Volatile Fatty Acids (VFA) Production and Recovery from Chicken Manure Using a High-Solid Anaerobic Membrane...

Area of Science:

• Biotechnology
• Environmental Science
• Waste Management

Background:

• Chicken manure (CM) presents a significant waste stream with potential for valorization.
• Volatile fatty acids (VFA) are valuable platform chemicals with diverse industrial applications.
• Current organic waste management strategies often lack efficient VFA recovery mechanisms.

Purpose of the Study:

• To investigate the efficacy of a semi-continuous immersed anaerobic membrane bioreactor (AnMBR) for VFA production and recovery from chicken manure.
• To evaluate the impact of pH and organic loading rates (OLR) on VFA yield and bioconversion efficiency.
• To assess the long-term performance and membrane filtration stability of the AnMBR system.

Main Methods:

• Utilized a semi-continuous immersed anaerobic membrane bioreactor (AnMBR) with thermal-shocked chicken manure (CM) as both inoculum and substrate.
• Investigated the effects of varying organic loading rates (OLR) and pH conditions on VFA production.
• Conducted long-term fermentation and filtration trials to assess system stability and performance.

Main Results:

• Achieved a high VFA yield of 0.90 g-VFA/g-VS without pH control at an OLR of 2 g-VS/(L·d), which was 24% higher than controlled pH conditions.
• Demonstrated enhanced hydrolysis and acidogenesis activities under weak alkaline conditions (~pH 8.2).
• Maintained stable membrane filtration performance for approximately 50 days under high-solid (37-45 g/L) and high-flux (20 L/(m²·h)) conditions during a 78-day operation.

Conclusions:

• The AnMBR process is a feasible and promising method for the efficient production and recovery of VFA from chicken manure.
• Operating AnMBR at a non-controlled, weak alkaline pH optimizes VFA yield.
• The AnMBR system demonstrates robustness for sustained VFA production and recovery from challenging high-solid waste streams.