Retrofit thiab Performance Study ntawm Fine-Bubble Aeration System nyob rau hauv Lub Nroog Lub Chaw Kho Dej Kho Dej

Retrofit thiab Performance Study ntawm Fine-Bubble Aeration System nyob rau hauv Lub Nroog Lub Chaw Kho Dej Kho Dej

Taw qhia

Tam sim no, cov txheej txheem dej khib nyiab tseem ceeb siv hauv Suav teb suav nrog oxidation ditch, SBR, activated sludge, thiab lwm yam. Cov txheej txheem oxidation ditch muaj teeb meem ntawm kev siv hluav taws xob siab, tshwj xeeb tshaj yog nyob rau hauv cov khoom siv roj ntsha, uas suav txog 65% -80% ntawm tag nrho cov kev siv hluav taws xob. Cov cuab yeej siv aeration uas siv rau hauv cov txheej txheem oxidation ditch suav nrog aeration txhuam, aeration discs, ntsug ncej aerators, thiab nplua - npuas aerators. Piv txwv li, tom qab lub chaw kho dej khib nyiab hauv nroog hauv qee lub nroog tau hloov pauv los ntawm cov khoom siv hauv av ib txwm ua kom zoo rau hauv qab zoo - npuas aeration, kev siv hluav taws xob tau txo los ntawm 20.11%, thaum kho cov dej zoo tau ruaj khov dua. Tsis tas li ntawd, nplua - npuas aeration muaj cov yam ntxwv ntawm zoned oxygen mov, uas tuaj yeem muab cov pa oxygen txaus raws li cov pa oxygen xav tau hauv ntau qhov chaw ntawm oxidation ditch, ntxiv kev txhim kho nitrogen thiab phosphorus tshem tawm efficiency.

Lub tshuab aeration ntawm ib qho chaw kho dej khib nyiab hauv nroog tau ua haujlwm rau ntau tshaj kaum xyoo, nrog rau cov cuab yeej loj thiab kev ua haujlwm nyuaj. Nws yog ib qho nyuaj kom ua tau raws li cov qauv tso tawm tshiab, ua kev kho kom sai sai. Qhov phiaj xwm no tau hloov kho qhov system mus rau qhov zoo - npuas aeration system, uas tuaj yeem txo qis kev siv hluav taws xob, ua kom zoo dua qub, ua kom lub neej ntev ntawm cov cuab yeej siv, thiab txo cov nqi tu, ua raws li lub teb chaws kev txuag hluav taws xob thiab kev txo cov pa phem. Qhov kev tsim kho tshiab no tau siv cov kev coj ua ntsuab thaum lub sij hawm siv cov khoom siv dismantling thiab installation: cais cov khoom qub, kev siv cov khoom siv ua ntej, thiab siv cov khoom siv qis qis, qis-emission machinery, ua tiav "txheej txheem-kev tsim kho" dual-siv lub zog txuag thiab txhawb kev kho cov dej khib nyiab.

1 Project Overview

1.1 Qhov xwm txheej tam sim no

Lub chaw kho dej khib nyiab hauv nroog hauv qee lub nroog muaj peev xwm ntawm 50,000 tons / hnub, tsim ua peb theem. Theem I tau txais cov txheej txheem oxidation ditch, Phase II thiab cov kev kho mob siab heev kuj tau txais cov txheej txheem oxidation ditch, nrog rau kev kho mob tom qab siv coagulation sedimentation + ntaub xov xwm pom + ultraviolet tshuaj tua kab mob txheej txheem. Theem III tau txais kev hloov kho A²O txheej txheem. Tam sim no, cov effluent ua tau raws li tus qauv DB32/1072-2018.

