Food waste-derived volatile fatty acids platform using an immersed membrane bioreactor

Area of Science:

• Biotechnology
• Environmental Engineering
• Chemical Engineering

Background:

• Volatile fatty acids (VFAs) are valuable intermediates from anaerobic digestion (AD) but face challenges in recovery and yield for large-scale applications.
• Existing methods for VFA recovery from AD are often inefficient, hindering their potential as platform chemicals.

Purpose of the Study:

• To design and evaluate a novel anaerobic immersed membrane bioreactor (iMBR) for simultaneous VFA production and in situ recovery.
• To address the limitations of VFA recovery and low yields in conventional AD processes.

Main Methods:

• Development of an anaerobic immersed membrane bioreactor (iMBR) with enhanced cleaning via frequent backwashing.
• Operation of the iMBR using food waste as feedstock without pH control.
• Investigation of continuous VFA recovery over 40 days at varying organic loading rates (OLRs).

Main Results:

• Achieved a high VFA yield of 0.54 g VFA/g VSadded.
• Demonstrated robust performance with stable permeate flux despite high suspended solids (31 g/L).
• Successfully operated at OLRs of 2 gVS/L/d and 4 gVS/L/d without significant flux decline.

Conclusions:

• The novel iMBR system effectively overcomes challenges in VFA recovery and production from complex AD media.
• This technology offers a promising pathway for the efficient and large-scale synthesis of valuable VFAs from waste streams.
• The system's stability and high yield support its potential for industrial application in biorefining.