| The ammonium removal strain C17 has been isolated from activated sludge of the coking wastewater. First, the strain was identified by 16 S r RNA. The ammonium degradation properties and pathway were further studied. Fllowing is the main experimental content.Based on the 16 S r DNA amplification and sequencing report, the ident of the strain is 100% with Alcaligenes faecalis strain BAB-1832 and the strain was named Alcaligenes sp. C17.The components of the initial culture medium are carbon source sodium citrate, nitrogen source ammonium sulphate, microelement magnesium sulphate,manganese sulfate and ferrous sulfate, acid-base buffer sodium dihydrogen phosphate and two potassium hydrogen phosphate, the initial concentration of ammonium 100 mg·L-1. Incubation temperature was set at 30℃, shaking speed120 r/min, incubation time 36 h, inoculation amount 2%. Growth curve and removal rate of ammonium were used as reference index. Refering to the accumulation of nitrite, hydroxylamine and nitrate, the optimal carbon sourcesodium pyruvate and nitrogen source ammonium sulphate were determined.Performance of nitrification and denitrification was detected by the growth status of the strain, the removal rate of ammonia nitroge,total nitrogen as well as the degradation rate of COD under the same experimental conditions above.According to the experimental results, the strain had entered the logarithmic phase of growth after 6h. The removal rate of ammonia nitrogen reached99.41%, total nitrogen 70.63% and the degradation rate of COD 81.71% after36 h. A small amount of hydroxylamine and nitrate were detected, but nitrite ammount was more. After 36 h, the hydroxylamine concentration was 0.11mg·L-1, nitrate concentration 0.06 mg·L-1 and nitrite ammount was 29.02mg·L-1.The ammonium degradation properties of the strain were investigated under different C/N ratio, temperature, p H and shaking speed. Results showed the strain exhibited efficient ammonia nitrogen degradation ability at a broad range of C/N, temperature and p H. Hence, it had the capability to be applied in the treatment of oligotrophic source water or adjusting wastewater p H. The strain still maintained a high ammonia removal rate of 99.37% with the low C/N of 4. The temperature range was 25~40℃, but the optimal was 30℃; the p H range was 4~10, but the optimal was 8 with a high ammonia removal rate of99.53%.Based on the influencing factors, activity of the strain was also explored by means of the tolerance to different initial concentrations of ammonia nitrogen,total nitrogen and COD removal rate. Meanwhile, Metabolic products were detected under the initial of ammonium concentrations. It was showed that the metabolites changed with different initial ammonia nitrogen. The accumulation of nitrite, hydroxylamine and nitrate was low under low initial concentration of ammonia nitrogen,with the increase of the initial concentration of ammonia nitrogen, the accumulation amount had an increasing trend and hydroxylamine and nitrate was obvious. When the initial ammonia concentration increased to300 mg·L-1, the maximum hydroxylamine accumulation reached 23.99 mg·L-1and nitrate reached mg·L-1.Nitrification and denitrification pathway was speculated according to metabolic products of the strain. Ammonium sulfate, nitrite and nitrate were used as the sole nitrogen source respectively. Trough product analysis and gas generation or not, nitrification pathway and denitrification pathway may were speculated. |
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