Noi Dung Hoan Chinh

8/3/2019 Noi Dung Hoan Chinh

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n tt nghipSVTH: Minh Ht GVHD: Ths. V Hng Thi

LI M U

1 t vn Trong qu trnh pht trin khng ngng ca x hi, loi ngi t c

nhiu thnh tu to ln trong cc lnh vc kinh t, x hi vi mt trnh khoa hc

k thut hin i, nhng ng thi cng gy ra nhiu hu qu nghim trng cho mi

trng, c bit l mi trng nc.

Cng vi vic bo v v cung cp ngun nc sch vic thi v x l nc

b nhim trc khi vo ngun l mt vn bc xc i vi ton th loi

ngi, n khng gii hn trong mt quc gia, mt khu vc m cn l mt vn

nng bng ca ton nhn loi.

Vit Nam mi ngy c hng triu m3 nc thi sinh hot c a vo mi

trng do s pht trin ca th ho, dn s ngy cng gia tng. Nc thi sinh

hot x thi trc tip ra ngun tip nhn s nh hng trc tip n ngun nc mt

nh: Lm gia tng mc ph dng ngun nc tip nhn do cc cht hu c v

phosphat c trong nc thi. Khi qu trnh ph dng xy ra s lm gim lng oxyha tan trong nc gy hin tng phn hy ym kh cc hp cht hu c v sinh ra

kh c hi nh H2S, mercaptanes gy cc mi hi v lm cho nc ngun tip

nhn c mu en. Bn cnh , cc cht du m gy nh hng n qu trnh ti

np oxy t khng kh v mt s cht nhim c bit nh ha cht, cht ty ra

(qu trnh hot ng ca nh bp) gy tc ng tiu cc n h thy sinh v qua dy

chuyn thc phm s gy tc hi cho ngi s dng do kh nng tch t sinh hc

cao ca chng.

T nhng tc ng trn, chnh ph ngy cng coi trng vn bo v mi

trng m c th l yu cu cc cht thi cn cx l trc khi x ra mi trng.

V th cc lut, nghnh, quy nh c ban hnh buc cc c s sn xut, kinh

doanh, dch v, nh my, x nghip phi x l ngun nhim pht sinh do qu

trnh hot ng.

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V vy, pht trin m khng lm suy thoi mi trng c bit l mi

trng nc th vic u t xy dng h thng x l nc thi ph hp l mt yu

cu cn thit m bo pht trin kinh t bn vng.

Do , vic u t xy dng mt trm x l nc thi cho cng ty TNHH

VMC Hong Gia trc khi x vo h thng knh, rch thot nc t nhin l mt

yu cu cp thit, nhm mc tiu pht trin bn vng cho mi trng trong tng

lai v bo v sc khe cng ng.

Chnh v l do ti Tnh ton thit k trm x l nc thi sinh

hot ca cng ty TNHH VMC Hong Gia, cng sut 205 m3/ngy.m c

lc chn lm n tt nghip ca trong bo co ny.

2 Mc tiu ti

Tnh ton thit k chi tit trm x l nc thi cho cng ty TNHH VMC

Hong Gia huyn Chu Thnh, tnh Ty Ninh t tiu chun x thi loiA (QCVN

14: 2008/BTNMT, ct A) trc khi x ra ngun tip nhn bo v mi trng

sinh thi v sc khe cng ng.

3 i tng v phm vi nghin cu i tng nghin cu

Cng ngh x l nc thi sinh hot

Phm vi nghin cu

ti gii hn trong vic tnh ton thit k trm x l nc thi cho cng ty

TNHH VMC Hong Gia bao gm:

+ Nc ma c thu gom bi cc h thu v theo cng ring thot thng ra

h thng thot nc chung ca khu vc sau khi qua h thng song chn rc gi

li rc c kch thc ln

+ Nc thi sinh hot ca cng ty c x l s b ti hm t hoi sau

dn vo trm x l nc thi cng sut 205 m3/ngy.m.

+ Nc thi sn xut: trong qu trnh sn xut khng pht sinh nc thi

Thi gian thc hin: 01/11/2010 03/2011.

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4 Ni dung nghin cu

Tm hiu v hot ng ca cng ty TNHH VMC Hong Gia c pht sinh ra

nc thi.

Xc nh c tnh nc thi: Lu lng, thnh phn, tnh cht nc thi, kh

nng gy nhim, ngun x thi.

xut dy chuyn cng ngh x l nc thi ph hp vi mc nhim

ca nc thi u vo.

Tnh ton thit k cc cng trnh n v trong h thng x l nc thi.

D ton chi ph xy dng, thit b, ha cht, chi ph vn hnh trm x l

nc thi.

5 Phng php thc hin

Phng php thu thp s liu:Thu thp cc ti liu v nc thi sinh hot,

tm hiu thnh phn, tnh cht nc thi v cc s liu cn thit khc.

Phng php nghin cu l thuyt: Tm hiu nhng cng ngh x l nc

thi sinh hot qua cc ti liu chuyn ngnh.

Phng php so snh: So snh u, nhc im ca cng ngh x l hin cv xut cng ngh x l nc thi ph hp.

Phng php ton: S dng cng thc ton hc tnh ton cc cng trnh

n v trong h thng x l nc thi, d ton chi ph xy dng, vn hnh

trm x l.

Phng php ha: Dng phn mm AutoCad m t kin trc cc

cng trnh n v trong h thng x l nc thi.

6 ngha khoa hc v thc tin

Xy dng trm x l nc thi t tiu chun mi trng gii quyt c

vn nhim mi trng do nc thi ca cng ty.

Gp phn nng cao thc v mi trng cho nhn vin cng nh Ban qun

l cng ty.

Khi trm x l hon thnh v i vo hot ng s l ni cc doanh nghip

ln cn, sinh vin tham quan, hc tp.

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CHNG 1: TNG QUAN V CNG TY TNHH VMC HONG GIA

1.1 Gii thiu chung v cng tyTNHH Hong Gia

1.1.1 V tr a l ca cng ty TNHH Hong Gia

Cng ty TNHH VMC Hong Gia nm trong cm cng nghip Chu Thnh,

thuc p Thanh Phc, x Thanh in, huyn Chu Thnh, tnh Ty Ninh. V tr

khu t nm trn quc l (QL) 22B v cch trung tm th x Ty Ninh khong 3km.

Pha Bc gip: ng quy hoch 28m Di: 400 m

Pha ng gip: ng quy hoch 28m. Di: 400 m

Pha Ty gip: ng quy hoch 28m Di: 400 m

Pha Nam gip: ng quy hoch 28m (QL 22B) Di: 400 m

Tng din tch cng ty c s dng theo Quyt nh s 380/Q CT ngy

29 thng 7 nm 2003 ca y Ban Nhn Dn tnh Ty Ninh: 89.257 m2.

1.1.2 iu kin t nhin ca khu vc

1.1.2.1 a hnha hnh khu vc nhn chung tng i bng phng, c dc t nhin v

hng Ty.

1.1.2.2 Kh tng

Khu vc x nc thi nm trn a bn p Thanh Phc, x Thanh in,

huyn Chu Thnh, tnh Ty Ninh mang c trng kh tng ca Ty Ninh nh sau:

+ Kh hu nhit i gi ma. Nhit quanh nm cao, bin dao ng

nhit nh. Ch ma, nng, gi th hin rt r gia ma ma v ma kh. Mt

khc Ty Ninh nm su trong lc a, t chu nh hng ca bo v nhng yu t

bt li khc.

+ Lng ma trung bnh hng nm t 1800 2200 mm, m trung

bnh trong nm vo khong 70 - 80%, tc gi 1,7m/s v thi iu ha trong nm.

Ty Ninh chu nh hng ca 2 loi gi ch yu l gi Ty Ty Nam vo ma

ma v gi Bc ng Bc vo ma kh.

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1.1.2.3 Thy vn

Trong khu vc xung quanh cng ty khng c sng sui hay ngun nc mt.

Nc ngm su 40m c lu lng v cht lng tt.

