Cng ngh x l nc thi

1. Mt s nguyn nhn nh hng ti qu trnh vn hnh cng trnh x l sinh hc v cch khc phc.

1.1. Bn lng km:

- Ni ln b mt: kh nitrat sinh ra N2 ,thiu dinh dng, xut hin vi khun

filamentous, hoc d dinh dng bn cht ni trn b mt.

- Sinh khi pht trin tn mn: do ti lng hu c cao hoc qu thp, d oxi, nhim c

- Sinh khi ng kt: thiu oxi, thiu dinh hng, cht hu c d phn hy sinh hc.

1.2. Oxi ha tan

- Ph thuc vo ti lng hu c v hm lng sinh khi. DO thch hp: 1- 2 mgO2l.

- Thiu oxy s lm gim hiu qu x l, xu hin vi khun hnh que, nm, gim kh nng lng v c ch qu trinh nitrat ha.

- BOD sau x l qu cao do: qu ti, thiu oxi, pH thay i, khuy trn km.

- N sau x l cn qu cao: cng ngh cha n nh, c s hin din cc hp cht N kh

phn hy, sinh khi bn trong b cao, nhim c, vi khun cht.

- N- NH3 cao do: pH khng thch hp (>6,5 hoc gim chi ph u t ban u . Ch hot ng c th thay i theo nc u vo nn rt linh ng.

Nhc im:

+ kim sot qu trnh rt kh, i hi h thng quan trc cc ch tiu tinh vi

+ do c nhiu phng tin iu khin hin i nn vic bo tr bo dng cng tr nn kh khn

+ c kh nng nc giai on x ra cun theo bng bn nh, kh lng v vng ni.

+ do c im l khng rt bn ra nn h thng thi kh d b nght.

+ nu cc cng trnh pha sau chu sc ti thp th phi c b iu ha ph tr.

4. B Methan : y l cng trnh x l cn hiu qu nht.

Thi gian ln men ngn t 6-20 ngy, th tch ngn bn nh.

Cc loi cn dn n b

Cn ti t b lng 1

Bn hot tnh d trn mng vi sinh.

Rc nghin

Cn c hm nng v xo trn to iu kin ti u cho qu trnh ln men.

Khi b lng lm vic bnh thng:

pH t 7-7.5

hm lng acid bo : 3-8 mg/l

kim 60-70 mg/l

nit ca kh amoni:600-800 mg/l

Cng qu trnh ln men ph thuc vo nhit , lng cn mc xo trn

5. B nn bn:

B nn bn c nhim v lm gim m ca bn.

B nn bn thng thit k dng trn ng.

Lng cn bao gm:

Cn x l sinh hc(d)

Cn x l ban u (SS)

Cn keo t phn

Nguyn l hot ng:

Dung dch cn long i vo bung phn phi t tm b, nc c thu bng mng vng quanh chu vi b a tr li khu x l.

Trong b t my gt cn y b v h thu trung tm.

to khe h cho nc chuyn ng ln trn mt, trn tay n ca my co cn gn cc thanh dc, khi my co chuyn ng quanh trc, h thanh dc ny khuy nh khi cn, nc tro ln trn lm cn c hn.

u im: n gin, r tin

S dng x l s b bn

Hiu sut kh cao, nht l vi bn hon ton ca b lng 1

6. Cc phng php x l Nito, Phospho

Kt hp x l Pht pho v Nit trong nc thi bng phng php sinh hc Mt trong nhng qu trnh x l bng phng php sinh hc ang c pht trin l kt hp x l c nit v photpho. Bng cch s dng bn hot tnh, cc hp cht trong cc qu trnh x l thiu kh (anoxic), x l hiu kh (aerobic), x l ym kh (anaerobic) kt hp hoc ring bit thc hin qu trnh kh nit v photpho. Ban u qu trnh ny c pht trin kh Photpho, sau l kt hp kh c nit v photpho. Cc cng ngh c s dng thng dng nht l:

Quy trnh A2/O

Quy trnh Bardenpho (5 bc)

