Taw qhia: Alkalinity yog qhov taw qhia tseem ceeb ntawm lub cev dej lub peev xwm, cuam tshuam ncaj qha rau kev ua haujlwm thiab kev kho mob ntawm cov kab mob hauv cov dej khib nyiab. Kab lus no qhia txog cov ntsiab lus tseem ceeb ntawm cov tshuaj biochemical uas koom nrog hauv kev tsim cov alkalinity thiab noj, suav nrog xya theem tseem ceeb: txo sulfate, phosphorus uptake, denitrification, organic teeb meem degradation, hydrolysis acidification, anaerobic phosphorus tso, thiab nitrification. Qhov no pab cov kws tshaj lij ib puag ncig nkag siab tob txog cov kev cai lij choj uas tswj hwm kev hloov pauv alkalinity, muab lub hauv paus kev tshawb fawb rau kev ua haujlwm txhua hnub thiab kev tswj xyuas cov txheej txheem.
I. Alkalinity yog dab tsi? Vim li cas nws thiaj tseem ceeb?
Alkalinity yog hais txog lub peev xwm ntawm cov dej kom tsis txhob muaj cov kua qaub, feem ntau qhia tias calcium carbonate (CaCO₃), nrog rau cov units ntawm mg / L. Nws qhia txog tag nrho cov khoom hauv dej uas tuaj yeem ua rau cov kua qaub muaj zog, feem ntau suav nrog cov tshuaj alkaline xws li bicarbonate (HCO₃⁻), carbonate (CO₃²⁻), thiab hydroxide (OH⁻). Hauv kev kho dej khib nyiab, alkalinity yog qhov tsis tseem ceeb ntawm cov dej tsis zoo, cuam tshuam ncaj qha rau kev ua haujlwm ntawm kev kho kab mob lom.
Feem ntau cov txheej txheem kho dej khib nyiab cia siab rau cov haujlwm metabolic ntawm cov kab mob, uas muaj cov kev cai nruj heev ntawm pH tus nqi ntawm lawv ib puag ncig. Feem ntau, cov kab mob nitrifying vam meej nyob rau hauv pH ntau ntawm 7.2–8.0, thaum polyphosphate- cov kab mob sib xyaw muaj qhov pom zoo phosphorus tso tawm pH ntawm thaj tsam 7.0. Thaum lub kaw lus alkalinity txaus, tus nqi pH tseem nyob ruaj khov, muab qhov chaw loj hlob zoo rau cov kab mob; conversely, tsis txaus alkalinity tuaj yeem ua rau poob qis hauv pH, ua rau txo qis microbial kev ua haujlwm thiab txawm tias lub cev tawg.
Cov ntsiab lus tseem ceeb: Alkalinity yog qhov tseem ceeb "acid-base buffer" hauv dej. Xav txog alkalinity raws li lub reservoir -thaum acidic tshuaj "tso nyob rau hauv," alkalinity yuav "absorb" thiab neutralize lawv, yog li tswj pH stability. Thaum lub pas dej no qhuav lawm, tus nqi pH yuav hloov pauv sai, zoo li tus dej tsis muaj dams.
Yog li ntawd, nkag siab txog cov qauv ntawm alkalinity hloov thaum lub sij hawm kho dej khib nyiab- uas yog, uas cov tshuaj tiv thaiv tsim alkalinity thiab uas siv nws - yog ib qho tseem ceeb rau kev ua kom muaj kev kho mob zoo, optimizing reagent ntau npaum, thiab txo cov nqi khiav hauj lwm.
II. Zuag qhia tag nrho ntawm Alkalinity Hloov
Raws li cov kev taw qhia ntawm kev cuam tshuam ntawm biochemical cov tshuaj tiv thaiv ntawm alkalinity, alkalinity hloov thaum lub sij hawm kho dej khib nyiab tuaj yeem muab faib ua ob pawg loj: cov tshuaj tiv thaiv uas tsim alkalinity (nce pH) thiab cov tshuaj tiv thaiv uas noj alkalinity (txo pH). Qhov kev faib tawm no pab peb txiav txim siab sai sai ntawm cov kev hloov pauv ntawm alkalinity hloov hauv lub cev thaum lub sijhawm ua haujlwm tiag tiag thiab ua raws li kev tswj xyuas raws li.