1.2 Cov teeb meem uas twb muaj lawm

1.2.1 External Pipe Network cuam tshuam

Cov dej khib nyiab nyob rau hauv qhov kev sau ntawm cov nroj tsuag cov yeeb nkab no suav nrog kev koom tes los ntawm ntau lub tuam txhab kev lag luam. Thaum lub sijhawm ua haujlwm txhua hnub, tuaj yeem cuam tshuam los ntawm cov dej khib nyiab txawv txav los ntawm kev lag luam, ua rau DO tus nqi hauv lub tank lom neeg tsawg, txawm tias ncav cuag 0 mg / L, ua tsis tau raws li qhov yuav tsum tau ua. Lub caij no, vim muaj kev hloov pauv hauv cov xwm txheej sab nraud, vim tias muaj kev lag luam ntau dua nyob rau hauv qhov chaw pabcuam tso dej pov tseg rau hauv cov yeeb nkab network, cov nroj tsuag no yuav ntsib kev cuam tshuam loj ntawm cov dej zoo yav tom ntej. Thaum muaj kev hloov pauv hloov pauv, cov pa oxygen yaj hauv lub tank lom yuav txo qis, thiab qhov kev hloov pauv ntawm qhov ntim ntawm cov rotating discs raug txwv. Hauv qee lub sijhawm, DO hauv lub tank aerobic nce mus txog 0 mg / L, yuam cov nroj tsuag kom txo tau cov peev xwm kho mob hauv cov lus teb, cuam tshuam rau qhov chaw aerobic ntawm lub tank lom thiab muaj peev xwm kho tau.

1.2.2 Tsawg DO hauv Aeration Tank

Vim yog kev sib hloov disc ua haujlwm tsis zoo ua rau tsis muaj oxygenation efficiency ntawm aerators, thaum lub sijhawm ua haujlwm tiag tiag, cov ntaub ntawv ua haujlwm keeb kwm qhia tau hais tias qhov nruab nrab DO qhov tseem ceeb los ntawm cov cuab yeej hauv nruab nrab thiab qhov hluav taws xob ntawm lub tank aeration tsis pub tshaj 1 mg / L, nrog qhov qis tshaj 0 mg / L, cuam tshuam rau biochemical cov tshuaj tiv thaiv.

1.2.3 Kev siv hluav taws xob siab

Theem I thiab II roj tanks ntawm cov nroj tsuag no yog nyob rau hauv oxidation ditch daim ntawv. Theem I oxidation ditch siv 8 rotating disc aerators nrog lub hwj chim ntawm 18.5 kW, nrog tag nrho nto aerator zog ntawm 148 kW. Phase II oxidation ditch yog plaub-channel Carrousel ditch hom, siv 13 Hitachi tus kheej-priming aerators, suav nrog 2 teeb ntawm 11 kW, 2 teeb ntawm 18.5 kW, thiab 9 teeb ntawm 15 kW, nrog rau tag nrho saum npoo aerator zog ntawm 19 kW. Raws li kev ua haujlwm ib txwm muaj, kom ntseeg tau tias cov dej ntim txaus, vim tias cov pa oxygenation tsis zoo ntawm cov khoom siv oxygen uas twb muaj lawm, tag nrho cov aerators yuav tsum tau qhib tag nrho.

Kev siv hluav taws xob ib tuj dej rau Phase I thiab II aerators yog: (18.5 kW * 7+194) * 24 * 0.75 / 25, 000=0.2392 RMB / ton. Raws li kev soj ntsuam ntawm kev siv hluav taws xob lom neeg ntawm ntau qhov chaw nyob ib puag ncig cov chaw kho dej khib nyiab hauv nroog, kev siv hluav taws xob rau 25,000 tons / hnub hauv nroog cov dej khib nyiab hauv tsev siv cov hauv qab zoo - npuas aeration system feem ntau yog 0.09-0.1 RMB / ton. Kev siv lub zog ntawm lub tshuab hluav taws xob tig yog 2.4-2.7 npaug ntawm qhov zoo hauv qab - npuas aeration system, qhia txog kev siv hluav taws xob ntau.

