Kev ua tau zoo thiab kev vam meej hauv zej zog Microbial nyob rau hauv Ib Nruam -Flow Anoxic MBBR-AAO Txheej Txheem Rau Txhim Kho Nitrogen Thiab Phosphorus Tshem Tawm Los Ntawm Cov Dej Dej Hauv Nroog

Kev ua tau zoo optimization thiab microbial Kev vam meej hauv zej zog ntawm Nruam -Flow Anoxic MBBR-AAO txheej txheem

Nyob rau hauv xyoo tas los no, kev kho siab heev ntawm cov dej phwj hauv nroog thiab kev ua kom muaj peev xwm rov ua dua tshiab tau dhau los ua cov ntsiab lus kub hauv thaj chaw dej. Txawm li cas los xij, cov txheej txheem tshem tawm cov tshuaj nitrogen thiab phosphorus tau dav siv los ntawm cov nroj tsuag kho dej khib nyiab tsis tsuas yog ua rau cov khoom siv pov tseg ntau dhau tab sis kuj nce nqi khiav lag luam [1]. Ntxiv mus, qhov maj mam txo qis hauv cov pa roj carbon- rau- nitrogen piv (C/N) ntawm cov dej phwj hauv nroog thiab qhov sib txawv ntawm qhov chaw nyob ntawm cov zej zog microbial sib txawv tau dhau los ua qhov tseem ceeb txwv rau cov thev naus laus zis kho dej.

Cov sludge- zaj duab xis hybrid MBBR txheej txheem sib txuas cov txheej txheem activated sludge nrog cov txheej txheem tshem tawm cov khoom siv biofilm kom ua tiav cov txheej txheem ua kom muaj txiaj ntsig zoo ntawm cov kab mob ua haujlwm, daws cov teeb meem ntawm thaj av loj thiab kev ua haujlwm tsis zoo - qhov kub thiab txias ntawm cov txheej txheem activated . sludge [2] Hauv xyoo 2008, Wuxi Lucun Cov Kev Kho Dej Ncua Dej Hauv Nroog Jiangsu, ua thawj lub chaw kho dej khib nyiab hauv Suav teb los ua cov kev kho dua tshiab thiab rov tsim kho dua tshiab rau Class IA cov qauv, ua tiav cov txiaj ntsig kev kho mob los ntawm kev ntxiv cov cab cab mus rau cov sludge system [3]; Hu Youbiao et al. [4] tshawb xyuas qhov kub thiab txias ntawm kev tshem tawm ammonia nitrogen thiab organic teeb meem hauv MBBR thiab activated sludge, thiab cov txiaj ntsig tau pom tias qhov kub thiab txias muaj qhov cuam tshuam me me rau MBBR tab sis muaj kev cuam tshuam ntau dua ntawm cov activated sludge; Zhang Ming et al. [5] siv cov txheej txheem A²O-MBBR los kho cov dej phwj tuaj nyob deb nroog, ua tiav cov kev tshem tawm siab ntawm COD, ammonia nitrogen, TP, thiab TN; Zhou Jiazhong et al. [2] pom los ntawm qhov me me - qhov kev sim ntsuas uas DO, qhov kub thiab txias tau zoo cuam tshuam nrog cov sludge- zaj duab xis hybrid MBBR system, thaum lub zog C / N piv tau cuam tshuam tsis zoo.

Cov txheej txheem anoxic MBBR (AM{0}}MBBR) tuaj yeem paub ib txhij denitrification thiab phosphorus tshem tawm hauv lub tank anoxic, uas kuj yog cov txheej txheem denitrifying phosphorus tshem tawm (DPR). Piv nrog rau cov txheej txheem kev kho dej khib nyiab, DPR txheej txheem tuaj yeem txuag cov organic carbon thiab txo qis kev siv oxygen. Zhang Yongsheng [6] et al. tsim ib qho txuas ntxiv -flow biofilm reactor, thiab cov txiaj ntsig tau pom tias nyob rau ntawm qhov kub ntawm 20 degree, DO concentration ntawm 5.5 mg / L, load ntawm 2.2 kg / (m³·d), thiab ib qho kev sib cuam tshuam ntawm aeration ntawm anaerobic 3 h / aerobic 6 h, qhov nruab nrab concentrations ntawm COD thiab phosphorus / phosphate yog 7 mg / h. 0.67 mg / L, nrog kev tshem tawm ntawm 72.9% thiab 78.5%, feem.

Txawm li cas los xij, rau cov sludge-film hybrid AM-AAO system, muaj kev sib raug zoo ntawm cov sludge flocculent sludge thiab txuas biofilm. Cov kev tshawb fawb yav dhau los tau tsom mus rau kev coj ua engineering xws li kev sib tw thiab kev tsim kho cov chaw kho dej khib nyiab, tab sis muaj qee qhov kev tshawb fawb txog synchronous nitrification thiab DPR los txhim kho nitrogen thiab phosphorus tshem tawm nyob rau hauv tas li- ntws sludge- zaj duab xis hybrid AM-AAO systems, thiab kev ruaj ntseg ntawm cov pa phem tshem tawm ib qho kev ua tau zoo ntawm DPR txheej txheem kev ua tau zoo.

Txoj kev tshawb no optimized pib-nce thiab kev lag luam cov tswv yim ntawm nruam- ntws (AAO) thiab nruam- ntws sludge- zaj duab xis hybrid (AM-AAO) cov txheej txheem, tsom rau kev tshawb xyuas qhov cuam tshuam ntawm aeration npaum li cas, muab tub lim ntau npaum li cas, hydraulic retention time (HRT), nitrification ratio, nitrification thiab kub. ntev -lub sij hawm nitrogen thiab phosphorus tshem tawm kev ua tau zoo ntawm AM-MBBR txheej txheem thiab denitrifying phosphorus tshem tawm efficiency hauv lub tank anoxic. Nyob rau tib lub sijhawm, kev ua tiav ntawm cov zej zog microbial thiab kev hloov cov cai ntawm kev ua haujlwm microbial cov zej zog hauv cov activated sludge thiab biofilm tau kawm.