Alkalinity tiam (nce pH):
1. Sulfate txo
2. Phosphorus uptake
3. Denitrification (3.57 mg/L alkalinity/mg NO₃⁻-N)
4. Organic teeb meem degradation
Alkalinity noj (txo pH):
1. Hydrolysis acidification
2. tso tawm anaerobic phosphorus
3. Nitrification (7.14 mg/L alkalinity/mg NH₃-N)
Raws li pom nyob rau hauv cov lus saum toj no, muaj plaub hom kev tshwm sim uas tsim alkalinity, thiab peb hom uas haus alkalinity. Txhua hom tshuaj tiv thaiv yuav raug piav qhia hauv qab no.
III. Reactions uas nce Alkalinity (Raising pH)
3.1 Sulfate txo
Sulfate txo yog hais txog cov txheej txheem nyob rau hauv anaerobic tej yam kev mob uas sulfate -txo cov kab mob (SRB) siv sulfate (SO₄²⁻) raws li ib tug electron txais oxidize thiab decompose organic teeb meem, ib txhij txo sulfate rau hydrogen sulfide (H₂S). Nws cov lus sib npaug classic tuaj yeem ua kom yooj yim raws li hauv qab no:
Schematic daim duab ntawm sulfate txo cov tshuaj tiv thaiv
SO₄²⁻ + organic teeb meem → H₂S + HCO₃⁻ + lwm yam khoom
Hauv cov tshuaj tiv thaiv no, theoretically, rau txhua 1 mol ntawm sulfate ions txo, 2 mol ntawm bicarbonate ions (HCO₃⁻) raug tsim. Bicarbonate yog ib qho tseem ceeb pab rau alkalinity; Yog li ntawd, sulfate txo cov tshuaj tiv thaiv tseem ceeb nce alkalinity ntawm lub cev. Los ntawm kev pom macroscopic, cov txheej txheem txo sulfate ua rau pH tus nqi ntawm cov dej los qhia txog kev nce siab.
Txawm li cas los xij, nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias thaum txo sulfate ua alkalinity, nws cov byproduct, hydrogen sulfide, yog tshuaj lom heev thiab muaj ntxhiab tsw phem. Hauv anaerobic digesters lossis chav kho anaerobic, kev txo cov sulfate ntau dhau tsis tsuas yog ua rau muaj teeb meem tsw, tab sis kuj tseem tuaj yeem cuam tshuam cov kab mob muaj txiaj ntsig xws li methanogens, cuam tshuam rau kev kho mob tag nrho. Yog li ntawd, hauv kev ua haujlwm tiag tiag, sulfate concentration hauv lub zog yuav tsum tau saib xyuas thiab tswj.
3.2 Phosphorus Uptake
Phosphorus uptake yog cov txheej txheem tseem ceeb hauv kev tshem tawm cov phosphorus lom. Nyob rau hauv aerobic los yog anoxic tej yam kev mob, polyphosphate- accumulating organisms (PAOs) heev nqus phosphate los ntawm dej, synthesizing nws mus rau hauv polyphosphates thiab khaws cia rau hauv lawv lub hlwb. Tib lub sijhawm, lawv siv cov polyhydroxyalkanoates (PHAs) khaws cia hauv lawv cov hlwb ua cov pa roj carbon thiab lub zog rau kev loj hlob thiab kev loj hlob.
Thaum lub sij hawm phosphorus uptake, PAO hlwb yuav tsum muaj kev sib npaug ntawm sab hauv thiab sab nraud. Thaum polyphosphate- khaws cov kab mob (PABs) nqus ntau cov phosphate tsis zoo (HPO₄²⁻ los yog H₂PO₄⁻), lawv tso cov cationic tshuaj xws li bicarbonate (HCO₃⁻) los yog potassium ions (K⁺) mus rau hauv qhov chaw electronecular extracellular. Cov txheej txheem physiological no ncaj qha ua rau muaj kev nce hauv qhov system alkalinity.
Mechanism ntawm Alkalinity Hloov hauv Phosphorus Uptake Reactions
Thaum PABs nqus phosphorus, kwv yees li 1 mol ntawm HCO₃⁻ raug tso tawm rau hauv qhov chaw ntxiv rau txhua 1 mol ntawm phosphorus absorbed (hauv daim ntawv ntawm HPO₄²⁻). Qhov no txhais tau hais tias nyob rau hauv lub aerobic theem ntawm ib tug lom phosphorus tshem tawm cov txheej txheem, alkalinity yuav nce, thiab tus nqi pH yuav nce raws li. Qhov no yog ib qho ntawm cov laj thawj vim li cas tus nqi pH hauv theem aerobic ntawm cov txheej txheem A² / O feem ntau yog me ntsis siab dua li ntawm theem anaerobic.