1.2.4 Cov cuab yeej siv siab tsis ua haujlwm

Raws li rotating disc aerators muaj hnub nyoog, cov khoom siv tsis ua hauj lwm maj mam nce. Tom qab 11 xyoo ntawm kev ua haujlwm ntawm cov nroj tsuag no, lub rotating disc aeration system tsim disc deformation, ua rau cov khoom siv siab load thiab kev co tseem ceeb. Kev siv lub sij hawm ntev - coj mus rau hauv qab loosening, ua rau misalignment ntawm ob qho tag nrho thiab lwm yam teeb meem, ua rau muaj zog bearing hnav thiab siab tsis ua hauj lwm tus nqi. Main shafts, impellers, couplings, thiab lub hauv paus zog tau ua ntau yam kev kho lossis hloov, qhov tseem ceeb mus txog qhov hloov pauv. Cov bearings thiab aerator taub hau hniav ntawm tus kheej -priming aerators tau hnyav heev. Cov txheeb cais tsis ntev los no qhia tau hais tias cov nroj tsuag tau ntsib ze li 30 qhov kev kho txhua xyoo rau kev hloov cov tshuab aerators thiab tus kheej -priming aerators.

2 Tsim Kev Txhim Kho Kev Lag Luam Retrofit

Tag nrho cov kev rov qab kho dua tshiab yog: tshem tawm cov qub rotating disc aerators thiab hloov lawv nrog hauv qab zoo - npuas aeration, nrog sib txuas ntxiv ntawm blowers; tsa lub effluent weir ntawm lub tank lom kom ua tau zoo dej tob ntawm cov roj ntsha tank; ntxiv mixers nyob rau hauv lub aerobic seem siv tus thawj channel qauv los tiv thaiv lub zos sludge tsub zuj zuj.

2.1 Aerator Xaiv thiab Layout

2.1.1 Aerator Disc Parameters

EPDM membrane aerator disc qauv DD330 raug xaiv, raws li qhia hauvDaim duab 1, nrog cov kev txwv tshwj xeeb qhia hauvTable 1.

2.1.2 Aerator Disc Layout

Tus naj npawb ntawm aerator discs: Theem I tank hauv qab net cheeb tsam 864 m², Phase II tank hauv qab net cheeb tsam 1,412 m², thaj tsam kev pabcuam nruab nrab 0.8 m² / disc, nrog rau kev nyab xeeb ntawm 1.05–1.10. Qhov kawg tag nrho cov aerator discs txiav txim siab: Theem I 1,150 discs, Phase II 1,900 discs.

Lub hauv paus ntsiab lus layout: sib npaug sib npaug hauv ib daim phiaj kab sib chaws tsis tu ncua. Tshem tawm ntawm phab ntsa tank Ntau dua lossis sib npaug li 0.3 m kom tsis txhob muaj qhov tuag; clearance los ntawm channel muab faib phab ntsa Ntau dua los yog sib npaug rau 0.4 m los pab txhawb kev txij nkawm. Muab faib raws cov dej ntws, nrog rau ib qho hluav taws xob cua tswj valve rau ib cheeb tsam kom ua tiav DO zonal tswj. Tsis txhob sludge twj tso kua mis suction ports, sampling troughs, thiab cable trays, hauv zos kho qhov nrug mus rau 1.5 m thaum tswj qhov chaw pab cuam ib disc Tsawg dua los yog sib npaug rau 0.8 m².

Kev teeb tsa qhov siab thiab cov yeeb nkab muab qhab nia: Qhov saum npoo ntawm daim nyias nyias yog 0.25 m ntawm lub tank hauv qab, kom ntseeg tau tias submersion Ntau dua lossis sib npaug li 5.0 m ntawm qhov tsawg kawg nkaus dej kom tsis txhob muaj kiv cua. Cov kav dej ceg siv ABS DN50 nrog perforated cua faib; Cov kav dej tseem ceeb tau teeb tsa hauv lub voj voog, nrog huab cua tshaj tawm tswj ntawm 10-12 m·s⁻¹, cov khoom siv SS304. Ib khub ntawm flange ceev- txuas fittings yog muab rau txhua txhua 10 discs, tso cai rau kev nqa tag nrho rau kev saib xyuas yam tsis tau tso lub tank.

2.2 Blower System Optimization

2.2.1 Ntxiv Blowers

Cov tshuab nqus tsev nqus cua nkag tau tau yuav los ua cov chav tseem ceeb, thiab chav tshuab tshuab tshiab tau tsim los nrog cov hlau tsis muaj cua ducts ntxiv.

