Core Logic thiab Qhov Zoo / Qhov Tsis Zoo ntawm AO Denitrification Process
Lub hauv paus ntawm AO denitrification txheej txheem yog kev ua haujlwm ua ntu zus ntawm ob theem: anoxic thiab aerobic. Nitrogen hloov dua siab tshiab thiab tshem tawm yog ua tiav los ntawm kev sib koom ua ke ntawm cov kab mob. Cov txheej txheem tshwj xeeb tuaj yeem muab faib ua peb kauj ruam:
Ammonification: Hauv theem anoxic (A tank, DO Less dua lossis sib npaug li 0.2 mg / L), cov kab mob heterotrophic hloov nitrogen los ntawm cov pa phem, xws li cov protein thiab cov rog hauv cov dej khib nyiab, mus rau hauv ammonia nitrogen (NH₃-N).
Nitrification: Hauv theem aerobic (O tank, DO=2-4 mg / L), cov kab mob nitrifying, nyob rau hauv cov pa oxygen txaus, oxidize ammonia nitrogen rau hauv nitrate nitrogen (NO₃⁻) lossis nitrite nitrogen (NO₂⁻).
Denitrification: Cov kua nitrified los ntawm theem aerobic rov qab mus rau theem anoxic ntawm sab hauv recirculation. Denitrifying kab mob, nyob rau hauv anoxic tej yam kev mob, txo nitrate nitrogen rau nitrogen gas (N₂), uas yog ces tso tawm los ntawm dej lub cev los ntawm aeration, ua kom tiav lub denitrification voj. Txoj kev tsim qauv no muaj ob qhov zoo tshaj plaws:
Ua ntej, nrog lub tank anoxic ua ntej lub tank aerobic, cov pa roj carbon monoxide hauv cov dej khib nyiab tuaj yeem siv ncaj qha los ntawm cov kab mob denitrifying, txo ob qho tib si organic load ntawm lub tank aerobic thiab tus nqi ntawm cov khoom siv sab nraud.
Thib ob, alkalinity tsim los ntawm denitrification compensates rau alkalinity noj los ntawm nitrification nyob rau hauv lub aerobic tank, pab tswj system pH stability.
Txawm li cas los xij, cov txheej txheem AO kuj tseem muaj qhov tsis zoo: nws qhov kev tshem tawm nitrogen tsis siab, feem ntau tsuas yog 70-80%, qis dua li 90-95% tshem tawm cov organic teeb meem. Txawm li cas los xij, rau feem ntau cov phiaj xwm dej khib nyiab, kev tswj hwm qhov tseem ceeb tuaj yeem txhim kho kev tshem tawm nitrogen kom zoo. Rau siab-ammonia-nitrogen pov tseg, ob-theem AO series tsim yog feem ntau txaus.
Yuav Ua Li Cas Txhim Kho Nitrogen Tshem Tawm Efficiency
MLSS (Mixed Liquor Suspended Solids Concentration): Lub MLSS concentration ncaj qha cuam tshuam rau cov kab mob nitrifying thiab denitrifying. Nws raug nquahu kom tswj nws siab dua 3,000 mg / L; hauv qab no tus nqi, qhov system lub peev xwm tshem tawm nitrogen yuav txo qis.
Sludge Loading (COD/MLSS): Nitrifying kab mob yog "slow-cov kab mob loj hlob." Yog hais tias cov organic load yog siab dhau lawm, cov kab mob heterotrophic yuav loj hlob sai, sib tw rau oxygen thiab cov as-ham. Nws raug nquahu kom tswj cov sludge loading tus nqi tsawg dua 0.10-0.15 kgCOD/kgMLSS·d. Qhov no tuaj yeem ua tiav los ntawm kev nce MLSS concentration lossis nce lub ntim ntim aeration, txo cov organic load, thiab muab qhov chaw txaus rau cov kab mob nitrifying kom proliferate.
Sludge Hnub nyoog: Qhov tsawg kawg nkaus kev loj hlob ntawm cov kab mob nitrifying tsuas yog 0.21 / d, deb tshaj li 1.2 / d ntawm cov kab mob heterotrophic. Txhawm rau tso cov kab mob nitrifying los ua hom tseem ceeb, lub hnub nyoog sludge yuav tsum muaj ntau dua 4.76 hnub. Txawm li cas los xij, lub hnub nyoog sludge ntawm cov txheej txheem sludge ib txwm siv tsuas yog 2-4 hnub, uas yog qhov laj thawj tseem ceeb vim li cas nitrification tsis tuaj yeem ua tiav.
Ammonia Nitrogen Load: Cov ammonia nitrogen load (organic nitrogen + ammonia nitrogen) rau nitrification yuav tsum tau tswj hauv qab no 0.05 gTKN / (gMLSS·d). Kev thauj khoom ntau dhau yuav muaj peev xwm kho tau cov kab mob nitrifying, ua rau ammonia nitrogen tsub zuj zuj thiab cuam tshuam ntawm denitrification.
Aeration Tank Influent Carbon Source: Yog tias qhov muaj txiaj ntsig BOD₅ concentration siab dhau (ntau tshaj 80 mg / L), cov kab mob heterotrophic yuav proliferate, sib tw nrog cov kab mob nitrifying rau oxygen, yog li inhibiting nitrification. Yog li, BOD₅ nkag mus rau hauv lub tank nitrification yuav tsum tau tswj qis dua 80 mg / L.
C/N ratio: Txhawm rau ua kom tiav denitrification, C / N piv yuav tsum tau tswj ntawm 4 thiab 6. Yog tias cov pa roj carbon ntau tsis txaus, denitrification tsis tuaj yeem ua tiav, thiab nitrate nitrogen yuav nyob twj ywm, ua rau muaj tag nrho cov nitrogen concentration hauv cov effluent.
