do an xuli nuoc thai _dau dinh giao

8/7/2019 do an xuli nuoc thai _dau dinh giao

1/56

TRNG I HC CNG NGHIP TP. HCMVIN KHCN & QL MI TRNG

--------------- --------------

MN:

X L NC THI

Chuyn :

Tnh ton v thit k h thng xl nc thi nh my bia bng

phng php sinh hc lu lng2000 m3/ngy m.

GVHD: Th.S Nguyn Xun HonThnh vin nhm:

Trn Nguyn Thi Hng

Trn c TnHunh Xun VitLp: HMT 1

TP. HCM, Thng 4 nm 2008

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M U

1. Tnh cp thit ca ti:

Sn xut bia l ngnh ung nn trong qu trnh sn xut phi s dng rt

nhiu nc. Nguyn liu cho sn xut bia bao gm malt, go. Nguyn liu ny cnghin nh sau a vo ch bin dch ng. Trong qu trnh nu, nc c s

dng nhiu cho nu, cung cp cho l hi sn xut hi nc phc v cho cng ngh;

nc dng lm mt cc my mc thit b. Nc dng trong cc qu trnh sn xut

chuyn thnh sn phm hoc dng dng hi th hu nh khng b thi b hoc thi

rt t. Nc thi trong sn xut bia ch yu pht sinh t qu trnh ra, v sinh my mc

thit b v v sinh nh xng; ch yu tp trung cc khu vc ln men, lc bia v

chit sn phm. Vi c th ca sn xut bia i hi phi s dng lng nc ra v

v sinh kh ln. Thc t cho thy, c tnh chung ca nc thi trong sn xut bia l

cha nhiu cht gy nhim vi ch yu cc cht hu c ha tan v dng keo, cht

rn dng lng v l lng; mt s cht v c ha tan, hp cht nit v pht pho. Tt

c cc cht gy nhim c trong nc thi u t cc thnh phn nh b malt, cn

lng trong dch ng ln men, cc ht tr lc trong khu lc bia, xc men thi khi ra

thng ln men, bia tht thot cng nc thi trong khu chit v khu lm ngui chai

sau khi thanh trng. Nc thi bia cha nhiu cht d phn hy sinh hc nn c mu

nu thm. Nc thi mt s b phn c pH khc nhau nhiu, thng nc thi qu

trnh ln men c tnh axt, nc thi ra chai c tnh kim. Hm lng xy ha tan

trong nc thi ca nh my bia rt thp. Nhu cu xy sinh hc BOD v ha hc COD

u rt cao vt qu tiu chun thi nhiu ln (COD hm lng 600-2400mg/l; BOD5

hm lng 310-1400mg/l), trung bnh ln hn 10 ln tiu chun cho php. Cc gi tr

BOD v COD thng thay i theo thi gian trong ngy. Cc gi tr cao l vo thiim x nc ra b ni nu v thng ln men. Vi cc ch s gy nhim nh trn v

h thng x l nc khng m bo nn cht lng nc thi sau khi x l khng t

tiu chun thi. Nc thi chy theo cng thot nc thi ring ca nh my sau

chy vo cng thot nc chung ca khu vc gy nh hng nhim mi trng. Do

, vic tnh ton v thit k h thng x l nc thi cho nh my bia l vn cp

thit cho qu trnh pht trin ngnh sn xut thc ung ca Vit Nam hin nay.

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2. Mc ch:

Tnh ton v thit k h thng x l nc thi nh my bia bng phng php

sinh hc lu lng 2000 m3/ngy m, vi thng s u vo nh bng 1, nc sau khi

x l t tiu chun loi B theo TCVN 5945-1995.

T

T

Ch tiu Nc thi trc

x l

Tiu chun thi

(TCVN 5945-1995)1 pH 6-12 6-92 Hm lng cn l lng, mg/l 300 1003 BOD5, mg/l 1500 504 COD, mg/l 2000 100

5 Tng Nit (TN) 15-45 606 Tng Phtpho (TP) 4,9-9,0 67 Coliform, MPN/100 ml


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Chng I. C s l thuyt

I.1. Phng php c hc:

I.1.1. Nguyn tc chung:

Nc thi c thnh phn ht sc phc tp. Trong nc thi khng ch cha ccthnh phn ho hc ho tan, cc loi vi sinh vt, m cn cha cc cht khng ho tan.

Cc cht khng ho tan c th c kch thc nh v c th c kch thc ln. Ngi ra

da vo kch thc v t trng ca chng loi chng ra khi mi trng nc,

trc khi p dng cc phng php ho l hoc cc phng php sinh hc.

Cc vt cht c kch thc ln nh cnh cy, bao b cht do, giy, gi rch,

ct, si v c nhng git du, m. Ngoi ra, vt cht cn nm dng l lng hoc

dng huyn ph.

Tu theo kch thc v tnh cht c trng ca tng loi vt cht m ngi ta

a ra nhng phng php thch hp loi chng ra khi mi trng nc. Nhng

phng php loi cc cht rn c kch thc ln v t trng ln trong nc c gi

chung l phng php c hc.

Phng php x l c hc c th loi b c n 60% cc tp cht khng ho

tan c trong nc thi v gim 20% BOD. Cc cng trnh trong x l c hc bao gm:

- Song chn rc hoc li lc.

- B lng ct.

- B lng.

- iu ho lu lng dng chy.

- Qu trnh tuyn ni.

I.1.2. Song chn rc:

Song chn rc nhm chn gi cc cn bn c kch thc ln hay dng si:giy, rau c, rc c gi chung l rc. Rc c chuyn ti my nghin nghin

nh, sau c chuyn ti b phn hy cn (b mtan). i vi cc tp cht < 5 mm

thng dng li chn rc. Cu to ca thanh chn rc gm cc thanh kim loi tit

din hnh ch nht, hnh trn hoc bu dc Song chn rc c chia lm 2 loi di

ng hoc c nh, c th thu gom rc bng th cng hoc c kh. Song chn rc c

t nghing mt gc 60 90 0 theo hng dng chy.

I.1.3. B tch du m

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B tch du m thng c ng dng trong x l nc thi cng nghip c

cha du m, cc cht nh hn nc v cc dng cht ni khc. i vi nc thi sinh

hot, do hm lng du m v cc cht ni khng ln cho nn c th thc hin vic

tch chng ngay b lng t mt nh cc thanh gt thu hi du m, cht ni trn bmt b lng.

I.1.4. B lng ct

B lng ct dng tch cc cht bn v c c trng lng ring ln hn nhiu

so vi trng lng ring ca nc nh x than, ct ra khi nc thi. Thng

thng cn lng c ng knh ht khong 0,25 mm (tng ng ln thu lc l

24,5) chim 60% tng s cc ht cn c trong nc thi.

Theo chiu dng chy, b lng c phn thnh: b lng ngang v b lng

ng.

Trong b lng ngang, dng nc chy theo phng ngang hoc vng qua b vi

vn tc ln nht Vmax = 0,3 m/s, vn tc nh nht Vmin = 0,15 m/s v thi gian lu nc

t 30 60 giy. i vi b lng ng, nc thi chuyn ng theo phng thng ng

t di ln vi vn tc nc dng t 3 3,7 m/s, vn tc nc chy trong mng thu

(xung quanh b) khong 0,4 m/s v thi gian lu nc trong b dao ng trong khong

2 -3,5 pht.

Ct trong b lng c tp trung v h thu hoc mng thu ct di y, ly ct

ra khi b c th bng th cng (nu lng ct < 0,5 m3/ngy m) hoc bng c gii

(nu lng ct > 0,5 m3/ngy m). Ct t b lng ct c a i phi kh sn phi

v ct kh thng c s dng li cho nhng mc ch xy dng.

