| Recent years, the content of nitrate in the waste water discharged into the water is becoming higher and higher that have caused the water nourishment, the water smelt fishy, the quality of water depravation or the lake degenerate, seriously the water become black and olid. Most water systems are becoming very fragility because the long time pollution of nourishment, Sometimes, the nourishment water will hurt the people health as the water source.Generally, nitrogen removal technology can be disparted two kinds: physical chemistry method or biology method. Physical chemistry method includes air blowing off, adding chlorine, flocculating and deposition, manual marsh. Now the biology method is the main method to remove the nitrogen in treating the waste water which is recognized the most economic, effect and development future method. Traditional removing nitrogen theory considers that ammonia nitrogen can be wipe off through nitrify moment and denitrification moment, which can not happen in the same time because the nitrification bacteria and denitrify bacteria has different environmental request. Nitrification reaction always happens in aeration condition, the homoerotic bacteria can use the oxygen as the electron acceptor to turn the NH4+ into NO2- and NO3-. Denitrification reaction always happens in anoxic and anaerobic condition, the heterotrophic bacteria can use NO2- and NO3- as the electron acceptor to turn the NH4+into N2.Recently, the new nitrogen removal technology is Shortcut nitrification-denitrification and Shortcut nitrification denitrification. Shortcut nitrification-denitrification use the physiological characteristic of the nitrify bacteria and the denitrifiaction bacteria, control the nitrification in the NO2- moment, then the denitrification. Shortcut nitrification denitrification use the impersonality phenomena that the oxygen can not be supplied asymmetry, control the reaction dynamics balance to make the nitrification reaction and denitrification reaction happen in the same time and space. While the traditional technic like A/O has the anoxic and anaerobic reaction section, then the nitrification and denitrification happens in different time.The adsorption-bioregeneration technology has disadvantages: biofilm detachment, biofilm forming time is long, the biomass in biofilm is limited.In this study, microbe which was acclimated and zeolite were combined immobilization. In static experiment, different diameter's zeolite and influences which using different components on removing ammonia nitrogen were presented. The mechanism that removing Ammonia Nitrogen from slightly-polluted water by Zeolite-Microbe Combined Immobilization was discussed in dynamic experiment.The results showed that, after 16 days'acclimation, the removal rate of ammonia nitrogen was more than 90%,and the nitrification performance was in evidence. when pH is 8.5, the aeration tank time is 19 hours, and C/N at 4～6, a higher nitrogen removal(SND) could realized. The phenomena of nitrite accumulation appears in the course of simultaneous nitrification and denitrification. It is inferred that it is via the short distance nitrification and denitrification.The bacteria's growth and the substrate's degradation of nitrobacteria and denitrifying bacteria were investigated separately taking ammoniac and nitrate as substrate.Study on the growth curve and its degrading rate, it can be found that the growth and substrate degradation of bacterium are nearly synchronic, and by reducing C/N, denitrification's rate is lower. zeolite adsorpted ammonia nitrogen fast, the sorption capacity of zeolite whose dia.〈0.5mm was higher than others; the adsorption rates of different components were different, each one has contribution, and the sequence was q0zeolite>q0zeolite-microbe>q0microbe;the process of combined immobilization removing low concentration ammonia nitrogen from slightly-polluted water has 4 phases: adsorption, adsorption saturated and microbe acclimating; nitrification performance and zeolite partial regeneration; bioregeneration, at last, zeolite adsorption- bioregeneration worked at dynamic balance, the removal rate of ammonia nitrogen was about 60%. |
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