Nrog rau kev nce qib ntawm eutrophication ntawm lub cev dej ntuj, kev tshem tawm cov nitrogen hauv cov dej qias neeg tau dhau los ua qhov teeb meem loj zuj zus. Wetlands ua lub luag haujlwm tseem ceeb hauv kev tiv thaiv thiab kev tswj hwm ntawm eutrophication ntawm cov dej ntuj. Ntuj ntub dej, ntxiv los ntawm kev ntsuas tsim nyog, tuaj yeem txhim kho kev ua haujlwm ntawm cov pa phem tshem tawm thiab cov teebmeem ecological. Ntawm lawv, kev tshem tawm nitrogen yog ib qho haujlwm tseem ceeb ntawm cov av ntub dej. Cov ntsiab lus ntawm kev tshem tawm nitrogen hauv cov av ntub dej rau kev kho dej phwj tuaj yeem muab lub hauv paus zoo rau kev tsim, kev ua haujlwm thiab kev tshawb fawb ntawm cov av ntub dej.
Denitrification mechanism ntawm dag wetlands
Artificial wetland systems tshem tawm nitrogen los ntawm cov dej phwj tuaj los ntawm ntau yam txheej txheem. Cov txheej txheem no feem ntau suav nrog cov tshuaj lom neeg lom neeg, lub cev thiab tshuaj lom neeg.
Nyob rau hauv lub anti-seepage dag wetland system, yog hais tias cov nitrogen pauv ntawm cov av dag thiab ib puag ncig cov dej lub cev yog ignored, cov kev ncig thiab transformation txoj kev ntawm nitrogen nyob rau hauv dag wetlands yog qhia nyob rau hauv daim duab hauv qab no, feem ntau suav nrog ammonia ntawm organic nitrogen, ammonia nitrogen volatilization. , biological nitrification thiab denitrification, cog microbial cov ntaub so ntswg uptake, matrix adsorption thiab anaerobic ammonia oxidation thiab lwm yam lub cev, tshuaj thiab lom cov txheej txheem.
Ntawm lawv, cov adsorption thiab nag lossis daus ntawm matrix muaj cov txiaj ntsig zoo hauv cov av tshwj xeeb matrix los yog nyob rau theem pib ntawm kev siv cov av ntub dej, tab sis rau cov neeg laus cog qoob loo uas tau ua haujlwm rau lub sijhawm ntev, kev hloov pauv thiab tshem tawm ntawm nitrogen nyob rau hauv cov av. kev txiav txim ntawm cov kab mob ib txwm tau suav tias yog txoj hauv kev tseem ceeb kom tshem tawm nitrogen. Lwm txoj hauv kev tshem tawm nitrogen xws li anaerobic ammonia oxidation yuav theoretically ua kom muaj txiaj ntsig zoo rau kev kho cov av ammonia nitrogen cov dej khib nyiab ntau dua.
National ecological hnub
Nitricification yog hais txog cov txheej txheem uas ammonia nitrogen yog oxidized rau nitrite nitrogen thiab txuas ntxiv oxidized rau nitrogen nyob rau hauv kev nqis tes ua ntawm cov microrganisms. Nitrification yog ua tiav los ntawm autotrophic cov kab mob hauv ob theem.
Thawj theem yog cov txheej txheem nitrite: uas yog, theem uas ammonia nitrogen yog oxidized rau nitrite nitrogen.
Muaj tsib lub cim loj ntawm Nitrite cov kab mob koom tes nrog rau theem no: Nitrosomonas, Nitrosocystis, Nitrosococcus, Nitrosospira thiab Nitrosospira. Ntawm lawv, lub luag haujlwm ntawm Nitrobacter tshwj xeeb tshaj yog.
Qhov theem ob yog txheej txheem nitrification: uas yog, theem nyob qhov twg nitrite nitrogen yog oxidized rau nitrate nitrogen.
Muaj peb lub ntsiab Generica ntawm nitrify cov kab ke koom nrog hauv qib no: Nitrobacter, nitrobaS thiab nitrococcus. Ntawm lawv, Nitrobacter yog lub ntsiab genus, thiab cov nquag yog nitrobacter watogradskyi thiab n.agilis.
Ntxiv rau cov lus hais saud tau hais txog, muaj ntau cov kab mob heterrophic hauv av, uas muaj peev xwm ua tau cov kab ke Tab sis cov kev tshawb fawb ntawm lawv lub luag haujlwm tshwj xeeb hauv Nitrification txheej txheem hauv cov khoom ntub dej yog tseem tsis txaus.
Lub Nitricification tshem cov nyhuv ntawm ammonia nitrogen sib txawv nrog tus qauv tsim qauv thiab qauv ntawm cov khoom ntub. Nyob rau hauv nto deg cov dej hiav txwv ntub, ntsug flatorial ntub thiab sib xyaw ua ke ntub, muaj txiaj ntsig ntawm nitrogen raug tshem tawm, tab sis cov qib sib txawv.