Influent Ammonia Nitrogen Concentration: Cov nyhuv ntawm ammonia nitrogen concentration ntawm nitrification qhia tau hais tias "nce ces poob" sib. Thaum qis concentrations, cov tshuaj tiv thaiv tus nqi nce nrog nce concentration. Txawm li cas los xij, thaum ammonia nitrogen concentration nyob rau pem hauv ntej kawg ntawm lub tank aerobic hauv cov dej khib nyiab hauv nroog ntau dua 100 mg / L, thiab hauv cov dej khib nyiab ntau tshaj 150 mg / L, nitrification yuav raug txwv. Rau siab -ammonia- cov dej khib nyiab nitrogen (xws li cov dej khib nyiab hauv dej hiav txwv thiab cov khib nyiab pov tseg), qhov kev tawm dag zog thawj zaug tuaj yeem raug txo los ntawm kev rov ua dua tshiab.
Internal Recirculation Ratio (Nitrification Liquid Recirculation): Ib qho kev hloov pauv ntau dua ua rau muaj tus nqi denitrification ntau dua, tab sis kuj nce nqi hluav taws xob. Nws feem ntau yog tswj los ntawm 300-500%, thiab tuaj yeem ua tau zoo -tuned raws li cov ntaub ntawv nitrogen tag nrho. Yog hais tias tag nrho cov nitrogen yog siab, lub recirculation ratio yuav tsim nyog nce. Yog tias cov nqi khiav haujlwm siab dhau lawm, nws tuaj yeem txo qis thaum tseem ua tau raws li cov qauv.
Dissolved Oxygen (DO) hauv Nitrification Tank: Nitrifying kab mob yog "cov kab mob aerobic," thiab cov pa oxygen txaus yog qhov yuav tsum tau ua ua ntej rau nitrification. Nws raug nquahu kom tswj hwm DO ntawm 2 thiab 4 mg / L. Raws li txoj cai, oxidizing 1 g ntawm NH₄⁺ yuav tsum tau 4.57 g ntawm oxygen. Yog tias DO poob qis dua 2 mg / L, cov tshuaj tiv thaiv nitrification yuav qeeb zuj zus.
Hydraulic Retention Time (HRT): Lub sijhawm khaws cia txaus yog qhov tseem ceeb rau kev ua tiav cov tshuaj tiv thaiv. HRT rau nitrification yuav tsum ntau tshaj 6 teev, thiab rau denitrification, nws yuav tsum yog 2 teev, nrog ib tug ratio ntawm 3: 1. Txwv tsis pub, nitrogen tshem tawm efficiency yuav poob sai.
pH thiab alkalinity: Qhov zoo tshaj pH rau cov kab mob nitrifying yog 8.0–8.4, thiab rau cov kab mob denitrifying, nws yog 6.5–7.5. Kev sib txawv ntawm pH los ntawm cov kab no yuav cuam tshuam rau kev ua haujlwm microbial. Tsis tas li ntawd, ua kom tiav nitrification ntawm 1 g ntawm ammonia nitrogen yuav tsum tau 7.1 g ntawm alkalinity (xws li CaCO₃), thaum lub alkalinity tsim los ntawm denitrification tuaj yeem them rau li ib nrab. Yog tias alkalinity tsis txaus, nws yuav tsum tau muab ntxiv kom sai (xws li, los ntawm kev ntxiv sodium carbonate) kom tsis txhob pH poob thiab inhibition ntawm nitrification.
Kub: Kub ncaj qha cuam tshuam rau microbial kev ua haujlwm. Qhov kub zoo rau nitrification yog 20-30 degree, thiab nws yuav luag tsis qis dua 5 degree. Qhov zoo tshaj plaws kub rau denitrification yog 20-40 degree, thiab tus nqi poob qis dua 15 degree. Thaum lub caij ntuj no kev ua haujlwm thiab kev saib xyuas, tus nqi denitrification yuav tsum tau tswj xyuas los ntawm kev ua kom muaj hnub nyoog sludge, txo cov load, thiab ncua sij hawm tuav hydraulic.
Salinity: Ntau salinity puas microbial cell membranes thiab cuam tshuam rau oxygen hloov, yog li inhibiting nitrification. Raws li ib txwm muaj, nitrification tuaj yeem ua tau ib txwm muaj thaum cov tshuaj chlorine tsawg dua 2,000 mg / L. Yog tias qhov muaj zog ruaj khov, ntsev- cov kab mob siab ntev tuaj yeem cog tau los ua haujlwm txawm tias muaj cov tshuaj chlorine concentration ntawm 5,000 mg / L. Nco tseg: Kev hloov pauv hauv salinity yog qhov txaus ntshai tshaj qhov salinity siab, vim lawv tuaj yeem yooj yim ua rau sludge poob.
Cov tshuaj lom thiab phom sij: Cov hlau hnyav, phenols, thiourea, dawb ammonia, tshuaj tua kab mob, thiab lwm yam, tuaj yeem tua cov kab mob nitrifying ncaj qha lossis inhibit lawv cov enzyme. Thaum kho cov dej khib nyiab uas muaj cov tshuaj no, kev kho ua ntej (xws li coagulation, sedimentation, thiab adsorption) yog qhov tseem ceeb, thiab kev qhia txog cov tshuaj lom thiab tsis zoo rau hauv lub tank kho tsiaj yuav tsum raug txwv nruj me ntsis.
Koj tuaj yeem xauj lwm yam khoom ntawm peb lub vev xaib. Thov hu rau peb yog tias koj muaj lus nug. Peb cia siab tias cov ntaub ntawv no yuav pab tau rau koj txoj kev kho dej khib nyiab.