Kev kho cov kab mob lom neeg tuaj yeem txo qis COD feem ntau hauv dej, thiab nrog kev sib ntxiv ntawm cov txheej txheem anoxic denitrification, tag nrho cov nitrogen tuaj yeem raug tshem tawm zoo. Txawm li cas los xij, rau phosphorus, hnyav hlau ions, thiab hardness ions, tshem tawm cov nyhuv ntawm cov txheej txheem lom neeg yooj yim yog txwv: cov kab mob tsuas tuaj yeem ua rau me me ntawm phosphorus los ntawm lawv tus kheej kev loj hlob thiab cov metabolism, uas tsis tuaj yeem ua raws li cov qauv; thaum cov hlau hnyav thiab hardness ions tsis tuaj yeem biodegraded, thiab cov kab mob lom tsis tuaj yeem ua tiav kev tshem tawm zoo. Hnyav hlau ions yog tshuaj lom rau cov kab mob, thiab me ntsis siab dua tuaj yeem cuam tshuam cov tshuaj lom neeg lom neeg; hardness ions yog yaj tag nrho hauv dej, thiab cov kab mob lom tsis tuaj yeem tshem tawm lawv.
Txhawm rau tiv nrog cov tshuaj no, cov tshuaj los nag yog tsim nyog- ntxiv cov tshuaj tua kab mob ua rau lub hom phiaj ions hloov ntawm lub xeev yaj mus rau lub xeev insoluble thiab precipitate, uas yog tom qab ntawd tshem tawm los ntawm cov khoom sib cais - kua.
I. Cov Ntsiab Cai ntawm Tshuaj Los nag
Lub hauv paus ntsiab lus ntawm cov dej nag lossis dej yog txoj cai ntawm cov khoom solubility: ntxiv cov neeg ua haujlwm precipitating rau cov dej khib nyiab ua rau cov kuab paug hauv dej ua ke nrog cov neeg ua haujlwm, tsim cov khoom uas nyuaj rau yaj hauv dej. Thaum cov ntsiab lus ntawm cov khoom no tshaj qhov kev txwv lub peev xwm (Ksp solubility khoom) ntawm lub cev dej, lawv yuav cia li los nag los ntawm dej, tsim cov sediment rau kev sib cais.
Qhov tseem ceeb yog tias cov precipitant ntxiv yuav tsum txaus kom txo cov concentration ntawm lub hom phiaj ions mus rau theem uas yuav tsum tau, tab sis tsis ntau dhau -cov nag lossis daus ntau dhau yuav ua rau muaj kuab paug rau theem nrab (xws li cov hlau seem thiab cov ntsev) thiab ua kom cov sludge ntau lawm.
II. Tshuaj phosphorus tshem tawm
Phosphorus yog lub ntsiab culprit ntawm eutrophication nyob rau hauv dej lub cev, thiab cov qauv tso tawm rau tag nrho cov phosphorus yog nce stringent. Kev tshem tawm cov phosphorus lom yog nyob ntawm polyphosphate- khaws cov kab mob kom tso cov phosphorus anaerobically thiab tom qab ntawd tshem tawm cov phosphorus ntau dhau nrog cov sludge ntxiv thaum lub sijhawm ua haujlwm aerobic. Txawm li cas los xij, tus nqi tshem tawm yog txwv. Thaum tag nrho cov phosphorus nyob rau hauv lub influent siab dhau lawm, kev tshem tawm cov phosphorus lom yog tsis txaus kom ntseeg tau raws li cov qauv, thiab tshuaj phosphorus tshem tawm yuav tsum tau siv raws li ib tug poob.
Lub hauv paus ntsiab lus: Ntxiv txhuas ntsev (PAC) los yog hlau ntsev (polyferric sulfate) ua rau cov hlau ions ua rau cov phosphate ions los ua txhuas phosphate los yog hlau phosphate precipitates; txiv qaub (Ca(OH)₂) kuj tuaj yeem ntxiv, tsim calcium hydroxyphosphate precipitates nyob rau hauv alkaline tej yam kev mob.
