Major Science and Technology Program for Water Pollution Control and Treatment (2014ZX07201010)

response relationship between the microbial community and water environmental factors and to identify changes in the microbial population in response to the addition of electronic donor NH4+-N, NO2--N, NO3--N. The results showed that the dominant microorganisms in groundwater were Exiguobacterium, Citrobacter, Acinetobacter and Pseudomonas, which accounted for more than 40% of the total microbes in the study area. When combined with the results of a water chemical factor test, the dominant bacteria were found to be correlated with Fe2+, Mn2+, NH4+, NO3-, NO2-, HCO3-, DOC, and pH in the water. However, the microbial population changed after the addition of the electron donor, with Pseudomonas, Serratia, Enterobacter, Azomonas, and Ewingella accounting for 97.06% of the total sequences. Indigenous nitrogen degrading bacteria suitable for low temperature, low oxygen and oligotrophic groundwater were screened out. The total removal efficiency of NH4+-N, NO2--N and NO3--N in 120 hours was 90.83%, 75.04% and 73.35%, respectively. According to the experimental results, the degradation reaction kinetics followed a pseudo-second-order equation. The results presented herein provide an important scientific basis for the microbial remediation of groundwater contaminated by ammonia.