1 Cov ntaub ntawv thiab cov txheej txheem

1.1 Kev sim ntsuas thiab kev ua haujlwm tsis ua haujlwm

Ib qho txuas ntxiv -Flow AAO cov tshuaj tiv thaiv (Daim duab 1) tau siv hauv txoj kev tshawb no. Nws yog ua los ntawm cov iav organic, nrog rau tag nrho ntawm 7 qhov chaw, txhua qhov loj ntawm 10 cm × 10 cm × 40 cm; Lub ntim ua haujlwm yog 21 L, thiab qhov ntim piv ntawm txhua lub tank yog anaerobic: anoxic: aerobic=2: 2: 3. Mechanical stirring tau saws nyob rau hauv lub tank anaerobic thiab anoxic; lub aerobic tank siv aeration xuab zeb taub hau li micro- ntxeem tau aerators thiab sab nraud quab yuam rau sludge- dej sib tov, thiab tus nqi aeration yog tswj los ntawm ib tug gas flow meter. Lub DO concentration nyob rau hauv lub aerobic tank ntawm lub reactor yog tswj ntawm 2 ~ 3 mg / L; lub thib ob sedimentation tank yog ib lub tog raj kheej nrog ib tug ua hauj lwm ntim ntawm txog 40 L; sludge retention time (SRT) yog 40 d, thiab sludge reflux ratio yog 50%. Lub reactor ua haujlwm rau tag nrho ntawm 263 d ( faib ua 6 theem ua haujlwm), thiab cov khoom siv polyethylene tau ntxiv rau lub tank anoxic pib txij hnub 159 mus ua haujlwm hauv AM-AAO hom. Cov kev ua haujlwm tshwj xeeb tau qhia hauv Table 1.

(Daim duab 1 Schematic daim duab ntawm AM-AAO txheej txheem cov cuab yeej: Daim duab muaj xws li lub thoob dej nkag, peristaltic twj tso kua mis, anaerobic tank, anoxic tank, aerobic tank, sedimentation tank, dej qhov hluav taws xob thoob, nrog rau sab hauv reflux, sludge reflux pipelines)

Table 1 Txheej txheem hom thiab kev khiav hauj lwm tsis

1.2 Inoculated Sludge thiab Influent Water Quality

Lub inoculated sludge nyob rau hauv qhov kev sim no yog muab los ntawm cov sludge tshaj tawm los ntawm lub thib ob sedimentation tank ntawm ib tug khib nyiab kho nroj tsuag. Tom qab inoculation, sludge concentration (MLSS) nyob rau hauv lub reactor yog 2.3 g / L, thiab sludge volatile solids (MLVSS) yog 2.1 g / L.

Lub zog ntawm lub reactor yog cov dej phwj hauv tsev los ntawm cov khw noj mov, uas tau ntxiv rau lub reactor tom qab lim impurities los ntawm cov ntxaij lim dej. Nws cov pa phem suav nrog NH₄⁺-N (35.0456.54 mg/L), NO₂⁻-N (00.42 mg/L), NO₃⁻-N (00.05 mg/L), COD (362.1605.1 mg/L), thiab PO₄³⁻-P (1 ~ 5.08 mg/L).

1.3 Kev txheeb xyuas cov khoom thiab cov txheej txheem tshuaj xyuas

1.3.1 Cov txheej txheem tshawb nrhiav niaj hnub

Sludge-cov qauv dej tau sau los ntawm lub zog, lub tank anaerobic, anoxic tank, aerobic tank, sedimentation tank, thiab effluent, thiab lim nrog 0.45 μm lim ntawv. NH₄⁺-N tau txiav txim los ntawm Nessler's spectrophotometer; NO₂⁻-N tau txiav txim los ntawm N-(1-naphthyl) ethylenediamine photometry; NO₃⁻-N tau txiav txim los ntawm ultraviolet spectrophotometric; COD tau txiav txim los ntawm Lianhua 5B-3A COD multi-parameter ceev ntes; pH / DO thiab kub tau txiav txim los ntawm WTW Multi3620 ntes; MLSS tau txiav txim siab los ntawm txoj kev gravimetric; MLVSS tau txiav txim siab los ntawm muffle furnace combustion poob txoj kev [7].

1.3.2 Extraction thiab Detection ntawm Extracellular Polymeric Tshuaj

Extracellular polymeric substances (EPS) raug suav hais tias yog tsim los ntawm polysaccharides (PS), proteins (PN), thiab humic acids (HA). Peb hom EPS, uas yog soluble extracellular polymeric tshuaj (S-EPS), loosely bound extracellular polymeric substances (LB-EPS), thiab tightly bound extracellular polymeric tshuaj (TB-EPS), raug cais thiab muab rho tawm. Txoj kev txiav txim siab ntawm PS yog sulfuric acid-anthrone txoj kev, thiab txoj kev txiav txim siab ntawm PN thiab HA tau hloov kho Folin-Lowry method [7].

1.3.3 Kev suav txheej txheem ntawm cov pa phem tshem tawm tus nqi

Tus nqi tshem tawm cov pa phem (SRE) tau siv los ua tus yam ntxwv ntawm tag nrho cov pa phem tshem tawm ntawm AM-AAO txheej txheem txheej txheem. Ntawm lawv, Sinf thiab Seff yog cov pa phem ntau ntawm cov influent thiab effluent, ntsig txog, uas tuaj yeem sawv cev rau qhov muaj kuab paug loj xws li NH₄⁺-N, NO₂⁻-N, NO₃⁻-N, COD hauv ⁻, thiab P.O. Cov kua dej, mg / L.

