| Excessive discharge of nitrogen will cause pollution and eutrophication of the receiving water,the denitrification treatment of the waste water becomes more and more important.At present,Chinese urban wastewater treatment plants adopt the traditional biological nitrogen technology generally.Although this process is very mature,it has many disadvantages such as high energy consumption,a large land occupancy,and complex operation procedures.The anaerobic ammonia oxidation(Anammox)process is known as one of the most promising biological denitrification processes,because of its advantages of high denitrification load,low sludge yield,simple and economical.However,nitrite,one of the anaerobic ammonia oxidation substrates,is difficult to obtain stably.Anaerobic ammonia oxidizing bacteria grow slowly,and it is difficult to enrich and culture.In addition,organic pollutants can have an inhibition effect on it,which limits the application of Anammox process.In this paper,the accumulation of nitrite in partial denitrification process was studied.The influence of Fe(II)and organic carbon source on the UASB reaction system of Anammox process were analyzed.Fluorescence spectrometry was used to characterize the Anammox process.The main contents and research results were as follows:1.The SBR partial denitrification reactor was operated for a long time,set sodium acetate as the only organic carbon source.The effects of initial nitrate concentration,different C/N ratios,and addition of nitrate nitrogen to the reaction system on the accumulation of nitrite nitrogen were investigated.During the 90 days,the quality of the effluent was stable and and a higher concentration of nitrite nitrogen was obtained.As the initial nitrate nitrogen concentration increased,the nitrite nitrogen accumulation rate would increase,correspondingly.Under different C/N ratio conditions,a higher concentration of nitrite nitrogen accumulation was also achieved,there were little relationship between the nitrite nitrogen accumulation rate and C/N ratio.Nitrate was chosen as the denitrifying bacteria in the system as the electron acceptor preferentially,and then nitrite.2.The concentration of ferrous ion in the influent of the UASB Anammox reactor was changed,and the optimal ferrous ion dosage was determined based on the nitrogen remove rate.Ferrous ion can promote the growth of microbial cells,and the additon of the ferrous ion concentration,could properly promote the accumulation of anaerobic ammonia oxidizing bacteria,and enhanced its activity.The study showed that it has the bestefficiency of substrate removal in the Anammox reactor when Fe(II)concentration in the synthetic wastewater was set as 5.00 mg/L.Three-dimensional fluorescence spectroscopy combined with parallel factor analysis could be used to resolve the EEM fluorescence spectra of the effluents successfully.They were protein-like substances and humic-like substances,which were mainly derived from the substrate metabolism and biological decay intermediates or final products.Fluorescence scores of the two substances could reflect the nitrogen remove efficiency of the UASB Anammox reactor.3.By adding organic carbon sources to synthetic waste water,the effects of different organic concentrations on the Anammox process were studied.The analysis results showed that it was feasible to add a small amount of organic carbon source to optimize the performance of UASB Anammox reactor.It could enhanced the cohesion between sludges,made it easier to form large sludge particles.Anaerobic ammonia oxidizing bacteria,aerobic nitrifying bacteria and heterotrophic nitrification bacteria could co-exist with each other,they worked together to increase the nitrogen remove efficiency in reaction system.4.Three-dimensional fluorescence spectroscopy combined with parallel factor analysis(PARAFAC)and fluorescence region integration(FRI)could improve the accuracy of spectral recognition,and realize the rapid characterization of the Anammox process. |
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