Study On Treatment Of Rare Earth Ammonia Nitrogen Wastewater By Anaerobic Ammonia Oxidation System

As an efficient and economic denitrification process,anammox process has attracted the attention of scholars at home and abroad because of its advantages over traditional biological denitrification process,such as high denitrification efficiency,no need for additional organic carbon source,no need for dissolved oxygen,low energy consumption,less sludge output,no secondary pollution,etc.,especially in the treatment of high ammonia nitrogen wastewater with low organic carbon The prospect of development and application,however,is restricted by the extremely slow growth of denitrification function bacteria anammox bacteria.In this paper,the above flow anaerobic sludge bed is used as reactor to inoculate anaerobic sludge and nitrified sludge,Under the condition of keeping HRT and pH of the reactor unchanged about 7.3,the anaerobic ammonia oxidation reactor was started by increasing the influent substrate concentration,and the influent NH₄⁺-N,NO₂-N ratio,HRT,temperature,pH and other influencing factors and reaction kinetics characteristics of the process were explored to make the reactor run to the optimal load.On this basis,the anaerobic ammonia oxidation reactor was operated with rare earth ammonia nitrogen wastewater to investigate the denitrification performance and microbial community structure change of rare earth ammonia nitrogen wastewater in this system.In addition,batch experiments were conducted to investigate the short-term effects of rare earth ions on anaerobic ammoxidation.The main results are as follows:When nitrifying sludge and anaerobic granular sludge are inoculated,the raw water is artificial simulated municipal sewage.The HRT is kept unchanged in the early stage,only the concentration of influent matrix is increased,and the HRT is shortened in the later stage.Under the condition of temperature of?35±2?°C and pH value of 7.5⁸.2,anaerobic ammoxidation granular sludge is cultivated after the reactor operates for 70 days.The rapid start-up of anammox was realized.The system has high efficiency of denitrification and shock load resistance,and has great potential of anaerobic ammonia oxidation;The long-term running ANAMMOX-UASB reactor was used to denitrify the rare earth ammonia nitrogen wastewater.The total nitrogen load of influent and total nitrogen removal reached 2.46 kg/m3/d and 1.43±kg/m3/d.The pH of influent water was controlled between 7.5-8.3 for 60 days,and the NH₄⁺-N removal rate was 83.69%.It can be seen that the anaerobic ammonia oxidation system has a good treatment effect on rare earth ammonia nitrogen wastewater,but the effluent can not be reduced to the national discharge standard only by this process link.In short-term batch experiments,La³⁺with concentration less than 1mg/L has a slight inhibitory effect on Anammox,and the inhibitory effect can be restored.When La³⁺concentration is greater than 1mg/L,the inhibitory effect is very obvious,which is caused by the bacterial community on Candidatus jettenia,which is mainly responsible for the degradation of NH₄⁺-N.During the operation,the diversity and corresponding abundance of microbial community in the inoculated sludge are constantly reduced.In the later period of operation,there are mainly two kinds of phylum,i.e.Fusarium and Proteus.At the same time,a small number of ammonia oxidizing bacteria and denitrifying bacteria are detected.The system is mainly composed of anammox bacteria,which is the main denitrification functional bacteria.But at the same time,it has the cooperation among facultative anammox bacteria,nitrifying spiral bacteria and denitrifying bacteria,whichmakes the reactor have good denitrification performance for rare earth ammonia nitrogen wastewater.