1.2 C s h tng

1.2.1 H thng giao thng

Cng ty TNHH Hong Gia rt thun li v mt giao thng v nm cnh quc

l 22B cch th x Ty Ninh 8 10km, cch trung tm huyn Chu Thnh 12 14

km. Ngoi ra trong khu vc cn c tnh l 786.

1.2.2 H thng cp thot nc

1.2.2.1 Ngun cung cp nc sch

Ngun nc ngm: nc ngm su 40m c lu lng v cht lng tt.

Hin nay ngi dn y ang khai thc cc tng ny phc v cho mc ch cp

nc sinh hot.

Ngun nc mt: cch cum cng nghip 1,5Km v pha ng c sng chy

qua.1.2.2.2 H thng thot nc

H thng cng thot nc ca cm cng nghip c thit k chy dc theo

cc trc ng giao thng trong cm cng nghip v c hng dng chy vo h

thng cng thot nc chy dc theo Quc L 22B. S dng h thng hn hp

cng b tng ct thp (BTCT) v mng h dn nc.

1.2.3 H thng cp in v phn phi in

H thng cung cp in cho cng ty TNHH Hong Gia l trm trung gian

110/22 (15) KV ca x Thanh in sau chia ra 2 nhnh 22(15) KV i dc theo

cc trc ng cung cp in cho cc nh my, x nghip

1.2.4 H thng thng tin lin lc

H thng cp quang thng tin lin lc c ch u t v Bu in tnh Ty

Ninh hp tc u t.

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1.3 Quy trnh sn xut

Cc nguyn liu th nh cao su, vi, da c ct, dp thnh cc chi tit

mt giy, lt trong, lt sau in la ri in ni. Sau may cc chi tit hon

chnh mt trn ca giy. Cc chi tit c lp rp, thoa keo, p , g mi, g hng,

sy nng, sy lnh, ty, vo hp v ng thng.

1.3.1 Qui trnh cng ngh sn xut giy

Hnh 1.1: S cng ngh sn xut ca Cng ty TNHH Hong Gia

1.3.2 Nguyn vt liu s dng cho sn xut

Cng ty sn xut gia cng cho nc ngoi nn lng nguyn liu s dng

hon ton ph thuc vo s lng sn phm c sn xut theo hp ng. Nguynvt liu c bn nc ngoi cung cp y theo s lng gia cng.

Nguyn liu sn xut giy bao gm nguyn liu chnh, ph. Ngoi ra cn

c bao b v cc phn ph khc.

Tng lng vn chuyn n hng nm: 20.000 tn/nm.

Ngun cung cp: Bn nc ngoi hp ng gia cng m bo cung cp ton

b nguyn ph liu, bao b theo hp ng.

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Nguyn liu

Ct cc chi tit mt giy, lt trong, lt In lua, in ni

May cc chi tit hon chnh mt trn ca giy

Thoa keo, p , g mi, g hngSy nng, sy lnhTy vo hp, ng thng


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1.3.3 Sn phm

Sn phm l cc loi giy dp da, gi da gia cng theo n t hng, ty

theo hp ng gia cng v yu cu ca th trng. S sn phm ca nm sn xut

n nh l: 2.000.000 sn phm/nm.

1.4 Cc ngun pht sinh v c tnh ca nc thi

1.4.1 Cht thi rn

Cht thi rn ch yu trong qu trnh sn xut l cc nguyn liu ri vi v

bao b, giy gi hng, ngoi ra cn c rc thi sinh hot t cc hot ng ca cng

nhn.

1.4.2 Kh thi

Cc my mc s dng trong dy chuyn cng ngh u chy bng in v

khng c khi thi, chi c cng on in xut hin sol kh trong mi trng lm vic.

Ngoi ra, cng ty c s dng my pht in nn thi ra mt lng kh thi nht nh

CO, CO2, NOx, SOx

1.4.3 Nc thiCng ty TNHH VMC Hong Gia chuyn sn xut v gia cng cc loi giy

dp. Cc cng on sn xut giy khng dng nc. Nc thi pht sinh ti cng ty

ch yu l nc thi t khu v sinh ca cn b cng nhn vin trong nh my

(nc thi sinh hot) v khu v sinh sn cc phn xng (nc thi sn xut)

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CHNG 2: TNG QUAN V NC THI SINH HOT & CC

PHNG PHP X L NC THI SINH HOT

2.1 Tng quan v nc thi sinh hot

2.1.1 Ngun pht sinh, c tnh nc thi sinh hot

Ngun pht sinh ti khu dn c t Mi ch yu l nc thi sinh hot trong

qu trnh hot ng v sinh ca dn c khu d n.

c tnh chung ca nc thi sinh hot thng b nhim bi cc cht cn

b hu c, cc cht hu c ho tan (thng qua cc ch tiu BOD5/COD), cc cht

dinh dng (Nit, phospho), cc vi trng gy bnh (E.Coli, coliform).

Mc nhim ca nc thi sinh hot ph thuc vo: lu lng nc thi;

ti trng cht bn tnh theo u ngi.

Ti trng cht bn ca nc thi sinh hot tnh theo u ngi ph thuc

vo: mc sng, iu kin sng, tp qun sng v cc iu kin a phng.

Ti trng cht bn c xc nh trong Bng 2.1.

Bng 2.1 Ti trng cht bn tnh theo u ngi.

Ch tiu nhim Khi lng (g/ngi.ngy)

Cht rn l lng (SS) 60-65

BOD5 nc thi lng 30-35

BOD5 nc thi cha lng 65

Nit ca cc mui Amoni (N-NH4) 8phosphat (P2O5) 3,3

Clorua (Cl-) 10

Cc cht hot ng b mt 2-2,5

Ngun: Tiu chun xy dng Vit Nam (TCXDVN 51-2008).

2.1.2 Thnh phn, tnh cht nc thi sinh hot

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Thnh phn v tnh cht ca nc thi sinh hot ph thuc rt nhiu vo

ngun nc thi. Ngoi ra lng nc thi t hay nhiu cn ph thuc vo tp qun

sinh hot.

Thnh phn nc thi sinh hot gm 2 loi :

Nc thi nhim bn do cht bi tit con ngi t cc phng v sinh;

Nc thi nhim bn do cc cht thi sinh hot: cn b, du m t cc nh

bp, cc cht ty ra, cht hot ng b mt t cc phng tm, nc ra v sinh sn

nh

c tnh v thnh phn tnh cht ca nc thi sinh hot t cc khu pht sinh

nc thi ny u ging nhau, ch yu l cc cht hu c, trong phn ln cc

loi carbonhydrate, protein, lipid l cc cht d b vi sinh vt phn hy. Khi phn

hy th vi sinh vt cn ly oxi ha tan trong nc chuyn ha cc cht hu c

trn thnh CO2, N2, H2O, CH4, Ch th cho lng cht hu c c trong nc thi

c kh nng b phn hy hiu kh bi vi sinh vt chnh l ch s BOD 5. Ch s ny

biu din lng oxi cn thit m vi sinh vt phi tiu th phn hy lng cht

hu c c trong nc thi. Nh vy ch s BOD 5 cng cao cho thy cht hu c ctrong nc thi cng ln, oxi ha tan trong nc thi ban u b tiu th nhiu hn,

mc nhim ca nc thi cao hn.

2.2 Cc thng s nhim c trng ca nc thi

2.2.1 Thng s vt l

2.2.1.1. Hm lng cht rn l lng

Cc cht rn l lng trong nc ((Total) Suspended Solids (T)SS - SS) c

th c bn cht l:

- Cc cht v c khng tan dng huyn ph (Ph sa, g st, bn, ht st);

- Cc cht hu c khng tan;

- Cc vi sinh vt (vi khun, to, vi nm, ng vt nguyn sinh).

S c mt ca cc cht rn l lng cn tr hay tiu tn thm nhiu ha cht

trong qu trnh x l.

2.2.1.2. Mi

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Hp cht gy mi c trng nht l H2S _ mi trng thi. Cc hp cht khc,

chng hn nh indol, skatol, cadaverin v cercaptan c to thnh di iu kin

ym kh c th gy ra nhng mi kh chu hn c H2S.

