Integrated anaerobic digestion and electrodialysis process model for enhanced volatile fatty acids recovery from thin stillage

Anaerobic digestion (AD) is widely applied for renewable energy recovery via biogas production. However, due to the abundant availability and low price of natural gas, biogas as a renewable energy source faces economic limitations. To enhance the sustainability and economic viability of AD, recent efforts have focused on uncoupling methanogenesis to produce valuable carboxylates, especially volatile fatty acids (VFAs). Efficient separation and recovery of these VFAs represent significant technological and economic challenges. This study focuses on modeling and optimizing integrated AD and electrodialysis (ED) processes for enhanced VFA production and separation. The Anaerobic Digestion Model No. 1 (ADM1) was modified within the QSDsan platform to accurately represent fermentation pathways, including lactate and ethanol formation. Experimental data obtained from continuous operation of hybrid bioreactors inoculated with cow manure, using glucose and thin stillage as substrates, were used to calibrate the model. Simulation results demonstrated the critical influence of operational pH on the metabolic pathways, promoting either biogas or VFA production. An ED process model developed in BioSTEAM allowed for the evaluation and optimization of key operational parameters such as membrane area, current density, and hydraulic retention time under steady-state and continuous conditions. Techno-economic analysis (TEA) revealed membrane area and current density as critical cost determinants, with optimized conditions significantly reducing energy consumption and operating costs. Overall, this integrated modeling approach provides valuable insights into the scalability and economic feasibility of sustainable carboxylate recovery processes, offering a competitive alternative to traditional separation methods such as multi-effect evaporation.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Park, Junhyung

Contributors dc:contributor

• Cusick, Roland

• Electrodialysis
• Anaerobic Digestion
• Volatile Fatty Acids
• Techno-economic Analysis
• Resource Recovery

Statement dc:rights

• Copyright 2025 Junhyung Park

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129775

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129775