1.3.4 Siab -Throughput Sequencing Method

Illumina siab -throughput sequencing method tau siv. Sludge cov qauv los ntawm lub tank anaerobic, anoxic tank, thiab aerobic tank hnub 1, 110, 194, thiab 237 tau sau thiab npe raws li pawg D01 (D01_A1, D01_A2, D01_O), pawg D110 (D110_A1, D110_9, D110_A2), (D194_A1, D194_A2, D194_O), thiab pawg D237 (D237_A1, D237_A2, D237_O), feem; biofilm sludge kuaj nyob rau hnub 194 thiab 237 tau sau thiab muab npe ua M194 thiab M237, raws li. Tag nrho ntawm 14 cov qauv sludge tau txheeb xyuas rau kev hloov pauv hauv cov zej zog microbial. DNA tau muab rho tawm siv Fast DNA SPIN cov khoom siv (MP Biomedicals, Santa Ana, CA, USA). Lub cheeb tsam V3-V4 ntawm cov kab mob 16S rRNA noob tau nthuav dav nrog 338F / 806R primers. Cov purified amplicons tau sequenced ntawm Illumina MiSeq PE300 platform (Illumina, USA) los ntawm Shanghai Majorbio Biomedical Technology Co., Ltd. (Shanghai, Tuam Tshoj) [7].

2 Cov txiaj ntsig thiab kev sib tham

2.1 Ntev-Lub Sijhawm Ua Phem Tshem Tawm Cov Cai hauv AAO thiab AM-AAO Cov Txheej Txheem

Lub sijhawm ntev - tshem tawm cov pa phem thaum lub sijhawm ua haujlwm ntawm qhov txuas ntxiv - ntws AAO txheej txheem (theem 13) thiab AM-AAO txheej txheem nrog tshem tawm polyethylene muab ntxiv (Theem 46) muaj nyob rau hauv daim duab 2.

Hauv Theem 1 (1 ~ 45 d), PO₄³⁻-P tso nyiaj (PRA) nyob rau hauv lub tank anaerobic, PO₄³⁻-P uptake npaum li cas hauv lub tank anoxic (PUAA), thiab PO₄³⁻-P uptake npaum li cas hauv lub aerobic tank (6.10.2 mg) mg, thiab 87.81 mg, raws li, thiab phosphorus uptake txheej txheem tau ua tiav hauv lub tank aerobic. Cov kev tshem tawm ntawm NH₄⁺-N thiab tag nrho cov inorganic nitrogen (TIN) yog 92.85% thiab 86.37%, feem, ua kom cov nyhuv denitrification. Tom qab zoo- kho qhov aeration (DO=2~ 3 mg/L), NH₄⁺{17}}N tshem tawm cov nyhuv tau nce mus rau 98.68%, thiab cov kua dej TIN concentration thiab tshem tawm tus nqi yog 1.75 mg / L thiab 95.75%, feem, raws li kev hloov kho ntawm DO yog qhov qhia txog kev kho kom haum rau DO. txheej txheem; COD tshem tawm cov nyhuv hauv lub tank anaerobic tsis muaj zog (91.60%). Tsis tas li ntawd, qhov nplua -tuning ntawm DO tsis muaj kev cuam tshuam rau PO₄³⁻{24}}P, nrog rau qhov nruab nrab ntawm 0.47 mg / L, uas yog raws li qhov xaus ntawm Yang Sijing li al. [8].

Hauv theem 2 (46 ~ 120 d), tom qab kho HRT=8 h, COD tshem tawm kev ua tau zoo hloov pauv me ntsis; qhov siab tshaj plaws ntawm PRA, PUAA, thiab PUAO mus txog 148.01 mg, 81.95 mg, thiab 114.15 mg, qhia tias qhov nce hauv cov dej ntws tsis cuam tshuam rau kev tshem tawm phosphorus, thiab tswj tau siab NH₄⁺ -N thiab TIN tshem tawm kev ua haujlwm. Hnub 72, cov nitrification kua reflux piv tau nce mus rau 300% thiab 400%. Qhov nce ntawm reflux piv txo TIN tshem tawm cov nyhuv, nrog rau kev tshem tawm ntawm 80.37% (300%) thiab 68.68% (400%), feem. Los ntawm hnub 108 txog 120, cov nitrification kua reflux piv tau txiav txim siab 250%. Cov nyiaj tshem tawm COD hauv lub tank anaerobic ntawm nitrification kua reflux piv ntawm 250% (127.1 mg / L) yog siab dua lossis sib npaug ntawm lwm tus (86.2 mg / L, 124.7 mg / L, thiab 128.0 mg / L rau 200%, 300%, thiab 400%, hwm); phosphorus effluent concentrations sib haum mus rau qhov sib txawv reflux piv yog 0.52 mg / L, 0.35 mg / L, thiab 0.06 mg / L, qhia tias nce nitrification kua reflux ratio nyob rau hauv ib tug tej yam ntau yam yuav txhawb nqa phosphorus tshem tawm. Tsis tas li ntawd, reflux piv ntawm 250% muaj kev ua tau zoo denitrification, nrog rau TIN tshem tawm tus nqi ntawm 86.86%.

