Study on Enhance Efficiency and Mechanism of BAC Process for Nitrogen Removal by Preoxidation
|School||Harbin Engineering University|
|Course||Disaster Prevention and Reduction Engineering and Protective Engineering|
|Keywords||Preoxidation BAC process Enhance efficiency Mechanism of nitrogen removal|
With the national problem of pollution in drinking water becoming more and more serious, preoxidation and BAC have turn into effective methods in enhancing technology of water treatment. The dissertation aims at pot of preoxidation and BAC in enhancing water treatment, by the experiment in the lab, contrasting the effect of pollution removal in the combined process between potassium permanganate-BAC and potassium ferrate-BAC, completing the separation and identification for the nitrobactraceae from the activated carbon, and researching the enhanced mechanism by the number of bacteria, nitrification characteristics and biological activity after preoxidation.The combined process of potassium permanganate-BAC and potassium ferrate-BAC has both enhanced the removal efficiency. The experiment analyzed the removal rate of turbidity and organics in the combined process. Compared against the BAC without preoxidation, the removal rate of turbidity, CODMn and UV254 all increased and the removal efficiency become more stable, and also the enhance mechanism of turbidity and organics removal was studied.The removal efficiency of pollutants in biological process was improved after permanganate preoxidation or ferrate preoxidation. Compared to BAC alone, the removal rate of ammonia and nitrite was analyzed in the process of BAC increased and the removal efficiency become more stable. Simultaneously, the activated carbon is the primary process to remove organics, ammonia and nitrite, especially on the top of the BAC.The preoxidation by permanganate or ferrate has stimulative effect on the growth and activity of bacteria. The number of bacteria on the carbon was studied by most probable number and the rate of nitrification and oxygen consumption was studied by linear regression method at 20cm,60cm and 100cm filter candle. Contrast to the BAC alone, The number of Nitrobactraceae on the carbon at the same height after preoxidation increased, and so do the rate of nitrification and oxygen consumption.15 strains ammonia-oxidizing bacterium and 16 strains nitrite-oxidizing bacterium were separated from the activated carbon by microscale broth dilution method and agar streak method, and strains identification was distincted by the colonial morphology, the individual feature and physiological-biochemical characteristic. And 5 strains nitrite bacteria and 6 strains nitrite bacteria which had good digest result were screened.Bacteria showed the trend of unicity by ferrate-preoxidation, but the species of the bacteria on the carbon din not change after preoxidation by permanganate. The enhanced effect of preoxidation was achieved by improving the biodegradation of raw water, enhancing the biofilm grwth and bioactivity.