Quickly Starting And Stable Operation Of Nitrification Granular In Sbr With Sewage Sludge

With nitrogen pollution of the water environment, ammonia removal process is also increasingly updated. Nitrification-anaerobic ammonium oxidation is a new nitrogen removal process, in which the nitrification process is the use of ammonia-oxidizing bacteria(AOB) 56% of the influent NH4+-N oxidized to NO2--N, anammox is that the remainder of the NH4+-N and generation NO2--N are produced N2. Therefore, nitrification-anaerobic ammonium oxidation has an advantage which is save carbon, oxygen consumption savings, low sludge production, etc. So it becomes a hot research denitrification. Nitrification is the front of anammox process and it is autotrophic denitrification process rate-limiting step, and therefore high load nitrification process can improve the overall nitrogen load, and nitrification granular sludge is good with a special structure oxygen granular sludge sedimentation because of its good performance and resistance to shock loading, long sludge retention time, no bulking, etc. And it can achieve higher load nitrosation. Therefore, how to quickly develop a nitrification granular sludge and stable operation of sludge particles become one of the issues to be resolved in the near future. In this study, it uses SBR reactor to research nitrification granular sludge sewage quick start strategy. Then after the formation of granular sludge, it compares the change in the particle size of the sludge settling time and rise by controlling the flow rate. And by changing the influent p H nitrification performance it can analysis of the changes. Finally, it will research for the best way to restore nitrification after the performance of granular sludge nitrification destroyed.Firstly, experiment uses R1 and R2 reactor, which is that R1 nitration flocculent sludge inoculated with 30% nitrosation granular sludge, R2 inoculated nitrifying sludge floc. And it controlls the reaction aeration device at 2L/min, sedimentation time in 10 min and 18 min and the FA to start nitrification granular sludge under the conditions of sewage. The results showed that, R1 starts successfully through 12d(48 cycles), R2 starts successfully through 42d(168 cycles), the two reactors nitrosation rate could be maintained stably at 95%, the mean particle size in section 60 days are up 922μm and 625μm. Nitrification and granulated using simultaneous strategies can quickly start nitrification granular sludge, inoculating part nitrification granular sludge can further reduce the startup time. Then the change of PS/PN in R1 is relatively stable, indicating that R1 microorganisms can adapt to the new environment and to resist changes in the environment. Turbidity and SVI test results show that the grain structure of R1 is more compact than R2 and coagulating sedimentation performance of R1 is much better than R2. So R1 is more conducive to the growth of the sludge concentration.Tests research the operating parameters of granular sludge further to ensure stable operation of granular sludge. During the test the precipitation of R1 gradually reduces to 10min-8min-5min-4min, and then the settling time of R2 is reduced to 15min-10min-8min-6min-4min. It obtains that when the particle size of the granular sludge reaches a maximum value, the discharge of water flocculent sludge does not change by changing the precipitation time and the particle size of the granular sludge also unchanged. Then mixed the sludge particles R1 and R2 granules, the sludge is redistributed evenly in different SBR reactor R3 and R4. R3 reactor is used to study the effect of different flow rates to increase particle size of the granular sludge. Test is respective 1L/min, 2L/min, 3L/min by controlling the aeration reactor R3 to analyze the changes of the particle size and sludge nitrification rates. By analyzing the experimental data, it obtains that when the aeration rate is 1L/min, the particle size of the granular sludge increases. When the aeration rate is 2L/min, the average granular sludge particle diameter is slightly reduced, but the average particle size substantially maintaines at 900μm or more. Studies have shown that low aeration should be controlled in order to maintain the size of the granular sludge in the nitrification granular sludge formation and subsequent particle size of stable. R4 reactor is used to study different p H on nitrification performance of the granular sludge, tests are adjusted at p H=6, p H=7, p H=8, p H=9, p H=10. It obtained that in order to make granular sludge nitrification rate maximum and stable,the p H of water is 8.0.Because of a long running of nitrification granular sludge, the nitrification rate of granular sludge decreases. If the long-running in this case, the performance of nitrification granular sludge will destroy. Therefore, in the end of test the recovery after the destruction of nitrification granular sludge is studied by inoculating nitrification granular sludge that nitrification performance has been destroyed. It is taken low dissolved oxygenthe, high FA and low dissolved oxygen or high FA to make the rate of nitrification granular sludge recovered. Studies have shown that at low dissolved oxygen, it need 50 days to recover nitrification, which is not only conducive to nitrification rapid recovery, but also affect the progress of the follow-up test. And under low dissolved oxygen and high ammonia, the cycle of the reactor is not only long, but when SBR is not used, denitrification will happened easily and sludge is easy to float, making many granular sludge out of the reactor at the time of drainage. While at high FA, due to the larger of the dissolved oxygen contents in the reactor, the sludge is not easy to go up. So the drainage carries little sludge, which can substantially reduce the loss of sludge and ensure MLSS. And it also be able to quickly restore the nitrification performance of nitrification granular sludge. So, high FA is the best way to recover granular sludge nitrosated quickly.In summary, by studying the quick start nitrification granular sludge method, as well as factors affecting the granular sludge and how to restore granular sludge nitrification, the test obtains a effective way to start nitrification granular sludge and granular sludge running most suitable control parameters and methods of recovery of nitrification. Finally, nitrification granular sludge will eventually keep long-term stable operation.