Study On The Modeling And Performance Of Inhibition Factors One-Stage Partial Nitritation/Anammox Process Treating High Ammomium Industrial Wastewater

The one-stage partial nitritation/Anammox(PN/A)process has shown a broad application prospect in the field of industrial wastewater treatment due to its characteristics of high efficiency,economy and energy saving.However,the inhibitory factors such as high salinity and antibiotics existing in industrial wastewater become the main bottleneck restricting the engineering application of the PN/A system.In this essay,the effect of two inhibitory factors on the denitrification performance of the PN/A system is studied by taking the residual high salinity,chlortetracycline(CTC)in typical high ammonia nitrogen industrial wastewater as an example.The effect of high salinity and CTC on the denitrification performance of the PN/A system is explored by analyzing the nitrogen removal rate(NRR),microbial activity,community structure and other changes of the PN/A system.At the same time,an inhibition model of high salinity and CTC on the denitrification performance of the PN/A system is established based on the bench-scale test with the fitting effect of the same being verified in the pilot-scale test.In addition,the recovery strategy of adding exogenous glycine betaine(GB)under the condition of high salinity inhibition and the strategy of adding exogenous hydrazine(N₂H₄)to enhance the activity of anaerobic ammonium oxidation bacteria(AnAOB)are developed,and a recovery and enhancement model under corresponding conditions is established.The main research results are as follows:(1)With regard to the problem of high salinity inhibition in high ammonia nitrogen industrial wastewater,the short-term and long-term changes of the denitrification performance of the PN/A system under different salinity conditions as well as the recovery strategy of adding exogenous betaine are explored.The results of short-term experiments show that the median inhibitory concentrations(IC₅₀)of Na Cl,Na₂SO₄ and Na F for the PN/A system are 15.2,12.7 and 1.46 g/L,respectively.The addition of exogenous GB can alleviate the inhibition under different conditions of high salinity,and the optimal adding concentration is 1 m M.In the long-term test process,when the salinity of influent water rises to 30 g/L Na Cl,the system NRR drops sharply from 0.360 kg N/m³/d to 0.084 kg N/m³/d.With the adaptation of the system to the condition of high salinity,the system NRR returns to the initial level after 70 days.The adaptation time of the PN/A system is shortened by adding exogenous GB.As a result,it is found that the recovery time in case of adding GB only once is 50 days,and the recovery time of adding GB continuously is further shortened to 40 days.In addition,The PN/A system further treats typical rare earth wastewater with high ammonia nitrogen and high salinity,and the NRR can be above 0.5kg N/m³/d,proving the feasibility of the PN/A system treating wastewater with high ammonia nitrogen and high salinity.(2)A mathematical modeling was established to systematically investigate the effects of salt and GB addition on the activities of AOB and AnAOB and the treatment performance of the PN/A process.The half-saturation constants K_GB,A and K_GB,N of GB for ammonium oxidation bacteria(AOB)and anaerobic ammonium oxidation bacteria(AnAOB)obtained are 0.86 and 0.75 m M,respectively,and the inhibitory constants of GB K_IG,Aand K_IG,N are 9.5 and 24.2 m M,respectively.The model fits satisfactorily the nitrogen removal performance of the PN/A system in treating high-salinity simulated wastewater(R²=0.960)and actual rare earth wastewater(R²=0.832)and simultaneously plays a guiding role in the pilot-scale test study of coal chemical wastewater(R²=0.778).In addition,the recovery model proposes the optimal sludge residence time(SRT,50 days)and the optimal addition amount of GB(1 m M)for the PN/A system in the process of treating rare earth wastewater with high ammonia nitrogen and high salinity.(3)With regard to the inhibition problem of antibiotics in industrial wastewater with high ammonia nitrogen,the change of denitrification efficiency of the PN/A system under different CTC concentrations is explored.The short-term inhibition results show that the IC₅₀ of CTC for AOB and AnAOB are 204.3 and 185.4 mg/L respectively.In the long-term inhibition process,the NRR gradually reduces from the initial 0.70kg N/m³/d to0.22kg N/m³/d under the condition of 60 mg/L CTC,and the system NRR continues to reduce to 0 kg N/m³/d after the CTC concentration of influent water reduces to 20 mg/L.However,after the CTC interference is completely removed,the NRR only recovers to0.10kg N/m³/d within 30 days.In addition,a CTC inhibition model for the denitrification performance of the PN/A system is successfully established,which fits satisfactorily the change of the denitrification performance of the PN/A system in treating simulated wastewater and actual aureomycin production wastewater(R²=0.978 and 0.903),proving the effectiveness and reliability of that inhibition model.(4)With regard to the problem of slow recovery after PN/A process inhibition,the strategy of enhancing the activity of AnAOB by adding exogenous N₂H₄ is developed.The short-term test results show that the activity of AnAOB increases by 42%after adding exogenous N₂H₄ with the degradation of NO₂^--N being accelerated and the maximum degradation rate reaching 212.02 mg N/g VSS/d.Based on the short-term test results,a model of AnAOB activity enhancement model by adding exogenous N₂H₄ is successfully established,with the semi-saturation constant K_N2H4 of N₂H₄ obtained being 5.88 mg/L,and the promotion coefficients C_NO2 and C_NO3for degradation of NO₂^—N,NO₃^--N being20.7 and 55.2 mg/L respectively.The model fits satisfactorily the recovery law of the AnAOB activity after long-term addition of exogenous N₂H₄(R²=0.967),and proves the effectiveness and reliability of that activity enhancement model.