Micro-polluted Source Water Was Purified By Oligotrophic Aerobic Denitrifying Bacterial Community GNY

In this paper, we in-depth studied the characteristics of poor nutrition aerobic denitrification aerobic denitrifying bacteria for micro-polluted raw water of nitrogen pollution. We got superior aerobic denitrification ecoflora which from our previous isolated in 23 poor nutrition denitrifying bacteria through islation and combination. The main results and conclusions of this study are as follows:(1)A heterotrophic nitrification-aerobic denitrification bacteria strain named Acinetobacter sp. Sxf14 was isolated from the sediment of a drinking water reservoir. The strain was inoculated into the micro-polluted source water(C/N as 1.2), and the total nitrogen(TN) removal rate was examined. The results showed that the strain could perform nitrification and denitrification well in nitrate medium, nitrite medium, and the reservoir water environment. The removal rate of nitrate reached 74.84±0.86% and that of nitrite reached 40.52±1.49% in 48 hours; the total nitrogen removal rates was up to 65.07±1.56% and 41.33± 0.98%.In 72 h, the concentration of TN of micro-polluted source water reduced from 2.46±0.02 mg/L to 1.68±0.01 mg/L, with the removal rate up to 31.7±0.14%. The results of this work demonstrated that strain Sxf14, with its aerobic denitrification ability and tolerance low carbon nitrogen ratio, can decrease the nitrogen concentration of micro-polluted source water, therefore, and may be a promising agent in bioremediation for micro-polluted source water.(2) Oligotrophic denitrifying functional bacteria populations GNY was formulated by Strain combination, and the functional bacteria were studied for different carbon and nitrogen ratio on denitrification performance of flora. The results showed that the reaction rate of aerobic denitrifying bacteria gradually increased, with the increase of the ratio of carbon and nitrogen, functional bacteria can adapt to nutrient-poor environment. C/N ratio of less than 3, the nitrate removal rate reached 57.18%, TN removal rate reached 43.52%, and can maintain long aerobic denitrification activity.(3) The ecoflora GNY were respectively inoculated into pure source of water and after sterilization, NO3--N removal rate of up to 35.9% and TN removal rate up to 46.78%. NO3--N removal rate up to 27.97% and TN removal rate up to 46.78% in pure source of water medium, the investment bacteria group nitrate removal higher 15.26% and TN removal higher 17.38%, compared with the blank group. The results show that the biological bacteria can adapt to oligotrophic raw water environment, and can effectively reduce nitrogen of micro-polluted water.(4) In the middle of reservoir depths of 7.5m, did inoculum concentration gradient hanging bottles experiments, the results show that the amount of bacteria administered 0.1ppm is the best, NO3--N removal rate up to 66.49% and TN removal rate up to 53.52%. There has the same result in the raw water reservoir static inoculum concentration gradient experiment, NO3--N removal rate up to 41.44% and TN removal rate up to 45.16%. Finally we can get the best inoculum concentration gradient of 0.1ppm.(5) Under conditions that the raw water TOC concentration of 6.40mg/L and TN concentration of 1.85mg/L, conducted oligotrophic aerobic denitrifying bacteria pilot experiment, according to 0.1ppm dosage of agents. The results showed that administration bacteria system was significantly better than blank system. After the system was stable, investment bacteria group nitrate removal remained at 43.57%, 22.34% higher than the control system, TN removal remained at 51.32%, 19.34% higher than the control system, at the same time, the biomass of investment bacteria group was significantly higher than the control group, aerobic denitrifying bacteria was also significantly higher, indicating that the biological agents can be used to bioremediation for micro-polluted source water.