I.1.5. B lng:B lng lm nhim v tch cc cht l lng cn li trong nc thi (sau khi qua

b lng ct) c t trng ln hn hoc nh hn t trng ca nc di dng lng xung

y b hoc ni ln trn mt nc. Thng thng b lng c ba loi ch yu: b lng

ngang (nc chuyn ng theo phng ngang), b lng ng (nc chuyn ng theo

phng thng ng), v b lng ly tm (nc chuyn ng t tm ra xung quanh)

thng c dng hnh trn trn mt bng. Ngoi ra, cn mt s dng b lng khc nh

b lng nghing, b lng c thit k nhm tng cng hiu qu lng.

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I.1.6. iu ho lu lng dng chy:

Trong qu trnh x l nc thi cn phi iu ho lng dng chy. Trong qu

trnh ny thc cht l thit lp h thng iu ho lu lng v nng cht nhim

trong nc thi nhm to iu kin tt nht cho cc cng trnh pha sau hot ng nnh. B iu ho dng chy c th b tr trn dng chy hay b tr ngoi dng chy.

I.1.7. Qu trnh tuyn ni:

Tuyn ni l qu trnh tch cc cht dng rn hoc dng lng, phn tn khng

tan trong nc thi c khi lng ring nh, t trng nh hn nc khng th lng

bng trng lc hoc lng rt chm. Phng php tuyn ni c thc hin bng cch

trn ln cc ht kh nh v mn vo nc thi, khi cc ht kh s kt dnh vi cc

ht ca nc thi v ko theo nhng ht vt cht ny theo bt kh ni ln b mt. Khi

ta c th d dng loi chng ra khi h thng bng thit b vt bt.

tng hiu sut to bt, ngi ta thng s dng cc cht to bt nh eresol,

phenol nhm gim nng lng b mt phn pha. Tu theo phng thc cp khng kh

vo nc, qu trnh tuyn ni bao gm cc dng sau:

Tuyn ni bng kh phn tn: Kh nn c thi trc tip vo b tuyn ni

to thnh cc bt kh c kch thc t 0,1 1 mm, gy xo trn hn hp kh - nc

cha cn. Cn tip xc vi bt kh, kt dnh v ni ln b mt.

Tuyn ni chn khng: bo ho khng kh p sut kh quyn, sau thot kh

ra khi nc p sut chn khng. H thng ny t s dng trong thc t v kh vn

hnh v chi ph cao.

Tuyn ni bng kh ho tan: Sc khng kh vo nc p sut cao (2-4 at), sau

gim p gii phng kh. Khng kh thot ra s to thnh bt kh c kch thc 20 -

100m.I.2. X l sinh hc

Qu trnh x l nc thi bng phng php sinh hc l qu trnh nhm phn

hy cc vt cht hu c dng ha tan, dng keo v dng phn tn nh trong nc

thi nh vo s hot ng ca cc vi sinh vt. Qu trnh ny xy ra trong iu kin

hiu kh hoc k kh tng ng vi hai tn gi thng dng l: qua trnh x l sinh hc

hiu kh v qu trnh x l sinh hc k kh (ym kh).

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Qu trnh x l sinh hc k kh thng c ng dng x l s b cc loi

nc thi c hm lng BOD5 cao (>1000 mg/l), lm gim ti trng hu c v to

iu kin thun li cho cc qu trnh x l hiu kh din ra c hiu qu. X l sinh hc

k kh cn c p dng x l cc loi bn, cn (cn ti t b lng t mt, bnhot tnh sua khi nn ) trong trm x l nc thi th v mt s ngnh cng

nghip.

Qu trnh x l sinh hc hiu kh c ng dng c hiu qu cao i vi nc thi

c hm lng BOD5 thp nh nc thi sinh hot sau x l c hc v nc thi ca

cc ngnh cng nghip b nhim hu c mc thp (BOD 5 < 1000 mg/l). Ty

theo cch cung cp oxy m qu trnh x l sinh hc hiu kh c chia lm hai loi:

- X l sinh hc hiu kh trong iu kin t nhin (oxy c cung cp t khng

kh t nhin do quang hp ca to v thc vt nc) vi cc cng trnh tng ng nh:

cnh ng ti, cnh ng lc, h sinh hc, t ngp nc

- X l sinh hc hiu kh trong iu kin nhn to (oxy c cung cp bi cc

thit b sc kh cng bc, thit b khuy trn c gii) vi cc qu trnh v cng

trnh tng ng nh sau:

Qu trnh vi sinh vt l lng (qa trnh bn hot tnh):

B bn hot tnh thi kh (Aerotank)

Mng oxy ha

H sinh hc

Qu trnh vi sinh vt dnh bm (Qu trnh mng vi sinh vt):

B lc sinh hc nh git (Biophin)

B lc sinh hc cao ti

Thp lc sinh hc

B lc sinh hc tip xc dng a quay (RBC): cng trnh ny cho

php x l nit v photpho trong nc thi (x l bc cao).

Qu trnh vi sinh vt kt hp: b sinh hc hiu kh tip xc (c cu to v

nguyn l hot ng ging nh b Aerotank nhng bn trong b c trang b thm cc

vt liu tip xc lm gi th cho cc vi sinh vt dnh bm)

I.3. X l ha hc:

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Bn cht ca qu trnh x l nc thi bng phng php ho l l p dng cc

qu trnh vt l v ho hc a vo nc thi cht phn ng no gy tc ng

vi cc tp cht bn, bin i ho hc, to thnh cc cht khc di dng cn hoc

cht ho tan nhng khng c hi hoc gy nhim mi trng. Giai on x l hol c th l giai on x l c lp hoc x l cng vi cc phng php c hc, ho

hc, sinh hc trong cng ngh x l nc thi hon chnh.

Nhng phng php ho l thng c p dng x l nc thi l : keo t,

ng t, hp ph, trao i ion, thm lc ngc v siu lc

I.3.1. Phng php keo t v ng t

Qu trnh lng ch c th tch c cc ht rn huyn ph nhng khng th

tch c cc cht gy nhim bn dng keo v ha tan v chng l nhng ht rn c

kch thc qu nh. tch cc ht rn mt cch c hiu qu bng phng php

lng, cn tng kch thc ca chng nh s tc ng tng h gia cc ht phn tn

lin kt thnh tp hp cc ht, nhm tng vn tc lng ca chng. Vic kh cc ht keo

rn bng lng trng lng i hi trc ht cn trung ha in tch ca chng, th n

l lin kt chng vi nhau. Qu trnh trung ho in tch thng c gi l qu trnh

ng t (coagulation), cn qu trnh to thnh cc bng ln hn t cc ht nh gi l

qu trnh keo t (flocculation).

I.3.2. Hp ph

Phng php hp ph c dng rng ri lm sch trit nc thi khi

cc cht hu c ho tan sau khi x l sinh hc cng nh x l cc b khi nc thi c

cha mt hm lng rt nh cc cht . Nhng cht ny khng phn hu bng con

ng sinh hc v thng c c tnh cao. Nu cc cht cn kh b hp ph tt v chi

ph ring cho lng cht hp ph khng ln th vic ng dng phng php ny l hpl hn c.

Cc cht hp ph thng c s dng nh: than hot tnh, cc cht tng hp

v cht thi ca vi ngnh sn xut c dng lm cht hp ph (tro, x, mt ca ).

Cht hp ph v c nh t st, silicagen, keo nhm v cc cht hydroxit kim loi t

c s dng v nng lng tng tc ca chng vi cc phn t nc ln. Cht hp

ph ph bin nht l than hot tnh, nhng chng cn c cc tnh cht xc nh nh :

tng tc yu vi cc phn t nc v mnh vi cc cht hu c, c l xp th c

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th hp ph cc phn t hu c ln v phc tp, c kh nng phc hi. Ngoi ra, than

phi bn vi nc v thm nc nhanh. Quan trng l than phi c hot tnh xc tc

thp i vi phn ng oxy ha bi v mt s cht hu c trong nc thi c kh nng

b oxy ho v b ho nha. Cc cht ho nha bt kn l xp ca than v cn tr vic tisinh n nhit thp.

