discipline

Environ Engr in Civil Engr

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Pyrolysis
• Biochar
• POTW
• Biosolids
• Carbon Sequestration
• TEA
• LCA
• WRRF
• Biogenic Refinery
• PFAS
• Drying Energy

Abstract

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.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

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

Copyright and License Information

Copyright 2025 Aaron Marszewski

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