2.2.1.3. mu

Mu ca nc thi l do cc cht thi sinh hot, cng nghip, thuc nhum

hoc do cc sn phm c tao ra t cc qu trnh phn hy cc cht hu c. n v

o mu thng dng l mgPt/L (thang o Pt _Co).

mu l mt thng s thng mang tnh cht cm quan, c th c s

dng nh gi trng thi chung ca nc thi.

2.2.2 Thng s ha hc

2.2.2.1. pH ca nc

pH l ch s c trng cho nng ion H+ c trong dung dch, thng c

dng biu th tnh axit v tnh kim ca nc.

pH ca nc c lin quan dng tn ti ca kim loi v kh ho tan trong

nc. pH c nh hng n hiu qu tt c qu trnh x l nc. pH c nh

hng n cc qu trnh trao cht din ra bn trong c th sinh vt nc. Do vy rtc ngha v kha cnh sinh thi mi trng

2.2.2.2. Nhu cu oxy ha hc (Chemical Oxygen Demand - COD)

COD l lng oxy cn thit oxy ho cc hp cht ho hc trong nc bao

gm c v c v hu c. Nh vy, COD l lng oxy cn oxy ho ton b cc

cht ho hc trong nc, trong khi BOD l lng oxy cn thit oxy ho mt

phn cc hp cht hu c d phn hu bi vi sinh vt.

COD l mt thng s quan trng nh gi mc nhim cht hu c

ni chung v cng vi thng s BOD, gip nh gi phn nhim khng phn hy

sinh hc ca nc t c th la chn phng php x l ph hp.

2.2.2.3. Nhu cu oxy sinh hc (Biochemical Oxygen Demand - BOD)

BOD (Biochemical oxygen Demand - nhu cu oxy sinh ho) l lng oxy

cn thit vi sinh vt oxy ho cc cht hu c theo phn ng:

Cht hu c + O2 CO

2+ H

2O + t bo mi + sn phm trung gian

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Trong mi trng nc, khi qu trnh oxy ho sinh hc xy ra th cc vi sinh

vt s dng oxy ho tan, v vy xc nh tng lng oxy ho tan cn thit cho qu

trnh phn hu sinh hc l php o quan trng nh gi nh hng ca mt dng

thi i vi ngun nc. BOD c ngha biu th lng cc cht thi hu c trong

nc c th b phn hu bng cc vi sinh vt.

2.2.2.4. Oxy ha tan (Dissolved Oxygen - DO)

DO l lng oxy ho tan trong nc cn thit cho s h hp ca cc sinh vt

nc (c, lng th, thu sinh, cn trng v.v...) thng c to ra do s ho tan t

kh quyn hoc do quang hp ca to.

Nng oxy t do trong nc nm trong khong 8 - 10 ppm, v dao ng

mnh ph thuc vo nhit , s phn hu ho cht, s quang hp ca to v v.v...

Khi nng DO thp, cc loi sinh vt nc gim hot ng hoc b cht. Do vy,

DO l mt ch s quan trng nh gi s nhim nc ca cc thu vc.

2.2.2.5. Nit v cc hp cht cha nit

Trong nc mt cng nh nc ngm nit tn ti 3 dng chnh l: ion

amoni ( NH4+

), nitrit ( NO2-

) v nitrat ( NO3-

). Di tc ng ca nhiu yu t hal v do hot ng ca mt s sinh vt cc dng nit ny chuyn ha ln nhau, tch

t li trong nc n v c c tnh i vi con ngi. Nu s dng nc c NO 2-

vi hm lng vt mc cho php ko di, tr em v ph n c thai c th mc

bnh xanh da v cht c ny cnh tranh vi hng cu ly oxy.

2.2.2.6. Phospho v cc hp cht cha phospho

Trong cc loi nc thi, Phospho hin din ch yu di cc dng

phosphat. Cc hp cht Phosphat c chia thnh Phosphat v c v Phosphat hu

c.

Phospho l mt cht dinh dng a lng cn thit i vi s pht trin ca

sinh vt. Vic xc nh Phospho tng l mt thng s ng vai tr quan trng

m bo qu trnh pht trin bnh thng ca cc vi sinh vt trong cc h thng x

l cht thi bng phng php sinh hc.

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Phospho v cc hp cht cha Phospho c lin quan cht ch n hin tng

ph dng ha ngun nc, do s c mt qu nhiu cc cht ny kch thch s pht

trin mnh ca to v vi khun lam.

2.2.2.7. Cht hot ng b mt

Cc cht hot ng b mt l nhng cht hu c gm 2 phn: k nc v a

nc to nn s phn tn ca cc cht trong du v trong nc. Ngun to ra cc

cht hot ng b mt l do vic s dng cc cht ty ra trong sinh hot v trong

mt s ngnh cng nghip.

2.2.3 Thng s vi sinh vt hc

Nhiu vi sinh vt gy bnh c mt trong nc thi c th truyn hoc gy

bnh cho ngi. Chng vn khng bt ngun t nc m cn c vt ch sng k

sinh, pht trin v sinh sn. Mt s cc sinh vt gy bnh c th sng mt thi gian

kh di trong nc v l nguy c truyn bnh tim tng, bao gm vi khun, virus,

giun sn.

Vi khun: Cc loi vi khun gy bnh c trong nc thng gy cc bnh vng rut, nh dch t (cholera) do vi khun Vibrio comma, bnh thng hn

(typhoid) do vi khun Salmonella typhosa...

Virus: c trong nc thi c th gy cc bnh c lin quan n s ri lon h

thn kinh trung ng, vim ty xm, vim gan... Thng thng kh trng bng cc

qu trnh khc nhau trong cc giai on x l c th dit c virus.

Giun sn (helminths): Giun sn l loi sinh vt k sinh c vng i gn lin

vi hai hay nhiu ng vt ch, con ngi c th l mt trong s cc vt ch ny.

Cht thi ca ngi v ng vt l ngun a giun sn vo nc. Tuy nhin, cc

phng php x l nc hin nay tiu dit giun sn rt hiu qu.

2.3 Tng quan v cc phng php x l nc thi

2.3.1 Phng php x l c hc

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

nc thi c gi chung l phng php c hc.

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X l c hc l khu s b chun b cho x l sinh hc tip theo. X l nc

thi bng phng php c hc thng thc hin trong cc cng trnh v thit b nh

song chn rc, b lng ct, b tch du m y l cc thit b cng trnh x l s

b ti ch tch cc cht phn tn th nhm m bo cho h thng thot nc hoc

cc cng trnh x l nc thi pha sau hot ng n nh.

Phng php x l c hc tch khi nc thi sinh hot khong 60% tp

cht khng tan, tuy nhin BOD trong nc thi gim khng ng k. tng cng

qu trnh x l c hc, ngi ta lm thong nc thi s b trc khi lng nn hiu

sut x l ca cc cng trnh c hc c th tng n 75% v BOD gim i 10

15%.

Mt s cng trnh x l nc thi bng phng php c hc bao gm:

2.3.1.1. Song chn rc

Song chn rc dng gi li cc tp cht th nh giy, rc, ti nilon, v cy

v cc tp cht c trong nc thi nhm m bo cho my bm, cc cng trnh v

thit b x l nc thi hot ng n nh.

Song chn rc l cc thanh an xp k tip nhau vi cc khe h t 16 n50mm, cc thanh c th bng thp, inox, nhc hoc g. Tit din ca cc thanh ny

l hnh ch nht, hnh trn hoc elip. B tr song chn rc trn mng dn nc thi.

Cc song chn rc t song song vi nhau, nghing v pha dng nc chy gi

rc li. Song chn rc thng t nghing theo chiu dng chy mt gc 50 n 900.

Thit b chn rc b tr ti cc mng dn nc thi trc trm bm nc thi

v trc cc cng trnh x l nc thi.

2.3.1.2. B thu v tch du m

B thu du:c xy dng trong khu vc bi v cu ra t, xe my, bi

cha du v nhin liu, nh git ty ca khch sn, bnh vin hoc cc cng trnh

cng cng khc, nhim v n nhn cc loi nc ra xe, nc ma trong khu vc

bi xe

B tch m:Dng tch v thu cc loi m ng thc vt, cc loi du c

trong nc thi. B tch m thng c b tr trong cc bp n ca khch sn,

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trng hc, bnh vin xy bng gch, b tng ct thp, thp, nha composite

v b tr bn trong nh, gn cc thit b thot nc hoc ngoi sn gn khu vc bp

n tch du m trc khi x vo h thng thot nc bn ngoi cng vi cc loi

nc thi khc.

