Experimental Study On Simultaneous Phosphorus Removal By SBR Treatment Of Domestic Wastewater

Compared with the whole process of nitrification,semi-nitrosation has the advantages of short reaction history,saving organic carbon source,reducing aeration and low sludge output.However,the realization of semi-nitrosation requires the control of the nitrification reaction at the stage of nitrite nitrogen.The essence is to use the difference in the activity of ammonia oxidizing bacteria?AOB?and nitrite oxidizing bacteria?NOB?to create a growth environment suitable for AOB,so that AOB Continue to grow and reproduce to become the dominant strain,and gradually eliminate NOB to achieve semi-nitrosation.In this paper,the actual domestic sewage is taken as the research object,and the anaerobic/aerobic operation mode is adopted to control the sludge age?SRT?to achieve the advantageous growth of AOB and the enrichment of PAO.Then the temperature,aeration,salinity and other influencing factors are adjusted and the working conditions are optimized to achieve simultaneous nitrogen and phosphorus removal by semi-nitrosation.This technology provides theoretical and practical references for the treatment of actual domestic sewage.The research results of this paper are as follows:?1?Explore the effect of SRT on the start of the semi-nitrosation synchronous phosphorus removal reactorExplore the effect of SRT on the start-up of the semi-nitrosation synchronous phosphorus removal reactor.The sludge was domesticated by adjusting the SRT,and the average ammonia nitrogen concentration in the influent was 63.23 mg/L.After the SRT was increased from 15 d to 25 d in the seventh cycle,the reactor was successfully started after 20cycles.SAOR increased to 18.38 mg/L,67.02%,0.17 g.?g.d?^-1,the nitrous acid concentration and its accumulation rate reached 17.15 mg/L and 88.15%,and the nitrous acid/ammonia nitrogen concentration after steady reached 0.96,It can be seen that increasing the SRT increases the specific oxidation rate and contributes to the start of semi-nitrosation.After 15cycles,the TP concentration and removal rate of the effluent stabilized to 3.26 mg/L and77.09%,respectively,and the system successfully achieved the enrichment of phosphorus-accumulating bacteria.?2?Explore the influence of aeration on the semi-nitrosation synchronous phosphorus removal reactorInvestigate the effect of aeration rate on the semi-nitrosation dephosphorization reactor.In the anaerobic/aerobic operation mode,three sets of SBR reactors with aeration of 180,150,and 120 L/h were set respectively,and the average concentration of ammonia nitrogen in the influent was 50.79 mg/L,respectively after 17,20,and 24 cycles.To achieve stable operation,the effluent ammonia nitrogen concentration is 14.47,13.99,17.12 mg/L,the removal rate is68.86,70.91,63.75%,the effluent nitrite nitrogen concentration is 18.64,20.67,19.72 mg/L,the accumulation rate is 89.11,97.48,89.14%.SAOR is stabilized to 0.19,0.18,0.13 g.?g.d?^-1,that is,when the aeration is reduced,SAOR is weakened,and the growth rate of autotrophic bacteria per unit time is reduced,and the time required to achieve semi-nitrosable stable operation long.After the reactor reaches stable operation,the COD removal rate can reach about 70%,that is,the aeration amount has little effect on the COD concentration of the effluent,and the three operating modes have good COD removal effects.The average metering ratios of the nitrous nitrogen in the effluent and the ammonia nitrogen in the effluent were 1.39,1.32,and 1.16,respectively,and the three groups of semi-nitrosation were achieved under the aeration intensity.The TP effluent concentration was 1.42,1.48 and 1.34mg/L,respectively,and the removal rate was stable to 85.46,86.55 and 91.21%.That is,when the aeration intensity is 120 L/h,the phosphorus removal performance is the best.In summary,when the aeration amount is 150 L/h,the performance of the semi-nitrosation synchronous phosphorus removal reactor is better.?3?Explore the effect of temperature on the semi-nitrosation synchronous phosphorus removal reactorExplore the effect of temperature on the semi-nitrosation dephosphorization reactor.Choose three identical SBR reactors,control the temperature to 29,24,and 19?respectively.The ammonia nitrogen in the effluent is stable at 14,26,and 31 cycles,and the concentration is 16.87,16.43,16.91 mg/L.The average removal of ammonia nitrogen the rates were70.44%,69.67%,70.53%.the nitrite nitrogen concentration of the effluent is 18.64,20.67,19.72 mg/L,the nitrite accumulation rate is stable to 89.11,93.53,89.14%,the average stoichiometric ratio of nitrous/ammonia nitrogen is 1.02,1.35,1.21,all three reactors are It can increase the appropriate water intake for anaerobic ammonia oxidation.SAOR stabilized to 0.22,0.20,0.17 g.?g.d?^-1,respectively.That is,the higher the temperature,the greater the SAOR.When the temperature is 19?,the phosphorus removal efficiency of the system reaches 87.54%,that is,the low temperature is beneficial to the removal of TP.After the reactor reaches stable operation,the SVI is basically maintained at about 100 mL/g,and the sludge has good settling performance;the f values are 0.80,0.79 and 0.65.respectively,and the sludge has high activity.?4?Explore the influence of salinity on the semi-nitrosation dephosphorization reactorExplore the effect of salinity on the semi-nitrosation dephosphorization reactor.In this experiment,the anaerobic/aerobic mode was adopted.The NaCl solution was added to control the influent salinity to 0,5,10,and 20 g/L,and the differences in semi-nitrosation and phosphorus removal performance were investigated.When the salinity control is 0,5,10,20g/L,the nitrite nitrogen concentration of the effluent after stable operation is 17.48,16.91,12.35,6.51 mg/L,and the nitrite accumulation rate is 90.38,92.65,89.91,94.32%.The results show that the higher the salinity,the more affected the semi-nitrosation system.The AOB activity decreased to 121.38,114.94,80.34,44.38%respectively,the inhibitory effect of NOB was gradually strengthened,and SAOR,SNiPR and SNaPR all continued to decline.That is,with the increase of salinity,the growth and metabolism of microorganisms such as AOB and NOB are inhibited,and the reaction rate in the system decreases.The average stoichiometric ratio of nitrous/ammonia nitrogen in the effluent is 1.23,1.12,0.75,0.27.Only when the salinity is 0 g/L and 5 g/L,the effluent meets the anaerobic ammonia oxidation influent requirements.After stable operation,the TP concentration of the effluent was 0.84 mg/L,1.47mg/L,2.60 mg/L,3.55 mg/L,indicating that when the salinity was greater than 5 g/L,the phosphorus-accumulating bacteria were significantly inhibited.That is,when the salinity is less than 5 g/L,the performance of simultaneous semi-nitrosation dephosphorization in the reactor is stable.