Hauv kev ua haujlwm niaj hnub ntawm kev rov qab osmosis systems, cov kws kho tsheb kho mob feem ntau ntsib qhov kev sib tw tsis tu ncua:biofouling. Nws tsis yog qhov ua tsis tiav tam sim ntawd tab sis maj mam nkag mus - cov ntaub so ntswg ua rau cov kab mob thiab lawv cov zais cia. Qhov no ua rau muaj kev poob qis hauv qhov system dej ntau lawm, kev hloov pauv hauv kev tsis lees txais ntsev, thiab tas li nce kev khiav hauj lwm siab thiab kev siv zog. Qhov no tsis yog tsuas yog nce qhov zaus thiab tus nqi ntawm cov tshuaj ntxuav tab sis kuj ua rau lub neej luv luv ntawm cov khoom kim heev RO membrane cov ntsiab lus. Nrhiav kev daws teeb meem ua ntej uas tuaj yeem tiv thaiv biofouling ntawm nws qhov chaw tau dhau los ua qhov kev cia siab ntawm kev lag luam ceev.
► Lub Tenacity ntawm Biofouling thiab Pretreatment Challenges
Kev tsim ntawm biofouling pib nrog kev txuas, colonization, thiab kev loj hlob ntawmmicroorganisms los ntawm dejrau ntawm daim nyias nyias. Lub extracellular polymeric tshuaj (EPS) lawv secrete tsim ib tug viscous biofilm uas nrees adheres rau daim nyias nyias, ua lub hauv paus ntawm fouling. Cov txheej txheem ua ntej ua ntej, xws li multi- media filtration ua ke nrog biocide dosing, feem ntau muaj kev txwv. Biocides tawm tsam kom ua tiav instantaneous thiab ua tiav inactivation. Cov kab mob seem, nrog rau cov colloids thiab cov organic teeb meem tsis zoo tshem tawm, nkag mus rau hauv RO system ua ke, dhau los ua "cov chaw yug me nyuam" rau tom ntej biofouling. Yog li ntawd, kev ntseeg siab ntawm theem pretreatment ncaj qha txiav txim siab kev ua haujlwm ntawm cov dej ntws RO daim nyias nyias.
► Kev Tiv Thaiv -Fuling Mechanism ntawm Ceramic Membranes: Kev Tiv Thaiv, Kev Sib Tham, thiab Kev Tu
ntsib qhov kev sib tw no, kev saws me nyuamceramic membranes rau RO pretreatmentyog ua kom pom cov txiaj ntsig zoo. Lawv lub peev xwm tiv thaiv - fouling muaj peev xwm tshwm sim los ntawm lub cev thiab tshuaj lom neeg lub zog ntawm cov khoom nws tus kheej, uas tuaj yeem suav tau tias yog qhov ua haujlwm triple ntawm"kev tiv thaiv, cuam tshuam, thiab tu."
Ua ntej yog qhov tshwj xeeb "tiv thaiv-adhesion" muaj peev xwm.Tubular ceramic membrane cov qauv tsim los ntawm cov ntaub ntawv xws li alumina thiab zirconia inherently muaj zog hydrophilicity thiab ib tug heev du nto. Hydrophilicity txhais tau tias cov dej molecules yooj yim dua ntub thiab tsim ib txheej hydration. Cov yeeb yaj kiab dej no zoo thaiv kev sib cuag ncaj qha ntawm hydrophobic organic teeb meem / kab mob thiab cov khoom siv membrane, ua rau kev sib txuas pib nyuaj. Qhov no sib piv nrog ntau cov polymeric daim nyias nyias uas yuav tsum tau tom qab- hloov kho kom ua tiav hydrophilicity.