I.3.3. Phng php trao i ion

Trao i ion l mt qu trnh trong cc ion trn b mt ca cht rn trao i

vi ion c cng in tch trong dung dch khi tip xc vi nhau. Cc cht ny gi l

cc ionit (cht trao i ion), chng hon ton khng tan trong nc.

Cc cht c kh nng ht cc ion dng t dung dch in ly gi l cationit,

nhng cht ny mang tnh axit. Cc cht c kh nng ht cc ion m gi l anionit v

chng mang tnh kim. Nu nh cc ionit no trao i c cation v anion gi l cc

ionit lng tnh.

Phng php trao i ion thng c ng dng loi ra khi nc cc kim

loi nh: Zn, Cu, Cr, Ni, Pb, Hg, M , cc hp cht ca Asen, photpho, Cyanua v

cc cht phng x.

Cc cht trao i ion l cc cht v c hoc hu c c ngun gc t nhin hay

tng hp nhn to. Cc cht trao i ion v c t nhin gm c cc zeolit, kim loi

khong cht, t st, fenspat, cht mica khc nhau v c tng hp gm silicagen,

pecmutit (cht lm mm nc ), cc oxyt kh tan v hydroxyt ca mt s kim loi nh

nhm, crm, ziriconi Cc cht trao i ion hu c c ngun gc t nhin gm axit

humic v than chng mang tnh axit, cc cht c ngun gc tng hp l cc nha c

b mt ring ln l nhng hp cht cao phn t.

I.3.4. Cc qu trnh tch bng mngMng c nh ngha l mt pha ng vai tr ngn cch gia cc pha khc

nhau .Vic ng dng mng tch cc cht ph thuc vo thm ca cc hp cht

qua mng. Ngi ta dng cc k thut nh: in thm tch, thm thu ngc, siu

lc v cc qu trnh tng t khc.

Thm thu ngc v siu lc l qu trnh lc dung dch qua mng bn thm

thu, di p sut cao hn p sut thm lc. Mng lc cho cc phn t dung mi i

qua v gi li cc cht ho tan. S khc bit gia hai qu trnh l ch siu lc thng

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c s dng tch dung dch c khi lng phn t trn 500 v c p sut thm

thu nh (v d nh cc vi khun, tinh bt, protein, t st ). Cn thm thu ngc

thng c s dng kh cc vt liu c khi lng phn t thp v c p sut

cao.I.3.5. Phng php in ho

Mc ch ca phng php ny l x l cc tp cht tan v phn tn trong nc

thi, c th p dng trong qu trnh oxy ho dng cc, kh m cc, ng t in v

in thm tch. Tt c cc qu trnh ny u xy ra trn cc in cc khi cho dng in

1 chiu i qua nc thi.

Nhc im ln ca phng php ny l tiu hao in nng ln

Chng II: Cng ngh sn xut bia v cc ngun pht sinh nc thi

II.1. Cng ngh sn xut bia:

Cc cng on chnh ca cng nghip sn xut bia bao gm:

- Chun b nguyn liu: Malt i mch v nguyn liu thay th (go, la m, ng)

c lm sch ri a vo xoay, nghin t tng b mt hot ng ca enzym v

gim thi gian nu.

- Lc dch ng thu nc nha trong v loi b malt. Qu trnh gm hai bc:

Bc 1: Lc hn hp dch ng thu nc nha u;

Bc 2: Dng nc nng ra b thu nc nha cui v tch b malt.

- Nu vi hoa houblon to ra hng v cho bia, sau nc nha c qua

thit b tch b hoa.

- Lm lnh: Nc nha t ni nu c nhit xp x 100oC c lm lnh ti

nhit thch hp ca qu trnh ln men, nhit vo khong 10 16 oC v qua haigiai on. Giai on 1 dng nc lnh h nhit xung chng 60oC v giai on 2

dng tc nhn lnh glycol h nhit xung cn chng 14oC.

- Ln men chnh v ln men ph: y l cc qu trnh quan trng trong sn xut

bia. Qu trnh ln men nh tc dng ca men ging chuyn ho ng thnh alcol

etylic v kh cacbonic:

+ 22

menln

612622 COOHHCOHC

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Nhit duy tr trong giai on ln men chnh (6 n 10 ngy) t 8 n 10 oC. Sau

tip tc thc hin giai on ln men ph bng cch h nhit ca bia non xung 1

n 3oC v p sut 0,5 n 1 at trong thi gian 14 ngy cho bia hi v 21 ngy cho bia

ng chai, lon. Qu trnh ln men ph din ra chm v thi gian di gip cho cc cnlng, lm trong bia v bo ho CO2, lm tng cht lng v bn ca bia. Nm men

tch ra, mt phn c phc hi lm men ging, mt phn thi c th lm thc n gia

sc. H nhit ca bia non thc hin giai on ln men ph c th dng tc nhn

lm lnh glycol.

- Lc bia nhm loi b tp cht khng tan nh nm men, protein, houblon lm

cho bia trong hn trn my lc khung bn vi cht tr lc l diatomit.

- Bo ho CO2 v chit chai: Trc khi chit chai, bia c bo ho CO2 bng

kh CO2 thu c t qu trnh ln men cha trong bnh p sut. Cc dng c cha bia

(chai, lon, kt) phi c ra, thanh trng m bo tiu chun v sinh, sau thc

hin qu trnh chit chai iu kin chn khng hn ch khc nhau m bo

cht lng trong thi gian bo hnh.

Trong cng ngh sn xut bia, nc c dng vo cc mc ch:

- Lm nguyn liu pha trn theo t l nht nh nghin t malt v go (hay

la m) v b sung tip trong qu trnh nu - ng ha.

- Sn xut hi nc dng cho qu trnh nu ng ho, nu hoa, thanh trng.

- Mt lng nc ln dng cho qu trnh ra chai, lon, thit b my mc v sn

thao tc.

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12

Tch b

Nu hoa

Nc thi

Nu - ng ho

Thnh phm

Chun b nguyn liu

Chit chai, lon

Lm lnh

Bo ho CO2

Lc dch ng

Ln men ph

Ln men chnh

ng np

Lc bia

Thanh trng

Nc cp Nc cpcho sn xut

Hi nng

Ra chai

Xt

GoMalt

Hnh. Cng ngh v nc thi nh my bia


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II.2. Cc ngun pht sinh nc thi v c tnh nc thi cng nghip sn xut

bia.

Nc thi cng ngh sn xut bia bao gm:

- Nc lm lnh, nc ngng, y l ngun nc thi t hoc gn nh khng b nhim, c kh nng tun hon s dng li.

- Nc thi t b phn nu - ng ho, ch yu l nc v sinh thng nu, b

cha, sn nh nn cha b malt, tinh bt, b hoa, cc cht hu c,

- Nc thi t hm ln men l nc v sinh cc thit b ln men, thng cha,

ng ng, sn nh, xng, c cha b men v cht hu c.

- Nc thi ra chai, y cng l mt trong nhng dng thi c nhim ln

trong cng ngh sn xut bia. V nguyn l ng chai th phi c ra qua cc

bc: ra vi nc nng, ra bng dung dch kim long nng (1 -3 % NaOH), tip

l ra sch bn v nhn bn ngoi chai v cui cng l phun kim nng ra bn trong

v bn ngoi chai, sau ra sch bng nc nng v nc lnh. Do , dng thi ca

qu trnh ra chai c ph cao vo lm cho dng thi chung c gi tr pH kim tnh.

