Biokinetic and biotransformation of nitrogen during photosynthetic bacteria wastewater treatment

Photosynthetic bacteria (PSB) show a strong potential to degrade pollutants and meanwhile produce valuable biomass, thus realising both wastewater treatment and nutrient recovery. This paper detailed the study of nitrogen distribution forms, biokinetics and transformation during PSB wastewater treatment. The results showed that the total nitrogen (TN) and ammonium (NH4+) removal reached 90.5% and 95.3%, respectively. The nitrogen removal and biomass production fit a quadratic and a cubic regression equation with an R2 of 0.9793 and 0.9730, respectively. Mass balance showed that the influent nitrogen was transformed into valuable PSB cells (63.2%), gaseous N2 (26.9%) and residual NH4+, nitrate (NO3−) and organic nitrogen in the effluent (8.9%). In addition, 53.0% of the influent nitrogen was bio-transformed to protein nitrogen. Excellent nitrogen resource recovery was thus achieved.