Hauv Theem 3 (121 ~ 158 d), nitrification kua reflux piv tau kho ntawm 250%. Nyob rau hnub 131, lub zog ntws tau nce mus rau 5 L / h, COD thiab phosphorus tshem tawm cov teebmeem txo qis, thiab cov dej ntws tawm yog 73.3 mg / L thiab 3.92 mg / L, raws li qhia tau hais tias qhov nce hauv cov dej ntws tau ua rau COD ntau dua tsis tau kho. Tsis tas li ntawd, qhov kev tshem tawm siab tshaj plaws ntawm NH₄⁺-N thiab TIN yog 93.82% thiab 79.12%, feem, ntawm cov NO₃⁻-N tau los ua cov pa phem tseem ceeb hauv cov kua dej (4.70 mg/L). Nyob rau hnub 139, cov dej ntws tau raug txo mus rau 4 L / h, cov dej tawm COD thiab tshem tawm tus nqi yog 55.7 mg / L thiab 85.97%, feem, uas yog siab dua qhov kev tshem tawm cov pa roj carbon monoxide ntawm HRT=5.6 h, qhia tias qhov txo qis ntawm HRT yuav ua rau txo qis hauv COD tshem tawm. Tsis tas li ntawd, qhov kev tshem tawm siab tshaj plaws ntawm NH₄⁺-N thiab TIN yog 100% thiab 97.41%, qhia tias kev hloov kho HRT txhawb nqa nitrification thiab denitrification, tab sis luv luv HRT yuav ua rau txo qis denitrification nyhuv. Yog li ntawd, thaum HRT=7 h, nws yog txaus rau cov tshuaj tiv thaiv nyob rau hauv txhua lub tank mus rau tag nrho, thiab ib tug tseem ceeb nce nyob rau hauv HRT muaj me ntsis txhawb cov nyhuv ntawm denitrification.

Hnub 159, 20% tshem tawm polyethylene muab tso rau hauv lub tank anoxic ntawm cov txheej txheem AAO. Hauv Theem 4 (159 ~ 209 d), COD thiab PO₄³⁻-P tshem tawm kev ua tau zoo dua. Pib txij hnub tim 172, qhov muaj txiaj ntsig NH₄⁺-N concentration tau nce mus rau 64.17 mg / L (C / N{11}}), COD effluent thiab tshem tawm tus nqi yog 77.7 mg / L thiab 86.06%, feem. Yog vim li cas tej zaum yuav yog tias biofilm loj hlob qeeb, thiab cov activated sludge ua lub ntsiab pab rau kev tshem tawm ntawm feem ntau COD; cov tshuaj muab tshem tawm tau nce PO₄³⁻-P tshem tawm tus nqi los ntawm 1.18%. Txawm li cas los xij, qhov nce hauv NH₄⁺-N nyob rau hauv lub tank anoxic ua rau xav tau cov pa roj carbon ntau ntxiv rau cov txheej txheem denitrification ntawm NO₃⁻-N, uas tsis tsim nyog rau cov phosphorus tso tawm thiab txhawb nqa PAOs; Nyob rau tib lub sijhawm, qhov kev ua haujlwm no tsis tau txo qis NO₃⁻-N, thiab qhov tsawg kawg nkaus cov dej ntws tawm yog 7.30 mg / L. Hnub 185, hloov HRT mus rau 5.6 h, nws tau pom tias COD tshem tawm cov nyhuv hloov pauv me ntsis, nrog tus nqi tshem tawm ntawm 86.05%; PO₄³⁻-P concentration nce 0.05 mg/L, nrog rau kev nce hauv PUAA (los ntawm 13.02 mg rau 18.90 mg), qhia tias cov sludge thiab biofilm synergistically exerted ib co phosphorus tshem tawm efficiency. Tsis tas li ntawd, cov kua dej NH₄⁺-N, NO₃⁻-N, thiab TIN concentrations yog 10.23 mg/L, 6.52 mg/L, thiab 16.82 mg/L, raws li qhia tau hais tias qhov txo qis ntawm HRT yuav ua rau muaj kev txo qis ntawm HRT. NH₄⁺-N thiab TIN. Hnub 195, HRT raug kho rov qab mus rau 7 h, thiab lub sijhawm no, cov pa phem hauv cov kua dej tau txo qis, thiab kev tshem tawm nitrogen thiab phosphorus thiab cov organic teeb meem tshem tawm ntawm lub cev maj mam rov zoo.

Nyob rau theem 5 (210 ~ 240 d), NH₄⁺-N concentration tau nce mus rau 84.06 mg/L (C/N=6.28), thiab cov activated sludge tseem ua lub luag haujlwm tseem ceeb rau kev tshem tawm cov organic teeb meem. Qhov nce hauv NH₄⁺-N tau cuam tshuam me ntsis rau kev tshem tawm COD. Qhov feem ntawm COD absorbed nyob rau hauv lub tank anaerobic yog 68.02%, thiab feem ntau ntawm cov organic teeb meem yog absorbed los ntawm PAOs nyob rau hauv lub anaerobic tank thiab synthesized rau hauv cov pa roj carbon qhov chaw (PHAs), thiab anaerobic phosphorus tso tawm tag nrho [9]. Qhov siab tshaj plaws PRA yog 72.75 mg, thiab PUAA thiab PUAO yog 35.82 mg / L thiab 48.20 mg / L, raws li, tab sis qhov tseem ceeb ntawm phosphorus uptake tseem tuaj ntawm lub tank aerobic. Hnub 221, qhov sib piv tau nce mus rau 30%, thiab cov kua dej NH₄⁺-N thiab TIN concentrations raug txo los ntawm 4.49 mg / L thiab 5.16 mg / L, raws li; ntawm lawv, NH₄⁺-N thiab NO₃⁻-N suav txog 70.11% thiab 28.75% ntawm cov dej ntws tawm TIN, raws li. Hnub 231, NH₄⁺-N cov concentration tau hloov kho rau 66.34 mg/L, thiab cov pa phem tshem tawm ntawm lub cev tau ruaj khov.

