Biological Nitrogen Removal And Fluorescence Spectrum Analysis Of Livestock And Poultry Wastewater

The huge scale livestock and poultry breeding industry have harmed to the natural environment in China.The large number of organic nitrogen compounds and ammonia nitrogen contained in livestock and poultry breeding wastewater can lead to eutrophication of the water body.The cost of the traditional biological nitrogen removal process is high,which added a burden to large-scale breeding farms.As a new denitrification process,anaerobic ammonia oxidation process has the characteristics of low sludge yield and simple process,it doesn’t need organic carbon source,So it can significantly reduce the denitrification cost,it is used to treat high ammonia nitrogen wastewater usually.The combined process of anaerobic digestion-shortcut nitrification and anaerobic ammonia oxidation was used to treat livestock and poultry breeding wastewater,The parallel factor analysis of effluent samples was carried out by fluorescence spectrometry in the paper.The main research contents and conclusions are as follows:1.The sequencing batch reactor was used for the start-up of shortcut nitrification.The inoculated sludge was taken from the aerobic tank of the sewage treatment plant in Economic Development Zone of Hefei.After 30 days continuous experiment in three phases of ammonia nitrogen load increase stage,pH adjustment stage and buffer addition stage,the ammonia nitrogen removal rate and the nitrite nitrogen accumulation rate were increased to90.7%and 88.9%respectively,the shortcut nitrification reactor was successfully started.The results showed that the high concentrations of ammonia nitrogen were beneficial to the start-up of shortcut nitrification;a higher pH value contributes to helps the accumulation of nitrite nitrogen,but if the pH value is too high,the activity of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria will be inhibited;the addition of sodium bicarbonate can cause the pH of the effluent increase significantly,and the ammonia removal rate and the nitrite nitrogen accumulation rate will increase.2.The up-flow anaerobic sludge bed reactor was used for the start-up of anaerobic ammonia oxidation.The inoculated sludge was taken from the oxidation ditch of the sewage treatment plant in Economic Development Zone of Hefei.After 75 days of continuous cultures,the removal rate of ammonia nitrogen and nitrite nitrogen reached 90.6%and 91.3%respectively,The reactor was started successfully.The different concentrations of organic carbon sources were added to the influent to observe the changes of ammonia nitrogen and total nitrogen removal rate in the reactor under different chemical oxygen demand（COD）concentrations.The results show that:the concentration of ammonia nitrogen in the effluent is higher than that in the influent due to the autolysis of bacteria when the reactor is just started.At this time,the concentration of nitrite nitrogen in the effluent is very low due to heterotrophic denitrification,but with the gradual consumption of organic matter in the reactor,the concentration of nitrite nitrogen in the effluent rises rapidly;the total nitrogen removal rate is the highest when the COD concentration of the influent is 90 mg·L^-1,the ratio of NO₂^--N consumed to NH₄⁺-N consumed and the ratio of NO₃^--N produced to NH₄⁺-N consumed are different from the theoretical value at the same time,it is indicated that heterotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria coexist in the reactor.3.After the reactors are all started successfully,the coupling experiment of shortcut nitrification-anaerobic ammonia oxidation process was firstly carried out;then,the artificial wastewater is replaced by the livestock and poultry wastewater after anaerobic digestion,the coupling experiment of anaerobic digestion-shortcut nitrification-anaerobic ammonia oxidation process was carried out,the total nitrogen removal rate of the coupling process is77.2%.The coupling results show that:after the inlet water of the shortcut nitrification reactor is changed from the artificial wastewater to the actual wastewater,the removal rate of ammonia nitrogen changes small,but the removal rate of COD is reduced significantly,It indicates that the actual breeding wastewater contains some organic matters which are difficult to remove.The method of simulating wastewater using simple organic substances such as glucose is unreasonable;it is feasible to mix the influent and effluent of the shortcut nitrification reactor as the influent of the anaerobic ammonia oxidation reactor,but the mixing ratio needs to be strictly controlled,otherwise,the total nitrogen removal rate will be relatively low.4.Three-dimensional fluorescence spectroscopy was used to analyze the livestock and poultry farming wastewater,the effluent from shortcut nitrification reactor and anaerobic ammonia oxidation reactor.The results are as follows:there are three main fluorescent components in the livestock and poultry farming wastewater as tryptophan-like substances,humic acid-like substances and fulvic acid-like substance;the effluent of the shortcut nitrification reactor has two fluorescent main components which are humic acid-like substance and fulvic acid-like substance;the effluent of the anaerobic ammonia oxidation reactor without organic carbon source has two fluorescent main substances which are fulvic acid-like substances and humic acid-like substances.In the case of containing organic carbon source,the effluent of the anaerobic ammonia oxidation reactor has three fluorescent main components,which are protein-like substances,fulvic acid-like substances and humic acid-like substances.