AnAOB Rapid Culture And Application Of PN-Anammox Technology In High Ammonia Nitrogen Industrial Wastewater

PN/A process has the advantages of less sludge production,no additional organic carbon source and low operating cost.It has great advantages in the treatment of wastewater with high ammonia nitrogen and low C/N.However,there are still many bottlenecks to be solved in the application of PN/A process in industrial wastewater,such as the rapid enrichment of An AOB and the inhibition of organic matter.In view of the slow start-up of Anammox reactor in PN/A process and the influence of environmental factors such as organic matter and dissolved oxygen on the stable operation of PN/A process,this paper first explore the feasibility of starting Anammox reactor by inoculating wetland sediment.Secondly,combined with the denitrification performance of the reactor and the change of microbial community structure,the regulation strategies of rapid start-up and stable operation of one-stage PN/A process and two-stage PN/A process are explored.On this basis,the effects of organic matter on nitrogen removal performance and microbial community structure of the two processes were studied.Finally,the effects of one-stage and two-stage PN/A processes on nitrogen removal from anaerobic effluent of brewery wastewater were investigated.The main conclusions are as follows:（1）Anammox reactor can be successfully started by inoculating wetland sediment and mixed sludge with UASB reactor（the sludge concentration ratio of anaerobic granular sludge to wetland sediment is 1:1）.The reactor inoculated with mixed sludge began to show obvious Anammox reaction characteristics on day 125,which was shorter than that inoculated with wetland sediment on day 155.After 219 days of operation,the total nitrogen removal rates of Anammox reactor inoculated with wetland sediment and mixed sludge reached 74.49%and67.12%,respectively,under the condition of influent nitrogen load of 0.275 kg-N·（m³·d）^-1.In the reactor inoculated with mixed sludge,anaerobic granular sludge with good sedimentation performance can be used as the carrier of An AOB to reduce An AOB washout,thus accelerating the enrichment of An AOB and shortening the start-up time of Anammox reactor.The high-throughput results showed that An AOB in Anammox reactor inoculated with wetland sediment and mixed sludge was Candidatus＿Brocadia,and their abundances reached9.82%and 10.70%on day 221,respectively.（2）Anammox reactor was successfully started by inoculating anaerobic ammonium oxidation sludge.After 154 days of regulation and operation,the total nitrogen removal rate of Anammox reactor was stable at more than 82.61%under the condition of influent nitrogen load of 0.500 kg-N·（m³·d）^-1.The PN reactor was successfully started up by dual inhibition of low DO and high FA.After 75 days of operation,under the condition of ammonia nitrogen load of 1.100 kg-N·（m³·d）^-1,the nitrite accumulation rate reached 94.59%,and the ratio of effluent ammonia nitrogen to nitrite nitrogen is 1:1.12.The two-stage PN/A process was successfully started after connecting the stable PN reactor and the Anammox reactor in series.（3）By adding organic matter with COD concentration of 100 mg·L^-1into the influent of two-stage PN/A process,it was found that the addition of organic matter could lead to the decrease of ammonia oxidation rate of PN reactor and further lead to the decrease of nitrogen removal performance of the system.However,the nitrogen removal performance of the system could be restored to the normal level by increasing the aeration rate of PN reactor.The high-throughput results showed that Nitrosomonas and Candidatus＿Kuenenia both existed in the PN and Anammox reactors.The abundance of Candidatus＿Kuenenia in the PN reactor increased to 0.69%after the addition of organic matter in the influent,while there was no significant change in the abundance of Candidatus＿Kuenenia in the Anammox reactor.It indicated that the COD at 100 mg·L^-1did not significantly inhibit the activity of An AOB.Two-stage PN/A process was successfully applied to treat the anaerobic effluent of brewery wastewater after 51 days of operation.Under the conditions of influent COD concentration of120～170 mg·L^-1and nitrogen load of 0.550 kg-N·（m³·d）^-1,the removal rates of COD and total nitrogen were more than 11.24%and 88.71%,respectively.（4）The one-stage PN/A reactor was successfully started up by inoculating aerobic nitrifying sludge and adding polyethylene fillers.The reactor began to show Anammox reaction characteristics on the 60th day.And the addition of fillers can reduce the loss of An AOB and shorten the start-up time of the reactor.Due to the increase of aeration rate of one-stage PN/A reactor,the addition of organic matter with COD concentration of 100 mg·L^-1in the influent did not significantly affect the ammonia oxidation performance and denitrification performance of the reactor.The high-throughput results showed that in the one-stage PN/A reactor,AOB is the main component in the bottom sludge,and An AOB is the main component in the filler biofilm.After the addition of organic matter in the influent,the abundance of An AOB in the bottom sludge and filler biofilm increased to 6.14%and 8.78%,respectively.It indicated that the COD at 100 mg·L^-1did not significantly inhibit the activity of An AOB.After 229 days of operation,one-stage PN/A reactor was successfully applied to treat the anaerobic effluent of brewery wastewater.Under the conditions of influent COD concentration of 190～280 mg·L^-1and nitrogen load of 0.550 kg-N·（m³·d）^-1,the removal rates of COD and total nitrogen were more than 28.63%and 74.38%,respectively.