Nyob rau theem 6 (241 ~ 263 d), qhov ntsuas kub ntawm lub tshuab hluav taws xob tau tswj xyuas los tshawb xyuas nws cov txiaj ntsig ntawm kev tshem tawm cov pa phem. Hnub 241, qhov kub tau txo mus rau 18 degree, COD tshem tawm tus nqi txo mus rau 84.37%, tab sis txoj cai hloov COD tsis hloov vim qhov kub thiab txias. Kev tshem tawm feem ntau hauv lub tank anaerobic yog qhov siab tshaj plaws, 62.02%, cov txheej txheem tshem tawm phosphorus denitrifying nyob rau hauv lub tank anoxic tau noj 26.72% ntawm COD, NO₃⁻-N concentration nyob rau hauv lub effluent ntawm lub aerobic tank yog 10.44 mg / L. NH₄⁺{13}}N tseem nyob; Tsis tas li ntawd, PRA tsis tshua muaj kev cuam tshuam los ntawm qhov kub thiab txias, tab sis phosphorus uptake kev ua tau zoo ntawm lub tank anoxic poob qis, nrog PUAA tsuas yog 19.77 mg, thiab phosphorus raug tshem tawm los ntawm 3.94 mg / L hauv lub tank aerobic. Feem ntau psychrophilic PAOs tau ua cov txheej txheem aerobic phosphorus uptake [10]. Thaum qhov kub thiab txias tau ntxiv mus rau 13 degree, qhov kev tshem tawm ntawm NH₄⁺-N thiab TIN poob los ntawm 6.38% thiab 6.25%, feem; Nyob rau tib lub sijhawm, PUAA thiab PUAO txo qis los ntawm 7.77 mg thiab 15.00 mg, feem, uas tej zaum yuav cuam tshuam nrog kev txo qis hauv microbial kev ua si thiab kev loj hlob thiab kev muaj peev xwm metabolism los ntawm qhov kub thiab txias. Jin Yu [11] pom tias thaum qhov kub thiab txias qis dua 14 degree, nws yog ib qho nyuaj rau lav qhov effluent pollutant concentration ntawm lub system.

(Daim duab 2 Kev tshem tawm cov pa phem hauv AAO thiab AM-AAO cov txheej txheem thaum lub sijhawm ua haujlwm ntev- lub sijhawm ua haujlwm: suav nrog (c) Curves ntawm NH₄⁺-N concentration thiab tshem tawm tus nqi hloov pauv nrog hnub ua haujlwm, (d) Curves ntawm NOₓ⁻-N concentration hloov nrog Curves hnub ua haujlwm, kab rov tav axis yog hnub ua haujlwm (0 ~ 260 d), thiab ntsug axes yog ρ (NH₄⁺-N)/(mg·L⁻¹), ρ (NO₃⁻-N)/(mg·L⁻¹), thiab tshem tawm tus nqi /%, raws li kev ua haujlwm.

2.2 Cov Cai Hloov Pauv Hloov Hauv Cov Cycles ntawm AAO thiab AM-AAO Cov Txheej Txheem

Txhawm rau tshawb fawb ntxiv txog kev tshem tawm cov pa phem ntawm AAO thiab AM- cov txheej txheem AAO, cov pa phem hloov pauv hauv cov voj voog ntawm cov haujlwm sib txawv tau txheeb xyuas, raws li pom hauv daim duab 3.

Nyob rau hnub 42 (Theem 1), cov txheej txheem AAO muaj qhov zoo denitrification thiab phosphorus tshem tawm kev ua haujlwm. Txawm li cas los xij, lub siab COD tsis txhim kho cov phosphorus tso tawm kev ua tau zoo, thiab PRA yog 9.13 mg / L nyob rau lub sijhawm no. Tsis tas li ntawd, NH₄⁺-N tau noj ua ntej thaum nkag mus rau hauv lub tank anoxic; ces, lub tank anoxic txo cov generated NO₃⁻-N rau N₂; Txawm li cas los xij, lub tank aerobic tsuas yog tshem tawm 3.52 mg / L ntawm NH₄⁺-N, uas tej zaum yuav yog vim HRT ntev nyob rau theem 1 ua rau muaj kev nce hauv DO rov qab mus rau lub tank anoxic, thiab feem ntau ntawm NH₄⁺-N tau ua tiav nitrification hauv lub tank anoxic concentration, ua rau lub tank qis dua.

Hnub 118 (Theem 2), nrog rau kev txo qis ntawm COD, cov phosphorus tso tawm thiab denitrification kev ua tau zoo tsis zoo. Cov phosphorus tso tawm concentration nyob rau hauv lub tank anaerobic yog 5.91 mg / L, thiab NO₃⁻-N concentration nyob rau hauv lub effluent ntawm lub aerobic tank yog 8.20 mg / L. Lub PO₄³⁻-P concentration hauv lub tank anoxic poob mus rau 2.78 mg/L, qhia tias PO₄³⁻-P tau raug tshem tawm hauv lub tank anoxic. Tsis tas li ntawd, nitrification kua reflux piv tau kho ntawm 250% lub sijhawm no. Piv nrog rau reflux ratios ntawm 300% thiab 400%, qhov kev tshem tawm nitrogen thiab phosphorus thiab organic teeb meem tshem tawm cov txheej txheem tau txhim kho, qhia tau hais tias ua kom cov nitrification kua reflux nyob rau hauv ib tug tej yam ntau yam yuav txhim khu cov pa phem tshem tawm cov nyhuv.

Hnub 207 (Theem 4), tom qab kho qhov muaj zog NH₄⁺-N thiab HRT hauv AM-AAO txheej txheem, COD tshem tawm tus nqi yog 86.15%; lub aerobic tank tshem tawm 13.34 mg/L ntawm NH₄⁺-N, qhov seem TIN concentration yog 7.51 mg/L, thiab 4.39 mg/L ntawm NO₃⁻-N tau tsim, thiab NO₃⁻-N tau los ua cov pa phem. Tsis muaj qhov sib txawv tseem ceeb hauv kev tshem tawm phosphorus pab cuam ntawm lub tank anoxic thiab aerobic tank. Tsis tas li ntawd, nce NH₄⁺-N tsis cuam tshuam rau cov nitrification, tab sis qhov nce hauv qhov muaj zog TIN concentration txo cov denitrification kev ua tau zoo ntawm AM-AAO txheej txheem, yog li cuam tshuam rau TIN tshem tawm.