Feem ntau hais lus, txij li cov nyhuv reoxygenation ntawm ntsug ntws zoo dua li ntawm kab rov tav subsurface ntws cov av ntub dej, qhov kev siv ntawm nitrification feem ntau yog ntau dua li ntawm kab rov tav subsurface flow wetlands. Tsis tas li ntawd, kev ua haujlwm sib txawv kuj tseem cuam tshuam rau kev siv nitrification. Piv txwv li, txoj haujlwm tidal hom siv nyob rau hauv ntsug ntws wetlands thiab lub aeration pretreatment nyob rau hauv thaum ntxov theem ntawm kab rov tav subsurface ntws wetlands ob qho tib si nce lub nitrification siv ntawm lub system.
Denitrifictrification Txheej Txheem
Cov txheej txheem Biochemical hais txog cov kab mob biochemical uas tsis kam lees cov khoom nitrogen (n2) los ntawm cov khoom lag luam nruab nrab (tsis muaj} {2}}, tsis muaj, n2o ).
Cov txheej txheem denitrification yog qhov tseem ceeb nyob hauv cov nitrogen voj voog hauv xwm thiab yog qhov txuas tseem ceeb hauv cov nitrogen voj voog. Nyob rau hauv cov nqe lus ntawm cov khoom siv dej qab zib, nws suav tau lub ntsiab hom kev siv roj ntsha ua ke nrog cov tshuaj tiv thaiv nitrification. Kev txwv ib puag ncig ntawm cov txheej txheem denitrification muaj ib puag ncig cov pa, redebox muaj peev xwm, qhov kub thiab txias thiab cov organic carbon. Nitrification yuav tsum tau rov kho ib puag ncig, tab sis tsis kam lees yuav tsum muaj kev ua kom lub neej tsis muaj kev txwv tsis pub muaj qhov tseem ceeb ntawm kev txwv thaj chaw ntub dej.
Qhov feem ntau cov phot tsim nyog tshaj plaws rau kev txheeb xyuas yog pH 6-8. Thaum tus pH tus nqi qis dua 5, kev siv ntawm denitricification tuaj yeem nqa tawm, tab sis nws tus nqi txo qis dua. Thaum tus lej py qis dua 4, kev txwv tsis pub muaj feem cuam tshuam tsis pub dhau. Qhov ntsuas kub kom haum rau kev cuam tshuam yog 30 ~ 35 degree, thiab qhov tsis muaj zog yog tsis muaj zog thaum qhov ntsuas kub qis dua 2 ~ 9 degree.
Los ntawm cov txheej txheem denitrification saum toj no, nws tuaj yeem pom tias cov khoom lag luam uas tsis pom zoo yog nitrogen (n2), thiab N2O yuav tsim tawm hauv lub xeev tsis tiav. Txij li n2o yog lub tsev cog khoom roj, nws lub ntiaj teb ua kom sov muaj peev xwm sib npaug nrog 310 lub sijhawm uas ntawm CO2. Txawm hais tias qhov kev tawm tsam ntawm cov neeg muaj kev tsis txaus ntseeg nyob rau hauv cov chaw nres nkoj tseem ceeb yog qhov tsis txaus ntseeg, nws muaj kev txhawj xeeb ntawm cov kws tshawb fawb tsis ntev los no.
Kev Cog Extraction
Nitrogen yog ib qho khoom noj tseem ceeb rau kev loj hlob ntawm cov nroj tsuag. Inorganic nitrogen tuaj yeem nqus tau thiab tsim los ntawm cov nroj tsuag hauv cov av ntub dej rau hauv cov khoom cog. Thaum kawg, ib feem ntawm cov inorganic nitrogen tuaj yeem raug tshem tawm tag nrho ntawm cov av ntub dej los ntawm kev sau qoob loo ntawm cov av saum toj no ntawm cov nroj tsuag ntub dej.
Cov nqus thiab kev tshem tawm ntawm inorganic nitrogen los ntawm cov nroj tsuag yog txwv los ntawm cov qoob loo ntawm cov ntaub so ntswg thiab cov nitrogen cov ntsiab lus hauv cov ntaub so ntswg. Daim ntawv thov ntawm kev txhim kho cov nyhuv tsis kam lees ntawm cov chaw cog qoob loo, vim tias cov khoom siv caij ntuj muaj peev xwm loj thiab thaj chaw ntub dej tuaj yeem loj hlob txhua xyoo puag ncig. Yog li ntawd, kev sau qoob ntawm cov nroj tsuag tuaj yeem nqa tawm ntau zaus los txhim kho cov nqus thiab kev tshem tawm ntawm cov nqaij mos hauv cov pob txha.
Ammonification
Cov txheej txheem ammonification feem ntau yog hais txog cov txheej txheem uas muaj nitrogen-muaj cov organic teeb meem xws li cov protein yog decomposed los ntawm cov kab mob hauv lub txaj ntub dej thiab hloov mus rau hauv ammonia. Kev tshawb fawb ntawm ammoniation nyob rau hauv lub voj voog nitrogen ntawm kev kho cov av ntub dej tsis zoo tsis tau nyiam cov neeg tshawb nrhiav thiab kev tshawb fawb xws li nitrification thiab denitrification.