Quy trnh UCT

Quy trnh VIP

K thut x l m k tip cng c kh nng kt hp kh Nit v Phtpho

1.4 Quy trnh A/O

y l cng ngh x l sinh hc gm hai bc k kh v hiu kh (Anaerobic/Oxic). Qu trnh ny rt ging vi qu trnh x l bn hot tnh truyn thng. Nc thi a vo bc k kh sau c dn tip sang bc hiu kh. Mt khc vic kt hp x l k kh v x l hiu kh rt hu hiu cho qu trnh kh photpho v cc cht hu c trong nc thi. Bn sau b lng th cp mt phn c tun hon li nhm nng cao hiu sut kh photpho. Nh vy qu trnh A/O rt thch hp x l nc thi c hm lng cht hu c v photpho cao, tuy nhin i vi nc thi c cha hm lng Nit cao th qu trnh ny x l khng trit . H thng ny c m t s lt nh sau:

Hnh 1: quy trnh A/O

1.5 Quy trnh A2/O

Quy trnh ny c ci tin t quy trnh A/O v b sung thm vng cp oxi kh nitrat. Giai on lu trong qu trnh thiu kh xp x mt gi. Ti vng anoxic (thiu oxy), vi sinh vt ly oxi t nitrat (NO3-) v nitrit (NO22-), lng nitrat v nitrit c b sung bi hn hp nc thi tun hon t sau vng aerobic. Hm lng phtpho tp trung trong nc nc thi nh hn 2mg/l l c th chp nhn c vi nc thi khng c cng on lc, v nh hn 1.5mg/l vi nc thi sau lc.

Hnh 2. Quy trnh A2/O

1.6 Quy trnh Bardenpho (5 giai on)

T b Bardenpho 4 giai on x l Nit, b sung thm 1 giai on kt hp kh c nit v photpho. Thm giai on th 5 l qu trnh ym kh anarobic kh photpho ln u tin ca quy trnh kt hp kh nit, photpho. S sp xp cc giai on v cch tun hon hn hp nc thi sau cc vng cng khc nhau v khc quy trnh x l A2/O. H thng 5 bc cung cp cc vng anaerobic, anoxic, aerobic kh c Nit, Photpho v hp cht hu c. Vng Anoxic (giai on 2) kh nitrat v c b sung nitrat t b aerobic (giai on 3). B aerobic cui cng tch kh N2 ra khi nc v gim hm lng Photpho xung ti a. Thi gian x l ko di hn quy trnh A2/O. Tng thi gian lu nc l 10-40ngy, tng sinh khi ca vi sinh vt

Hnh 3. Quy trnh Bardenpho (5 giai on)

1.7 Quy trnh UCT

c sng to ti trng i hc Cape Town, ging quy trinh A2/O nhng c 2 s khc bit. Th nht, bn hot tnh c tun hon n b Anoxic thay v b anaerobic. Th hai, xut hin vng tun hon t b anoxic n anaerobic. Bn hot tnh n b anoxic, hm lng nitrat trong b anaerobic s b loi b, theo ta tch c photpho trong b anaerobic. Bn cht ca vng tun hon gia cc b l cung cp hp cht hu c n b anaerobic. Hp cht t b anoxic bao gm cc hp cht hu c ha tan (BOD) nhng hm lng nitrat rt t, to iu kin tt nht ln men k kh trong b anaerobic. Vo nm 1989, cha c nh my no ti M s dng qu trnh ny.

Hnh 4. Quy trnh UCT

7. Cc phng php x l hiu kh

7.1. Mng oxi ha

Mng oxy ha l mt dng ci tin ca aerotank khuy trn hon chnh lm vic vi iu kin hi kh ko di vi bn hot tnh. (sinh trng l lng ca vi sinh vt trong nc thi) chuyn ng tun hon trong mng.Thng s dng vi nc thi c nhim cao BOD20=1000-5000 mg/l

Cng ngh ny da trn s pht trin sinh hc dng l lng gi l bn hot tnh duy tr trong mi trng giu oxy. S pht trin sinh hc ny rt nhanh gip ph hy cht hu c c trong nc thi u vo. S ph hy cc cht hu c bng bn hot tnh gy ra khi lng t bo cht ln, lm tng khi lng cht rn bn hot tnh.