Kim tra nc thi t cc my ra chai i vi loi chai 0,5lit cho thy mc

nhim nh trong bng 2:

Bng 2: nhim nc thi t nh my bia

Thng sHm lng, mg/l

Thp Cao Trung bnhCOD 810 4480 2490BOD5 330 3850 1723

Nit +4

NH 2,05 6,15 4,0P tng 7,9 32,0 12,8

Cu 0,11 2,0 0,52

Zn 0,20 0,54 0,35AOX 0,10 0,23 0,17pH = 8,3 n 11,2

Nc tiu th ra 1 chai = 0,3 n 0,5litTrong nc thi ra chia c hm lng ng v km l do s dng loi

nhn dn chia c in n bng cc loi thuc in c cha kim loi. Hin nay, loi nhn

dn chia c cha kim loi b cm s dng nhiu nc. Trong nc thi c tn ti

AOX l do trong qu trnh kh trng c dung cht kh l hp cht ca clo.

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Trong sn xut bia, cng ngh t thay i t nh my ny sang nh my khc,

s khc nhau c th ch l s dng phong php ln men chm hay ni. Nhng s khc

nhau c bn l vn s dng nc cho qu trnh ra chai, lon, my mc thit b, sn

nh, iu dn n ti lng nc thi v hm lng cc cht nhm ca ccnh my bia rt khc nhau. cc nh my bia c bin php tun hon nc v cng

ngh ra tit kim nc th lng nc thp. S liu trung bnh ca nhng thng s

nhim nh sau:

- Lng nc cp cho 1000 lt bia l 4 8 m3

- Nc thi tnh t sn xut 1000 lt bia l 2,5 6 m3

- Ti trng BOD5 l 3 6 kg/1000 lt bia

- T l BOD5/COD l 0,55 0,7

- Hm lng cc cht gy nhim trong nc thi nh sau:

BOD5: 1100 1500 mg/l

COD : 1800 3000 mg/l

Tng Nit : 30 100 mg/l

Tng Photpho : 10 30 mg/l

Chng III: La chn phng n x l nc thi nh my bia

III.1. Phng n 1:

14

B Axit ho

B tuyn ni

B lng ct

B iu ho v nnh pH

B UASB

B Aerotank

B lng II

B tip xc

My nn kh

B nn bn My p bn

Sn phi ct

Clo

BCL

San lp

x l lmphn bn

Song chn rc

Nc thi


15/56

Thuyt minh quy trnh cng ngh:

Nc thi t qu trnh sn xut qua song chn rc, ti y rc c kch thc ln

c loi b, rc c a n ni chn lp. Nc thi n b lng ct ngang, cc htcn c th lng c s c gi li y, ct s c mang n sn phi ct mang

c chn lp hoc sang lp. Nc thi c a n b tuyn ni c thi kh, cc ht

cn khng th lng b lng ct v du m s c tch ra khi nc thi. Nc thi

c a n b iu ho, ti y nc thi c n nh v lu lng v nng .

Sau nc thi qua b axit ho iu chnh pH v trung tnh. Nc thi tip tc

c a qua b UASB, ti y hm lng BOD v COD gim xung mt cch nhanh

chng. Kh thot ra c tn dng cung cp nng lng cho qu trnh sn xut.

15


16/56

Nc thi qua b Aerotank, hm lng BOD v COD cng gim xung, nc thi tip

tc n b lng 2, lng bn d s c gi li, mt phn bn s c tun hon v b

aerotank, mt phn a qua b nn bn ri n my p bn, bn sau c x l lm

phn bn. Nc thi t b lng 2 c a n b tip xc, ti y nc c khtrng bng Clorine v thi ra ngun tip nhn.

u im:

Hiu qu x l cao, nc sau khi x l c th thi trc tip ra ngoi mi trng.

C th thu hi nng lng b UASB cung cp cho qu trnh sn xut.

Bn c x l lm phn bn.

Nhc im:

C nhiu cng trnh n v do chi ph u t cao.

Chim mt din tch kh ln.

III.2. Phng n 2:

Hnh: S h thng x l nh my bia Bavane Lieshout, H Lan

Thuyt minh quy trnh cng ngh

Nc thi c a vo b cha (1), ti b ny lu lng nc thi c lm

n nh v iu chnh pH. Nc thi tip tc qua b Axit ho (2), do nc thi u vo

c pH tng i cao nn cn phi iu chnh pH v trung tnh. Ti y, nc ti b

axit ho cng c tun hon v b cha (1) tng hiu qua n nh pH ca nc

thi. Nc thi c a qua b UASB, hm lng COD v BOD b ny gim

16


17/56

xung rt nhanh, kh sinh ra c tn dng lm nng lng cho qu trnh sn xut.

Tip tc, nc thi qua b tip xc (4) ri n b aerotank (5), hm lng COD v

BOD y cng gim xung nhanh chng. Nc tip tc qua b lng 2 (6), mt phn

bn s c tun hon v b Aerotank, nc t b lng 2 c thi ra ngun tip nhn.Nu nc thi c pH trung ho v hm lng COD, BOD thp th s trc tip

a v b tip xc 4.

u im:

Hiu qu x l COD v BOD cao

Chi ph xy dng thp

t tn din tch

Kh thot ra t b UASB c th tn dng to ra nng lng cung cp cho qu

trinh sn xut

Nhc im:

Quy trnh x l nc thi ny ch ph hp cho lu lng nc thi thp.

Khng c song chn rac, do d lm tc nghn cho cc cng trnh phia sau.

Khng c giai on kh trng, nc c thi ra ngun tip nhn thng cha

nhiu vi sinh vt gy bnh.

III.3. Phng n 3:

17


18/56

Thuyt minh quy trnh cng ngh:

Nc thi t qu trnh sn xut qua song chn rc, ti y rc c kch thc ln

c loi b, rc c a n ni chn lp. Nc thi n b lng ct ngang, cc htcn c th lng c s c gi li y, ct s c mang n sn phi ct mang

c chn lp hoc sang lp. Nc thi c a n b tuyn ni c thi kh, cc ht

cn khng th lng b lng ct v du m s c tch ra khi nc thi. Nc thi

c a n b iu ho, ti y nc thi c n nh v lu lng v nng ,

iu chnh pH v trung tnh. Nc thi qua b lng 1, hm lng SS gim i mt cch

ng k v cn bn c ua v b nn bn Nc thi tip tc c a qua b

UASB, ti y hm lng BOD v COD gim xung mt cch nhanh chng. Kh thot

18

Song chn rc

B lng ct

B iu ho v nnh pH

B lng I

B UASB

B Aerotank

B lng II

B tip xc

My nn kh

B nn bn My p bn

Sn phi ct

Clo

BCL

San lp

x l lm

phn bn

Nc thi


19/56

ra c tn dng cung cp nng lng cho qu trnh sn xut. Nc thi qua b

Aerotank, hm lng BOD v COD cng gim xung, nc thi tip tc n b lng

2, lng bn d s c gi li, mt phn bn s c tun hon v b aerotank, mt

phn a qua b nn bn ri n my p bn, bn sau c x l lm phn bn. Ncthi t b lng 2 c a n b tip xc, ti y nc c kh trng bng Clorine

v thi ra ngun tip nhn.

u im:

Hiu qu x l cao, nc sau khi x l c th thi trc tip ra ngoi mi trng.

C th thu hi nng lng b UASB cung cp cho qu trnh sn xut.

Bn c x l lm phn bn.

Nhc im:

C nhiu cng trnh n v do chi ph u t cao.

Chim mt din tch kh ln.