Hnub 262 (Theem 6), qhov kub ntawm lub reactor yog 13 degree, thiab COD tshem tawm tus nqi yog 83.67% nyob rau lub sijhawm no. Nyob rau tib lub sijhawm, 6.95 mg / L ntawm phosphorus raug tso tawm hauv lub tank anaerobic; 20.22 mg/L ntawm NH₄⁺-N tau noj los ntawm lub tank anoxic thiab denitrification tau ua, thiab NO₃⁻-N concentration nyob rau hauv cov effluent ntawm lub tank anoxic yog 5.07 mg/L; lub tank aerobic muaj TIN poob ntawm 1.32 mg / L; TIN tshem tawm tus nqi yog 77.00%, thiab cov kua dej TIN muaj 11.24 mg / L ntawm NH₄⁺-N, qhia tias qhov kub thiab txias txo qhov kev ua ntawm cov kab mob nitrifying thiab denitrifying cov kab mob, ua rau kev tshem tawm tsis tiav ntawm cov pa phem hauv cov dej phwj tuaj. Tsis tas li ntawd, PRA txo qis mus rau 6.95 mg / L, thiab phosphorus uptake ua yeeb yam ntawm lub tank anoxic thiab aerobic tank txo mus rau 2.41 mg / L thiab 3.61 mg / L, raws li qhia tau hais tias qhov txo qis hauv reactor kub inhibited phosphorus tshem tawm kev ua haujlwm ntawm PAOs, ua rau lub tank siab thiab txo qis. phosphorus concentration.

(Daim duab 3 Cov kev hloov pauv tsis huv hauv cov voj voog ib txwm muaj: suav nrog (a) Hnub 42 ntawm AAO txheej txheem, (b) Hnub 118 ntawm txheej txheem AAO, (c) Hnub 207 ntawm AM-AAO txheej txheem, (d) Cov pa phem hloov pauv nkhaus nyob rau hnub 262 ntawm AM- txheej txheem AAO tal. Cov txheej txheem axis yog cov txheej txheem axis. (mg/L) ntawm txhua cov pa phem (COD, NH₄⁺-N, NO₃⁻-N, PO₄³⁻-P))

2.3 Kev hloov pauv hauv Cov Txheej Txheem thiab Cov Ntsiab Lus ntawm Cov Khoom Siv Hluav Taws Xob Extracellular Polymeric (EPS) hauv AAO thiab AM-AAO Cov Txheej Txheem

Thaum lub sijhawm sim, cov kev hloov pauv hauv cov ntsiab lus thiab cov ntsiab lus ntawm EPS hnub 101 (AAO txheej txheem) thiab hnub 255 (AM-AAO txheej txheem) tau txiav txim siab thiab tshuaj xyuas, raws li pom hauv daim duab 4. Zuag qhia tag nrho, tag nrho EPS cov ntsiab lus nyob rau hnub 101 thiab 255 tuaj yeem raug ntaus nqi los ntawm kev nce hauv TB-EPS cov ntsiab lus tseem ceeb, thiab TB-EPS; Nyob rau hnub 101, tag nrho cov ntsiab lus EPS hauv lub tank anaerobic, anoxic tank, thiab aerobic tank pom qhov nce ntxiv (0.12 mg / gVSS, 0.29 mg / gVSS, thiab 0.37 mg / gVSS, ntsig txog); ntawm lawv, cov ntsiab lus EPS tau nce ntau heev thaum lub sij hawm nitrification, uas tej zaum yuav yog vim muaj cov metabolism hauv cov kab mob hauv lub cev thaum lub cev ua haujlwm nyob rau hauv cov pa roj carbon siab -rau-nitrogen piv (C / N=5.9) cov xwm txheej [12]. Txawm li cas los xij, TB-EPS ua lub luag haujlwm zoo hauv kev tsim cov sludge flocs, thaum S-EPS thiab LB-EPS muaj qhov tsis zoo [8]; Hauv qhov kev sim no, cov ntsiab lus ntawm S-EPS thiab LB-EPS tau qis, uas tsim cov xwm txheej rau kev loj hlob sludge; nyob rau hauv tas li - ntws sludge- zaj duab xis hybrid system, lub luag hauj lwm ntawm flocculent sludge yog irreplaceable [2].

Tsis tas li ntawd, cov kev hloov pauv ntawm PN / PS nyob rau hauv cov txheej txheem sib txawv ntawm cov sludge nyob rau hauv txhua lub tank cov tshuaj tiv thaiv sib txawv. Lub PN nyob rau hauv txhua lub tank yog ib txwm siab dua PS. Hnub 101, PN/PS ratios nyob rau hauv S-EPS, LB-EPS, thiab TB-EPS ntawm cov sludge yog 0.06, 1.62, thiab 2.67, raws li, thaum nyob rau hnub 255, lawv yog 0.03, 1.27 qhov piv txwv, thiab nce PN 3. los ntawm txheej txheej mus rau sab hauv ntawm sludge cell. Txawm li cas los xij, thaum lub reactor kub tau txo mus rau 13 degree, tag nrho EPS cov ntsiab lus nyob rau hauv peb lub tso tsheb hlau luam pom ib qho kev nce ntxiv (0.28 mg / gVSS, 0.41 mg / gVSS, thiab 0.63 mg / gVSS, feem). Qhov laj thawj yog vim li cas cov kab mob tsis tuaj yeem hloov mus rau qhov kub tsis tshua muaj neeg tuag los yog autolyzed, thiab cov kab mob tuag no tso tawm EPS, ua rau muaj kev nce hauv EPS cov ntsiab lus ntawm sludge, los yog kub qis induced qee cov kab mob psychrophilic kom zais ntau EPS kom hloov mus rau qhov kub thiab txias hauv reactor [13].