2.2.2 Blower Xaiv

Raws li cov kev ua haujlwm tiag tiag ntawm cov nroj tsuag thiab xav txog kev hloov pauv dej hauv lub neej yav tom ntej, qhov muaj txiaj ntsig COD concentration hauv cov phiaj xwm retrofit tsis txawv txav ntawm tus nqi tsim, nrog qhov nruab nrab concentration ntawm 320 mg / L. BOD concentration yog xam raws li Phase III tsim tus nqi ntawm 150 mg/L, thiab lwm yam influent indicators tau xam raws li Phase III tsim influent concentrations. Qhov yuav tsum tau ua haujlwm huab cua ntim rau Phase I thiab II ntawm cov nroj tsuag yog 103.7 m³ / min (6,225.1 m³ / h, ob chav ua haujlwm thiab ib qho standby, ib chav tsev cua ntim 50 m³ / min).

Raws li kev txiav txim siab ntau yam, ob lub tshuab xa tawm cua tshuab nqus tsev NX75-C060 tau yuav los ua cov chav tseem ceeb rau Phase I thiab II. Ib chav tshuab tshuab tshiab yuav tsum tau tsim ua, tentatively nyob rau sab qab teb ntawm tus thawj sludge dewatering Rhiav, nrog stainless hlau cua ducts ntxiv rau oxidation ditch. Blower tsis: cua siab 0.049 MPa, huab cua ntim 50 m³ / min, nrog siab tshaj plaws tso zis zog ntawm 64.3 kW nyob rau hauv cov kev khiav hauj lwm tej yam kev mob.

2.2.3 Aeration System Retrofit

Txoj kev aeration tau hloov mus rau hauv qab aeration. Theem I thiab II cov tso tsheb hlau luam lom neeg siv cov lej sib raug ntawm cov tshuab hluav taws xob thiab UPVC aeration kav. Kev rov ua kom zoo dua qub: Theem I biological tank yuav tsum siv 780 teeb ntawm DD330 disc aerators thiab UPVC aeration kav, Phase II biological tank yuav tsum siv 1,276 teeb ntawm DD330 disc aerators thiab UPVC aeration kav, nrog ib qho aerator ua haujlwm huab cua ntim ntawm m³ 3.45. Lub aerator taub hau layout yog qhia nyob rau hauvCov duab 2 thiab 3.

2.3 Txheej txheem Parameter Optimization

2.3.1 Oxidation Ditch Zoning thiab DO Control Strategy

Raws li cov dej ntws kev taw qhia ntawm oxidation ditch, aeration seem muab faib ua plaub thaj tsam. Zone 1: DO 0.3–0.5 mg/L, Zone 2: DO 0.2–0.3 mg/L, Zone 3: DO 1.5–2.0 mg/L, Zone 4: DO 1.0–1.5 mg/L. Cov txheej txheem ammonia nitrogen yog ntsia rau ntawm qhov siab tshaj plaws nitrification cov tshuaj tiv thaiv ntawm Zone 2 thiab Zone 3, thaum kawg tswj cov dej ntws tawm NH₃-N Tsawg dua lossis sib npaug li 1.5 mg / L.

2.3.2 Aeration Period Optimization

Ib qho "intermittent aeration" module tau ntxiv rau SCADA uas twb muaj lawm, tsim DO online ntsuas + lub sijhawm kaw ob lub voj kom paub tseeb tias DO nyob rau hauv nruab nrab ntawm ntu aerobic tseem nyob ntawm 0.2 mg / L. Yog DO<0.2 mg/L at the end of the air-off period, an additional 5 minutes of micro-aeration is automatically added (to protect mixers). After the cycle count reaches 12 times (6×24/120=12), the blower is forced to rest for 30 minutes (to prevent overheating from frequent start-stop cycles).

3 Retrofit Effect Analysis

Qhov cuam tshuam ntawm qhov engineering retrofit ntawm tag nrho cov txheej txheem kev ua haujlwm tau tshuaj xyuas los ntawm kev sib piv cov kev hloov pauv hauv cov pa phem ua ntej thiab tom qab rov ua dua.