Nc thi sau khi lu ti mng oxy ha khong 24h, hn hp gm nc thi v bn hot tnh thng c gi l cht lng hn hp c chuyn ti b lng bc hai phn tch khi nc thi u ra qua x l v bn kt. Mt phn bn thi ny c ti tun hon n u dn nc thi vo b mng oxy ha v tr li thnh bn hot tnh, ph hy thm ti lng BOD5hu c.

Phn cn li ca bn lng ny c thi ra mt quy trnh lm snh ri n cng on tho nc trong qu trnh a bn thi cn li ra khi cng trng nh my. im khc ca quy trnh x l oxy ha l khng i hi b lng bc 1. Nc thi tho u vo c th c dn thng n cc b mng oxy ha x l.S quy trnh cng ngh:

Nc t trm bm B tip nhn Li chn rc B sc kh lin tc (B phn ng) B lng cui B kh trng X.

Bn t b sc kh lin tc (b phn ng) + b lng th cp B cha bn thi My tch nc Sn cha bn Bi chn lp.

Mt phn bn ca b lng 2 s c tun hon tr li b sc kh lin tc tng hiu sut kh BOD cho b.

Do mng oxy ha c hiu qu x l BOD5, Nit, photpho cao, qun l n gin, th tch ln, t b nh hng bi s dao ng ln v cht lng v lu lng ca nc x l. Nn c p dng x l nc thi nhng ni ngoi vic x l BOD cn cn phi x l Nit v photpho v c bin dao ng ln v lu lng v cht lng gia cc gi trong ngy.

Tuy nhin mng oxy ha i hi din tch ln nn ch thch hp nhng ni t rng.u im: Chi ph u t kinh ph xy dng cng trnh thp, chi ph vn hnh rt r, kh trit BOD, N, P, din tch xy dng nhnc thi sau x l t ct A quy chun BTNMT ban hnh.

Nhc im: ch ph hp vi cc h thngx l nc thic lu lng trn 3000m3/ngy.

Cc yu t nh hng n cc cng trnh x l nc thi sinh hc hiu kh:

- Qu trnh x l hiu kh chu nh hng nng bn hot tnh, tc ph thuc vo ch s b. Ch s bn cng nh th nng bn cho vo cng trnh x l cng ln hoc ngc li.

- Nng oxy cng nh hng mnh m n qu trnh ny. Khi tin hnh qu trnh phi cung cp y lng oxy vo lin tc sao cho lng oxy ha tan trong nc ra khi b lng t II >= 2 (mg/l).

- Khc vi qu trnh k kh, ti trng hu c trong x l hiu kh thng thp hn nn nng cc cht bn hu c nc thi qua Aerotank c BOD ton phn phi =< 1000 (mg/l), cn trong b lc sinh hc th BOD ton phn ca nc thi = 9 v lc ny s ph hy cn bng nguyn sinh cht t bo lm cho vi sinh vt cht v pH < 4 s thc y nm pht trin. Thng thng pH ti u cho vi sinh vt pht trin tt nht trong khong 6,5 7,5.

- Nhit : cng l yu t quan trng i vi s pht trin ca vi sinh vt. Nc thi c nhit thch nghi vi a s vi sinh vt ti u t 25oC 37oC hoc t 20 - 80 oC hoc t 20 40oC ( ti u 25oC 37oC).

- Ngoi ra qu trnh x l hiu kh cn ph thuc vo nng mui v c, lng cht l lng chy vo b x l cng nh cc loi vi sinh vt v cu trc cc cht bn hu c.7.2. Biophin: b lc sinh hc nh git

Biophin l mt cng trnh nhn to trong nc thi c lc qua lp vt liu lc rn c bao bc lp mng vi sinh vt. Hot ng da trn nguyn l x l sinh hc sinh trng dnh bm hiu kh

Biophin bao gm b phn chnh sau: phn cha vt liu lc, h thng phn phi nc trn ton b b mt h thng thu v dn nc sau khi lc, h thng dn v phn phi kh cho b lc.

Cu to: c vt liu tip xc khng ngp nc.

Cc lp vt liu c rng v din tch ln nht (nu c th).

Nc thi c phn phi u.

Nc thi sau khi tip xc VL to thnh cc ht nh chy thnh mng nh lung qua khe h VL lc.

b mt VL lc v cc khe h gia chng cc cn bn c gi li to thnh mng _ Mng sinh hc.

