| Liangtan river, which flows through JiuLongpo District, ShaPingba District and BeiBei District, originates from JiuLongpo Distict of ChongQing. It is a major tributary of JiaLing river. Because of the pollution caused by agricultural activities, municipal waste, poultry and domestic sewage , the water quality of the Liangtan river is become increasingly bad ,which affects the safety of drinking water and irrigation.This study selected Liangtan river as a research object and isolated indigenous microorganisms, such as Saccharomyces, Nitrifying bacteria, photosynthetic bacteria and poly-P bacteria, from this river .After the selection of highly efficient degradation strains and determination of the best ratio of efficiently degradation strains in compound bacteria, this study developed a waste water treatment technology based on microorganism immobilization, which was suitable for treating the polluted water in Liangtan river.16 strains were isolated in this study, including 5 strains of Saccharomyces, 2 strains of Nitrifying bacteria, 3 strains of photosynthetic bacteria and 6 strains of poly-P bacteria. And then colony characteristics observation and microscopic observation were both employed to identify these 16 strains. The results showed that these strains were really what we had expected.Then, these microorganism strains were used to degrade the pollutants in Liangtan river. The results indicated that when the dosage of single strain was 100mg/L, Saccharomyces 3#, Nitrifying bacteria 2#, photosynthetic bacteria 3# and poly-P bacteria 5# had the highest degradation capacity.COD removal rate was 51.66% for Saccharomyces 3#; COD and NH3-N removal rates for Photosynthetic bacteria 3# were 46.62% and 49.02%,respectively; NH3-N removal rate for Nitrifying bacteria 2#was 57.42%; and TP and NH3-N removal rates for poly-P bacteria 5# were 43.55% and 45.10% respectively. In addition, a series of experiments were carried out to find the best conditions for the treatment of this polluted water. The dosage experiment showed that when the dosage of microorganism strain was 100~200mg/L, the best removal of pollutants could be achieved; the interaction experiment indicated that most combined strains could increase the removal rates of COD, NH3-N and TP to some extent; and primarily experiment found out that when the dosage ratio of Saccharomyces 3#,Nitrifying bacteria 2#, photosynthetic bacteria 3# and poly-P bacteria 5# was 6:7:8:7, COD, NH4-N and TP were removed simultaneously with a relatively better removal rates , 72.28%, 84.59% and 43.94%.After that, a contrast experiment was implemented to compare the pollutants removal rates of unmodified filler and modified filler. The results indicated that modified filler had no negative impacts on the removal rate of pollutants, and after modification better removal rates, COD, NH3-N and TP were 83.09%,89.52% and 55.37%, could be obtained.At last, field experiment was also carried out .The results showed that the highest removal rates of COD, NH3-N and TP were 24.76%,18.72% and 10.00%,respectively. These low removal rates may be resulted from the impacts of weather and temperature. Then, Analysis of the correlation found that the increasing rate of DO was positively correlated with the removal rates; the flow rate was negatively correlated with the removal rates; and temperature was positively correlated with the removal rates. Furthermore, cubic fitting curves indicated that dynamic process for the removal of COD, NH3-N and TP wih compound bacteria showed high similarity .
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