2.3.1.3. B iu ho

Lu lng v nng cc cht nhim trong nc thi cc khu dn c,

cng trnh cng cng nh cc nh my x nghip lun thay i theo thi gian ph

thuc vo cc iu kin hot ng ca cc i tng thot nc ny. S dao ng

v lu lng nc thi, thnh phn v nng cht bn trong s nh hng

khng tt n hiu qu lm sch nc thi. Trong qu trnh lc cn phi iu ho

lu lng dng chy, mt trong nhng phng n ti u nht l thit k b iu ho

lu lng.

B iu ho lm tng hiu qu ca h thng x l sinh hc do n hn ch

hin tng qu ti ca h thng hoc di ti v lu lng cng nh hm lng

cht hu c gim c din tch xy dng ca b sinh hc. Hn na cc cht c ch

qu trnh x l sinh hc s c pha long hoc trung ho mc thch hp chocc hot ng ca vi sinh vt.

2.3.1.4. B lng

B lng ct

Trong thnh phn cn lng nc thi thng c ct vi ln thy lc =

18 mm/s. y cc phn t v c c kch thc v t trng ln. Mc d khng c

hi nhng chng cn tr hot ng ca cc cng trnh x l nc thi nh tch t

trong b lng, b mtan, lm gim dung tch cng tc cng trnh, gy kh khn

cho vic x bn cn, ph hu qu trnh cng ngh ca trm x l nc thi. m

bo cho cc cng trnh x l sinh hc nc thi sinh hc nc thi hot ng n

nh cn phi c cc cng trnh v thit b pha trc.

Ct lu gi trong b t 2 n 5 ngy. Cc loi b lng ct thng dng cho

cc trm x l nc thi cng xut trn 100m3/ngy. Cc loi b lng ct chuyn

ng quay c hiu qu lng ct cao v hm lng cht hu c trong ct thp. Do

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cu to n gin b lng ct ngang c s dng rng ri hn c. Tuy nhin trong

iu kin cn thit phi kt hp cc cng trnh x l nc thi, ngi ta c th dng

b lng ct ng, b lng ct tip tuyn hoc thit b xiclon h mt tng hoc xiclon

thu lc.

T b lng ct, ct c chuyn ra sn phi ct lm kh bng bin php

trng lc trong iu kin t nhin.

B lng nc thi

Dng tch cc cht khng tan dng l lng trong nc thi theo nguyn

tc da vo s khc nhau gia trng lng cc ht cn c trong nc thi. V vy,

y l qu trnh quan trng trong x l nc thi, thng b tr x l ban u th b

tr ni tip nhau, qu trnh lng tt c th loi b n 90 95% lng cn c trong

nc hay sau khi x l sinh hc. c th tng cng qu trnh lng ta c th thm

vo cht ng t sinh hc. S lng ca cc ht xy ra di tc dng ca trng lc.

Da vo chc nng v v tr c th chia b lng thnh cc loi: b lng t

mt trc cng trnh x l sinh hc v b lng t hai sau cng trnh x l sinh hc.

Theo cu to v hng dng chy ngi ta phn ra cc loi b lng ngang, blng ng v b lng ly tm.

2.3.2 Phng php x l ho l

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

cc qu trnh vt l v ha hc loi bt cc cht nhim m khng th dng qu

trnh lng ra khi nc thi. Cc cng trnh tiu biu ca vic p dng phng php

ha hc bao gm:

2.3.2.1. B keo t, to bng

Qu trnh keo t to bng c ng dng loi b cc cht rn l lng v

cc ht keo c kch thc rt nh (10-7-10-8cm). Cc cht ny tn ti dng phn

tn v khng th loi b bng qu trnh lng v tn rt nhiu thi gian. tng hiu

qu lng, gim bt thi gian lng ca chng th thm vo nc thi mt s ha cht

nh phn nhm, phn st, polymer, Cc cht ny c tc dng kt dnh cc cht

Trang 15


16/84


khuch tn trong dung dch thnh cc ht c kch c v t trng ln hn nn s lng

nhanh hn.

Cc cht keo t dng l phn nhm: Al2(SO4)3.18H2O, NaAlO2, Al2(OH)3Cl,

KAl(SO4)2.12H2O, NH4Al(SO4)2.12H2O; phn st: Fe2(SO4)3.2H2O, FeSO4.7H2O,

FeCl3 hay cht keo t khng phn ly, dng cao phn t c ngun gc thin nhin

hay tng hp.

Phng php keo t c th lm trong nc v kh mu nc thi v sau khi

to bng cn, cc bng cn ln lng xung th nhng bng cn ny c th ko theo

cc cht phn tn khng tan gy ra mu.

2.3.2.2. B tuyn ni

Tuyn ni l phng php c p dng tng i rng ri nhm loi b cc

tp cht khng tan, kh lng. Trong nhiu trng hp, tuyn ni cn c s dng

tch cc cht tan nh cht hot ng b mt.

Bn cht ca qu trnh tuyn ni ngc li vi qu trnh lng v cng c

p dng trong trng qu trnh lng xy ra rt chm v rt kh thc hin. Cc cht

l lng nh du, m s ni ln trn b mt ca nc thi di tc dng ca cc btkh to thnh lp bt c nng tp cht cao hn trong nc ban u. Hiu qu

phn ring bng tuyn ni ph thuc kch thc v s lng bong bng kh. Kch

thc ti u ca bong bng kh l 15 - 30.10-3 mm.

Hp ph

Hp ph l phng php tch cc cht hu c v kh ha tan ra khi nc

thi bng cch tp trung cc cht trn b mt cht rn (cht hp ph) hoc bng

cch tng tc gia cc cht bn ha tan vi cc cht rn (hp ph ha hc).

2.3.3 Phng php x l ho hc

X l nc thi bng phng php ho hc thng l khu cui cng trong

dy chuyn cng ngh trc khi x ra ngun yu cu cht lng cao hoc khi cn

thit s dng li nc thi. Cc qu trnh x l ha hc c trnh by trong Bng

2.2.

Bng 2.2 ng dng qu trnh x l ho hc.

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Qu trnh ng dngTrung ho trung ho cc nc thi c kim hoc axit cao.Kh trng loi b cc vi sinh vt gy bnh. Cc phng php thng s

dng l: chlorine, chlorine dioxide, bromide chlorine, ozoneCc qu trnh

khc

Nhiu loi ho cht c s dng t c nhng mc tiu

nht nh no . V d nh dng ho cht kt ta cc kim loi

nng trong nc thi.

2.3.4 Phng php x l sinh hc

Cc cht hu c dng keo, huyn ph v dung dch l ngun thc n ca vi

sinh vt. Trong qu trnh hot ng sng, vi sinh vt oxy ho hoc kh cc hp cht

hu c ny, kt qu l lm sch nc thi khi cc cht bn hu c.

X l nc thi bng phng php sinh hc hiu kh: Qu trnh x l nc

thi c da trn s oxy ho cc cht hu c c trong nc thi nh oxy t do ho

tan. Nu oxy c cp bng thit b hoc nh cu to cng trnh, th l qu trnh

sinh hc hiu kh trong iu kin nhn to. Ngc li, nu oxy c vn chuyn v

ho tan trong nc nh cc yu t t nhin th l qu trnh x l sinh hc hiu

kh trong iu kin t nhin.

X l nc thi bng phng php sinh hc k kh: Qu trnh x l c

da trn c s phn hu cc cht hu c gi li trong cng trnh nh s ln men k

kh. i vi cc h thng thot nc qui m va v nh ngi ta thng dng cc

cng trnh kt hp vi vic tch cn lng vi phn hu ym kh cc cht hu c

trong pha rn v pha lng.

2.3.4.1 X l sinh hc trong iu kin t nhin Cc cng trnh x l nc thi trong t

Cc cng trnh x l nc thi trong t l nhng vng t quy hoch ti

nc thi nh k gi l cnh ng ngp nc (cnh ng ti v cnh ng lc).