Cov tshuaj tiv thaiv txhuas ntsev: Al³⁺ + PO₄³⁻ → AlPO₄↓;
Hlau ntsev cov tshuaj tiv thaiv: Fe³⁺ + PO₄³⁻ → FePO₄↓;
Cov tshuaj tiv thaiv kab mob: 5Ca²⁺ + 4OH⁻ + 3PO₄³⁻ → Ca₅(OH)(PO₄)₃↓;
Ntxiv qhov chaw: Muaj peb txoj kev xaiv. Ua ntej- ntxiv ua ntej lub tank kho cov tshuaj lom neeg ua rau lub sijhawm ntev, tab sis qhov cuam tshuam ntawm txhuas ntsev ntawm cov kab mob tseem muaj teeb meem; ib txhij ntxiv nyob rau hauv qhov kawg ntawm aerobic seem ntawm cov tshuaj lom neeg lub tank siv aeration thiab agitation los txhawb cov tshuaj tiv thaiv, uas yog cov feem ntau txoj kev nyob rau hauv lub nroog cov dej khib nyiab kho nroj tsuag, thiab cov coagulant txhawb activated sludge flocculation; post- ntxiv tom qab cov sedimentation tank thib ob, nyob rau hauv cov kev kho mob siab heev, ncaj qha thiab meej tshem tawm cov phosphorus residual, yuav tsum tau siv tsawg kawg nkaus, tsim cov sludge tsawg tshaj plaws, tab sis yuav tsum muaj cais cov tshuaj tiv thaiv thiab sedimentation chaw. Qhov kev xaiv tshwj xeeb yog nyob ntawm cov txheej txheem ntws thiab phosphorus ua raws cai.
Cov ntsiab lus tseem ceeb ntawm Kev Ua Haujlwm: Tus yuam sij rau kev tshem tawm cov tshuaj phosphorus yog txuam nrog cov tshuaj ntau npaum li cas nrog rau tag nrho cov phosphorus concentration hauv cov influent. Thaum tag nrho cov phosphorus concentration nyob rau hauv lub influent fluctuates ho, ib tug online tag nrho phosphorus meter los yog periodic sampling yog tsim nyog los kho qhov ntau npaum. Lub pH ntawm cov kua dej xav tau kev saib xyuas- ntxiv ntawm txhuas thiab hlau ntsev siv alkalinity, thiab phosphorus tshem tawm efficiency txo thaum pH qis dua 6; Qhov sib ntxiv ntawm txiv qaub yuav nce pH effluent, yuav tsum tau kho. Cov tshuaj sludge tsim los ntawm kev tshem tawm phosphorus muaj ntau cov teeb meem inorganic thiab muaj kev ua haujlwm zoo dewatering; nws yuav tsum tau muab pov tseg cais tawm ntawm cov sludge lom ntau li ntau tau.
III. Hnyav Hlau Tshem Tawm
Cov dej khib nyiab los ntawm kev lag luam xws li electroplating, metallurgy, mining, thiab electronics muaj hnyav hlau ions xws li tooj liab, zinc, lead, cadmium, nickel, thiab chromium. Cov hlau hnyav yog cov tshuaj lom thiab tsis yog -degradable, yuav tsum tau tswj nruj heev.
Lub hauv paus ntsiab lus: Ntxiv alkali (NaOH, Ca(OH)₂) los yog sulfides (Na₂S, NaHS) ua rau hnyav hlau ions los nag ua hydroxides lossis sulfides. Hydroxide nag lossis daus yog ib qho yooj yim thiab tsawg - tus nqi txoj kev, ua nws txoj hauv kev loj. Sulfide nag lossis daus muaj cov khoom siv me me thiab kev tshem tawm ntau dua (tshwj xeeb tshaj yog rau cov mercury thiab cadmium), tab sis cov sulfide ntau dhau ua rau H₂S cov pa phem, xav tau cov kab mob alkaline los tiv thaiv H₂S khiav. Rau hexavalent chromium (Cr⁶⁺) nyob rau hauv chromium- muaj cov dej khib nyiab, nws yuav tsum xub txo qis rau trivalent chromium (Cr³⁺) nrog tus neeg sawv cev txo qis (sodium bisulfite, sodium metabisulfite), thiab tom qab ntawd los nag li Cr(OH)₃ nrog alkali.
