Simultaneous removal of organic carbon and nitrogen by a plunging liquid jet bioreactor with crossflow filtration operated under zone-limited aeration.

Abstract

Simultaneous removal of organic carbon and nitrogen by a plunging liquid jet bioreactor with crossflow filtration was investigated under zone-limited aeration conditions in which dispersion of air bubbles was limited to the upper zone of the reactor. In the suspended growth system, TOC removal was about 95%, and nitrogen removal was about 45%. To enhance the nitrogen removal performance, biomass carrier was loaded into the reactor. In the attached growth system, nitrification proceeded successfully and the nitrogen removal was much improved. TOC and nitrogen removal efficiencies were about 98% (the effluent TOC concentration was about 2 g/m3) and 75% (the effluent T-N concentration was about 3 g/m3), respectively. Excellent organic carbon and nitrogen removal was carried out by the reactor in the attached growth system. The cake layer deposit on the membrane acted as a dynamically formed ultrafiltration membrane. The removal of organic carbon and nitrogen by the cake layer largely contributed to the overall performance. It was concluded that the bioreactor system operated under zone-limited aeration had high potentiality for the small-scale treatment of domestic wastewater.