3.1 Kev sib piv ntawm cov dej ntws zoo ua ntej thiab tom qab rov ua dua

Cov dej tsis zoo ua ntej thiab tom qab rov ua dua tau zoo nyob ruaj khov, raws li qhia hauvDaim duab 4. Ua ntej thiab tom qab retrofit, qhov nruab nrab effluent COD tseem qis dua 30 mg/L, TP yeej tseem tsawg dua los yog sib npaug rau 0.3 mg/L, NH₃-N Less dua los yog sib npaug rau 1.5 mg/L, thaum TN fluctuated nyob ib ncig ntawm 10 mg/L. Tag nrho cov dej zoo tau mus txog quasi-Class IV cov qauv dej saum npoo av, deb tshaj li cov qauv tso tawm uas xav tau rau cov nroj tsuag.

Txhawm rau txheeb xyuas qhov xav tau ntau ntxiv txog qhov cuam tshuam ntawm qhov rov ua tau zoo ntawm cov dej zoo, ib qho - xyoo effluent water quality trends ua ntej thiab tom qab retrofit tau muab piv, yieldingDaim duab 5. Nws tuaj yeem pom los ntawm daim duab uas, yam tsis xav txog qhov cuam tshuam ntawm cov kev hloov pauv muaj txiaj ntsig, qhov hloov pauv hauv COD thiab TP cov dej ntws tawm tom qab rov qab tau ruaj khov dua li ua ntej retrofit. Txawm hais tias qhov nruab nrab qhov tseem ceeb ntawm cov ntsuas nitrogen tau nce ntxiv piv rau ua ntej retrofit, tag nrho cov qauv yog qhov ruaj khov, uas ua rau txo qis tag nrho cov nroj tsuag siv zog thiab kev txuag tshuaj.

3.2 Kev sib piv ntawm kev tshem tawm cov pa phem ua ntej thiab tom qab Retrofit

Raws li kev txhim kho hauv cov txheej txheem aeration, tag nrho cov nroj tsuag siv hluav taws xob txo qis los ntawm 1.7% piv rau yav dhau los, thaum muaj peev xwm kho tau nce 8.33%, thiab cov pa phem txo qis kuj nce ntxiv, raws li qhia hauvDaim duab 6. Tom qab kev suav, COD txo tau nce 948.5 tons, TP nce 7.0 tons, NH₃-N nce 100.4 tons, thiab TN nce 125.9 tons.

Kev tshem tawm cov pa phem tiag tiag kuj hloov pauv raws li qhia hauvRooj 2. Tom qab retrofit, tsuas yog txo qis hauv NH₃-N tshem tawm tus nqi, tshem tawm tus nqi rau tag nrho lwm qhov ntsuas tau nce.

3.3 Kev sib piv kev siv hluav taws xob ua ntej thiab tom qab Retrofit

Lub zog noj ntawm qhov project retrofit no yog qhia hauvTable 3. Tom qab retrofit, lub hwj chim noj ib tuj dej rau Phase I biological tank aeration system txo los ntawm 67.3%, thiab rau theem II txo los ntawm 80.9%. Tag nrho cov nroj tsuag nruab nrab siv hluav taws xob ib tuj dej poob los ntawm 55.3%, ua kom pom lub zog tseem ceeb - txuag cov teebmeem. Tag nrho cov nroj tsuag siv hluav taws xob ib tuj ntawm cov dej tau txo qis rau 0.21 kW·h / m³, nyob rau hauv qhov ntau ntawm cov nqi siv hluav taws xob rau cov txheej txheem oxidation zoo sib xws thoob ntiaj teb (0.292 ± 0.192) kW·h / m³. Lub zog noj ib chav tsev hnyav ntawm cov pa phem ua ntej thiab tom qab retrofit rau tag nrho cov nroj tsuag yog qhia nyob rau hauvRooj 4. Tom qab retrofit ntawm tag nrho cov nroj tsuag aeration system, lub hwj chim noj ib 1 kg ntawm COD kho tau txo los ntawm 26.2%, ib 1 kg ntawm TP kho tau txo los ntawm 15.7%, ib 1 kg ntawm NH₃-N kho tau txo los ntawm 29.3%, thiab ib 1 kg ntawm TN kho tau txo los ntawm 36} zoo zog{1%.

