Cov pa nitrogen ntau dhau thiab phosphorus muaj kuab paug hauv cov dej hauv lub cev yog qhov tseem ceeb ntawm cov teeb meem dej hauv ib puag ncig xws li eutrophication, algal blooms, thiab cov dej ntws liab, ua rau muaj teeb meem xws li dej tsis zoo, dej ecosystem tsis txaus, thiab kev hem thawj rau kev nyab xeeb dej haus. Piv nrog rau cov txheej txheem kev kho tshuaj thiab lub cev, cov cuab yeej siv tshuaj lom neeg nitrogen thiab phosphorus tshem tawm tau dhau los ua cov txheej txheem tseem ceeb rau kev kho cov dej khib nyiab hauv cov dej khib nyiab tam sim no vim nws cov txiaj ntsig zoo xws li kev kho mob ruaj khov, tsis muaj nqi khiav lag luam, tsis muaj kev ua qias tuaj, thiab kev hloov mus rau hauv nroog thiab kev kho dej khib nyiab. Lub hauv paus ntsiab lus tseem ceeb ntawm kev tshem tawm cov nitrogen thiab phosphorus hauv cov dej khib nyiab yog siv cov kev ua haujlwm metabolic ntawm cov kab mob sib txawv hauv kev tswj hwm kev hloov pauv anaerobic, anoxic, thiab aerobic ib puag ncig kom maj mam hloov cov pa phem xws li cov organic nitrogen, ammonia nitrogen, thiab tag nrho phosphorus hauv dej khib nyiab rau hauv cov dej khib nyiab uas tso tawm los ntawm cov dej hauv lub cev los ntawm cov dej khib nyiab. ua tiav dej purification.
I. Cov Ntsiab Cai Tseem Ceeb ntawm Kev Tshem Tawm Tsiaj Nitrogen los ntawm cov dej khib nyiab
Nitrogen hauv dej khib nyiab muaj nyob rau hauv cov ntaub ntawv nyuaj, feem ntau suav nrog cov organic nitrogen, ammonia nitrogen, nitrite nitrogen, thiab nitrate nitrogen. Kev tshem tawm cov nitrogen lom tsis yog ib qho kev tawm dag zog nkaus xwb, tab sis yog peb - cov kab mob microbial biochemical cov tshuaj tiv thaiv -ammoniation, nitrification, thiab denitrification- uas thaum kawg hloov ntau hom nitrogen rau hauv cov roj nitrogen, tshem tawm ntawm lub cev dej thiab ua tiav tag nrho cov nitrogen tshem tawm. Tag nrho cov txheej txheem tso siab rau cov haujlwm metabolic ntawm cov kab mob sib txawv hauv lawv qhov chaw tshwj xeeb.
(I) Ammoniation Reaction (Organic Nitrogen Conversion)
Nyob rau hauv aerobic los yog anaerobic tej yam kev mob, organic nitrogen cov pa phem nyob rau hauv cov dej khib nyiab, xws li cov proteins, urea, thiab amino acids, yog hydrolyzed thiab oxidized rau inorganic ammonia nitrogen (NH₃-N) los ntawm decomposition thiab metabolism ntawm ammonifying kab mob. Cov tshuaj tiv thaiv no yog qhov tseem ceeb ua ntej- tawm tsam ntawm kev tshem tawm cov nitrogen lom, hloov tau zoo rau ib puag ncig, thiab tsis tas yuav tsum muaj kev tswj hwm nruj xws li cov pa oxygen thiab qhov kub thiab txias, tso cai rau nws mus ua haujlwm zoo raws li kev kho dej khib nyiab. Cov txheej txheem tshuaj tiv thaiv hloov cov organic nitrogen ntau rau hauv cov organic nitrogen yooj yim, muab cov substrates rau cov tshuaj nitrification thiab denitrification tom ntej, thiab yog thawj kauj ruam hauv kev tshem tawm nitrogen.
