Nitrogen and Biomass Recovery from Low Carbon to Nitrogen Ratio Wastewater by Combing Air Stripping and Microalgae Cultivation

Abstract

an air stripping-microalgae cultivation system was proposed to recover nitrogen and produce biomass from biogas fertilizer production wastewater. air stripping was firstly used for reducing the nitrogen to low levels. Then microalgae were used for absorbing the residual nitrogen. Results showed that the nitrogen removal reached 95.0%, with a microalgae productivity and biomass yield of 0.21 (g/L/d) and 4.29 (g-biomass/g-nitrogen), respectively. For the system, 87.7% of the total nitrogen was recycled, from which 83.9% came from air stripping and 3.8% from microalgae absorption. This system enables carbon-emission reduction, wastewater treatment and the promotion of nitrogen recovery.