Study On Partial Denitrification With Anaerobic Ammonium Oxidation Process To Treat Sewage

This paper studied the feasibility of simultaneous removal of nitrogen and organic matter from wastewater by partial denitrification and anaerobic ammonium oxidation（PD/A）process,and discussed the possibility and stability of simultaneous nitrogen removal of nitrogen pollutants and organic matter in landfill leachate.The PD/A process was characterized by three-dimensional fluorescence spectroscopy and ultraviolet spectroscopy,and the mechanism of nitrogen and carbon removal was studied in terms of microbial community structure and sludge particle size change compared with the results of conventional chemical analysis.The main contents and research results were as follows:（1）The PD/A reaction was successfully started by inoculating anaerobic sludge with UASB reactor.In the first stage（1～92 days）,the coupling process was started successfully under the condition of COD/NO₃^--N was 2,the removal rates of NH₄⁺-N and NO₃^--N reached 98.54%and 54.27%,respectively.The results of microbial high-throughput sequencing of effluent on day 92 showed that the relative abundance of Proteobacteria and Planctomycetes reached 40.56%and 28.58%,respectively.The results of particle size analysis showed that the average particle size of sludge reached 654.34±24.01μm after 92 days.The results of three-dimen-sional fluorescence spectroscopy combined with parallel factor analysis showed that the main components of dissolved organic matter（DOM）in the effluent were protein-like,fulvic acid and humic-like acid.With the extension of the reactor running time,the fluorescence intensity scores of the three components all decreased synchronously and tended to be stable.（2）In order to acquire the optimal operating conditions and parameters of the system,the effects of different COD/NO₃^--N,HRT,p H,temperature and substrate concentration on the nitrogen removal performance in the system were explored.The results showed that the NH₄⁺-N removal rate reached 99.22%when the initial COD/NO₃^--N of the system was 3.5.When it was 4.0,the NO₃^--N removal rate was the highest,up to 79.55%.The fluorescence intensity of protein-like protein in the effluent showed an obvious upward trend when the COD/NO₃^--N of the influent is4.0.The partial least squares method was used to establish the relationship model between the UV spectral data and the sample concentration.The correlation coefficients between the measured and predicted values of NO₃^--N and NO₂^--N reached 0.9852 and 0.9486,respectively.When the HRT was 6 hours,the nitrogen removal efficiency was the worst,and the removal rates of NH₄⁺-N and NO₃^--N were 89.98%and 58.10%respectively.When the HRT was 48 hours,the nitrogen removal efficiency was the best,and the removal rates of NH₄⁺-N and NO₃^--N were 99.41%and 72.84%,respectively.The extension of HRT can significantly improv the removal efficiency of NH₄⁺-N and NO₃^--N.When the p H was 6.5 and 9.0 respectively,NH₄⁺-N removal rate was lower than90%.The weak alkaline environment was more conducive to the removal of NO₃^--N.The removal rate increased gradually with the increase of p H.When p H was 9.0,the removal rate of NO₃^--N was 84.27%.When the temperature was 20℃～35℃,the nitrogen removal effect of the system was positively correlated with the temperature;When the temperature was set as 40℃,the nitrogen removal effect of the system was the worst,and the removal rates of NH₄⁺-N and NO₃^--N were 88.58%and 63.17%respectively.High temperature inhibited the activity of microorganisms.When the initial COD/NO₃^--N of the system was 3.0 and the influent NH₄⁺-N and NO₃^--N were both 50 mg/L,the removal rates of NH₄⁺-N and NO₃^--N were96.71%and 72.25%respectively;When NH₄⁺-N and NO₃^--N in the influent were100 mg/L,the removal rates of NH₄⁺-N and NO₃^--N were 92.64%and 78.11%respectively,which showed that high substrate concentration is more conducive to PD,but had certain inhibition effect on Anammox process.（2）The aerobic nitrified landfill leachate was used as the influent of the PD/A reactor to investigate the possibility of deep nitrogen and carbon removal from landfill leachate by PD/A process.The results showed that the effluent concentratio-ns of NH₄⁺-N and COD were 8.47～9.47 mg/L and 31.89～32.75 mg/L respectively.In addition,the chroma of landfill leachate also decreased.Figure[27]Table[11]reference[119]...