Study On Optimization Of Stable Operation Of Coupling Partial Nitrification And Denitrification-Anaerobic Ammonia Oxidation

Single-stage autotrophic denitrification,based on nitrification-Anammox,has become a research hotspot in biological denitrification field.However,simple inorganic nitrogen removal process is difficult to apply and spread in practical engineering,for the ammonia nitrogen removal is difficult to separate from organic removal in the engineering.In recent years,many scholars have found the possibility of co-existence of short-range nitrification and denitrification,and even the possibility of anaerobic oxidation and denitrification.These possibilities provide a broader field of view for solving the engineering adaptability of the process containing anaerobic ammonium oxidation,and it is expected to solve the problem of adaptability of pollutants containing organic matter and other pollutants containing anaerobic ammonium oxidation from engineering means.This paper targets at the wastewater of high ammonia concentration and low carbon concentration,to study the startup,running stability and performance optimization of the partial nitrification and denitrification reactor;the activity recovery and improvement,the response mechanism to the influence of organics of the Anammox reactor;and the running stability of the coupling process reactor.On this basis to reveal the activity of the main function bacteria andcharacteristics of sludge,during the optimization process of nitrogen and carbon removal performance in the system.Thesis mainly draws the following conclusions:1.Inoculated with nitrification sludge in SBR1 reactor,to acclimate the sludge with running mode of anaerobic-aerobic period.The NH₄⁺-N removal efficiency was steady at around 90%after 67d of running,with NO₂^--N accumulation efficiency of70.09%and COD removal efficiency of 52.96%.Using pattern of gradient increased the substrate concentration to increase system loading,then 65%of NH₄⁺-N removal efficiency and 60%of COD removal efficiency were achieved with the NH₄⁺-N concentration of 500 mg/L and the COD/NH₄⁺-N ratio of 1,which indicated the successful startup and running stability of the partial nitrification and denitrification SBR reactor.Combined with FA inhibition and pH regulating strategy,the rate of NO₂^--N accumulation efficiency was increased from 85.60%to 92.31%.2.Content of polysaccharide and protein in EPS would affect the hydrophobicity and flocculating-settling performance of the activated sludge.Analysis results of extracellular PN and PS content in SBR1 reactor of different stages showed that:the EPS content was gradually increased,from the initial 58.72 mg/gMLSS to 83.16mg/gMLSS with the increase of operation time,of which the PN content was mainly increased from 36.64 mg/gMLSS to 53.16 mg/gMLSS,with a slight increase of PS content.In addition,the PN accounted for a larger proportion in the EPS?PN/PS greater than 1?,and also the PN/PS value showed a trend of slow increase,which can explain the optimization of sedimentation performance of the sludge in the system.3.Combined with low load pattern with N₂H₄ strengthen measure to startup the Anammox process in SBR2 reactor,using the low activity Anammox granules as the inoculation source.Activity of Anammox granules was recovered quickly after 15d of running,with TN removal efficiency increased from 60%to 95%.Since then,increased the influent nitrogen concentration of the reactor gradually to increase the volumetric load,and the TN load of the system increased from 0.258 kg/?m³?d?to1.002 kg/?m³?d?after 15d of running.4.In the construction of synergistic anaerobic ammonium oxidation and denitrification system,the effects of organic matter on Anammox were investigated.When the COD was above 100 mg/L,the effect of organic matter on Anammox was weak,AAOB was dominant in the system.When the COD was increased to 200 mg/L,the AAOB activity was inhibited obviously,while the heterologous DNF rapidly proliferated,and the Anammox Nitrogen contribution rate was only about 25%.The effect of substrate on the inhibitory kinetics of Anammox was studied by batch test.The Monod model was used to fit the SAA values at different initial substrate concentrations.The results showed that the q_maxax of the anaerobic ammonium oxidation granules was 741.28 mgN/?gVSS?d?and the half-saturation constant Ks was65.37 mg/L,the q_maxax was 534.62 mgN/?gVSS?d?and the half-saturation constant Ks was 41.29 mg/L when COD was 200 mg/L.Indicating that COD would inhibit the Anammox reaction and further affect its kinetic properties.5.The removal efficiency of the coupling process was stable during 20 days,when the NH₄⁺-N concentration was about 500 mg/L and C/NH₄⁺-N=1.The TN and COD removal rates of the combined process were 88%and 80%,respectively.From the analysis of economic characteristics,the coupling process has significant advantages in terms of saving aeration and no need for an additional carbon source.The coupling process can reduce the actual oxygen demand of about 48.99%and save100%plus carbon source at the C/N=1.