Performance Of Denitrification By ANAMMOX In A Hybrid Constructed Wetland

Anaerobic ammonia oxidation (Anammox) was first discovered in the20th centuryby the Dutch, which is a biological reaction with NH4+-N as an electron donor, NO2--N as an electron acceptor, hydroxylamine and hydrazine as key intermediates andnitrogen as final product. Based on anammoxphenomenon, several biological nitrogenremoval technologies have been developed, such as ANAMMOX,SHARON-ANAMMOX, CANON and other methods which are low-cost andlow-consumed denitrification process.Currently Anammox technology has beensuccessfully applied to sewage treatment plants based on activated sludge in the city,however,it is rarely reported in a constructed wetlands natural enrichment. Aim atResearch team developed a novel hybrid CW, vertical-baffled flow wetland/horizontalsubsurface flow wetland,with efficient denitrification, the study was conducted in theQinghe Agro-park wasterwater treatment plant to explore whether the existence ofanammox reaction in order to provide technical support for the design of constructedwetland systems.This paperfirstly analyzes overall operation of the wastewater treatment plant inthe high temperature season, including physicochemical analysis and nitrogen removalefficiency of along structures, which showed that a novel hybrid CW had goodoperationeffect with removal efficiency of NH4+-N and TN81.0%å'Œ74.7%in the case of low C/N, and efficient denitrification phenomenon compared with common wetland.The paperemphasis analyzes variation law along the novel horizontal subsurfaceflow wetland with repeating aerobic, anoxic and anaerobic conditions supports anoptimum environment for ammonia nitritation and anammox, which contribute to thesimultaneous removal of both NH4+-N and TN at a low C/N ratio flow. Organic carbonand nitrogen removal ratio does not meet the traditional biological nitrification anddenitrification requirements also reflect that the horizontal subsurface flow wetland hasoccurred non-conventional ammonia nitritation and anammox.On the basis of the efficient denitrification phenomenon of the novel horizontalsubsurface flow wetland, this paper conducted DAN polymerase chain reactionamplification and cloning of PCR products, sequencing and developmental tree analysisand quantitative polymerase chain experiments with microorganisms of the underlyingsubstrate and wasterwater inthe structure, whether is the presence of anammox bacteria in them.The results found a bacteria with the currently known autotrophic anammoxbacteria Candidatus Anamoxoglobus Propionicus100%homology, which areautotrophic anammox genus of bacteria,and that the serial number was registeredKF709433in the NCBI,finally that number anammox gene wetland system was2.37%of the total number of genes.To explore the contribution of anammox denitrification rate,then the paperdesigned15N isotope tracer experiments and the results showed that the maindenitrification pathway have denitrification, anaerobic ammonia oxidation and ammoniavolatilization in construted wetlands and ultimately escapeinto the atmospherein gasform of N2and NH3, then the contribution rate are80.7%,9.6%and9.7%respectively.