Study On The Removal Of Nitrate Produced In ANAMMOX Process By Bio-Electrode Reactor

Nowadays, the problem of nitrogen pollution of water becomes more and more serious, which accelerates the study on high-efficiency nitrogen removal biotechnology. Numbers of new high-efficiency nitrogen removal biotechnologies have been developed, and SHARON and ANAMMOX are two typical representatives of these processes. These two skills not only offseted the disadvantages of classical nitrogen removal biotech, increased the nitrogen removal efficiency, reduced the cost of treatment, but also filled in the blank of high nitrogen concentrated wastewater treatment. However, besides the removement of ammonia and nitrite, the ANAMMOX reaction always produces certain proportion of nitrate. Therefore, to avoid the recontaminant of natrual water and to decrease the thretening for drinking water, it is very necessary to give deeply treat to the ANAMMOX effluent.NITROSATION-ANAMMOX process is fit for treating wastewater with high ammonia concentration but low COD. Based on this point, choose Bio-Electrode Reactor(BER) to finish the autotrophic denitrification on Nitrosation-ANAMMOX effluent. Researches were also carried out on the infections to the denitrify performance of the reactor, from different kinds of inoculating sludges, materials of the electrode, design of reactor configuration and the operation parameters. Main achievements from this report are as follows:The BER was successfully started up by using autotrophic denitriying sludge as inoculations, plumbago sticks as anode and cathodes and granular active carbon as fillers. The BER taked synthetic wastewater which contains nitrate as influent, and studies were maded on its autotrophic denitrifying effects. The results of this experiment proved that nitrate could be removed through autotrophic denitrification. The removal efficiency of nitrate and TN were not high. The max removal rate of them were 31.36% and 19.93% respectively. A new BER was successfully started up with ordinary denitrifying sludge as inoculating bacterias. This BER used plumbago stick anode, metal cathode and granular active carbon filler. Experiment results showed that the denitrification efficiency of this new BER reactor was very high. Electric current intension and influent load are two key factors of the BER's denitrification capability. When the influent nitrate-nitrogen concentration was 80mg/L, HRT=30h, the optimal electric current intension for this BER was 200mA at normal temperater. The max 87.7% nitrate removal rate and max 66.2g-N/m3·d TN removal load was achieved during this experiment period.It is doable to add BER behind the NITROSATION-ANAMMOX process to form a three grades process to complete the totally autotrophic nitrogen removement, and the MTNER have good nitrate removal effects. During this experiment period, the max nitrate removal rate is 50.2%, the max TN removal rate is 62.8%. Max 100% ammonia removal rate and max 92% TN removal rate was gained through the whole process. The final effluent concentration of the whole process was: ammonia 37.2mg/L, nitrate 28.3mg/L and TN 80.0mg/L.According to the experiment results, this paper raised a integrate process which was fit for treating the wastewater with high ammnia concentration but low COD. By adding the BER to the existing NITROSATION-ANAMMOX process, this process made it better and with stronger applicability.