Lng oxy cn thit cp lm oxy ho cht bn i t y ln.

Nhng mng VS cht s cng nc thi ra khi b c gi b lng 2

7.3. u im:

- Rt ngn c thi gian x l

- ng thi c th x l hiu qu nc thi qua qu trnh kh Nitrat hoc phn nitrat ha.

- Gim vic trng coi.

- Tit kim nng lng, khng kh c cp trong hu ht thi gian lc lm vic bng cch lu thng t nhin t ca thng gi i vo qua lp vt liu.

7.4. Nhc im:

Hiu sut lm sch nh hn cng vi mt ti lng khi

Rt nhy cm vi nhit

Khng khng ch tt qu trnh sc kh rt d sinh ra mi.

Chiu cao hn ch

Bn d khng n nh

Khi lng vt liu tng i nng v gi thnh cao.

D b tc nghn.

8. xut cng ngh:

8.1. Nc thi m in:

Nc thi t qu trnh xi m c thnh phn a dng v nng v pH bin i rng t 2 3 n 10 11.

c trng chung ca nc thi ngnh xi m l cha hm lng cao cc mui v c v kim loi nng. Tu theo kim loi ca lp m m ngun nhim c th l Cu, Zn, Cr, Ni, v cng tu thuc vo loi mui kim loi c s dng m nc thi c cha cc c t nh xianua, sunfat, amoni, crmat, Cc cht hu c t c trong nc thi xi m, phn ch yu l cht to bng, cht hot ng b mt nn BOD, COD thng thp v khng thuc i tng x l. i tng x l chnh l cc ion v c m c bit l cc mui kim loi nng nh Cr, Ni, Cu, Fe, STTThng sn vGi trQCVN 40:2011/BTNMT

Loi B ( Cmax)

1Lu lng dng thim3/ngy30--

2Lu lng ngun tip nhnm3/s40--

3pH-25,5-95,5-9

4SSMg/l200100108

5CuMg/l1.522,16

6NiMg/l300.50,54

7ZnMg/l1033,24

8Du m khongMg/l301010,8

9ColiformMPN/100ml050005000

Theo ta c:

Kq= 0,9 da vo Q ngun tip nhnKf=1,2 da vo Q ngun thiCmax=C.Kq.Kf=C.0,9.1,2=C.1,08 xut cng ngh:

So snh vi QCVN 40:2011/BTNMT theo tiu chun Loi B ta thy cc thng s cn x l l: pH, SS, Ni,Zn,du m khong.Vi pH ta dung b trung ha kt hp trong b iu ha ri chm NaOH vo nng pH ln.Vi SS=200mg/l>150 mg/l ta s dng Lng 1+ vt du m. kh c kim la ta dng chui b : b phn ng, b keo t to bng, b lng, kt hp keo t vi lng.

8.2. Nc thi sinh hot: (300 h)

X l nc thi sinh hotl x l lng nc qua s dng ca con ngi. c th l nc thi nh v sinh, tm git, nc t nh bp, ty ra c im ca nc thi sinh hot thng c th nhn thy bng cch chia lm hai loi:

- Nc thi sinh hot do cc cht thi sinh hot gy ra: Cc cht ra tri, v sinh sn nh v cn b t nh bp.

- Nc t cc nh v sinh: nc thi nhim bn do cht bi tit ca con ngi.

Cc ni pht sinh nc thi sinh hot nh: ta nh, khch sn, nh hng, trung tm thng mi, nh hay khu dn c. Cn phix l nc thisinh hottrc khi x thi trnh gy nhim mi trng.

Cc thnh phn nhim tng qut ca nc thi sinh hot ch yu c ngun gc hu c d phn hy sinh hc (60% hu c, 40% v c). Cc cht hu c trong nc thi sinh hot c tnh cht ha hc nh protein, hydrat carbon, cht bo, du m, Ure. Cc cht dinh dng nh nit v phtpho cng gy nhim nc (ph dng ha). Nit trong nc thi sinh hot tnh theo NTK (nito hu c v amoni) thng chim 15 20 BOD, khong 10 15g/ngi/ngy m. Photpho khong 4g/ngi/ngy m. Cc cht hot ng b mt nh ABS dng ty ra gy nn hin tng si bt trng b. Cc cht v c trong nc thi sinh hot nh: ct, t st, cc axit, baz v c, du khong Ngoi ra ngun nc thi sinh hot c cha mt lng ln vi khun tnh theo Coliform cng c tnh l thnh phn nhim. V vy, vicx l nc thi sinh hotl tht s cn thit.