3.4 Kev sib piv tshuaj ua ntej thiab tom qab Retrofit

Ua ntej retrofit, vim nquag aeration system tsis ua hauj lwm, DO nyob rau hauv cov kab mob lom yog nyuaj rau tswj, thiab ua tau raws li cov qauv qhia nitrogen yuav tsum tau ntxiv cov pa roj carbon monoxide los xyuas kom meej kev tshem tawm. Tom qab retrofit, sab nraud cov pa roj carbon ntxiv yog qhov tseem ceeb ntxiv lawm. Tom qab retrofit, lom phosphorus tshem tawm thiab denitrification efficiency ho txhim kho, thiab nrog phosphorus tshem tawm cov tshuaj PAC thiab sludge dewatering tshuaj PAM tau correspondingly txo. Cov nqi tshuaj txhua xyoo tau txo los ntawm 167,000 RMB piv rau ua ntej. Cov kev hloov tshwj xeeb muaj nyob rau hauvTable 5.

3.5 Kev sib piv kev nqis peev ua ntej thiab tom qab Retrofit

Ua ntej retrofit, tus nqi txhua xyoo rau saum npoo aerators yog 1.6281 lab RMB, nrog cov khoom siv kho txhua xyoo tsis pub tsawg dua 250,000 RMB. Tom qab retrofit, tus nqi txhua xyoo rau tshuab tshuab thiab tov khoom yog 714,600 RMB. Raws li qhov kev suav no, kev txuag hluav taws xob txhua xyoo yog 913,500 RMB, ntxiv rau cov nqi kho txhua xyoo ntawm 250,000 RMB, tag nrho cov nyiaj txuag txhua xyoo ntawm 1.1635 lab RMB. Raws li tag nrho cov peev ntawm 3.704 lab RMB, lub sijhawm them rov qab yog 3.18 xyoo.

3.6 Txheej Txheem Stability

Ua ntej retrofit, thaum lub sijhawm ua haujlwm tsis zoo, cov pa oxygen yaj hauv lub tank lom neeg feem ntau khaws cia qis dua 1.0 mg / L. Tom qab retrofit, yaj oxygen nyob rau hauv lub biological tank nruab nrab yog 1.5-2.0 mg / L. Raws li kev xav tau ntawm cov kev xav tau zoo thiab cov txheej txheem, qhov kev hloov pauv oxygen yaj tuaj yeem yog 1.0-2.5 mg / L. Thaum muaj kev cuam tshuam loj heev, cov pa oxygen ib txwm yaj hauv lub tank lom neeg kuj tuaj yeem tswj hwm los ntawm kev kho lub tshuab tawm. Yog li ntawd, tom qab retrofit, ruaj khov effluent ua raws li kev txaus siab.

4 Kev xaus

Before technical renovation, this plant faced common problems with the oxidation ditch process: aging rotating discs → attenuation of oxygenation efficiency → insufficient DO, along with skyrocketing energy consumption and failure rates. Replacing them with a bottom fine-bubble aeration-mixer-blower system can reversely amplify the oxygen mass transfer coefficient, increase HRT in section A, and improve zonal oxygen supply precision, simultaneously enhancing denitrification without adding carbon sources. For similar plants: any oxidation ditch that has been in operation for ≥10 years, with aeration power consumption per ton of water >0.23 kWh, DO nquag<1 mg/L, and annual repair cost increases >15%, tuaj yeem rov ua qhov kev kho dua tshiab no. Raws li 55.3% kev txuag hluav taws xob, 3.18- lub sijhawm them rov qab xyoo, thiab cov txiaj ntsig marginal ntawm 3%-5% nce hauv cov pa phem txo tus nqi los ntawm qhov piv txwv no, kev txhim kho kev lag luam muaj kev nyab xeeb siab thiab tuaj yeem qhib cov pa roj carbon txo cov peev txheej tam sim ntawd, muab cov kev hloov pauv thiab txaus rau ntsuab thiab qis-carbon hloov kho cov qub oxidation.