Qhov thib ob yog qhov tseeb "kev cuam tshuam lub cev" ua haujlwm.Raws li kev ua haujlwm zoo ultrafiltration membrane, ceramic membranes, nrog rau lawv cov yam ntxwv thiab meej microporous lossis ultrafiltration -theem pore qhov ntau thiab tsawg, tuaj yeem cuam tshuam ze li 100% ntawm cov kab mob, algae, tshem tawm cov khib nyiab, thiab feem ntau cov colloids thiab macromolecular organic teeb meem. Qhov no sib npaug rau kev txhim kho lub cev muaj zog nyob rau hauv pem hauv ntej ntawm RO daim nyias nyias, txo cov fouling load nyob rau hauv cov dej pub thiab ua tau siab - zoo permeate nrog tus nqi qis SDI heev. Qhov no nteg lub hauv paus ruaj khov rau RO pretreatment biofouling tswj.
Thaum kawg, thiab nws cov txiaj ntsig tseem ceeb, yog qhov tsis sib xws "kev huv thiab rov ua kom rov zoo" los ntawm kev ntxuav tshuaj lom neeg- qhov kawg tshwm sim ntawmanti -fouling membraneyam ntxwv.Polymeric daim nyias nyias muaj kev cia siab rau oxidants thiab huab pH, tiv thaiv kom tiav cov biofilm tshem tawm. Ceramic daim nyias nyias, txawm li cas los xij, muaj cov tshuaj lom neeg tsis muaj zog thiab lub zog siv tshuab, ua rau lawv tuaj yeem tiv taus siab -cov ntsiab lus oxidative biocides (xws li sodium hypochlorite), muaj zog acids, muaj zog alkalis, thiab txawm tias siab - kub tu. Qhov no tso cai rau cov neeg ua haujlwm siv cov tswv yim tu kom nruj dua li Chemically Enhanced Backwash (CEB) lossis cov txheej txheem ntxuav offline, ua kom huv si thiab tshem tawm cov txheej txheem ceramic biofouling thiab kho cov membrane flux kom ze rau - theem pib. Qhov no hauv paus daws qhov teeb meem ntawm irreversible fouling.
► Txhim khu kev khiav hauj lwm thiab ntxuav cov tswv yim
Raws li cov yam ntxwv no, kev ua haujlwm thiab kev saib xyuas lub tswv yim rau cov tshuab siv ceramics rau RO pretreatment yog hloov tau yooj yim thiab meej. Cov huab cua niaj hnub-Kev ntxuav dej rov qab tuaj yeem tshem tawm cov khaubncaws sab nraud povtseg zoo. Periodic Chemically Enhanced Backwash (CEB) tom qab ntawd dhau los ua cov haujlwm tseem ceeb rau kev tswj xyuas yuav ua li cas tiv thaiv daim nyias nyias fouling. Nyob ntawm cov dej tsis zoo thiab cov fouling tej yam kev mob, alkaline tu, oxidant tu, los yog alternating acid -alkali ntxuav ntawm txawv concentrations yuav xaiv tau. Qhov no muaj peev xwm ua kom muaj peev xwm ua kom ntev - lub sijhawm ua haujlwm ruaj khov thiab txo cov nqi khiav lag luam zoo los ntawm kev ua haujlwm ntawm daim nyias nyias.
Hauv cov ntsiab lus,ceramic membranes rau RO pretreatmenttsim kom muaj kev tswj hwm biofouling xws li kev tiv thaiv kom ua tiav kev kho mob los ntawm lawv cov yam ntxwv peb npaug ntawm hydrophilic anti-adhesion, kev cuam tshuam meej, thiab muaj tshuaj lom neeg huv. Nws tsis tsuas yog ncua fouling tab sis muab kev ruaj ntseg dej huv tsis tau pom dua rau RO systems los ntawm ob qho tib si lub cev thaiv thiab cov tshuaj rov qab los saib xyuas, tuav lub peev xwm los "kawg" ntev - lub sijhawm ua haujlwm npau suav phem tshwm sim los ntawm biofouling. Rau kev txiav txim siab txog kev ua haujlwm- cov neeg tsim khoom tau cog lus los txhim kho qhov kev ntseeg tau thiab txo cov nqi ntawm lub neej, cov thev naus laus zis no nthuav tawm cov kev xaiv tshiab tsim nyog ntawm - kev ntsuas qhov tob.