Nutrient utilization and oxygen production by Chlorella vulgaris in a hybrid membrane bioreactor and algal membrane photobioreactor system

Abstract

This work studied oxygen production and nutrient utilization by Chlorella vulgaris at different organic/inorganic carbon (OC/IC) and ammonium/nitrate (NH4+-N/NO3−-N) ratios to design a hybrid aerobic membrane bioreactor (MBR) and membrane photobioreactor (MPBR) system. Specific oxygen production by C. vulgaris was enough to support the MBR if high growth is accomplished. Nearly 100% removal (or utilization) of PO43−-P and IC was achieved under all conditions tested. Optimal growth was achieved at mixotrophic carbon conditions (0.353 d−1) and the highest NH4+-N concentration (0.357 d−1), with preferable NH4+-N utilization rather than NO3−-N. The results indicate the potential of alternative process designs to treat domestic wastewater by coupling the hybrid MBR – MPBR systems.