Pretreatment And Removal Of Ammonia Nitronia From Micro-polluted Water Source In North China

China is a country in serious shortage of water in the world,and water source is even more serious shortage.China's water sources are scarce,but there are also different degrees of pollution.Ammonia nitrogen is one of the most common pollutants in water pollution.Moreover,the pollution of ammonia nitrogen to water sources is aggravated in the low temperature period,which makes the situation of ammonia nitrogen pollution in northern areas with obvious seasonal pollution more significant.The water treatment process relying only on the conventional coagulation precipitation filtration and disinfection is very limited for the removal of ammonia nitrogen,which can only remove about 20% of the total ammonia nitrogen pollution,which is difficult to meet the purification requirements of the northern areas with seasonal ammonia nitrogen pollution.Therefore,it is more urgent and significant to solve the problem of ammonia nitrogen pollution in water sources in the north.In order to solve the problem of the ammonia nitrogen pollution in north China,this article through the establishment of an evaluation system on the basis of the analytic hierarchy process(ahp),the evaluation data and implement the evaluation process of the three links of 11 th five-year plan and the twelfth five-year "science and technology major projects" water pollution control and governance of BAF(biological aerated filter)pretreatment-enhanced coagulation technology,biological aerated filter technology,seasonal water polluted conventional process improved processing technology,water high ammonia nitrogen and winter wetland to strengthen ammonia nitrogen removal techniques the four mature scientific evaluation on the source water ammonia nitrogen treatment technology,The most suitable treatment technology for micro-polluted water source in north China was evaluated.The final scores of each technology were 93.129 points for BAF pretreatment enhanced coagulation technology,95.975 points for aerated biological filter technology,86.211 points for strengthened treatment of conventional process of seasonal polluted water source,89.135 points for high ammonia nitrogen in source water and 89.135 points for strengthened removal of ammonia nitrogen in winter wetland.Aerated biofilter technology was the best,scoring95.975 points.Therefore,aerated biological filter is the most suitable treatmenttechnology for micro-polluted water source in north China..And then to evaluate the biological aerated filter technology for single stage become a bipolar structure adjustment and improvement,and in different temperature,different pH,different gas water ratio,running under the conditions of different hydraulic loading single-stage and two-stage biological aerated filter,get the best operation parameters are 26 to 30 ? temperature,pH 7.1 to 8.0,gas water ratio of 1.0,:1.0,4 m~3 / m~2 h.hydraulic load.The removal efficiency of ammonia nitrogen and permanganate index was restored to the pre-backwash level at 16 h and 24 h after backwash.According to the comparison of operation efficiency,the final form of the reactor was determined to be bipolar aerated biological filter.Finally,the reactor operation efficiency was investigated by running the reactor in a two-stage form with the best parameters under the transition period of low temperature,normal temperature and temperature respectively.At room temperature,the removal efficiency of ammonia nitrogen and organic matter is relatively stable,keeping above 80% and 30% respectively.The lower filter material contributed more to the removal rate.At low temperature,the removal efficiency of ammonia nitrogen and organic matter decreased significantly.The contribution of the lower filter to the removal rate decreased.The purification efficiency of ammonia nitrogen in the temperature transition reactor decreased with the temperature,and then began to rise after the microorganisms adapted to the low temperature.