Guangdong nongye kexue (Dec 2022)
Screening and Identification of a Strain of Heterotrophic Nitrification Bacteria and Its Application in Wastewater Treatment of Rural Farming
Abstract
【Objective】Aiming at the problem of being difficult to treat the high concentration of NH4+-N in farming wastewater, one heterotrophic nitrification bacterium was isolated and screened from the lake sediment.【Method】The screened strains were subjected to Gram staining, scanning electron microscopy and strain identification. Homology analysis of 16SrDNA sequencing results was performed in the Blast database and phylogenetic trees were constructed. The heterotrophic nitrification and aerobic denitrification properties of this strain under different nitrogen sources were studied, and the denitrification characteristics were studied with different inoculum levels, carbon source, initial pH, temperature, C/N, and initial NH4+-N concentration as environmental factors. Finally, the strain was added to the actual rural pig wastewater to evaluate its application ability.【Result】The strain of heterotrophic nitrification strain was identified as Acinetobacter sp and named L-1. Univariate experiments showed that L-1 had the best heterotrophic nitrification effect under inoculation ratio of 2%, carbon source of sodium citrate, pH 6-9, temperature 20-30 ℃, C/N 10-20, and NH4+-N initial concentration of 50 mg/L. In the actual pig wastewater, L-1 was added to the wastewater for nitrogen removal, in which the 1 000 mg/L NH4+-N wastewater was reduced to 298.46 mg/L at the 96th hour. The removal rate of NH4+-N reached 70.15%, which was 45.78% higher than that of the blank control group, while both concentrations of NO3--N and NO2--N were decreased.【Conclusion】The strain L-1 has the ability of heterotrophic nitrification and aerobic denitrification, which has certain reference value in the study of heterotrophic nitrification bacteria for the treatment of pig wastewater.
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