Chng IV: Tnh ton - thit k h thng x l nc thi nh my bia

(Phng n 3)

19


20/56

IV.1. Lu lng nc thi tnh ton:

Lu lng trung bnh ngy m: Qtb = 2000 m3/ngy m

Lu lng trung bnh gi:

hmQQ tbhtb /33,8324

2000

24

3===

Lu lng trung bnh giy:

smQ

Q tbs

tb /023,0360024

2000

360024

3

=

=

=

IV.2. Tnh ton song chn rc:

Nc thi dn vo h thng x l nc trc ht phi qua song chn rc. Ti

y cc thnh phn rc c kch thc ln nh: vi vn, v hp, l cy c gia

li. Nh trnh lm tc nghn v bo mn bm, ng ng hoc knh dn. y l

bc quan trng nhm m bo an ton v iu kin lm vic thun li cho c h

thng x l nc thi.

Tnh ton song chn rc:

Chiu su lp nc song chn rc ly bng chiu cao lp nc ca cng dn

nc thi : h1 = 0,2 m

S khe h song chn rc c tnh:

905,12,002,065,0

023,00

1

=

=

= khbV

Qn

s

tb khe

Trong

k0 = 1.05 - h s tnh n mc cn tr dng chy, co rc bng c gii.

n: s khe hsQmax : lu lng giy ln nht ca nc thi

V: tc nc chy qua song chn rc (0,4-0,8 m/s); chn v = 0,65 m/s

b = 0,02 khong cch gia cc khe h ca song chn.

Vy chiu rng mi song chn rc l:

Bs = S.(n1 +1) + b.n1 = 0,008.(9+1) + 0,02 .9 = 0,26 (m)

Trong

S: chiu dy thanh song chn = 0,008m

20


21/56

Kim tra li vn tc dng chy ti v tr m rng ca mng trc song chn

ng vi lu lng nc thi nh nht nhm trnh s lng cn ti . Vn tc ny phi

> 0,4 m/s.

smsmhB

QVs

s

kt /4,0/44,02,026,0

023,0.

1

max>=

==

Tn tht p lc qua song chn rc:

mmmmmg

VVh kts 1 501 201 2,0

81,92

44,065,0

7,0

1

27,0

12222


22/56

B rng ca b lng ct ngang:

Xy b lng ct gm mt ngn cng tc v mt ngn d phng vi kch thcmi ngn l: Chiu di L = 9 m v chiu rng B = 0,3 .

Kim tra ch lm vic ca b lng ct ngang tng ng vi smQstb /023,03

=

smHBn

QV

s

/153,05,03,01

023,0max=

=

=

Thi gian lu nc trong b lng ct ng vi smQs /039,0 3max =

)(7,46

15,0

7s

v

Lt ===

Lng ct trung bnh sau mi ngy m l:

ngaydemmqQ

W tbc /3,01000

15,02000

1000

30=

=

=

Trong , q0 = 0,15 m3/ngy m l lng ct trong 1000 m3 nc thi.

Chiu cao lp ct trong b lng ct ngang trong 1 ngy m:

mnBL

tWh cc 143,0

13,07

13,0=

=

=

Vi t = 1 ngy m l chu k x ct.

Chiu cao xy dng ca b lng ct ngang:

mHhHH bvcxd 943,03,0143,05,0 =++=++=

Vi Hbv = 0,3 m l chiu cao bo v

Tnh ton sn phi ct:

Nhim v sn phi ct l lm ro nc trong hn hp ct-nc cho d dng vn

chuyn ct i ni khc.

Chn: Chiu di ca sn phi ct Ls = 5m

Thi gian phi ct = Chu k x ct = 1 ngy m

Th tch ct Wc = 0,3 m3/ngy m

Chiu rng ca sn phi ct:

mLht

WB

s

c

s 2

503,01

3,0=

=

=

Vy din tch ca sn phn ct l: mmBL ss 25 =

22

mH

B 3,05,0

153,0 ===


23/56

IV.4. Tnh ton b iu ho:

Lu lng v cht lng nc thi t cng thu gom chy v trm x l nc

thi, c bit i vi dng thi cng nghip v dng nc ma thng xuyn dao ng

theo thi gian trong ngy. Khi h s khng iu ha k 1,4 th nn xy dng b iuha m bo cho cng trnh x l lm vic n nh v t c gi tr kinh t.

C hai loi b iu ha: b iu ha lu lng v cht lng v b iu ha cht

lng.

Mc ch xy dng b iu ha:

Gim bt s dao ng ca hm lng cc cht bn trong nc do qu trnh sn

xut thi ra khng u.

Tit kim ha cht trung ha nc thi.

Gi n nh lu lng nc i vo cc cng trnh x l tip theo.

Hm lng BOD, COD, SS sau b iu ha t:

BOD = 95% x 1500 = 1425 mg/l

COD = 95% x 2000 = 1900 mg/l

SS = 85% x 300 = 255 mg/l

Tnh ton b iu ho:Chn thi gian lu nc thi trong b l 4 gi

Th tch b iu ho:3

32,333433,83 mtQW htbdh ===

Th tch thc t ca b iu ho: Wth = 1,2 . Wdh = 1,2 . 333,32 = 400 m3

Chn chiu su mc nc l Hdh = 4. Din tch ca b iu ho:

2

100

4

400m

H

WS

dh

dh===

Chiu cao xy dng ca b iu ho: Hxd = Hdh + Hbv = 4 + 0,5 = 4,5m

Xy b iu ho hnh ch nht c kch thc l :

mmmHBL xddhdh 5,4812 =

Tnh ton h thng cp kh cho b iu ho (bng kh nn)

Lng khng kh cn thit:

hmaQL htbkhi /65,31174,333,833

===

Vi a = 3,74m3 kh/m3nc thi l lu lng khng kh cp cho b iu ho.

23


24/56

Chn h thng ng cp kh bng thp c c l, c 4 ng t dc theo chiu di

ca b iu ho, mi ng cch nhau 2m.

Lu lng kh trong mi ng:

hmvLq

ong

khiong /165,31

10

65,311 3===

Trong ongv l vn tc kh trong ng, ongv = 10 15 m/s. Chn ongv =10m/s

ng knh ng dn kh:

mmmv

qd

ong

ong

ong 33033,0360010

165,314

3600

4

==

=

=

Chn ng mm30= . ng knh cc l 2 5 mm, chn dl = 4mm v vn

tc kh qua l chn vl = 15m/s (vl thay i t 5 10 m/s).

hmdv

q lololo /1884,04

004,01 5

4

3

22

=

=

=

S l trn mi ng: 1651884,0

165,31===

lo

ong

q

qN l

S l trn 1m chiu di ng:

78,1312

165

12

===N

n l

Chn n = 14 l/m ng.

Tnh ton bm dng trong b iu ho:

Ti b iu ha c t bm chm bm nc thi qua b lng 1, do ta phi

tnh cng sut ca bm t ti y.

Ct p ton phn ca bm: H = 4,5m + 0,3m = 4,8m

Lu lng bm: Q = 2000 m3/ngy.m

Cng sut ca my bm:

( )kWgHQ

N 36,1864008,01000

20008,481,91000

1000

=

==

Cng sut thc t ca my bm:

( )kWNNTT 635,136,12,12,1 ===

Ta chn 2 bm, mt bm lm vic v mt bm d tr. Cng sut ca mi bm

l: 2 Kw

24


25/56

Tnh ton my nn kh:

Lng kh cn cp cho b l : Lkh = 311,65m3/h = 0,087m3/s

p lc cn thit cho h thng ng kh nn:

Hd = hd + hc + hf+ HTrong :

o hd, hc: tn tht p lc do ma st dc theo chiu di trn ng ng dn v

tn tht cc b ti cc im un, khc quanh.

hd + hc 0,4m

o hf: tn tht qua h thng phn phi kh

hf 0,5m

o H: ngp su ca ng phn phi kh, ly bng chiu cao hu ch ca b

iu ha

H = 4m

Vy p lc cn thit :

Hd = 0,4m + 0,5m + 4m = 4,9m

p lc khng kh s bng:

, ,1 0 33 4 9 ,1 47,10 33

P at += =

Cng sut my nn kh c tnh theo cng thc:

, ,0 29 0 29( ) ( , ) , 34400 1 34400 1 47 1 0 087,4 3

,1 02 1 02 0 8

P qN Kw

= = =

IV.5. Tnh ton b lng 1:

Loi b cc tp cht l lng cn li trong nc thi qua b iu ha. y cc

cht l lng c t trng ln hn t trn ca nc s lng xung y. Hm lng chtl lng sau khi qua b lng t 1 cn t 150 mg/l.