Cov ntsiab lus tseem ceeb ntawm kev ua haujlwm: pH tswj yog qhov tseem ceeb tshaj -txhua cov hlau hnyav muaj qhov zoo pH ntau rau hydroxide nag lossis daus (feem ntau ntawm 8 txog 10), thiab cov kab no sib txawv. Kev sib koom ua ke ntawm ntau cov hlau hnyav hauv cov dej khib nyiab sib xyaw yuav tsum tau txiav txim siab, xaiv tus nqi pH cuam tshuam los yog nag lossis daus. Tom qab cov tshuaj tiv thaiv los nag ua tiav, ib qho coagulant (PAC + PAM) yuav tsum tau ntxiv los txhim kho cov khoom sib cais - kua; Txwv tsis pub, nplua precipitate particles yuav permeate rau hauv effluent. Cov complexes tuaj yeem cuam tshuam nrog nag lossis daus-piv txwv li, cyanide- muaj cov hlau hnyav hnyav yuav tsum tau ua kom tawg ua ntej nag lossis daus.
PIV. Kev tshem tawm Hardness (Softening)
Hardness ions feem ntau yog calcium (Ca²⁺) thiab magnesium (Mg²⁺) ions. Lawv ua rau scaling nyob rau hauv daim nyias nyias systems (RO, NF), daim ntawv teev nyob rau hauv lub tshav kub exchanger cov cuab yeej txo tshav kub exchanger efficiency, thiab cuam tshuam rau tu zoo nyob rau hauv lub lag luam khaub ncaws.
Lub hauv paus ntsiab lus: Los ntawm kev siv cov tshuaj siv tshuaj los hloov cov calcium thiab magnesium ions rau hauv CaCO₃ thiab Mg(OH)₂, feem ntau calcium thiab magnesium ions tuaj yeem raug tshem tawm.
Cov Ntsiab Lus Ua Haujlwm: Lub pH ntawm cov kua dej softened yog siab thiab yuav tsum tau hloov kho rau nruab nrab los ntawm kev ntxiv cov kua qaub ua ntej nkag mus rau tom qab kev kho mob los yog raug tso tawm. Cov tshuaj tiv thaiv nag lossis daus yuav tsum muaj lub sijhawm khaws cia txaus thiab yuav tsum tau ua ke nrog coagulation thiab flocculation los txhim kho cov nag lossis daus. Softened sludge yog tsim nyob rau hauv ntau qhov ntau, feem ntau yog tsim los ntawm calcium carbonate thiab magnesium hydroxide, uas tuaj yeem dewatered thiab siv los ua cov khoom siv hauv tsev lossis xa mus rau qhov chaw pov tseg.
V. Qhov chaw ntawm peb cov txheej txheem nag lossis daus hauv cov txheej txheem ntws
Kev tshem tawm cov tshuaj phosphorus feem ntau ua tiav ib txhij nrog rau theem kev kho mob lom lossis tom qab theem siab; Kev tshem tawm cov hlau hnyav yog pretreatment ntawm lub zog kawg los tiv thaiv cov kab mob lom; softening kom tshem tawm hardness feem ntau yog nqa tawm nyob rau hauv pem hauv ntej kawg ntawm kev siv rov qab kho (ua ntej lub membrane system). Qhov peb tuaj yeem siv ua ke nyob ntawm qhov yuav tsum tau muaj dej zoo- hlau hnyav- muaj cov dej khib nyiab feem ntau ua rau cov dej nag los tshem tawm cov hlau hnyav ua ntej nkag mus rau hauv cov txheej txheem tshuaj lom neeg; Kev tshem tawm phosphorus ib txhij + kev tshem tawm phosphorus siab heev yog kev coj ua rau cov dej khib nyiab hauv nroog; thiab nyob rau hauv reuse tej yaam num, softening yog ua ua ntej daim nyias nyias.