Modeling of Sustainable Base Production by Microbial Electrolysis Cell

Area of Science:

• Environmental microbiology
• Electrochemical engineering
• Biotechnology

Background:

• Wastewater treatment often generates undesirable byproducts.
• Microbial electrolysis cells (MECs) offer a sustainable approach to wastewater treatment and resource recovery.
• Controlling pH is crucial for maintaining microbial activity in MECs.

Purpose of the Study:

• To establish and validate a predictive model for microbial/electrochemical base formation from wastewater.
• To compare model predictions with experimental results in a microbial electrolysis cell.
• To investigate the feasibility of generating a strong base using specific microbial strains and electrochemical conditions.

Main Methods:

• Development of a predictive model for microbial and electrochemical base generation.
• Experimental validation using a microbial electrolysis cell with Shewanella oneidensis MR-1.
• Anolyte composition varied, including Na2 SO4 /K2 SO4 and bicarbonate buffers.
• Applied voltages ranged from 0.3 to 1.1 V.

Main Results:

• The predictive model accurately matched experimental results when using a Na2 SO4 /K2 SO4 anolyte.
• A strong base (pH ≈ 13) was successfully generated using Shewanella oneidensis MR-1 within the tested voltage range.
• The use of bicarbonate in the anolyte maintained a stable pH, crucial for microbial viability.

Conclusions:

• The developed predictive model is a reliable tool for understanding and optimizing microbial/electrochemical base formation.
• Shewanella oneidensis MR-1 can efficiently produce high pH environments in MECs.
• Bicarbonate buffering is essential for sustaining microbial activity during base generation in MECs.