Txawm hais tias tus nqi ntawm alkalinity tsim los ntawm phosphorus uptake tsis yog qhov tseem ceeb ntawm denitrification, nws txoj kev koom tes rau alkalinity nyob rau hauv cov txheej txheem uas lom phosphorus tshem tawm yog lub hom phiaj tseem ceeb tseem ceeb heev. Kev nkag siab meej txog kev hloov pauv alkalinity ntawm phosphorus uptake cov tshuaj tiv thaiv pab txhim kho cov txheej txheem tsis zoo rau kev ua haujlwm anaerobic thiab aerobic.
3.3 Denitrification
Denitrification yog ib kauj ruam tseem ceeb hauv kev tshem tawm nitrogen thaum kho cov dej khib nyiab. Nyob rau hauv cov xwm txheej anoxic, cov kab mob denitrifying siv nitrate (NO₃⁻) los yog nitrite (NO₂⁻) raws li cov khoom siv hluav taws xob thiab cov khoom organic xws li cov khoom siv hluav taws xob (cov khoom siv carbon) kom maj mam txo cov nitrate rau nitrogen gas (N₂), uas thaum kawg khiav tawm hauv dej.
Schematic equation rau denitrification cov tshuaj tiv thaiv
2NO₃⁻ + 5[CH₂O] + 2H⁺ → N₂↑ + 5CO₂ + 6H₂O
Denitrification yog "lub zog tseem ceeb" hauv alkalinity tiam thaum kho dej khib nyiab. Raws li txoj cai, txo 1 mg ntawm nitrate nitrogen (NO₃⁻-N) tuaj yeem tsim kwv yees li [ntau qhov ploj] ntawm alkalinity (xws li CaCO₃). Tus nqi no yog tus nqi tseem ceeb hauv kev tsim qauv thiab kev ua haujlwm txhua hnub.
Raws li tuaj yeem pom los ntawm qhov sib npaug ntawm cov tshuaj tiv thaiv, denitrification siv hydrogen ions (H⁺) hauv dej, uas yog sib npaug rau ntxiv cov tshuaj alkaline rau hauv lub cev. Yog li ntawd, denitrification tsis tsuas zoo tshem tawm tag nrho cov nitrogen tab sis kuj ntxiv rau lub cev alkalinity, ua lub luag haujlwm tseem ceeb hauv kev tswj hwm qhov chaw alkaline uas yuav tsum tau muaj rau cov tshuaj tiv thaiv nitrification tom ntej.
Hauv kev tsim kho vaj tse, siv tag nrho cov alkalinity tsim los ntawm ua ntej - denitrification (theem A ntawm cov txheej txheem A/O) los them rau cov alkalinity noj los ntawm cov tshuaj nitrification tom ntej yog ib qho kev lag luam thiab kev ua haujlwm zoo. Ntau cov dej khib nyiab kho tau ua tiav alkalinity tus kheej- txaus los ntawm kev faib cov ntim qhov sib piv ntawm thaj chaw anoxic thiab aerobic, yog li txo tus nqi ntawm cov pa roj carbon monoxide thiab alkalinity reagents.
Tswv yim Engineering: Thaum cov pa roj carbon zoo- rau- nitrogen piv (C/N) tsawg, cov organic carbon qhov xav tau rau denitrification tsis txaus, thiab cov alkalinity ntau lawm kuj yuav txo qis raws li. Hauv qhov no, nws yog ib qho tsim nyog yuav tsum xav txog kev ntxiv cov pa roj carbon monoxide (xws li methanol, sodium acetate, thiab lwm yam) kom ntseeg tau tias denitrification efficiency thiab alkalinity replenishment.
3.4 Organic Matter Degradation
Organic teeb meem degradation yog cov txheej txheem biochemical tseem ceeb tshaj plaws hauv kev kho dej khib nyiab. Txawm hais tias nws yog cov kab mob heterotrophic metabolism nyob rau hauv aerobic tej yam kev mob los yog acid - ua fermentation nyob rau hauv anaerobic tej yam kev mob, lub decomposition ntawm organic teeb meem (qhia raws li COD los yog BOD) yuav cuam tshuam rau alkalinity thiab pH ntawm lub cev rau qee yam.