Cnh ng ngp nc c tnh ton thit k da vo kh nng gi li, chuyn ho

cht bn trong t. Khi lc qua t, cc cht l lng v keo s c gi li lp

trn cng. Nhng cht to nn lp mng gm v s vi sinh vt c kh nng hp

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18/84


ph v oxy ho cc cht hu c c trong nc thi. Hiu sut x l nc thi trong

cnh ng ngp nc ph thuc vo cc yu t nh loi t, m ca t, mc

nc ngm, ti trng, ch ti, phng php ti, nhit v thnh phn tnh

cht nc thi. ng thi n cn ph thuc vo cc loi cy trng trn b mt.

Trn cnh ng ti ngp nc c th trng nhiu loi cy, song ch yu l loi cy

khng thn g.

H sinh hc

H sinh hc l cc thu vc t nhin hoc nhn to, khng ln m y din

ra qu trnh chuyn ho cc cht bn. Qu trnh ny din ra tng t nh qu trnh

t lm sch trong nc sng h t nhin vi vai tr ch yu l cc vi khun v to..

Theo bn cht qu trnh x l nc thi v iu kin cung cp oxy ngi ta

chia h sinh hc ra hai nhm chnh: h sinh hc n nh nc thi v h lm thong

nhn to.

H sinh hc n nh nc thi c thi gian nc lu li ln (t 2 3 ngy

n hng thng) nn iu ho c lu lng v cht lng nc thi u ra. Oxy

cung cp cho h ch yu l khuch tn qua b mt hoc do quang hp ca to. Qutrnh phn hu cht bn dit khun mang bn cht t nhin.

Theo iu kin khuy trn h sinh hc lm thong nhn to c th chia thnh

hai loi l h sinh hc lm thong hiu kh v h sinh hc lm thong tu tin.

Trong h sinh hc lm thong hiu kh nc thi trong h c xo trn gn nh

hon ton. Trong h khng c hin tng lng cn. Hot ng h gn ging nh b

Aerotank. Cn trong h sinh hc lm thong tu tin cn c nhng vng lng cn

v phn hu cht bn trong iu kin ym kh. Mc xo trn nc thi trong h

c hn ch.

2.3.4.2 X l sinh hc trong iu kin nhn to

a. X l sinh hc hiu kh trong iu kin nhn to

X l sinh hc bng h vi sinh vt bm dnh

Cc mng sinh vt bao gm cc loi vi khun hiu kh, vi khun tu tin,

ng vt nguyn sinh, giun, b hnh thnh xung quanh ht vt liu lc hoc trn

Trang 18


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b mt gi th (sinh trng bm dnh) s hp th cht hu c. Cc cng trnh ch

yu l b lc sinh hc, a lc sinh hc, b lc sinh hc c vt liu lc nc

Cc cng trnh x l nc thi theo nguyn l bm dnh chia lm hai loi:

Loi c vt liu lc tip xc khng ngp trong nc vi ch ti nc theo chu

k v loi c vt liu lc tip xc ngp trong nc ngp oxy.

B lc sinh hc nh git

B lc sinh hc nh git dng x l sinh hc hon ton nc thi, m

bo BOD trong nc thi ra khi b lng t hai di 15 mg/l.

B c cu to hnh ch nht hoc hnh trn trn mt bng. Do ti trng thy

lc v ti trng cht bn hu c thp nn kch thc vt liu lc khng ln hn

30mm thng l cc loi cc, cui, than cc. Chiu cao lp vt liu lc trong b

t 1,5 2 m. B c cp kh t nhin nh cc ca thng gi xung quanh thnh vi

din tch bng 20% din tch sn thu nc hoc ly t di y vi khong cch

gia y b v sn vt liu lc cao 0,4 - 0,6 m. lu thng hn hp nc thi

v bn cng nh khng kh vo trong lp vt liu lc, sn thu nc c cc khe h.

Nc thi c ti t trn b mt nh h thng phn phi vi phun, khoan l hocmng rng ca.

a lc sinh hc

a lc sinh hc c dng x l nc thi bng phng php sinh hc

theo nguyn l bm dnh. a lc l cc tm nha, g, hnh trn ng knh 2

4 m dy di 10 mm ghp vi nhau thnh khi cch nhau 30 40 mm v cc khi

ny c b tr thnh dy ni tip quay u trong b nc thi. a lc sinh hc

c s dng rng ri x l nc thi sinh hot vi cng sut khng hn ch.

Tuy nhin ngi ta thng s dng h thng a cho cc trm x l nc thi

cng sut di 5000 m3/ngy.

B lc sinh hc c vt liu lc ngp trong nc

B lc sinh hc c vt liu lc ngp trong nc hot ng theo nguyn l lc

dnh bm. Cng trnh ny thng c gi l Bioten c cu to gn ging vi b

lc sinh hc v Aerotank. Vt liu lc thng c ng thnh khi v ngp trong

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nc. Kh c cp vi p lc thp v dn vo b cng chiu hoc ngc chiu vi

nc thi. Khi nc thi qua lp vt liu lc, BOD b kh v NH4+ b chuyn ho

thnh NO3- trong lp mng sinh vt. Nc i t di ln, chy vo mng thu v

c dn ra ngoi.

X l sinh hc bng h vi sinh vt sinh trng l lng

X l sinh hc bng phng php bn hot tnh

Bn hot tnh l tp hp vi khun, x khun, nm, ng vt nguyn sinh

thnh cc bng bn xp, d hp th cht hu c v d lng (vi sinh vt sinh trng

l lng). Cc cng trnh ch yu l cc loi b Aerotank, knh oxy ho hon ton

Cc cng trnh ny c cp kh cng bc oxy cho vi khun oxy ho cht hu

c v khuy trn u bn hot tnh vi nc thi.

B Aerotank:Khi nc thi vo b thi kh (b Aerotank), cc bng bn hot

tnh c hnh thnh m cc ht nhn ca n l cc phn t cn l lng. Cc loi vi

khun hiu kh n c tr, pht trin dn, cng vi cc ng vt nguyn sinh, nm,

x khun, to nn cc bng bn mu nu sm, c kh nng hp th cht hu c

ha tan, keo v khng ha tan phn tn nh. Vi khun v sinh vt sng dng chtnn (BOD) v cht dinh dng (N, P) lm thc n chuyn ho chng thnh cc

cht tr khng ho tan v thnh t bo mi. Trong Aerotank lng bn hot tnh

tng dn ln, sau c tch ra ti b lng t hai. Mt phn bn c quay li v

u b Aerotank tham gia qu trnh x l nc thi theo chu trnh mi.

B sinh hc theo m SBR (Sequence Batch Reactor)

Sequencing Batch Reactor (L phn ng theo chui) l h thng bn hot

tnh kiu lm y-v-rt, mt h thng phn ng kiu khuy trn hon ton bao

gm tt c cc bc ca qu trnh bn hot tnh xy ra trong mt b n nht, hot

ng theo chu trnh mi ngy. SBR khng cn s dng b lng th cp v qu trnh

tun hon bn, thay vo l qu trnh x cn trong b.

Cc qu trnh hot ng chnh ca b sinh hc tng m gm:

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Qu trnh sinh hc hiu kh dng kh BOD: bi s tng sinh khi ca

qun th vi sinh vt hiu kh c tng cng bi khuy trn v cung cp oxy, to

iu kin phn ng giai on (b).

Qu trnh sinh hc hiu kh, k kh dng kh BOD, kt hp kh nit

photpho: bi s tng qun th visinh vt hiu kh, k kh. Tng cng khuy trn

cho qut trnh k kh, khuy trn v cung cp oxy cho qu trnh hiu kh, khuy trn

cho qu trnh hiu kh, to iu kin cho giai on (b). Giai on (b) c th hin

r trong s 2.1.

Hnh 2.1: S phn ng trong sinh hc tng m c kt hp kh N, P

Giai on 3: xy ra trong qu trnh nitrat ha v oxy ha cht hu c.

