Experimental Study On Rapidly Start-up And Influencing Factors Of ANAMMOX Reactor

The anaerobic ammonia oxidation（ANAMMOX） process is a new type ofbiological nitrogen removal process with high denitrification capacity， low oxygenconsumption and carbon source consumption and other advantages. However， therestill are some problems need to be addressed before the ANAMMOX process used inthe actual project that are time-consuming of start-up phase， how to restore thenitrogen removal when facing high nitrogen load，high nitrate content of effluent. Basedon start-up the ANAMMOX reactor， this article studied the factors which affecting theperformance the reactor.Experimental results are as follows:（1）The6.3L up-flow reactor which inoculated4L returned sludge of municipalwastewater treatment plant， applied inverted A²O process， aimed to cultivatedenitrifying bacteria was under the operation conditions which concluded pH=7.6±0.2of influent， HRT=1d， inner circulating reflux rate of200%， nitrate70mg/L andCOD=200mg/L of influent. The nitrate removal ratio of the that was stable at about80%after6d.（2） In the acclimatization stage of the anaerobic ammonium oxidizing bacteria， thedenitrifying bacteria was used as the inoculate sludge. The reactor conditions has beenchanged for that pH=7.3±0.2of influent， HRT=1d， inner circulating reflux ratioof500%， reactor temperature of32±2℃，ammonium and nitrite of influent from70mg/L，34d to140mg/L，18d， then to210mg/L，11d， at last to420mg/L，7d. After75d’s running， the anaerobic ammonia oxidation reactor startedsuccessful. While NH₄⁺-N and NO₂^-N of influent were405.23mg/L and488.24mg/L， the removal rate were80.00%and95.22%. The influent nitrogen load of reactor was1.05kg-N/（d·m³）， and the remove load was up to0.93kg-N/（d·m³）. The differencebetween this article and other reports is that the boot experientment cost a shorter timeattributed mainly to take before starting denitrifying bacteria enrichment strategies.（3） It is demonstrated from two simulated influent matrix load impact tests that thereactor threshold value of influent nitrite was between550-620mg/L. Activity of theANAMMOX bacteria will reduce， even lost comletely under high nitrite. The nitrogenremoval performance of reactor was restored by two means of which nitriteconcentration of influent was reduced to140mg/L and which nitrite concentration ofinfluent was reduced to half with hydroxylamine hydrochloride. The results show thatthe two methods are able to restore the denitrification performance of the reactor， butthe former method is used in a shorter time.（4）With the HRT of reactor gradually being reduced to0.3d from2d， the nitrogenload of the reactor finally reached2.0kg-N/（d·m³） and the removal load was1.57kgN/（d·m³）. The reactor nitrogen removal rate decreased with the decrease of HRT.（5） With the NO₂^--N/NH₄⁺-N of influent being adjusted from1.0，1.2，1.4to1.6，anaerobic ammonia oxidation reactor gradually increased.In the case of excessivenitrite， anaerobic ammonia oxidizing bacteria activity was maintained at a high state，and the denitrification was decreased the competitiveness of nitrite.（6） To add in the reactor water plus0.15g/L and0.2g/L glucose， the reaction ofammonia nitrogen removal rate increased19%and26%，and the removal rate of nitriteincreased6%and9%， the reactor effluent nitrate less than the influent nitrate14mg/Land18mg/L. This indicates that the activity of denitrifying bacteria in the reactor hasbeen in the suppressed state， mainly due to the lack of carbon source.