Nyob rau hauv aerobic tej yam kev mob, cov organic teeb meem yog oxidized thiab decomposed rau hauv carbon dioxide (CO₂). CO₂ dissolves hauv dej los tsim carbonic acid (H₂CO₃), uas theoretically txo cov pH. Txawm li cas los xij, vim tias cov txheej txheem aeration strips ntau ntawm CO₂ rau cov dej saum npoo av, cov nyhuv pH hauv cov theem aerobic yog nyob ntawm qhov sib npaug ntawm cov khoom siv CO₂ thiab tus nqi stripping. Nyob rau hauv txaus aeration, pH yuav txawm nce me ntsis.
Thaum lub sij hawm anaerobic digestion, cov organic teeb meem yog thawj zaug decomposed rau hauv volatile fatty acids (VFA) los ntawm hydrolytic acidifying kab mob. Cov theem no ua rau txo qis pH; Txawm li cas los xij, cov kab mob methanogenic tom qab hloov VFA rau hauv methane (CH₄) thiab CO₂, ua rau pH nce ntxiv. Cov txiaj ntsig ntawm tag nrho cov txheej txheem anaerobic digestion feem ntau tshwm sim raws li kev nce hauv alkalinity, uas yog vim li cas anaerobic digestion broth feem ntau muaj alkalinity siab thiab buffering peev xwm.
Qhov cuam tshuam ntawm cov organic teeb meem degradation ntawm alkalinity yog tshwm sim los ntawm ntau yam, thiab nws cov txiaj ntsig zoo nyob ntawm qhov sib xyaw ua ke ntawm ntau yam xws li hom kev kho mob, kev ua haujlwm, thiab cov qauv hauv zej zog microbial.
IV. Cov tshuaj tiv thaiv uas siv Alkalinity (Lowering pH)
4.1 Hydrolysis Acidification
Hydrolysis acidification yog thawj theem ntawm kev kho anaerobic lom. Nyob rau theem no, complex macromolecular organic teeb meem (xws li cov proteins, carbohydrates, thiab cov rog) yog hydrolyzed rau hauv me me soluble organic molecules los ntawm extracellular enzymes, thiab ces hloov mus rau hauv acidic khoom xws li volatile fatty acids (VFAs), cawv, thiab CO₂ los ntawm acidifying kab mob.
Vim tias qhov sib xyaw ntawm VFAs tso tawm ntau cov hydrogen ions (H⁺), cov txheej txheem hydrolysis acidification tau siv cov alkalinity hauv lub cev, ua rau txo qis pH. Yog tias tsis muaj kev tswj xyuas kom zoo, tus nqi pH yuav poob qis dua 5.0, cuam tshuam kev ua haujlwm ntawm cov kab mob methanogenic tom qab thiab tseem ua rau tsis ua haujlwm ntawm tag nrho cov kev kho mob anaerobic.
Cov yam ntxwv ntawm Alkalinity Consumption hauv Hydrolysis Acidification
Tus nqi ntawm alkalinity noj thaum lub sij hawm hydrolysis acidification theem yog ze ze rau cov organic teeb meem concentration thiab cov kev ua ntawm cov hydrolytic acidifying kab mob. Qhov siab dua qhov muaj zog COD concentration, qhov ceev ntawm acidification tus nqi thiab ntau dua alkalinity noj. Nyob rau hauv kev kho mob ntawm siab -concentration organic wastewater, feem ntau nws yog tsim nyog los ntxiv alkalinity (xws li, los ntawm kev ntxiv NaHCO₃ los yog txiv qaub) kom muaj ib tug haum pH ib puag ncig nyob rau hauv lub reactor.
Hauv cov txheej txheem kho anaerobic xws li ABR (Anaerobic Baffled Reactor) thiab UASB (Upflow Anaerobic Sludge Blanket), hydrolysis acidification feem ntau tshwm sim hauv tib lub reactor li cov txheej txheem methanogenesis. Kev txaus siab ntawm alkalinity yog ib qho tseem ceeb ntawm kev ua kom muaj kev sib koom tes ntawm ob txoj haujlwm no. Thaum lub kaw lus alkalinity qis dua 1000 mg / L (raws li CaCO₃), pH qauv yuav tsum tau saib xyuas zoo.