Hm lng sau khi ra khi b lng 1 phi t:

BOD = 80% x 1425 = 1140 mg/l

COD = 80% x 1900 = 1520 mg/l

SS = 55% x 255 = 140,25mg/l 150 mg/l

Tnh ton b lng 1:

25


26/56

Chn b lng t 1 dng trn, nc thi i vo t ng trung tm, thu nc theo

chu vi b.

Th tch tng cng ca b lng 1 c xc nh theo cng sut:3

max 1255,133,83 mtQWh

===

Trong t l thi gian lng c

xc nh bng thc nghim v ng hc

lng. Trng hp khng tin hnh thc

nghim c, thi gian lng (t) i vi b

lng 1 c th ly bng 1,5h.

Chn 2 b cng tc v mt b d

phng,, th tch ca mi b l:

3

15,62

2

125

2

mW

W ===

Din tch ca mi b lng trong mt

bng:

2

1

1

1652,15

4

5,62m

H

WF ===

Trong : H1 l chiu su vng

lng ly tm c th ly t 1,5 n 5 m.

Chn H1 = 4m

ng knh ca mi b lng:

mF

D 46,4652,1544

1=

=

=

Ly D(lt) = 4,5 m

ng knh thc t ca b lng l: mDD lttt 4,55,42,12,1 )( ===

ng knh ng trung tm: mDd tt 08,14,5%20%20 ===

Chn: Chiu cao lp bn lng hb = 0,7 m

Chiu cao an ton h = 0,5 m

Vy chiu cao tng cng ca b lng 1

Htc= H1 + h + hb = 4 + 0,5 + 0,7 = 5,2 m

Chiu cao ng trung tmmHh 4,24%60%60

1===

26


27/56

Ta chn 3 b, hai b cng tc v mt b d phng. Kch thc mi b lng:

mmHD tctt 2,54,5 =

Thng s Gi trDy c trngThi gian lu nc (gi) 1.5-2.5 2Ti trng b mt (m3/m2ngay) 32-48Lu lng trung bnh 32-48Lu lng cao im 80-120Ti trng mng trn (m3/m.ngay) 125-500ng trung tm

ng knh

Chiu cao

%15 20d D=

% 55 65h H=

Chiu su b lng (m) H=3-4,6 4ng knh b lng (m) D=3-60 8,53 dc y (mm/m) 62-167 83Tc thanh gt bn

(vng/pht)

0,02-0.05 0,03

Bng 3: Thng s thit k c trng cho b lng ly tm

Hiu qu ca qu trnh lng cc cht l lng:

Tc lng ca ht cn l lng trong b lng c tnh theo cng thc:

smmt

HU /74,0

5,16,3

4

6,3

1=

=

=

Hiu sut lng ca cht l lng trong nc thi b lng 1 ph thuc vo tc

lng ca ht cn l lng trong nc thi (U = 0,74 mm/s) v hm lng ban u

ca ht cn l lng (Cdv = 255 mg/L) v c th ly theo bng 4:

Hiu sut lng

ca cht llng(%)

Tc lng ca ht cn l lng, U (mm/s) ng vi hm lng

ban u ca cht l lng C (mg/L)150 200 250 300

30 1,30 1,80 2,25 3,2035 0,90 1,30 1,90 2,1040 0,60 0,90 1,05 1,4045 0,40 0,60 0,75 0,9550 0,25 0,35 0,45 0,6055 0,15 0,20 0,25 0,4060 0,05 0,10 0,15 0,20

27


28/56

Bng 4: Hiu sut lng ca cht l lng trong nc thi b lng 1

Vi Cdv = 255 mg/L v U = 0,74. Chn hiu sut lng E1 = 45%

Hm lng cht l lng trii theo nc ra khi b lng 1 c tnh theo cng

thc:

LmgLmgEC

C dv /150/25,140100

)45100(255

100

)100(1

=

=

=

Ti trng mng trn

3 32000

, / . .1 1 7 95 500,5 4

tbs

tt

QL m m ngay m ngay

D = = = F1, vy din tch b mt ti trng cht rn l din tch tnh tonng knh b lng:

mn

FD 56,8

2

12544=

=

=

n: s b lng t II cng tc, chn n = 2

ng knh ng trung tm:

d = 20% D = 20% 8,56 = 1,7m

Chn chiu su hu ch ca b lng hL= 4 m, chiu cao lp bn lng hb= 1,2mv chiu cao bo v hbv=0,3. Vy chiu cao tng cng ca b lng II:

Htc = hL + hb + hbv = 4+1,2 + 0,3 =5,5m

Chiu cao ng trung tm:

h = 60%hL= 0,6 4 =2,4m

Th tch ca b lng II c tnh theo cng thc:

W = FH = 125 4 = 500m3

H: chiu cao cng tc ca b lng II

Chn 3 b trong c 2 b cng tc, mt b dng d phng.

Kim tra li thi gian lu nc ti b lng:

Th tch phn lng:

( ) ( ) 322222 24047,156,844

mmmHdDVL ===

Thi gian lu nc

( )hh

hm

m

QQ

Vt

r

5,153,1/33,833,73

240

3

3

>=+

=+

=

Th tch phn cha bn:

Vb = F hb = 125 1,2 = 150m3

Thi gian lu gi bn trong b:

hhngayngaymhm

m

QQ

Vt

rw

bb 03,2

)24/1/78,15(/3,73

150

33

3

+

=+

=

Trong

43


44/56

Qr: lu lng bn tun hon

Qw: lu lng bn d cn x l

Ti trng mng trn:

ngaymmngaymDQQL rs ./8,128

56,8/)17602000( 3

3

=+=+=

Gi tr ny nm trong khong cho php < 500m3/m.ngay

Tnh bm

Bn hot tnh t b lng II c m cao: 99,4% - 99,7%. Mt phn ln loi bn

ny c dn tr li b aeroten ( loi bn ny gi l bn hot tnh tun hon), phn

bn cn li gi l bn hot tnh d c dn vo b nn bn. Ti b lng hai ta c t

2 bm bm bn v b Aeroten v b nn bn.Cng sut ca mi bm:

1000

Q gHN

=

Trong

Q:lu lng nc thi trung bnh ngy m, m3/ngym

H:p sut ton phn ca bm, mH2O

: khi lng ring ca cht lng

Khi lng ring ca bn l 1006kg/m3

g: gia tc trng trng, g 9,81m/s2

: hiu sut ca bm, = 0,73 0.9

Chn

= 0,8Ct p ton phn ca my bm bm bn tun hon v b Aeroten:

H = 5,5m + 1,5m = 7m

Cng sut ca my bm bn tun hon:

KwgHQ

N 016,0864008,01000

81,9100678,157

1000

=

==

Cng sut thc t ca bm:

44


45/56

N1 = 2 0,02 = 0,04Kw

Ct p ton phn ca my bm bm bn ti b nn bn:

H = 1,5m + 4,5m = 6m

Cng sut ca my bm bn v b nn bn:

KwgHQ

N 5,136008,01000

81,910063,736

1000

=

==

Cng sut thc t ca bm:

N1 =1,7 1,5= 2,55 Kw

II.9. Kh trng nc thi, tnh ton b tip xcSau cc giai on x l: c hc, sinh hc,, song song vi vic lm gim nng

cc cht nhim t tiu chun quy nh th s lng vi trng cng gim ng k

n 90 95%. Tuy nhin, lng vi trng vn cn cao v vic kh trng l iu cn

thit. thc hin vic kh trng nc thi, c th s dng cc bin php nh clo ha,

zon ha, kh trng bng tia hng ngoi UV. Vic kh trng bng clo tng i n

gin, r tin v hiu qu chp nhn c nn c s dng nhiu cng trnh x li.