(II) Nitrification (Ammonia Nitrogen Oxidation)
Nitrification yog ib qho oxidation cov tshuaj tiv thaiv los ntawm aerobic autotrophic microorganisms, muaj ob theem: nitrification thiab nitrification. Cov pa oxygen txaus yuav tsum tau nyob thoob plaws hauv cov txheej txheem, thiab cov kab mob ua rau pom qhov kev loj hlob qeeb, lub caij nyoog ntev, thiab siab rhiab heev rau qhov kub thiab txias, pH, thiab yaj oxygen. Thawj theem yog nitrification, qhov twg cov kab mob nitrifying oxidize ammonia nitrogen rau nitrite nitrogen; theem ob yog nitrification, qhov twg cov kab mob nitrifying ntxiv oxidize nitrite nitrogen kom ruaj khov nitrate nitrogen.
Nitrifying kab mob yog autotrophic, txhais tau tias lawv tsis haus cov organic paug hauv dej khib nyiab. Hloov chaw, lawv siv cov tshuaj siv hluav taws xob tsim los ntawm oxidation ntawm ammonia nitrogen los ua lub zog los kho cov pa roj carbon dioxide thiab ua kom lawv cov khoom sib txuas. Cov txheej txheem no yog cov kauj ruam tseem ceeb oxidation hauv kev tshem tawm nitrogen, paub txog kev hloov pauv ntawm kev txo nitrogen rau oxidizing nitrogen thiab muab cov tshuaj tiv thaiv substrates rau tom ntej denitrification.
(III) Denitrification (Nitrate Nitrogen Tshem Tawm)
Denitrification yog qhov txo qis cov tshuaj tiv thaiv los ntawm anaerobic heterotrophic microorganisms thiab yog cov kauj ruam kawg hauv kev tshem tawm cov nitrogen lom. Nyob rau hauv ib qho chaw anaerobic tsis muaj cov pa oxygen molecular tab sis muaj nitrate nitrogen, cov kab mob denitrifying siv cov organic carbon hauv cov dej khib nyiab raws li cov khoom siv hluav taws xob kom maj mam txo cov nitrate nitrogen thiab nitrite nitrogen uas tsim nyob rau hauv cov tshuaj nitrification, thaum kawg tsim cov roj nitrogen (N₂) uas khiav tawm mus rau hauv dej, tshem tawm cov nitrogen los ntawm cov dej khib nyiab.
Cov txheej txheem denitrification yuav tsum nruj me ntsis qhov txawv ntawm qhov chaw anaerobic thiab anoxic: ib puag ncig anaerobic tsis muaj cov pa oxygen molecular tab sis muaj cov pa sib xyaw ua ke (nitrate nitrogen), tso cai rau cov tshuaj tiv thaiv denitrification tshwm sim ib txwm; thaum ib puag ncig anaerobic tsis muaj oxygen ua ke, tiv thaiv cov tshuaj tiv thaiv denitrification. Ib txhij, ib qho organic carbon qhov chaw yog qhov tseem ceeb rau denitrification; Cov pa roj carbon tsis txaus ncaj qha ua rau txo qis hauv kev tshem tawm nitrogen kom zoo. Hauv kev tsim vaj tsev, kev ntxiv nrog cov pa roj carbon monoxide feem ntau yog siv los ua kom muaj txiaj ntsig tshem tawm nitrogen.
II. Cov Ntsiab Cai Tseem Ceeb ntawm Biological Phosphorus tshem tawm ntawm cov dej khib nyiab
Cov kab mob tseem ceeb ua haujlwm rau kev tshem tawm cov phosphorus lom yog polyphosphate-cov kab mob sib sau (PAOs). Cov kab mob no muaj cov yam ntxwv metabolic tshwj xeeb, ua rau lawv ua tiav "phosphorus tso tawm-phosphorus uptake" lub voj voog nyob rau hauv alternating anaerobic thiab aerobic ib puag ncig, thaum kawg ua tiav tag nrho cov phosphorus tshem tawm ntawm lub cev dej los ntawm kev tawm ntawm cov sludge ntau dhau. Tsis zoo li denitrification, lom phosphorus tshem tawm ua tsis muaj gaseous byproducts. Hloov chaw, nws solidifies phosphates hauv dej hauv cov kab mob, tso lawv li sludge.