4.2 Anaerobic Phosphorus tso tawm
Kev tso tawm anaerobic phosphorus yog ib kauj ruam tseem ceeb hauv kev tshem tawm cov phosphorus lom. Nyob rau hauv nruj me ntsis anaerobic tej yam kev mob (tsis muaj nitrate nitrogen, tsis yaj oxygen), polyphosphate - cov kab mob sib sau ua ke (PABs) decompose polyphosphates khaws cia hauv lawv lub hlwb, tso phosphates rau hauv dej. Nyob rau tib lub sijhawm, lawv siv absorbed tsawg-molecular- hnyav cov organic teeb meem los ua ke polyhydroxyalkanoates (PHAs) thiab khaws cia rau hauv cellularly, muab lub zog cia rau cov phosphorus ntau dhau tom qab nyob rau hauv aerobic tej yam kev mob.
Thaum lub sij hawm phosphorus tso tawm, PPAs haus ib qho equimolar npaum li cas ntawm bicarbonate (HCO₃⁻) kom tswj cov nqi sib npaug ntawm sab hauv thiab sab nraud ntawm tes thaum tso phosphates los ntawm hauv lub cell. Cov txheej txheem no ncaj qha ua rau txo qis hauv qhov system alkalinity thiab poob hauv pH.
Kev txiav txim siab ua haujlwm tseem ceeb: Qhov ua tau zoo ntawm anaerobic phosphorus tso ncaj qha txiav txim siab qhov ua tau zoo ntawm cov tshuaj aerobic phosphorus tom ntej. Yog tias nitrate nitrogen muaj nyob rau hauv theem anaerobic (denitrifying kab mob nyiam siv cov pa roj carbon monoxide), nws yuav cuam tshuam cov phosphorus tso tawm haujlwm ntawm PPAs, uas ua rau txo qis hauv phosphorus tshem tawm efficiency. Lub caij no, yog tias cov alkalinity noj thaum lub sij hawm phosphorus tso tawm tsis tau ntxiv rau lub sij hawm, tus nqi pH yuav poob qis dua qhov zoo tshaj plaws rau polyphosphate accumululation (PAC) kev ua, ntxiv rau kev tshem tawm phosphorus.
Hauv kev tsim thiab kev ua haujlwm ntawm A² / O lossis hloov kho A² / O cov txheej txheem, lub sijhawm hydraulic tuav (HRT) ntawm theem anaerobic feem ntau tswj ntawm 1.5 thiab 2.5 teev. Txawm hais tias lub sijhawm khaws cia ntev ntev yog qhov zoo rau kev tso tawm phosphorus txaus, lawv tuaj yeem ua rau muaj kev noj ntau dhau ntawm VFAs thiab ntau dhau alkalinity poob, yuav tsum muaj kev lag luam tawm - tawm hauv kev ua haujlwm tiag tiag.
4.3 Nitrification
Nitrification yog thawj kauj ruam hauv cov txheej txheem tshem tawm nitrogen ntawm kev kho dej khib nyiab thiab kuj yog cov tshuaj tiv thaiv uas siv cov alkalinity tshaj plaws. Nyob rau hauv aerobic tej yam kev mob, nitrite- oxidizing kab mob (AOB) thawj oxidize ammonia nitrogen (NH₄⁺) rau nitrite (NO₂⁻), thiab ces nitrate- oxidizing kab mob (NOB) ntxiv oxidize nitrite rau nitrate (NO₃⁻). Ob qho ntawm cov tshuaj tiv thaiv no xav tau ntau qhov alkalinity.
Ob - cov txheej txheem ntawm nitrification:
Kauj Ruam 1 (Nitrosation): NH₄⁺ + 1.5O₂ → NO₂⁻ + 2H⁺ + H₂O
Kauj Ruam 2 (Nitrosation): NO₂⁻ + 0.5O₂ → NO₃⁻
Tag nrho cov tshuaj tiv thaiv: NH₄⁺ + 2O₂ → NO₃⁻ + 2H⁺ + H₂O
Los ntawm kev sib npaug tag nrho cov tshuaj tiv thaiv, nws yog qhov tseeb tias rau txhua 1 mg ntawm ammonia nitrogen (NH₃-N) oxidized, 2 mol ntawm hydrogen ions (H⁺) raug tsim, sib npaug li siv li 1/3 ntawm alkalinity (xws li CaCO₃). Tus nqi no yog ob npaug ntawm alkalinity uas tsim los ntawm denitrification (3.57 mg / L), txhais tau hais tias tsis muaj ua ntej -denitrification los ntxiv alkalinity, nitrification yuav sai sai deplete alkalinity cia nyob rau hauv lub system.