Ni dung tnh ton gm:

II.9.1.Kh trng nc thi bng clo

Lng clo hot tnh cn thit kh trng nc thi c tnh:

1000a

a QY

=

Trong :

Q: lu lng tnh ton ca nc thi

Qtb.h = 83,33m3/h

A: liu lng hot tnh ly theo iu 6.20.3 TCXD -51-84.

Nc thi sau x l c hc: a = 10g/m3

Nc thi sau x l sinh hc hon ton: a = 3 g/m3

Nc thi sau x l sinh hc khng hon ton: a = 5 g/m3

Chn a = 3 g/m3 tnh ton.

45


46/56

ng vi lu lng trung bnh gi:

. , 3 83 33 , /0 2 51 000 1 000

tb htb

a QY kg h

= = =

nh lng clo, xo trn clo hi vi nc cng tc, iu ch clo nc cn s

dng thit b kh trng, gi l clorator chn khng. cung cp lng clo hot tnh

trong gii hn ng vi cc lu lng c trng nh tnh( y 0,09 0,42), chn hai

clorator, mt cng tc, mt d phng. Cng sut mi ci l 0,4 2,05 vi cc c tnh

k thut sau:

p lc nc trc Ejector: 2,5kg/h

Lu lng nc: 2m3/h

Trng lng ca Clorator: 37,5kgTheo bng c tnh k thut ca mt kiu clorator chn khng Loni-100

sch X l nc thi th v cng nghip (Lm Minh Trit Nguyn Thanh Hng

Nguyn Phc Dn).

S balng cha clo cn thit cho trm clorator c tnh theo cng thc sau:

5,05,0

25,0===

q

Yn tb

Trong : q l lng clo ly ra t mt balng cha clo trong iu kin bnhthng, q = 0,5 0,7, chn q = 0,5 tnh ton.

Bng c tnh k thut ca balng cha clo:

Dung tich thng cha clo Kch thc(mm) Trng lng

(kg)Lt Kg Clo L l

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20

25

27

3033

36

40

45

50

55

25

31

33,5

37,541

45

50

56

62

69

770

925

985

10801170

1205

1390

1545

1700

1855

675

825

890

9751065

1125

1275

1427

1575

1725

35

40,5

43

4751

55

60

66,5

73

79,5

Chn loi balng cha clo vi dung tch cha 20l vi cc thng s k thut nh

bng trn.

Vic kim tra lng clo cc thng cha trong qu trnh kh trng c ngha

quan trng v c thc hin bng cn chuyn dng. S lng balng cha clo d tr

cho nhu cu s dng trong mt thng c tnh ton theo cng thc:

1

2 4 30 ,0 2 5 2 4 30 , balng7 2 72 5

tbYNq

= = =

q1: lng clo cha trong 1 balng, q1 = 25kg

vn chuyn cc balng trong phm vi ca trm clorator, thng trang b cc

loi xe chuyn dng.

Lng nc tng cng cn thit cho nhu cu ca trm clo c xc nh:

hm

qY

Q

tb

n /4

,0

1000

)35024,11000(25,0

1000

)11000(3

=+

=+

=

Trong : q l lu lng cn thit lm bc hi clo. Chn q = 350l/kg

: lng nc cn thit ha tan 1 gam clo, ph thuc vo nhit ca nc

thi. Chn = 1,24 vi nhit ca nc thi 300C.

II.9.2. Tnh ton mng trn

Chn mng trn kiu ln thc hin s xo trn u nc thi v clo trc

khi dn vo b tip xc.

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Din tch tit din ca mng trn c tnh:

203,0

8,0

023,0m

v

QF s ===

Qmax: lu lng giy ln nht

V: tc ca nc thi trong mng trn v = 0,8 0,9m/s

Vi lu lng 23l/s chn cc kch thc c bn:

L =2500mm, l = 1755mm, b = 300mm, h1 = 700mm, h2 = 1030mm, b1 =

110mm, b2 =150mm, b3 = 130mm, b4=110mm. Vi bx: chiu rng cc khe ln.

Tra trong bng 4-6: Kch thc c bn ca mng trn kiu ln sch x l

nc thi th v cng nghip, tnh ton thit k cng trnh (Lm Minh Trit

Nguyn Thanh Hng Nguyn Phc Dn).

Chiu su lp nc sau mng trn: mb

FH 1,0

3,0

03,0===

Tn tht p lc qua mi khe ln:2 2,0 8

, ,2 5 0 08,2 2 9 81

vh m

g= = =

Trong

Vi : h s b tr ch ln cng chiu dng nc.

Khi b tr ch ln thun chiu dng nc,

=2,5Khi b tr ch ln ngc chiu dng nc, =3

v: Tc chuyn ng ca pha nc qua khe ln, chn v = 0,8m/s

Din tch tit din ngang ca mi khe ln:

mv

QF skh 03,0

8,0

023,0===

Chiu su lp nc trc cc khe ln th 1:

mb

FH kh 273,011,003,0

1

1===


2

1

,0 03,0 2

,0 1 5khFH m

b= = =


3

1

,0 03,0 2 3

,0 1 3khFH m

b= = =


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4

1

,0 03,0 273

,0 1 1khFH m

b= = =

II.9.3. Tnh ton b tip xc

Nhim v ca b tip xc l thc hin qu trnh tip xc gia clo v nc saukhi qua mng trn kiu ln. Chn thi gian tip xc gia clo v nc thi l 30

pht tnh c thi gian nc thi chy t b tip xc n ming x vo ngun nc. B

tip xc thc cht l mt b lng nhng khng c thit b co cn( theo iu 6.20.5

TCXD-51-84). Chn b lng dng ngang.

Tnh ton b tip xc

Th tch hu ch ca b tip xc:

W = Qh t = 83,33 27,6/60 = 38m3

Vi t l thi gian tip xc ring trong b tip xc

1 00, 30 30 27 6

,60 0 7 60md

Lt phut

v= = =

Lmd l chiu di mng dn t b tip xc n ming x v v l tc dng

chy trong mng vi v = 0,7 0,8 m/s.

Din tch b tip xc dng b lng ngang trn mt bng s l:

F = W/Hct = 38/2 = 19m2

(Hct chiu cao cng tc ca b tip xc, Hct = 1,5-3m, chn Hct = 2m).

Chn din tch mt ngn trong mt bng:

F1= L b = 4 2 = 8 m2

Trong :

L l chiu di ca b, ly L = 4m

B l chiu ngang mi ngn, ly b = 2mS ngn tng cng ca b tip xc: n = F/F1 = 19/8 = 2,4 2 ngn.

m ca cn b tip xc l 96%. Cn lng c x ra khi b tip xc bng

p lc thy tnh ( 1 1,5m ct nc).

IV.8.B nn bn:

Bn hot tnh d ngn lng c m cao, cn phi t n d m thch hp

xy dng trc khi cho qua cc cng trnh s l tip theo hoc thi ra mi trng

lm phn bn (nu lng cn ti t).

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Cc thng s tnh ton b nn bn ng c xc nh:

Lng bn d: l tng lng bn sinh ra t b lng I, b UASB, v b lng II

Lu lng bn thu t b lng 1: ngaymQtuoi /812,53

=

Lng bn ti l: ngyKgSSMtuoi /306=

Lu lng bn thi ra b UASB c bm vo b cha bn l:

ngaymQW /155,13=

Lng bn thi ra khi b UASB ngaykgVSMss /26=

Lu lng bn thi b b lng 2 c a vo b cha bn

vi ngymQb /78,153=

Lng bn thi b trong b lng 2

ngaykgSSXQM thbb /24,126878,15 ===

Vi X th =8000mg/l:Nng VSS trong bn thi.

