Experimental Study On Inhibitor-enhanced Nitrosation And Anaerobic Ammonia Oxidation Process For Treating Low C/N Wastewater

The anaerobic ammoxidation process has the advantages of low energy consumption,small sludge production,and high nitrogen removal load.It can improve the treatment of low C/N wastewater represented by municipal sludge liquid.How to accumulate a large amount of nitrite quickly restricts the development of anaerobic ammonia oxidation process engineering.This paper is a pilot study on the treatment of low C/N wastewater by the SBBR-UASB combined process in which nitrification inhibitors are used to enhance nitrosation.By adding nitrification inhibitors,a large amount of nitrite is rapidly accumulated.Analyze the process conditions and lay the foundation for the engineering application of anaerobic ammonia oxidation.Using sodium chlorate as an inhibitor to control the nitrosation process,SB BR and UASB reactors were used to experimentally study the treatment effect of the nitrosation process and anaerobic ammonia oxidation process.The main research contents are:experimental studies on nitrosation controlled by sodium chlorate inhibitors;experimental studies on anaerobic ammonia oxidation processes;experimental studies on some combined nitrosation-anaerobic ammonia oxidation processes.The test results show that the addition of sodium chlorate inhibitor can effectively shorten the start-up time of the nitrosation reactor,from the traditional 30d to 20d.To test the effect of each factor,determine the level of the best environmental factors SB BR nitrosation reaction:T=30?,p H=7.5?8.0,??DO?=1.0mg·L^-1,??Na Cl O₃?=1.0mol·L^-1,and?(COD_Cr)?150mg·L^-1.At this stage,the average N H₄⁺-N removal rate of the reactor was 92.61%,and the NO₂^--N accumulation rate was as high as 88.62%.When??NH₄⁺-N?=250mg·L^-1,adjust the operating conditions of the reactor to water inlet?instantaneous?-aeration?195min?-sedimentation?165min?-drainage?instantaneous?-idle?120min?.Part of the nitrosation process that matches the anaerobic ammoxidation is realized to run stably.In this test,the anaerobic nitrification sludge of the sewage plant was used as the inoculation sludge,and the UASB reactor was successfully started over 112 days in a low temperature and low matrix method.Subsequently,the TN volume load in the reactor was gradually increased to realize stable operation of the reactor.A small scale experiment was conducted to determine the optimum environmental factors for anaerobic ammonia oxidation of UASB:the temperature was 30?,HRT=12h,and p H=8.The average removal rate of NH₄⁺-N,NO₂^--N and TN were 90.69%,96.25%and 87.40%.When?(COD_Cr)=50mg·L^-1,the system runs stably and efficiently removes nitrogen.Analyzing?NO₂^--N/?NH₄⁺-N and?NO₃^--N/?NH₄⁺-N in the reactor.It is found that there is a slight deviation between the two and the ideal value,indicating that there are a small number of denitrifying bacteria and anaerobic ammonia in the reactor.After adaptive commissioning,the SBBR-UASB combined system has a better effect on low-C/N wastewater treatment.During stable operation,the average removal rates of NH₄⁺-N and TN were 92.48%and 80.26%,and the average removal rate of COD_Cr was 88.12%.Adding sodium chlorate inhibitor can quickly achieve a large amount of nitrite accumulation.Partial nitrosation-anaerobic ammonia oxidation combined process with inhibitor-enhanced nitrosation is feasible in the direction of treating low C/N wastewater.It makes up for the high consumption and low efficiency of the traditional nitrification-denitrification process,and its strong denitrification performance helps to solve the problems faced by China's sewage treatment.