Isolation and Identification of a Carbon-Fixing Bacteria Strain and Its Efficiency for Nitrogen and Phosphorus Removal from Viaduct Rainwater

In order to explore bacteria resources that are applicable for purification of viaduct rainwater, a carbon-fixing bacteria strain numbered 1C-1 was isolated from the sediment of a viaduct rainwater tank. The strain was identified through morphological characteristics and 16S rDNA sequences. The effects of three main factors (the simulated viaduct rainwater concentration, the carbon source dosage, and the inoculation amount) on the nitrogen and phosphorus removal rate of the strain were tested using simulated viaduct rainwater. Based on this, the nitrogen and phosphorus removal efficiencies for the actual viaduct rainwater were verified. The results showed that the strain belonged to Streptomyces sp. Under different simulated viaduct rainwater concentrations, the strain exhibited relatively high efficiency for nitrogen and phosphorus removal at the original concentration of simulated viaduct rainwater; other conditions remaining unchanged, the purification efficiency was relatively high when the glucose dosage was 800 mg, and the removal rates of ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) were 71.48%, 47.86%, and 10.43%, respectively; other conditions remaining unchanged, the purification efficiency was relatively high when the inoculation amount was 1%, and the removal rates of NH4+-N, TN, and TP reached 58.62%, 58.35%, and 27.32%, respectively. Under the above optimal process conditions of an original concentration of viaduct rainwater, a carbon source dosage of 800 mg, and an inoculation amount of 1%, the strain removed 92.62%, 6.98%, and 6.16% of NH4+-N, TN, and TP, respectively from the actual viaduct rainwater; more interestingly, the removal rates of NH4+-N and TN were 43.26% and 78.02%, respectively, even without carbon source addition. It seems that there is no need for carbon source addition to remove nitrogen from the actual viaduct rainwater for the strain. To sum up, the carbon-fixing bacteria 1C-1 presents an obvious nitrogen and phosphorus removal effect (especially for nitrogen) for viaduct rainwater treatment and has application potential.