(I) Anaerobic Phosphorus Release Stage
Nyob rau hauv ib puag ncig nruj anaerobic, tsis muaj molecular oxygen thiab nitrate nitrogen, polyphosphate-accumulating bacteria (PABs) tsis tuaj yeem siv cov pa tawm sab nraud rau kev ua pa aerobic, txwv tsis pub lawv lub zog metabolic. Hauv lub xeev no, PPAs decompose cov polyphosphates khaws cia hauv lawv lub hlwb, tso tawm lub zog kom nqus tau qis -molecular- hnyav cov organic carbon xws li volatile fatty acids (VFAs) los ntawm cov dej khib nyiab, hloov mus rau hauv polyhydroxyalkanoates (PHAs) rau khaws cia hauv lub hlwb. Thaum lub sijhawm ua haujlwm no, cov phosphates intracellular tau tso rau hauv cov dej khib nyiab, ua rau lub sijhawm nce ntxiv ntawm cov dej phosphorus cov ntsiab lus - qhov no yog cov txheej txheem tso tawm anaerobic phosphorus.
(II) Aerobic Excess Phosphorus Absorption Stage
Thaum ib puag ncig hloov mus rau hauv lub xeev aerobic, PPAs tsis nqus cov pa roj carbon monoxide lawm tab sis hloov pauv cov PHAs khaws cia rau hauv theem anaerobic, tau txais ntau lub zog los ntawm oxidation thiab decomposition ntawm cov organic teeb meem. Siv lub zog no, polyphosphate- khaws cov kab mob (PACs) ntau dhau nqus phosphate los ntawm cov dej khib nyiab, ntau tshaj li qhov tso tawm thaum lub sij hawm anaerobic. Tom qab ntawd cov phosphate ntau dhau yog khaws cia rau hauv lub hlwb li polyphosphate, ua tiav phosphorus enrichment thiab tshem tawm ntawm dej.
Thaum kawg, phosphorus -PACs nplua nuj nyob nrog cov sludge thiab raug tshem tawm tag nrho los ntawm cov dej khib nyiab los ntawm cov txheej txheem pov tseg sludge, yog li ua tiav tag nrho cov txheej txheem tshem tawm cov phosphorus lom. Cov yam ntxwv ntawm kev hloov pauv metabolic ntawm PACs yog lub hauv paus tseem ceeb ntawm kev tshem tawm cov phosphorus lom, thiab qhov ruaj khov anaerobic -aerobic ib puag ncig hloov pauv yog qhov tseem ceeb rau kev ua kom muaj kev tshem tawm phosphorus.
III. Cov ntsiab lus tseem ceeb cuam tshuam rau kev tshem tawm cov roj ntsha nitrogen thiab phosphorus
Qhov ua tau zoo ntawm cov tshuaj lom neeg nitrogen thiab phosphorus tshem tawm yog nyob ntawm kev ua haujlwm ntawm microbial. Cov yam ntxwv metabolic ntawm cov kab mob ua rau txiav txim siab qhov tseem ceeb ntawm cov txheej txheem kev ua haujlwm. Lub ntsiab cuam tshuam muaj xws li ob pawg: ib puag ncig tsis zoo thiab dej tsis zoo.
1. Dissolved Oxygen: Nitrification thiab aerobic phosphorus uptake xav tau cov pa oxygen txaus; anoxic denitrification yuav tsum tau nruj me ntsis - oxygen ib puag ncig; thiab anaerobic phosphorus tso tawm yuav tsum muaj ib qho chaw anaerobic kiag li. Kev cuam tshuam nyob rau hauv ib puag ncig oxygen yuav ncaj qha ua rau tsis ua haujlwm ntawm nitrogen thiab phosphorus tshem tawm.
2. Cov ntsiab lus Carbon: Ob leeg denitrifying kab mob thiab polyphosphate- cov kab mob sib sau cia siab rau cov organic carbon rau cov metabolism. Thaum cov pa roj carbon-rau-nitrogen piv thiab carbon-rau-phosphorus piv ntawm cov dej khib nyiab tsawg dhau lawm, cov pa roj carbon monoxide exogenous xws li sodium acetate thiab qabzib yuav tsum tau ntxiv; txwv tsis pub, kev tshem tawm tsis tiav nitrogen thiab qis phosphorus tshem tawm efficiency yuav tshwm sim.