Tus tshaj tawm ammoniation siv ntawm cov khoom ntub dej yog 0. 004-0. 530 g / (M230 D).
Ammonia nitrogen volatilization
Qee cov nitrogen thiab nitrogen hauv cov tshuab ntub dej tuaj yeem khiav tawm ntawm lub system los ntawm kev kub siab. Tus nqi ntawm ammatilization cuam tshuam los ntawm cov yam xws li huab cua, cov xwm txheej hydraulic, thiab cog qoob loo xwm txheej.
When the pH value is lower than 7.5, the ammonia volatilization effect can be ignored. Only when the pH value is greater than 9.3, the ammonia volatilization effect is more significant. Wetland ammonia volatilization includes wetland ground ammonia volatilization and plant leaf ammonia volatilization. Among them, wetland ground ammonia volatilization needs to occur when the water pH>8. Feem ntau, tus nqi ntawm tus nqi ntawm cov khoom ntub yog 6 ~ 7. Yog li ntawd, Ammonia nitrogen poob los ntawm ntub dej hauv av volatilization tuaj yeem tsis quav ntsej.
Txawm li cas los xij, thaum muaj cov khoom siv dag zog yog muaj nrog limestone thiab lwm yam nqi hauv cov kab tawm hauv lub nroog Watorland yuav muaj kev cuam tshuam ntau heev, thiab kev poob ntawm ammatilization yuav tsum tau txiav txim siab.
Anaerobic ammonia oxidation
Cov txheej txheem anaerobic ammonia oxidation yog cov txheej txheem tshuaj lom neeg uas siv cov kab mob anaerobic ammonia-oxidizing siv nitrite ua cov khoom siv hluav taws xob thiab ammonia nitrogen raws li tus neeg pub khoom siv hluav taws xob los ncaj qha oxidize ammonia nitrogen rau hauv cov pa roj nitrogen hauv cov xwm txheej anaerobic.
Cov tshuaj tiv thaiv no feem ntau muaj cov kev cai nruj rau cov xwm txheej sab nraud (pH nqi, kub, yaj oxygen, thiab lwm yam), tab sis nws qhov zoo yog: txij li ammonia nitrogen siv ncaj qha los ua tus neeg pub khoom siv hluav taws xob rau cov tshuaj tiv thaiv denitrification, qhov sib ntxiv ntawm exogenous organic teeb meem (xws li. methanol) tuaj yeem zam tau, uas tuaj yeem txuag cov nqi khiav lag luam thiab tiv thaiv cov pa phem thib ob.
Txij li feem ntau ntawm cov ammonia tsis tau ua tiav cov txheej txheem nitrification thiab koom ncaj qha rau hauv cov tshuaj tiv thaiv anaerobic ammonia oxidation, kev siv cov pa oxygen tau nce, lub zog noj cov pa oxygen txo, thiab cov kua qaub txo qis. Qhov no tuaj yeem txo cov tshuaj reagents xav tau rau kev ua haujlwm nruab nrab, txo cov nqi khiav lag luam, thiab txo cov pa phem thib ob.
Tam sim no, cov cuab yeej no tau maj mam siv rau hauv kev lag luam kho cov dej khib nyiab, khib nyiab pov tseg thiab lwm yam dej khib nyiab. Txawm hais tias muaj cov ntaub ntawv qhia txog kev kho cov dej phwj tuaj yeem, cov kev tshawb fawb ntsig txog tseem tsis txaus.
Nitrous oxide tso tawm
Nws feem ntau ntseeg tias lub ntsiab ntawm kev tshem tawm nitrogen hauv cov av ntub dej yog tias nitrogen hauv cov dej phwj tuaj nws thiaj li khiav tawm hauv daim ntawv ntawm N2 thiab N2O gases nyob rau hauv kev sib xyaw ua ke ntawm nitrification thiab denitrification los ntawm cov kab mob. Txij li thaum N2O yog cov roj cua sov muaj zog, nws cov txiaj ntsig hauv tsev cog khoom yog kwv yees li 298 npaug ntawm CO2, thiab nws qhov cuam tshuam rau lub ntiaj teb ib puag ncig yog lub sijhawm ntev thiab muaj peev xwm, yog li nws tseem ceeb heev rau kev kawm txog txoj cai ntawm N2O tso tawm hauv cov av ntub dej.
Kev tshawb fawb ntawm N2O emissions nyob rau hauv cov av tsim hluav taws xob tau pib hauv xyoo 1997, thaum Freeman thawj zaug tau hais tias kev siv cov cuab yeej siv hluav taws xob tsim hluav taws xob los ntxuav cov dej phwj tuaj yuav tso qee qhov N_2O mus rau hauv huab cua. Txij thaum ntawd los, cov ntaub ntawv tshawb fawb ntsig txog tau muab luam tawm txawv teb chaws. Kev tshawb fawb txog kev lag luam hauv tsev tau pib lig, thiab cov ntaub ntawv tshawb fawb ntxov tshaj plaws tau pom hauv xyoo 2009.