(Daim duab 4 Kev hloov pauv hauv EPS cov ntsiab lus thiab muaj pes tsawg leeg ntawm Hnub 101 (AAO txheej txheem) thiab Hnub 255 (AM-AAO txheej txheem): Sab laug yog txheej txheem AAO, thiab sab xis yog AM-AAO txheej txheem. Cov kab rov tav yog lub tank cov tshuaj tiv thaiv (kawg ntawm anaerobic, kawg ntawm anoxerobic, LAB type, thiab kawg ntawm TB). sab laug ntsug axis yog EPS cov ntsiab lus (mg·gVSS⁻¹), thiab txoj cai ntsug axis yog PN/PS piv Nws suav nrog histograms ntawm PN, PS, thiab tag nrho EPS cov ntsiab lus thiab kab ntawv ntawm PN / PS piv).

2.4 Microbial Diversity thiab Population Dynamic Community Succession Rules

Cov txiaj ntsig siab -throughput sequencing tau pom tias tus lej ntawm 14 cov qauv sludge yog 1,027,419, thiab tus naj npawb ntawm OTU sequences ntawm txhua tus qauv yog qhia nyob rau hauv Table 2. Cov kev pab them nqi ntawm cov qauv yog siab tshaj 0.995, qhia tau hais tias cov sequencing tau muaj siab. Pab pawg D01 tau piav qhia txog cov qauv hauv zej zog pib microbial, nrog rau qhov siab Ace Performance index, qhia tias cov sludge muaj cov kab mob microbial siab thaum pib- nce ntawm lub cev. Nrog rau kev hloov pauv ntawm lub kaw lus los ntawm AAO mus rau AM-AAO txheej txheem, Ace Performance index poob qis, thiab kev nplua nuj ntawm cov zej zog microbial hauv AM-AAO system poob qis. Tsis tas li ntawd, Simpson Performance index poob qis, qhia tias kev sib txawv ntawm cov zej zog microbial txo. Raws li qhov kev hloov pauv ntawm Ace Performance index, tag nrho cov tsiaj nyob rau hauv lub zej zog microbial ntawm anoxic tank biofilm pom ib qho kev poob qis; Qhov kev txo qis ntawm Shannon Performance index tau ua pov thawj tias ntau haiv neeg ntawm microbial zej zog hauv biofilm txo qis.

Table 2 Variation of microbial diversity index

The main phyla with relative abundance >10% ntawm 14 cov qauv tau txheeb xyuas (Daim duab 5a). Qhov tseem ceeb phyla hauv pawg D01 yog Actinobacteriota (25.76%32.90%), Proteobacteria (21.98%)27.16%), Bacteroidota (15.50%)18.36%), thiab Firmicutes (10.37%)13.77%); Txawm li cas los xij, cov txheeb ze ntau ntawm Actinobacteriota (16.89%19.16%) thiab Firmicutes (3.83%)6.52%) hauv pawg D110 poob qis, thiab cov txheeb ze ntawm Proteobacteria ntau ntxiv (32.96% ~ 40.75%). Hauv AM-AAO txheej txheem txheej txheem, Actinobacteriota poob sai, txawm tias tsawg dua 3% hauv pawg D237, thaum Proteobacteria (33.72%43.54%), Bacteroidota (17.40%)24.19%), and Chloroflexi (12.46%~12.77%) have become the phyla with relatively high abundances. In addition, in sample M194, the phyla with relative abundance >10% yog Proteobacteria (35.26%) thiab Bacteroidota (30.61%), qhia tias lub zej zog microbial qauv ntawm biofilm zoo ib yam li cov activated sludge. Hauv cov qauv M237, cov txheeb ze ntau ntawm Firmicutes poob qis dua 2%, thiab qhov ntau ntawm Acidobacteriota (5.33%) tau nce.

By creating a heat map (Figure 5b), the 14 samples were compared at the genus level (relative abundance >3%). Nws tau pom tias cov genera tseem ceeb hauv pawg D01 yog Candidatus_Microthrix (11.32%20.65%), norank_f__norank_o__norank_c__SJA-28 (3.97%6.36%), Trichococcus (6.99%)9.95%), thiab Ornithinibacter (3.99%)6.41%); tom qab lub kaw lus tau ua haujlwm hauv AM-AAO txheej txheem, qhov txheeb ze ntawm Candidatus_Microthrix poob qis rau 0.02% (paub pawg D237); thaum norank_f__norank_o__norank_c__SJA-28 pom qhov sib txawv ntawm thawj qhov nce thiab tom qab ntawd txo qis (pawg D237, 1.91%2.91%). Thaum cov txheej txheem tau ua haujlwm ruaj khov, Azospira tau los ua ib qho ntawm cov tseem ceeb tshaj plaws (pawg D237, 7.37%18.41%). Tsis tas li ntawd, cov biofilm genera yeej zoo ib yam li cov sludge, thiab cov txheeb ze ntawm norank_f__norank_o__Run-SP154 hauv M194 thiab M237 yog 6.61% ~ 7.66% thiab 7.43%, feem.

Tag nrho ntawm 12 genera thiab 1 tsev neeg ntawm ammonia- cov kab mob oxidizing (AOB), nitrite- cov kab mob oxidizing (NOB), glycogen- cov kab mob sib sau (GAOs), thiab phosphorus- cov kab mob sib sau (PAOs) hauv qhov system tau xaiv 3 qhov kev tshuaj xyuas). Nws tau pom tias hauv pawg D01, Nitrosomonas (0.02%0.03%), Ellin6067 (0.01%)0.02%) thiab Nitrospira (0.04%)0.07%) tuaj yeem ua kom muaj kev ua haujlwm oxidation ntawm NH₄⁺-N. Qhov txo qis ntawm Nitrosomonas thiab Nitrospira hauv pab pawg D110 tuaj yeem tshwm sim los ntawm qhov sib piv ntawm sab hauv siab, tab sis Ellin6067 (0.01%0.02%) tsis cuam tshuam. Hauv pab pawg D194, lub kaw lus tau ua haujlwm hauv AM-AAO txheej txheem, thiab kev txo qis ntawm HRT tau ntxuav tawm NOB thiab qee qhov AOB. Qhov kev nce hauv qhov muaj zog ammonia nitrogen tuaj yeem yog vim li cas rau qhov nce ntawm cov txheeb ze ntau ntawm cov saum toj no peb genera hauv pawg D237 (Daim duab 5b). Ntxiv rau, AOB (Nitrosomonas thiab Ellin6067, 0.03%0.07%) thiab NOB (Nitrospira, 0.01%0.02%) hauv cov qauv M237 pom qhov nce me ntsis, qhia tias biofilm pab cov sludge system kom ua tiav cov txheej txheem denitrification.