Cov alkalinity-kev siv cov nitrification ua rau nws muaj kev txhawj xeeb tseem ceeb hauv kev ua haujlwm thiab kev tswj hwm ntawm ntau qhov chaw kho dej khib nyiab. Thaum lub influent alkalinity tsis txaus los txhawb nitrification, cov hauv qab no yuav tshwm sim:
• pH tus nqi poob qis dua 7.0, txo qis nitrifying kab mob kev ua si thiab ammonia nitrogen tshem tawm tus nqi.
• Ua rau muaj kev pheej hmoo ntawm nitrite tsub zuj zuj, ua rau ntau dua effluent nitrite nitrogen concentration.
• Hloov cov ammonia dawb (FA) thiab dawb nitrite (FNA) ntau, ua rau muaj toxicity rau cov microbial zej zog.
• Cov sludge daws kev ua haujlwm tsis zoo, ua rau cov dej ntws ntau dua SS.
Txhawm rau kom muaj kev vam meej nitrification, qhov seem alkalinity nyob rau hauv lub system feem ntau yuav tsum tsis pub tsawg tshaj 70-100 mg / L (raws li CaCO₃). Hauv kev xyaum, kev ntsuas alkalinity feem ntau suav nrog: siv cov alkalinity tsim los ntawm ua ntej- denitrification, ntxiv sodium bicarbonate (NaHCO₃), ntxiv sodium hydroxide (NaOH), lossis ntxiv txiv qaub (Ca(OH)₂). Ntawm cov txheej txheem no, ntxiv NaHCO₃ yog feem ntau siv vim nws muaj alkalinity me ntsis thiab tsis qhia cov cations ntau dhau.
Kev txiav txim siab txog kev lag luam: Kev siv cov khoom siv dej khib nyiab uas muaj peev xwm kho tau txhua hnub ntawm 100,000 tons thiab qhov muaj zog ammonia nitrogen concentration ntawm 30 mg / L raws li piv txwv, ua kom tiav nitrification yuav tsum muaj kwv yees li 21.4 tons ntawm alkalinity txhua hnub (xws li CaCO₃). Yog tias NaHCO₃ siv los ntxiv alkalinity, tus nqi reagent txhua hnub tuaj yeem ncav cuag kaum txhiab yuan. Yog li ntawd, tag nrho siv cov alkalinity them nyiaj ua haujlwm ntawm pre- denitrification yog ib lub tswv yim tseem ceeb los txo cov nqi khiav lag luam.
V. Alkalinity Balance: Qhov "Sib npaug" rau kev ua haujlwm ruaj khov
Raws li kev soj ntsuam saum toj no, alkalinity hloov pauv hauv qhov kev kho dej khib nyiab yog qhov tseem ceeb ntawm kev ua si dynamic ntawm cov tshuaj tiv thaiv uas tsim alkalinity thiab cov tshuaj tiv thaiv uas noj alkalinity. Qhov system alkalinity
Qhov kev hloov pauv tuaj yeem qhia tau los ntawm cov qauv yooj yim hauv qab no:
Alkalinity Balance Equation
ΔAlkalinity=Σ(Alkalinity Produced) - Σ(Alkalinity Consumed) + Externally Added Alkalinity - Alkalinity Loss
Hauv cov txheej txheem A²/O, lub ntsiab "cov neeg siv khoom" ntawm alkalinity yog nitrification (-7.14 mg/L alkalinity/mg NH₃-N), thaum lub ntsiab "tsim" yog denitrification (+3.57 mg/L alkalinity/mg NO₃⁻-N). Txij li thaum denitrification tsim tsuas yog ib nrab ntawm alkalinity noj los ntawm nitrification, txawm tias 100% tag nrho cov nitrogen rov qab mus rau nitrified cawv rau denitrification, qee qhov alkalinity tsis txaus yuav tseem muaj nyob hauv lub cev. Qhov kev tsis txaus no feem ntau yog them los ntawm cov alkalinity nqa los ntawm lub zog thiab los ntawm kev ntxiv alkalinity reagents.