V nc thi sinh hot ca 300 h dn > 50 h

Nn ta c K=1

Theo ta c:

Cmax=C.K=C.1=C

Vy nng bng vi QUY CHU N K THUT QUC GIA V NC THI SINH HOT (QCVN 14 : 2008/ BTNMT)

STTThng sn vGi trQCVN 14 : 2008/ BTNMT

Loi BCmax

1Lu lng dng thim3/ngy150--

2pH-6,85-95-9

3TSSMg/l200100100

4BOD5Mg/l2005050

5CODMg/l350--

6NO3-Mg/l1005050

7Du m TVMg/l1002020

8ColiformMPN/100ml700050005000

xut cng ngh:Cc thnh phn cn x l l: TSS, BOD5, COD, NO3-, DU M, COLIFORM.

Vi TSS ta dng lng 1.Du m s c tch ngay trong lng 1.

BOD5, COD, NO3- s c kh lng b sinh hc nh: aerotank,SBR, RBC, biophin, biofor.

Coliform ta s kh trng.

8.3. Nc thi dt nhum:

c trng ca nc thi dt nhum l: T l COD/BOD cao, nhit cao, tnh cht nc thi thay i lin tc theo gi, lu lng nc thi lun t bin, pH ca nc thi bin ng, cao hay thp ph thuc vo cng ngh nhum v thuc nhum, mu cao do lng thuc nhum d i vo nc, hm lng cht c Sunfit, kim loi nng, hp cht halogen h c trong thnh phn thuc nhum ln vo nc thi.

Thnh phn nc thi cng nghip dtrt a dng, bao gm cc cht nhim dng hu c thuc nhum, tinh bt, tp cht) v dng v c( cc mui trung tnh, cc cht tr nhum)..

STTThng sn vGi trQCVN 14 : 2008/ BTNMT

Loi BCmax

1Lu lng dng thim3/ngay1500-

2Lu lng tip nhnm3/s50-

3pH-7,85,5-95,5-9

4TSSMg/l25010090

5BOD5Mg/l3005045

6CODMg/l1500150135

7MuPt-Co800150135

8Du m TVMg/l554,5

9ColiformMPN/100ml1000--

Theo ta c:

Kq= 0,9 da vo Q ngun tip nhnKf=1 da vo Q ngun thiCmax=C.Kq.Kf=C.0,9.1=C.0,9 xut cng ngh:Cc thnh phn cn x l: TSS,DU, BOD5, COD, MU.

8.4. Nc thi y t:

Nc thi t phng khm: dch, mu, cc loi ha cht dng xt nghim, kh trng, ty ra, cc loi vaccin, du m ng thc vt, cc ph phm thuc, dung mi ha hc, d lng thuc khng sinh, cc kim loi nng, vi sinh vt gy bnh, nn cn phi x l trc khi thi ra ngoi mi trng.

- y l loi nc thi c nhiu cht hu c v cc vi trng gy bnh

- Nng BOD5, COD trong nc thi khng cao, rt thch hp cho qu trnh x l sinh hc kt hp vi mng lc MBR.

STTThng sn vGi trQCVN 14 : 2008/ BTNMT

Loi BCmax

1Lu lng dng thim3/ngay200-

2pH-6.86,5 8,56,5 8,5

3TSSMg/l75100100

4BOD5Mg/l2305050

5CODMg/l300100100

6NO3-Mg/l1505050

7Du m TVMg/l152020

8ColiformMPN/100ml2000050005000

V nc thi bnh vin vi 300 ging bnh

Nn ta c K=1

Theo ta c:

Cmax=C.K=C.1=C

xut cng ngh:Cc thnh phn cn x l: BOD5, COD, NO3-, COLIFORM.

SCR

Bi chn lp

SCR

Bi chn lp

SCR

Bi chn lp

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