| At present the nitrogen pollution in water has become an important problem of environmental protection in china. It is very important to study the processing technology and its basic application of denitrification treatment. Compare to the physical and chemical method, biological nitrogen removal has higher economic benefit, is the most widely used technology at present. Temperature had great effects on denitrification, resulting in cold area of China sewage treatment plant in winter effect is not ideal, and the development of low temperature resistant denitrifying bacteria can solve this problem effectively. In this study, The three cold resistant denitrifying bacteria LTD-03, LTD-05, LTD-16 stored in the laboratory. According to the nitrogen removal characteristics of three strains of bacteria, Development psychrotolerant denitrifying agent. characteristics and nitrogen removal characteristics Research of psychrotolerant denitrifying agent. Use the agent to achieve nitrogen removal from domestic waste water, observe and study preparation of environmental conditions and treatment effect on low temperature.Nitrate degradation ability and nitrite nitrogen accumulation are different in three strains of bacteria. The situation of nitrate nitrogen and total nitrogen removal rate LTD-03< LTD-16 <LTD-05; The situation of nitrite nitrogen accumulation LTD-03< LTD-16 <LTD-05. On the basis of this, using three strains development of mixed agent, found that when the mixed agent ratio was 2:1:3, achieve less nitrite accumulation and higher nitrate degradation rate at the same time, the mixed inoculants marked as agent CM.Study on growth characteristics of CM, The best C/N for CM growth is 20:1, if the C/N too low, there is no enough supply of energy for denitrification; While with the increase of temperature, strain CM grow stronger, but when the initial OD600 was about 0.40, after 60 h inoculation the OD600 value about 1.21, the average growth rate of bacteria reached 0.52d-1, bacteria can also grow very well at 10℃. The best p H was 8, growth rate under p H=6 only 10% of growth rate under p H=8; the optimum liquid quantity is 400 m L, growth rate is 1.69 times of 100 m L.Study on the nitrogen removal characteristics of strain CM showed that, in the range of low temperature of 5~15℃, CM can be good for denitrification, while the nitrogen removal capacity with temperature increasing, but at a temperature of 10℃, after inoculated CM 60 h nitrate nitrogen removal rate could reach 89.80%; nitrate degradation rate of initial nitrate nitrogen concentration under 200mg/L is 2.26 times 50mg/L; the concentration of ammonia over 20mg/L nitrate nitrogen removal rate was severely inhibited; the best p H was 8, The nitrate nitrogen removal rate of p H=8 is 63.91% higher than that of p H=6; the optimal C/N is 20:1, compared with C/N for 5:1 nitrate nitrogen removal rate increased almost 32.47%.External carbon source is necessary in the nitrogen removal from domestic waste water, after addition carbon source, nitrogen removal rate is 4.11 times higher than Without adding carbon source. The original sewage microorganisms will not impact nitrogen removal ability of agent CM. The best inoculation is 3%, The nitrate nitrogen removal rate of 3% inoculation amount is 40.52% higher than that 1% inoculation amount. the best p H was 8, The nitrate nitrogen removal rate of p H=8 is 73.15% higher than that of p H=6. Coupling agent CM and activated sludge can quickly remove the nitrate nitrogen in sewage in 3h, and the removal rate reached 100%, compared with activated sludge only the nitrate removal rate is 23.50% higher, this effect is beneficial to nitrogen removal system start under 10℃.The climate in North China is cold, the sewage treatment plant in general average water temperature at about 10℃. Agent CM can rapidly and stably treating waste water under low temperature conditions, and has good application prospect. The project research provides a new method for nitrogen removal of domestic sewage treatment in China, the increasingly serious shortage of water resources and water pollution control has important significance. |
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