Tng lng bn

M = 306 + 26 + 126,24 = 458,24 kgSS/m3

Vy tng lu lng bn vo trong b cha bn l

Qnen = 5,812 + 1,155 + 15,78 = 22,747 m3/ngy.Din tch b nn bn

264,7

60

24,458m

a

MA ===

Vi a: ti trng ring ca hn hp bn b lng 1 v bn hot tnh

a = (50-70)kgSS/m2.ngy. Chn a = 60kgSS/m2.ngy

Din tch b mt ng trung tm

2222

3055,064,704,004,04

2.0

4

mADd

f tt ===

=

=

ng knh ca b nn bn

mfA

D 053,3)3055,064,7(4)(4

=+

=+

=

ng knh ng trung tm

d = 16%D = 0,16 3,053 = 0,488 m m5,0

ng knh phn loe ca ng trung tm:

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d1= 1,35 d = 1,35 0,5 = 0,675m

ng knh tm chn:

dch= 1,3 d1= 1,3 0,675 = 0,9m

Chiu cao phn lng ca b nn bn tnh theo cng thc:

H1= v1 t 3600 = 0,0001 8 3600 = 2,88 3m

vi t l th gian lng bn, t = 8 gi

v1 vn tc lng, chn v1= 0,0001m/s

Chiu cao phn hnh nn vi gc nghing l 45 0, ng knh b D = 2m, v ng

knh ca nh y b l 0,5m bng :

mmD

h 3,128,12

5,0

2

053,3

2

5,0

22

===

Chiu cao phn bn hot tnh nn:

hb= h2 h0 hth = 1,3 0,2 0,2 = 0,9m

vi h0, hth ln lt l khong cch t ng loe n tm chn, v chiu cao lp trung ho.

Chiu cao tng cng ca b nn bn:

Htc = h1 + h2 +h3 = 3 + 1,3 + 0,4 =4,7m

vi h3 l khong cch t mc nc trong b nn bn ti thnh b.

IV.11. Tnh ton my p bn lc p dy ai

Thit b lc p dy ai l thit b dng

kh nc ra khi bn vn hnh bng cch chobn lin tc vo thit b. Thit b ny thng

c ch to vi b rng dy ai t 0,5 3,5m.

Ti trng bn t 90 680kg/m.h.

Khi lng bn cn p: 458,24 kgSS/m3

Nng bn sau khi nn: 2%

Nng bn sau khi p: 18%

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Khi lng bn sau khi p ngaykgSS /48,82100

1824,458=

=

S gi hot ng ca thit b: 8h

Ti trng bn tnh trn 1m chiu rng bng p chn bng 90kh/m.h

Chiu rng bng p mhmkgngaygio

ngaykg636,0

./90/8

/24,458=

=

Chn mt thit b p dy ai, b rng dy ai 1m

Chng V: Tnh ton kinh t

V.1. Chi ph u t xy dng

STT Tn cngtrnh ThTch(m3) S Lng(ci)

n

gi(ngVN)

Thnh tin(ngVN)

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1Song Chnrc 1 5.000.000 5.000.000

2 B lng ct 8,65 2 1.500.000 25.950.000

3 Sn phi ct 3,8 1 1.500.000 5.700.000

4 B iu ha 82,8 1 1.500.000 124.200.0005 B lng 1 18,5 4 1.500.000 111.000.000

6 B UASB 37,8 8 1.500.000 453.600.000

7BAEROTANK 115,7 1 1.500.000 173.550.000

8 B lng 2 22,4 2 1.500.000 67.275.000

9 B nn bn 12,3 1 1.500.000 18.450.000

10 B kh trng 3,68 1 1.500.000 5.520.000

11 My p bn 1 1 444 000 000 444 000 000

12

Cc cngtrnh kmtheo(nglng) 50 000 000 50 000 000

Tng cng 1.484.245. 000

Bng: Gi vt liu xy dng

Tn vt t Chi tit S lng n gi Thnh tin

Bm

Bm Nc t

b iu ha

sang lng 1

Q = 83,33 m3/h

N = 2 kw2 12 500 000 25 000 000

Bm bnT b lng I

v b nn bn

H =6m

Q=5,812 m3/ngy

N = 0,0075kw2 2 000 000 4 000 000

Bm bn

Tun hon v

aerotank ti b

lng 2

H =7m

Q=15,78m3/ngy

N = 0,04kw2 5.000 000 10 000 000

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Tn vt t Chi tit S lng n gi Thnh tin

Bm bn v

b nn bn

H = 6m

Q=73,3m3/h

N=2,55kw

2 8 000 000 16 000 000

Bm inh

lng2 11 000 000 22 000 000

ng

ng(ng dn

bn, ng dn

nc thi, ngdn kh)

150 000 000 150 000 000

H thng in

ng lc v

chiu sng

50 000 000 50 000 000

My thi kh2 50 000 000 100 000 000

a thi kh 147 880 000 129 360 000

Tng cng 506 360 000

Bng: Gi trang thit b ph

Tng tin u t

(1.454.245. 000 + 480 360 000) x 1,2 = 2.388.726.000 (VN ng)

V.2. Chi ph vn hnh trm

V.2.1. Lng ho cht s dng

Tn ho chtLiu

lng

Nng

S dng n gi Thnh tin

NaOCl 10 mg/l 10% 6kg/ngy 2.300 /kg 13.800

Bng: Lng ha cht cn dng

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Chi ph ho cht cho 1m3 nc: 13 800 2000 m3 = 6,9 ng/m3

V.2.2. Chi ph in

c tnh : 800kW/ngy

in nng tiu th tnh cho 1m3

nc800 kw/ngy 2000 m3 = 0,4 kw/m3

Gi cung cp in cng nghip: 2500 ng/kw

Chi ph in tnh cho 1 m3 :

2000 ng/kw 0,4 kw/m3 =800 ng/m3.

V.2.3. Chi ph nhn cng

S lng nhn vin : 4 ngi, 3 cng nhn v 1 k sMc lng thng:

Cng nhn : 2.000.000 ng/ngi.thng

K s: 3.000.000 ng/ngi.thng

Chi ph tng cng : 3 2.000.000 + 3.000.000 = 9.000.000 ng/thng

Chi ph nhn cng tnh cho 1m3 nc

150

200030

000.000.9=

ng/m

3

V.2.4. Chi ph vn hnh trm x l

Phn loi chi ph Chi ph n v, ng/m3

Chi ph ho cht 6,9

Chi ph in 800

Chi ph lng 150

Cng 956,9

Bng :Bng phn tch chi ph

V.2.5.Gi thnh x l mt m3 nc thi

Tng chi ph u t: S =2.388.726.000 (VNng)

Gi thnh mt m3 nc thi

1300

103652000

000. . .2 388 7269,956 =

+ (VN ng)

vi nin hn s dng : 10 nm

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Vy chi ph 1m3 nc thi l 1300 ng /m3

KT LUN

Ngy ny, nhu cu v nc gii kht v bia ru ca con ngi tng cao buc

cc ny sn xut phi y mnh sn xut. Do qu trnh y mnh sn xut, nc thi t

cc nh my ny ngy cng thi ra nhiu cht nhim hn. Nu cc nh my nykhng c h thng x l nc thi th nc thi t cc nh my ny s lm nhim

mi trng mt cch nghim trng. V th, vn tnh ton v thit k h thng x l

nc thi nh my sn xut nc gii kht v bia ru l mt vn t ra trong qu

trnh pht trin ca ngnh cng nghip nc gii kht v bia ru, trong xy dng

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