Muaj ntau hom PAOs hauv pawg D01, suav nrog Acinetobacter, Candidatus_Accumulibacter, Candidatus_Microthrix, Defluviimonas, Pseudomonas, thiab Tetrasphaera. Kev hloov pauv ntawm Candidatus_Microthrix (10.93% ~ 11.88%) thiab PAOs nrog cov txheeb ze ntau<5% in group D110 may be the reasons for the decrease of PRA in Stage 2. In group D194, the relative abundances of Candidatus_Microthrix and Tetrasphaera decreased to 0.711.14 thiab 0.31%0.39% [14]. Hauv pab pawg D237, Candidatus_Microthrix yuav luag raug tshem tawm (0.02%), thiab PAOs uas hloov nws mus rau kev tshem tawm phosphorus muaj nuj nqi yog Defluviimonas (0.70%1.07%) thiab Dechloromonas (0.95%)1.06%); Tsis tas li ntawd, tsev neeg Comamonadaceae kuj tau lees paub tias muaj phosphorus tshem tawm kev ua tau zoo [8], thiab cov txheeb ze ntawm Comamonadaceae nyob rau hauv lub tank anaerobic lossis anoxic tank yog qhov siab, txog ob npaug ntawm lub tank aerobic. Tsis tas li ntawd, Candidatus_Competibacter thiab Defluviicoccus yog cov genera tseem ceeb ntawm GAOs nyob rau hauv tag nrho cov qauv, tab sis cov abundance ntawm ob genera nyob rau hauv pawg D01 yog.<1%. In the remaining samples, the growth of Defluviicoccus lagged behind that of Candidatus_Competibacter. In group D237, the abundances of the two genera were 2.96%~3.89% and 0.54%~0.57%, respectively. GAOs are considered to compete with PAOs for organic matter, thereby causing the deterioration of biological phosphorus removal performance, but recent studies have found that GAOs can carry out endogenous denitrification to achieve denitrification (the average TIN removal rate was 83.08% when the system was stable) [7].

(Daim duab 5 Microbial zej zog muaj pes tsawg leeg: (a) Bar chart of txheeb ze abundance ntawm phylum theem. Kab rov tav axis yog cov qauv, thiab ntsug axis yog cov txheeb ze abundance/%. axis yog qhov tseem ceeb genera Qhov tob ntawm cov xim qhia txog qib ntawm cov txheeb ze abundance.

Table 3 Muaj ntau pab pawg ua haujlwm hauv 14 cov qauv tshuaj lom neeg

3 Cov lus xaus

Siv cov dej phwj tuaj tiag tiag raws li cov khoom siv kho mob, kev ua haujlwm ntawm AM-AAO txheej txheem tau ua kom zoo dua. Nws tau pom tias thaum cov txheej txheem ua haujlwm nyob rau hauv cov xwm txheej ntawm HRT=7 h, kub txog 25 degree, sab hauv reflux=250%, SRT=40 d, sludge reflux=50}%, thiab anoxic tank filling tus nqi =30%, cov pa phem tshem tawm yog qhov zoo tshaj plaws. Qhov siab tshaj plaws NH₄⁺-N tshem tawm tus nqi yog 98.57%; NO₃⁻-N concentration, PO₄³⁻-P concentration, TIN tshem tawm tus nqi, thiab COD tshem tawm tus nqi yog 6.64 mg / L, 0.42 mg / L, 83.08%, thiab 86.16%, feem.

Lub tank anaerobic ua tau zoo cov organic tshem tawm thiab cov txheej txheem tso tawm phosphorus, nrog 64.51% ntawm COD tshem tawm thiab 9.77 mg / L ntawm phosphorus tso tawm tib lub sijhawm; lub tank anoxic ua tau zoo denitrifying phosphorus tshem tawm cov tshuaj tiv thaiv; lub tank aerobic tau ua tiav cov txheej txheem nitrification thiab phosphorus uptake, nrog rau NH₄⁺-N tshem tawm tus nqi thiab PUAO yog 97.85% thiab 59.12 mg, raws li.

Thaum cov txheej txheem AM-AAO tau ua haujlwm ruaj khov, qhov nce ntawm AOB (Ellin6067 thiab Nitrosomonas, 0.02% ~ 0.04% → 0.04%0.12%) thiab NOB (Nitrospira, 00.01% → 0.02%0.04%) tau ua kom muaj kev vam meej txaus ntawm nitrification, thiab NH₄⁺-N tshem tawm tus nqi nce 8.35%; GAOs (Candidatus_Competibacter thiab Defluviicoccus, 1.31%1.61% → 3.49%4.46%) dominated cov txheej txheem endogenous denitrification; kev loj hlob ntawm PAOs (Defluviimonas, Dechloromonas, thiab Comamonadaceae tsev neeg, 3.29%8.67% → 3.79% ~ 9.35%) yog vim li cas rau kev tswj kom zoo phosphorus tshem tawm kev ua haujlwm; Nyob rau hauv tas li ntawd, lub microbial zej zog qauv ntawm lub anoxic tank biofilm yog yeej zoo ib yam li cov activated sludge, uas sib koom guaranteed nitrogen thiab phosphorus tshem tawm kev ua tau zoo ntawm lub system.