Kev nkag siab txog qhov sib npaug ntawm qhov sib npaug no muaj kev taw qhia ncaj qha rau kev suav alkalinity thaum lub sijhawm tsim qauv thiab reagent optimization thaum lub sijhawm ua haujlwm. Nov yog qee cov tswv yim tswv yim rau kev tswj alkalinity:
Cov ntsiab lus tseem ceeb ntawm kev tswj hwm
Kev saib xyuas tsis tu ncua: Kev saib xyuas txhua hnub ntawm cov muaj txiaj ntsig, txhua theem txheej txheem, thiab cov dej alkalinity thiab pH qhov tseem ceeb, thiab npaj cov duab kos duab alkalinity.
Optimized Reflux Ratio Design: Optimize nitrification cawv reflux ratio raws li influent alkalinity thiab ammonia nitrogen concentration kom siv tau cov denitrification alkalinity.
Tswj Carbon-Nitrogen Ratio: Xyuas kom muaj cov pa roj carbon txaus nyob rau theem denitrification kom tsis txhob txo cov alkalinity vim yog cov pa roj carbon tsis txaus.
Precise Dosing: Tsim kom muaj cov qauv siv tshuaj lom neeg raws li cov ntaub ntawv ntawm -lub sij hawm alkalinity kom tsis txhob overdosing thiab pov tseg.
Them sai sai rau kev hloov raws caij nyoog: Nitrifying cov kab mob kev ua haujlwm txo qis thaum dej kub poob; pH stability tuaj yeem tswj tau los ntawm kev ua kom zoo alkalinity.
VI. Xaus
Alkalinity hloov pauv yog ib qho tseem ceeb ntawm cov dej tsis zoo hauv kev kho dej khib nyiab. Los ntawm kev txheeb xyuas qhov cuam tshuam ntawm xya qhov tseem ceeb biochemical tshwm sim ntawm alkalinity -sulfate txo, phosphorus uptake, denitrification, thiab organic teeb meem degradation generating alkalinity, thaum hydrolysis acidification, anaerobic phosphorus tso tawm, thiab nitrification noj alkalinity {{2} ntau yam txheej txheem.
Ntawm qhov kev ceeb toom tshwj xeeb yog qhov ze alkalinity "complementarity" ntawm nitrification thiab denitrification: denitrification generates 3.57 mg / L ntawm alkalinity rau txhua txhua 1 mg ntawm NO₃⁻-N txo, thaum nitrification noj 7.14 mg / L ntawm alkalinity rau txhua txhua 1 mg⁻ oxidized NH⁻ Nkag siab txog qhov kev sib raug zoo ntawm cov khoom no yog qhov tseem ceeb rau kev tswj hwm alkalinity.
Hauv kev ua haujlwm tau zoo, nws raug pom zoo tias cov kws kho mob ib puag ncig suav nrog kev tshuaj xyuas alkalinity rau hauv lawv qhov kev ntsuas dej zoo niaj hnub, tsim cov ntaub ntawv alkalinity tshuav nyiaj li cas, thiab kho cov kev khiav hauj lwm tsis zoo thiab cov tswv yim reagent dosing raws cov txheej txheem cov yam ntxwv thiab cov kev hloov hauv cov dej zoo. Tsuas yog los ntawm kev nkag siab tag nrho cov cai tswj hwm kev hloov pauv alkalinity peb tuaj yeem ua tiav kev tswj xyuas cov dej khib nyiab tiag tiag thiab xyuas kom muaj cov dej ntws zoo sib xws.
Alkalinity, txawm tias zoo li tsis tseem ceeb, muaj kev cuam tshuam loj heev. Nws ua zoo li "tus neeg saib xyuas tsis pom" hauv cov dej khib nyiab, ua ntsiag to tswj cov kua qaub- puag ncig qhov tseem ceeb rau kev muaj sia nyob microbial. Cia peb pib hnub no los ua tib zoo saib xyuas ntau dua rau alkalinity, qhov no zoo li zoo tib yam tab sis tseem ceeb heev rau cov dej tsis zoo, thiab pab tsim kom muaj txiaj ntsig zoo dua, ruaj khov, thiab ib puag ncig tus phooj ywg kev kho dej khib nyiab.