Giai on 4: xy ra qu trnh kh nitrat

y l qu trnh tng hp c hiu qu kt hp kh BOD cacbon v cc cht

hu c ha tan N, P. Trong qu trnh kh N c th tng cng ngun cacbon bn

ngoi bng Metanol giai on 4

Cc qu trnh sinh hc din ra trong b vi s tham gia ca cc vi sinh vt

trong qu trnh oxy ha cht hu c, c bit l c s tham gia ca hai chng loi

Nitrosmonas v Nitrobacter trong qu trnh nitrat ha v kh nitrat kt hp.

Trang 21

MetanolNT vo

(1)Lm y

(2)Anaerobic( khuy )

(3)Aerobic(khuy +

O2

)

(4)Anoxic

(Tt O2+ khuy)

(5)Lng

(6)Tch nc

x bn

Giai on (b)


22/84


b. X l sinh hc k kh trong iu kin nhn to

Phn hy k kh (Anaerobic Descomposotion) l qu trnh phn hy cc cht

hu c thnh cht kh (CH4 v CO2) trong iu kin khng c xy. Vic chuyn ho

cc axit hu c thnh kh mtan sn sinh ra t nng lng. Lng cht hu c

chuyn ho thnh kh vo khong 80 90%.

Hiu qu x l ph thuc vo nhit nc thi, pH, nng MLSS. Nhit

thch hp cho phn ng sinh kh l t 32 35oC.

u im ni bt ca qu trnh x l k kh l lng bn sn sinh ra rt thp,

v th chi ph cho vic x l bn thp hn nhiu so vi cc qu trnh x l hiu kh.

Trong qu trnh ln men k kh, thng c 4 nhm vi sinh vt phn hy vt

cht hu c ni tip nhau:

- Cc vi sinh vt thy phn (Hydrolytic) phn hy cc cht hu c dng

polyme nh cc polysaccharide v protein thnh cc monomer. Kt qu ca s b

gy mch cacbon ny cha lm gim COD;

- Cc monomer c chuyn ha thnh cc axit bo (VFA) vi mt lng

nh H2. Cc axit ch yu l Acetic, propionic v butyric vi nhng lng nh caaxit Valeric. giai on axit ha ny, COD c gim i i cht (khng qu 10%);

- Tt c cc axit c mch carbon di hn axit acetic c chuyn ha tip

thnh acetac v H2 bi cc vi sinh vt Acetogenic.

Phng php x l k kh vi sinh trng l lng

Phng php tip xc k kh

B ln men c thit b trn v b lng ring. Qu trnh ny cung cp phn ly

v hon lu cc vi sinh vt ging, do cho php vn hnh qu trnh thi gian lu

t 6 12 gi.

Cn thit b kh kh (Degasifier) gim thiu ti trng cht rn bc phn

ly.

x l mc cao, thi gian lu cht rn c xc nh l 10 ngy

nhit 32oC, nu nhit gim i 11oC, thi gian lu i hi phi tng gp i.

B UASB (Upflow anaerobic Sludge Blanket)

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Nc thi c a trc tip vo pha di y b v c phn phi ng

u, sau chy ngc ln xuyn qua lp bn sinh hc dng ht nh (bng bn) v

cc cht hu c b phn hy.

Cc bt kh mtan v NH3, H2S ni ln trn v c thu bng cc chp thu

kh dn ra khi b. Nc thi tip theo chuyn n vng lng ca b phn

tch 2 pha lng v rn. Sau ra khi b, bn hot tnh th hon lu li vng lp

bng bn. S to thnh bn ht v duy tr c n rt quan trng khi vn hnh

UASB.

Thng cho thm vo b 150 mg/l Ca2+ y mnh s to thnh ht bn v

5 10 mg/l Fe2+ gim bt s to thnh cc si bn nh. duy tr lp bng bn

trng thi l lng, tc dng chy thng ly khong 0,6 0,9 m/h.

Hnh 2.2 B UASB

Phng php x l k kh vi sinh trng gn kt

Lc k kh vi sinh trng gn kt trn gi mang hu c (ANAFIZ)

Lc k kh gn vi s tng trng cc vi sinh vt k kh trn cc gi th. B

lc c th c vn hnh ch dng chy ngc hoc xui.

Gi th lc trong qu trnh lu gi bn hot tnh trn n cng c kh nng

phn ly cc cht rn v kh sn sinh ra trong qu trnh tiu ha.

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Lc k kh vi lp vt liu gi lng trng n (ANAFLUX)

Vi sinh vt c c nh trn lp vt liu ht c gin n bi dng nc

dng ln sao cho s tip xc ca mng sinh hc vi cc cht hu c trong mt n

v th tch l ln nht. u im:

- t b tc nghn trong qu trnh lm vic vi vt liu lc;

- Khi ng nhanh chng;

- Khng ty tri cc qun th sinh hc bm dnh trn vt liu;

- C kh nng thay i lu lng trong gii hn tc cht lng.

2.3.5 X l bn cn

Nhim v ca x l cn (cn c to nn trong qu trnh x l nc thi):

- Lm gim th tch v m ca cn

- n nh cn

- Kh trng v s dng li cn cho cc mc ch khc nhau

Rc (gm cc tp cht khng tan kch thc ln: cn b thc vt, giy, gi

lau) c gi li song chn rc c th ch n bi rc (nu lng rc khng

ln) hay nghin rc v sau dn n b mtan tip tc x l.Ct t b lng c dn n sn phi ct lm ro nc v ch i s dng

vo mc ch khc.

gim th tch cn v lm ro nc c th ng dng cc cng trnh x l

trong iu kin t nhin nh: sn phi bn, h cha bn, hoc trong iu kin nhn

to: thit b lc chn khng, thit b lc p dy ai, thit b ly tm cn). m

ca cn sau x l t 55-75%.

My p bng ti: bn c chuyn t b nn bn sang my p gim ti

a lng nc c trong bn. Trong qu trnh p bn ta cho vo mt s polyme

kt dnh bn.

Lc chn khng: Thit b lc chn khng l tr quay t nm ngang. Tr

quay t ngp trong thng cha cn khong 1/3 ng knh. Khi tr quay nh my

bm chn khng cn b p vo vi bc.

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Quay li tm: Cc b phn c bn l rt hnh cn v ng rng rut. Rt v

ng quay cng chiu nhng vi nhng tc khc nhau. Di tc ng ca lc li

tm cc phn rn ca cn nng p vo tng ca rt v c dn ln n khe h,

ra thng cha bn ngoi.

Lc p: Thit b lc gm mt s tm lc v vi lc cng gia nh cc trc

ln. Mi mt tm lc gm hai phn trn v di. Phn trn gm vi lc, tm xp v

ngn thu nc thm. Phn di gm ngn cha cn. Gia hai phn c mng n hi

khng thm nc.

tip tc lm gim th tch cn c th thc hin sy bng nhit vi nhiu

dng khc nhau: thit b sy dng trng, dng kh nn, bng ti Sau khi sy,

m cn 25-30% v cn dng ht d dng vn chuyn.

i vi trm x l cng sut nh, vic x l cn c th tin hnh n gin

hn: nn sau lm ro nc sn phi cn trn nn ct.

2.4Mt s h thng x l nc thi sinh hot ang p dng ti cc cng ty

2.4.1 Cng ty TNHH lin doanh Ch Hng, KP M Hip, TT Thi Ha,

huyn Tn Uyn, tnh Bnh Dng.Thng s c bn

Tng lu lng nc thi: 1200m3/ng

Lu lng trung bnh gi (24h): 50 m3/h

Lu lng ti a: 98 m3/2h

Tnh cht c bn ca nc thi du vo

pH = 6 - 9

SS = 67mg/l

BOD5 = 450mg/l

COD = 790mg/l

Yu cu: nc thi u ra phi c x l t tiu chun loi B (QCVN 14-2008)

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S cng ngh

Hnh 2.3: S cng ngh h thng x l nc thi sinh hot cng ty TNHH lin

doanh Ch Hng

Cng ngh ch o:

Cng ngh truyn thng x l sinh hc vi bn hot tnh sinh trng l lng.

u im: - Cng ngh n gin, d vn hnh.

- S dng trong trng hp nc thi c lu lng ln.

- H thng c iu khin hon ton t ng, vn hnh n gin, tsa cha.

