Bioconversion of wastewater by photosynthetic bacteria: Nitrogen source range, fundamental kinetics of nitrogen removal, and biomass accumulation

There is great potential for nitrogen removal in wastewater treatment by photosynthetic bacteria (PSB) bioconversion. Protein-rich cells can be cultured simultaneous to nitrogen removal. For the first time, efficient nitrogen source range, kinetics of nitrogen removal and biomass accumulation of PSB bioconversion technology were studied. Results are that efficient nitrogen range is 3–8000 mg·L⁻¹, which covers most wastewaters. Biokinetics was fit to Michaelis–Menten model, Monod model and inhibition models including Haldane, Edwards, and Aiba models. The data were best fitted by Aiba model, with an R² of 0.97. V_max, K_m, and K_i of nitrogen degradation were 0.065 d⁻¹, 1344 mg·L⁻¹, and 6525 mg·L⁻¹, respectively, and μ_max, K_s, and K_i of biomass accumulation were 5.88 d⁻¹, 883 mg·L⁻¹, and 1521 mg·L⁻¹, respectively. PSB bioconversion technology is more suitable than others for high nitrogen wastewater treatment.