Study On The Anaerobic Oxidation Process Of Ammonia In The Artificial Wetland In The Ao Mountain Of Ma An Shan City

In recent years,anaerobic ammonium oxidation?ANAMMOX?has been found in inland lakes and marine sediments,and ANAMMOX process has a significant impact on the global nitrogen cycle.The wastewater produced by mining process is a difficultly purgative industrial wastewater,and artificial wetland is a better effective biological treatment technology to repair the pollution of mining wastewater.The Ao Mountain wetland in Ma An Shan is mainly used for treatment of mining wastewater,its typical characteristic is rich in sulfur and iron.Although previous studies have shown that sulfate and Fe?III?may have an effect on the efficiency or type of ANAMMOX reaction,the action process is not clear.Therefore,the research object is Ao Mountain artificial wetland,collecting fresh wetland sediments,ammonia or nitrite that is as nitrogen source was added into the sediment after pretreatment,using acetylene inhibitor technology and adding exogenous ferrihydrite,studing ammonia oxidation and denitrification process under the action of Fe?III?in anaerobic conditions.The research results will help us further understand the cycling rule and biogeochemical mechanism of the nitrogen,sulfur and iron element in mining area,and provide new ideas for the biological removal of nitrogen from wastewater by using ANAMMOX technology.The results of the study show that:1.In anaerobic condition,the addition of acetylene inhibitor can inhibit the nitrite dominated anaerobic oxidation ammonium?N-ANAMMOX?activity and N₂O reduction process.Therefore,ao mountain wetland sediments was added ammonia for exogenous nitrogen source,the process that ammonia was transform into nitrogen was the use Fe?III?of Feammox;added nitrite for exogenous nitrogen source,S-ANAMMOX and denitrification process transform nitrite to nitrogen;added ammonia and nitrite for exogenous nitrogen source,the ways of producing nitrogen was more complicated,as the interaction system of N-ANAMMOX,Feammox and denitrification process.2.Exogenous sulfur and nitrite were used as substrates in the sediments of the ao mountain wetland.The experimental results showed that the S-ANAMMOX process existed in the sediments,and sulfur ions were used as electron donors,nitrite was used as the electron acceptor to produce nitrogen gas.3.Adding exogenous ferrihydrite control research results showed that the main metabolites of Feammox process is nitrogen gas in the rich iron and sulfur sediments of the Ao Mountain wetland.Meanwhile,in acidic condition,the Feammox process caused a small accumulation of greenhouse gas N₂Oand NO₃^-.4.The addition of exogenous ferrihydrite promoted the Feammox process,the ammonia oxidation rate that dominated by the Feammox process was enhanced from1.69 mg·?kg·d?^-11 to 2.72 mg·?kg·d?^-1,and then Feammox process took ammonia oxidation contribution rate from 28%to 42%.But meanwhile,the addition of ferrihydrite made the significantly reduced effect of ANAMMOX,thus reducing by about 25%of the total quantity of ammonia to nitrogen gas in the wetland system.The results showed that the mineralization of ferrihydrite to goethite can lead to the inhibition of N-ANAMMOX process,and ferrihydrite promotes Feammox competing for the electron donor of S-ANAMMOX,and then inhibiting the S-ANAMMOX process.