Nhc im: - Din tch xy dng ln.

- i hi nhiu nng lng trong sut qu trnh hot ng.

- Khng phng c s c kim loi nng, d gy cht bn.

- Hiu qu x l Nit thp nn hm lng vn cn vt qu tiu

chun cho php.

2.4.2 Cng ty C Phn Ch Bin Hng Xut Khu Long An - Nh my

iu Long An

a ch: s 81B, Quc l 62, Phng 2, Thnh ph Tn An, Tnh Long An.

Thng s c bn

Lu lng dng thi thit k: 200m3/ngy.m.

Lu lng trung bnh gi (24h): 8,4 m3/h

Tnh cht nc thi u vo

Trang 26

Nc thi vo

Ngun tip nhnQCVN 14-2008, Ct B

Nc ti s dng

H lng

H cha nc xl

Bn lc ctbm

H cha bn

H iu ha

H x l hiu kh

H x l k kh

H cha nc thi

SCR

Thit b khuy trn

H cha nc hilu

My p bn

Thi b

Hilu

bnlngThit b sc kh

Thit b sc kh

Thit b sc kh


27/84


pH = 6 8,5

COD = 600 750 mg/l

BOD = 350 400 mg/l

SS = 180 290 mg/l

Yu cu: nc thi u ra phi c t tiu chun loi A (QCVN 14 2008)

S cng ngh

Trang 27

Nc thi

B iu ha k kh

B hiu kh sinh hc(AEROTANK)

B lng bn vi sinh

B trung gian

Nc sau x l

B cha bnsinh hc

My cpkh nn

Ha chtkh trng

Thu khsinh hc

B lc p lc

B kh trng

Nc ra lc

Tunhonbn


28/84


Hnh 2.4: S cng ngh h thng x l nc thi sinh hot Cng ty C

Phn Ch Bin Hng Xut Khu Long An - Nh my iu Long An

Cng ngh ch o:

S dng cng ngh sinh hc hiu kh vi bn hot tnh aerotank truyn thng.

u im: - Cng ngh n gin, d vn hnh.

- Kh nng x l nc thi c BOD cao.

Nhc im: - Chi ph u t ban u cao, tn nhiu din tch xy dng.

- i hi nhiu nng lng trong sut qu trnh hot ng.

- Hiu qu x l nit thp.

2.4.3 Cng Ty Ch Bin Xut Nhp Khu Nng Sn Thc Phm ng

Nai-DONAFOODS

a ch: Khu ph 2 - Phng Long Bnh - Bin Ha - ng Nai

Lu lng nc thi thit k: 200m3/ng

Tnh cht nc thi u voBOD5 = 410 mg/l

COD = 800 mg/l

SS = 200 mg/l

pH = 5 - 9

Yu cu: nc thi u ra phi c x l t tiu chun loi A (QCVN 14 - 2008)

Trang 28


29/84


S cng ngh

Trang 29


30/84


Hnh 2.5: S cng ngh h thng x l nc thi Cng Ty Ch Bin Xut

Nhp Khu Nng Sn Thc phm ng NaiDONAFOODS

Cng ngh ch o:

Trang 30

Nc thi

Q = 200 m3/ngy m

Ngun tip nhn

(QCVN 14:2008/BTNMT, Ct A)

B iu ha

B Anoxic

B kh trngHa

cht

B cha bn

MyCt B

X l theo quy nh

B Aerotank

B lng ng Bn

d

Bntunh

on

My

khuy chm

B tch du

H thu

My

thi kh

N

ctun

hon


31/84


S dng cng ngh bn hot tnh theo phng php thiu kh v hiu kh c

in.

u im:

- Kh nng x l nc thi c BOD cao, kh Nit, tit kim din tch.

Nhc im:

- i hi ngi vn hnh phi c trnh cao, vn hnh phc tp, chi ph

xy dng tn km.

- i hi nhiu nng lng cp cho my thi kh trong sut qu trnh hot

ng.

- Chi ph u t xy dng b lc than hot tnh khng hp l, tn km do

phi thay than hot tnh theo nh k, nc thi c th khng cn qua giai on ny

m vn t hiu qu.

2.4.4 Doanh Nghip T Nhn Bin Ct

a ch: 8 Nguyn nh Chiu Phan Thit Bnh Thun

Cng sut thit k: 250m3/ngy.m

Yu cu: nc thi u ra phi c x l t tiu chun loi A (QCVN14-2008)

S cng ngh

Trang 31


32/84


Hnh 2.6: S cng ngh h thng x l nc thi sinh hot Doanh

Nghip T Nhn Bin Ct

u im:

- Kh nng x l nc thi c BOD cao, kh Nit, tit kim din tch.

- t tn din tch xy dng.

Nhc im:

- Vn hnh phc tp.

- Ngi iu hnh cn c k nng: Theo di, kim tra cc ch tiu u ra

thng xuyn.

CHNG 3: PHN TCH LA CHN V XUT CNG NGH PH

HP X L NC THI SINH HOT CNG TY TNHH VMC HONG

GIA

Trang 32

Nc thi

B iu ha

B sinh hc hiu khdng m (SBR)

B trung gian

Nc sau x l

B cha bnsinh hc

My cpkh nn

Ha chtkh trng

My cpkh nn

B lc p lc

B kh trng

Nc ra lc


33/84


3.1 C s la chn cng ngh

xut cng ngh x l nc thi da vo:

- Cng sut trm x l.

- Cht lng nc sau x l.

- Thnh phn, tnh cht nc thi sinh hot.

- Nhng quy nh x vo cng chung v vo ngun nc.

- Hiu qu qu trnh.

- Din tch t sn c ca cng ty

- Quy m v xu hng pht trin trong tng lai ca cng ty.

- Yu cu v nng lng, ha cht, cc thit b sn c trn th trng.

3.2 Thnh phn tnh cht nc thi ti cng ty TNHH VMC Hong Gia

3.2.1 Lu lng nc thi

H thng x l nc thi ca Cng ty TNHH VMC Hong Gia xy dng vi

cng sut Q = 205 m3/ngy.m. Nc thi sau khi qua h thng x l s t

QCVN 14: 2008/BTNMT, ct A v c thira ngun tip nhn l h thng thot

nc chung ca Cm Cng Nghip3.2.2 Thnh phn v tnh cht nc thi

Thnh phn v lu lng nc thi l hai thng s quan trng nht, ng vai

tr quyt nh trong vic xc nh cng ngh, tnh ton thit k cc cng trnh n

v, cng nh la chn thit b

c c s nh gi cht lng nc thi ca Cng ty TNHH VMC

Hong Gia, ngy 10/11/2010, Vin Nghin Cu Cng Ngh Mi Trng & Bo H

Lao ng, s 314 Trng Chinh, P.13, Q Tn Bnh, Tp. HCM tin hnh ly mu

nc thi ca Cng ty ti v tr ng ng x thi ra ngun tip nhn. Kt qu phn

tch mu nc c th hin trong bng 3.1.

Bng 3.1: Thnh phn tnh cht nc thi cng ty TNHH VMC Hong Gia

v yu cu sau khi x l

Trang 33


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ST

T

Ch tiu n v Gi tr

u voQCVN

14:2008/BTNMT

(loi A)

01 pH 6,74 5 9

02 BOD5 (20oC) mg/l 215 30

03 COD mg/l 421 -04 Cht rn l lng (SS) mg/l 36,7 50

05 Phosphat (PO3-4) (tnh theo P) mg/l 11,7 606 Amoni (tnh theo N) mg/l 32,5 5

07 Nitrat (NO3-) ( tnh theo N) mg/l 12,5 3008 Sulfua (tnh theo H2S) mg/l 0.4 1,0

09 Du m thc vt mg/l 1,25 10

10 Coliform MPN/100ml 2,2 x 105 3000

(Ngun: Vin Nghin Cu Cng Ngh Mi Trng & Bo H Lao ng)

Nhn xt: Bng thnh phn tnh cht nc thi trc v sau x l cho thy

sau khi nc thi c x l s b ti hm t hoi c bn t ch tiu ngun tip

nhn ch cn mt s thng s nh BOD, Phosphat, Amoni, Coliforms cn kh cao

v cn tip tc x l t loi A - QCVN 14:2008/BTNMT trc khi x vo ngun

tip nhn.

