Reverse osmosis processing of organic model compounds and fermentation broths

Area of Science:

• Environmental Science
• Chemical Engineering
• Biotechnology

Background:

• Anaerobic fermentation broths contain complex organic compounds requiring effective post-treatment.
• Wastewater management and water recovery are critical in biohydrogen production processes.
• Reverse osmosis (RO) is a potential technology for separating organic compounds from fermentation broths.

Purpose of the Study:

• To evaluate the efficacy of a prototype reverse osmosis (RO) system for post-treatment of anaerobic fermentation broth.
• To determine the rejection and recovery efficiencies of key organic compounds in the broth using RO.
• To assess the feasibility of RO for wastewater management and water recovery in biohydrogen production.

Main Methods:

• A 150 gal/day single cartridge prototype RO system was utilized.
• Baseline tests were performed using six model organic compounds (ethanol, butanol, acetic acid, oxalic acid, lactic acid, butyric acid) at 25°C.
• Rejection and recovery efficiencies were correlated with feed pressure, with and without retentate recirculation.
• Actual fermentation broth from a continuous-flow biohydrogen process was treated under similar conditions.

Main Results:

• The RO system achieved greater than 95% removal of total organic carbon from the actual fermentation broth.
• Baseline tests provided correlations for individual and mixed organic compound removal and recovery.
• Operating conditions were optimized based on feed pressure and retentate recirculation.

Conclusions:

• Reverse osmosis is a highly effective technology for removing organic compounds from anaerobic fermentation broth.
• The RO system demonstrated significant potential for wastewater management and water recovery in biohydrogen production.
• Further studies are warranted to integrate RO into field-deployable systems for sustainable wastewater treatment.