Benchmark study of photosynthetic bacteria bio-conversion of wastewater: Carbon source range, fundamental kinetics of substrate degradation and cell proliferation

Photosynthetic bacteria (PSB)-bioconversion is a novel method for wastewater treatment and resource recovery. But fundamental knowledge on effective substrate range, cell proliferation and substrate degradation kinetics are lacking. This paper studied the efficient range of carbon source (in terms of COD) and the fundamental kinetics of COD degradation and cell proliferation of this technology. Results showed that the efficient concentration range of carbon source was 500–40,000 mg·L−1 COD for PSB, which covers most organic wastewaters. Then the substrate degradation and cell proliferation kinetics were studied using Michaelis-Menten equation and Monod equation. The Vmax, Km, μmax and Ks was 4.80 d−1, 7382 mg·L−1, 1.23 d−1 and 7714 mg·L−1 under light-anaerobic condition, and they were 4.27 d−1, 4813 mg·L−1, 0.59 d−1 and 21,295 mg·L−1 under dark-aerobic condition; which fell in the range of conventional biological wastewater technologies. This benchmark study lays foundation for further study and scale-up of this novel technology.