Ammonia recovery from acidogenic fermentation effluents using a gas-permeable membrane contactor

A gas-permeable membrane (GPM) contactor was used to recover ammoniacal nitrogen from a synthetic and a biowaste fermentation broth under different pH (from 6 to 11) and temperatures (35 and 55 ?). Ammonia mass transfer constant (K-m) increased as pH and temperature increased. For synthetic broth, pH 10 provided the best results, when considering the K-m (9.2.10(-7) m.s(-1)) and the reagents consumption (1.0 mol NaOH.mol(-1) TAN and 0.6 mol H2SO4.mol(-1) TAN). Biowaste fermentation generated a broth with a high concentration of ammoniacal nitrogen (4.9 g N.L-1) and volatile fatty acids (VFA) (41.1 g COD.L-1). Experiments using the biowaste broth showed a lower K-m (5.0.10(-7) m.s(-1) at pH 10) than the synthetic broth, related to the solution matrix and other species interference. VFAs were not detected in the trapping solution. Overall, these results show that GPM is a suitable technology to efficiently separate ammoniacal nitrogen and VFA from fermentation broths.

Automated summary

A gas-permeable membrane (GPM) contactor is a suitable technology to efficiently separate ammoniacal nitrogen and volatile fatty acids (VFA) from fermentation broths under different pH and temperature conditions.