Study On The Start-up Mode Of Municipal Wastewater Treatment By CANON Process

With the increasingly serious pollution of nitrogen in the water,human health has been affected.Therefore,the emission of N and P is becoming more and more strict.The new emission standard puts forward higher requirements for the nitrogen removal process,and the traditional denitrification process can not meet the requirements of sustainable development.Therefore,the new and efficient nitrogen removal process needs to be developed urgently.Compared with the traditional biological nitrogen removal process,the whole process of autotrophic nitrogen removal?CANON?has the advantages of energy saving,no additional organic carbon source,low operating cost and no pollution.At present,CANON process has been widely used in the field of high ammonia nitrogen wastewater treatment,and its application in the treatment of low ammonia nitrogen wastewater is still in the exploratory stage.The rapid start-up of CANON process to treat low ammonia nitrogen wastewater and long-term stable operation of the process is the focus of current research.In order to study the feasibility of CANON process for treatment of low ammonia wastewater,this paper adopted the new composite type baffle plate?HABR?as the reaction device,and respectively with activated sludge and anaerobic ammonium oxidation sludge as seed sludge,start the CANON process through the gradually shortened HRT,examine the similarities and differences between operation characteristics of CANON under different starting process the way,in order to find the more suitable CANON low ammonia wastewater process start way,provide a reference for the application of CANON technology in domestic sewage.The experimental research process is divided into two stages:The first stage is the quick start-up and operation efficiency of CANON reactor.By inoculating activated sludge in water temperature: 28³2 degrees,NH₄⁺-N:38⁴0 mg/L,PH:7.3⁷.9.By gradually shortened HRT startup of the reactor,investigated the start-up and stable operation,the nitrogen removal rate of nitrogen removal efficiency of CANON process.The main findings are as follows:?1?A new type of HABR reactor,which has been successfully operated for a period of 88 days,has realized the rapid start-up of CANON process,and has been running steadily to 188 d.In the reactor ofstable operation stage,the reactor effluent NH₄⁺-N maintained at below 1.8 mg/L,the effluent TN maintained at 9.7mg/L,and tended to be stable,the removal rate reached 93% and 81% respectively.The total nitrogen removal rate reached 0.14kg/?m³×d?,it can be seen that the reactor has high nitrogen removal efficiency,stable operation can be a point.?2?In the stable operation stage,NH₄⁺-N and TN concentration range decreased gradually in the reactor of the effect of anaerobic ammonia oxidation bacteria activity by pH,the changes of p H could reflect the device of nitrification and anaerobic ammonia oxidation reaction conditions.And the change of MLSS was positively correlated with the change of NH₄⁺-N concentration.?3?After the operation of 77 d,the influent NH₄⁺-N concentration was changed,the removal rate of NH₄⁺-N reached to 94%,and the removal rate of TN reached to 83%.It can be seen that the nitrogen removal performance of the reactor is good in the treatment of domestic sewage.Quick start-up and operation efficiency of second stage CANON reactor ii.The anammox sludge inoculation in the reactor,the main parameters are as follows,NH₄⁺-N:48⁵1 mg/L,water temperature:29³1 degrees,PH:7.3⁷.7,HRT by changing the startup of the reactor,investigated the start-up and stable operation,the nitrogen removal rate of nitrogen removal efficiency of CANON process.The main results are as follows:?1?In the experiment,the inoculated sludge used in the start-up of the CANON process is an anaerobic ammonium oxidation sludge.In the water temperature is?30±1??,pH is 7.3⁷.7,after 113 d cultivation and domestication,reactor II successfully started CANON process.In the stable operation of the reactor,the average concentration of effluent NH₄⁺-N was 2.46 mg/L,the average concentration of effluent TN was about 11.21 mg/L,the average removal rate was up to 92% and 76%,and the total nitrogen removal load of the reactor was 0.21 kg/?m³×d?.?2?In the stable operation stage,the reactor II along the p H first and then decreased,indicating the anammox reaction in early third lattice began to decline,the rate of anaerobic ammonia oxidation reaction is affected by the NH₄⁺-N and NO2--N concentration decreased.The change of MLSS in reactor 2 was positively correlated with the change of NH₄⁺-N concentration.The start-up time,operating efficiency,the parameters of the process and the microbial morphological characteristics of the CANON were compared.The main conclusions are as follows:?1?the reactor of shorter start-up time,and start the process of nitrogen removal is superior to II reactor.?2?at the stage of stable operation of reactor I,the effluent NH₄⁺-N and TN of the reactor were stable below 1.8mg/L and 9.7mg/L,respectively,and the removal rates of NH₄⁺-N and TN reached 93% and 81%respectively.In the stable operation stage of reactor II,NH₄⁺-N and TN in reactor effluent were stable at2.95 mg/L and 11.78 mg/L,respectively,and the removal rate of NH₄⁺-N and TN reached 92% and 76%respectively.The nitrogen removal efficiency of reactor is better than that of reactor ii.?3?by scanning electron microscopy can be seen,two stable stage reactor,microbial biofilm morphology is very similar,mainly for ellipsoidal and spherical bacteria,AOB and AnAOB for speculation in the reactor exist at the same time,and the same as the dominant bacteria.