3. pH thiab Kub: Qhov zoo tshaj pH rau cov kab mob nitrifying yog 7.5-8.5, thaum lub pH zoo tshaj plaws rau cov kab mob polyphosphate-accumulating yog 6.5-8.0. Qhov zoo tshaj plaws kub rau cov kab mob yog 20-30 degree. Qhov kub qis yuav txo qis cov kab mob ua haujlwm thiab kev kho mob zoo.
4. Sludge Age: Nitrifying kab mob muaj lub voj voog ntev, yuav tsum muaj lub hnub nyoog sludge ntev dua los xyuas kom cov kab mob muaj sia nyob. Polyphosphate- khaws cov kab mob, ntawm qhov tod tes, muaj cov sludge luv dua; Cov sludge ntev ntev tuaj yeem ua rau phosphorus tso tawm ntawm cov sludge. Yog li ntawd, cov txheej txheem tiag tiag yuav tsum sib npaug ntawm lub hnub nyoog sludge kom ntseeg tau tias nitrogen thiab phosphorus tshem tawm efficiency.
IV. Mainstream Txheej Txheem Daim Ntawv Thov
Raws li cov hauv paus ntsiab lus saum toj no ntawm kev tshem tawm nitrogen thiab phosphorus, kev lag luam tau tsim ntau yam txheej txheem paub tab, txhua yam ntawm lub hom phiaj los tsim kev hloov pauv anaerobic, anoxic, thiab aerobic cov tshuaj tiv thaiv ib puag ncig. Cov txheej txheem A² / O yog cov txheej txheem tshem tawm nitrogen thiab phosphorus ntau tshaj plaws. Nws ua tiav cov phosphorus tso tawm thiab cov pa roj carbon khaws cia los ntawm polyphosphate- khaws cov kab mob hauv thaj chaw anaerobic, denitrification hauv thaj chaw anoxic, thiab nitrification thiab phosphorus ntau dhau los ntawm polyphosphate- khaws cov kab mob hauv thaj chaw aerobic. Thaum kawg, ib txhij tshem tawm nitrogen thiab phosphorus yog ua tiav los ntawm sludge sedimentation thiab tawm. Tsis tas li ntawd, hloov kho A² / O, SBR, thiab cov txheej txheem oxidation ditch yog tag nrho raws li cov txheej txheem biochemical, optimizing tank qauv thiab kev khiav hauj lwm ib ntus kom hloov mus rau qhov sib txawv ntawm kev kho dej zoo.
V. Xaus
Qhov tseem ceeb ntawm kev tshem tawm cov nitrogen thiab phosphorus los ntawm cov dej khib nyiab yog siv cov txheej txheem metabolic sib txawv ntawm cov kab mob ua haujlwm thiab ua kom muaj kev tswj hwm cov dej hauv dej kom ua tiav cov kev hloov pauv ntawm nitrogen thiab phosphorus pollutants thiab tshem tawm ntawm lub cev dej. Kev tshem tawm Nitrogen tso siab rau cov tshuaj tiv thaiv ib ntus ntawm ammonification, nitrification, thiab denitrification kom ua tiav gaseous tshem tawm, thaum tshem tawm phosphorus cia siab rau cov metabolism hauv cyclical ntawm polyphosphate- khaws cov kab mob - anaerobic phosphorus tso tawm thiab aerobic phosphorus} ua kom tiav thiab ua tiav {{3} phosphorus solidification. Kev nkag siab zoo ntawm nws cov ntsiab lus biochemical yog lub hauv paus tseem ceeb rau kev txhim kho cov txheej txheem dej khib nyiab, txhim kho nitrogen thiab phosphorus tshem tawm efficiency, thiab daws qhov teeb meem ntawm eutrophication hauv dej. Nws tseem muab kev txhawb nqa theoretical tseem ceeb rau kev txuag hluav taws xob, txo qis emission, thiab txhim kho kev kho dej khib nyiab.