3.3 xut quy trnh cng ngh x l ph hp

Da trn vic phn tch lu lng, thnh phn nc thi, yu cu mc x

l, iu kin kinh t, k thut xut 2 phng n x l nc thi cho cng ty

TNHH VMC Hong Gia nh sau:

3.3.1 Phng n 1

Trang 34

Ngun tip nhnQCVN 14-2008, Ct A

B iu ha

B SBR

Ha chtkh trng

Chn lp

B kh trng

Sn phi bn

Bn d

Nc thi sinh hot205 m3/ngy.m

Nc tch t b nn v sn phi bn

B trung gian

B lc p lc

Hng mchin hu

H thu nc thi

Gi chn rc

Bm

Bm

Bm

Bm

B cha vnn bn

Bm

My thi kh

H thu nc thi


35/84


Hnh 3.1 S quy trnh cng ngh phng n 1

Trang 35


36/84


3.3.2 Phng n 2

Hnh 3.2: S quy trnh cng ngh phng n 2

Trang 36

Ngun tip nhnQCVN 14-2008, Ct A

B iu ha

Aerotank

Ha cht khtrng

NH K HT BN

B cha v nnbnBn d

Nc thi sinh hot 205m3/ngy.m

H thu nc thi

Gi chn rc

B kh trng

Nctch

bn

B lng 2

Bm

BmMy thi kh

Bm

Bm

Hng mchin hu


37/84


3.3.3 So snh 2 phng n x l

Bng 3.2: So snh 2 phng n x l

Phng n Phng n 1

(B SBR)

Phng n 2

(B Aerotank)u im - Qu trnh x l n gin, n

nh khng b nh hng nhiu

khi lu lng thay i t ngt.

- Khng cn h thng bn tun

hon.

- Khng cn b lng II.

- Gim din tch t xy dng

v chi ph u t.

- C kh nng kh c cc

hp cht cha N, P.

- B Aerotank ph hp s dng

trong trng hp nc thi c

lu lng bt k.

- H thng c iu khin

hon ton t ng, vn hnh

n gin, t sa cha.

- D khng ch cc thng s

vn hnh

- Hiu qu x l BOD, COD

kh cao

Nhc im - Cng ngh sinh hc - b SBR

i hi s n nh tnh cht

nc thi trc x l.

- Ngi vn hnh phi c kinh

ngim v thng xuyn theo

di cht ch cc giai on

XLNT ca b SBR.

- Lng bn sinh ra nhiu

- Kh nng x l N, P khng

cao

Nhn xt: Sau khi so snh u, nhc im 2 cng ngh x l thy rng:

Phng n 1 c nhiu u im ph hp vi yu cu thit k cho trm x l nc

thi cng ty TNHH VMC Hong Gia v quy m, kinh t, qun l, vn hnh. Chnh

v vy chn phng n 1 tnh ton thit k cho trm x l nc thi cng ty

TNHH VMC Hong Gia cng sut 205m3/ngy.m.

3.3.4 Thuyt minh quy trnh cng ngh la chn ( Phng n 1 )

Trang 37


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Nc thi t hm t hoi ca nh v sinh t chy v h thu ca trm x l

nc thi theo ng ng chnh. Nc thi trc khi i vo h thu i qua gi chn

rc loi b nhng loi rc th bo v bm trong h thu. Nc thi t h thu

c lun phin bm bng 2 bm chm vo b iu ha.

B iu ha c nhim v iu ha lu lng v hm lng cht thi trong

nc thi i vo trm x l, B iu ho c lp t h thng sc kh khuy

trn v gim mt phn BOD. Nc thi t b iu ha c bm qua b

Sequencing Batch Reactor (SBR) bng 2 bm chm.

Trong b SBR (Sequencing Batch Reactor) ta b tr h thng phn phi kh

trn khp din tch b. B hot ng gm 5 pha thc hin ni tip nhau: pha lm

y (Fill), pha phn ng (React), pha lng (Settle), pha tho nc sch (Decant),

pha ch (Idle).

Thi b bn khng nm trong cc hot ng ca b SBR v khng c thi

gian nh cho qu trnh thi b. Bn thng c thi b trong pha lng hoc pha

ch. Khi lng bn v tng s thi bn c quy nh da vo hiu qu x l

mong mun. Do qu trnh sc kh v lng din ra trong cng mt b nn khng cbn cht trong qu trnh phn ng v khng cn phi tun hon bn duy tr nng

bn trong b phn ng. Bn c x ht nh k v b cha nn bn gim

lng m c trong bn n mc cho php trc khi bm ln sn phi bn. Cn

phn nc trong c thu bng mt thit b t bit dng cho b SBR chy v b

cha trung gian. T b cha trung gian c bm ln b lc p lc tch cc cn

l lng cn li trong nc thi ri t y c dn sang b tip xc, tip xc vi

clorine trong mt thi gian nht nh sau khi thi ra b kh trng, nc thi t

tiu chun i vi ngun thi loi A theo QCVN 14 2008 v c th x ra ngun

tip nhn.

CHNG 4: TNH TON CNG TRNH X L

Trang 38


39/84


4.1 Mc tiu

Tnh ton thng s dng vt cht, kch thc cng trnh.Ga tr lu lng dng thit k:

H s khng iu ha ca nh my l: Kmax = 2,5, Kmin = 0,4

QTB = 205 m3/ngy = 205 m3/24h = 8,54 m3/h

Qmax = 2.5QTB = 2,5 x 205 m3/ngy = 512,5 m3/24h = 21,35 m3/h

Qmin = 0.4QTB = 0,4 x 205 m3/ngy = 82 m3/24h = 3,42 m3/h

Bng 4.1 Cc thng s lu lng dng trong thit k.

Thng s K hiu, n v Gi trLu lng gi trung bnh QTB (m3/h) 8,54Lu lng gi ln nht Qh,max (m3/h) 21,35Lu lng gi nh nht Qh,min (m3/h) 3,42

4.2 Tnh ton

4.2.1 Gi chn rc:

Gi chn rc gi li cc tp cht c kch thc ln hn 5mm.

Do cng sut nh v lng rc khng nhiu, chn gi chn rc th cng dng

gi cha. Khung gia cng bng V3 inox 304, li bao bng inox 304 l 3 5 ly.

Rc thu gom c hp ng vi cng ty mi trng th thu gom v x l.

Bng 4.2Cc thng s chn gi chn rc

Thng s Lm sch th cngKch thc gi chn rc:

Rng, mm

Di, mm

Cao, mm

Kch thc l, mm

300

300

500

3-5

4.2.2 Hm bm tip nhn

4.2.2.1 Nhim v:

Trang 39


40/84


Hm tip nhn nc thi l ni tp trung ton b nc thi t cc hm t hoi ca

cng ty m bo lu lng ti thiu cho bm nc v b iu ha hot ng an

ton.

4.2.2.2 Tnh ton:

Hm bm c cng ty TNHH VCM Hong Gia xy sn v trang b hai

bm chm bm vo cng thot nc chung ca khu vc.

Kch thc thc t ca hm bm: Di x Rng x Cao = 3,5 x 1,8 x 3m

Th tch thc ca b: V = 18,9 m3

Theo l thuyt th tch hm bm c tnh:

V = Qh,max .t

Trong : V Th tch hm bm, V = 18,9 m3

Qh,max : lu lng ln nht trong mt gi

t: thi gian lu nc ca hm bm

153885,0/35,21

9,183

3

phutmhm

m

Q

Vt ===

Vi thi gian lu nc hm bm t = 53 pht hon ton tha mn quy phm 10

30 pht. Chn hm tip nhn ny lm hm bm bm nc vo b iu ha.

Ti hm tip nhn cng ty TNHH VMC Hong Gia trang b hai bm chm

bm nc thi vo mng li thot nc chung ca khu vc. Cng sut ca mi

bm N=1 Hp, ct p H=8m, lu lng 12,5m3/h, hng sn xut HCP i Loan.

ng chuyn nc t hm tip nhn v b iu ha l ng nha uPVC 90mm. Do

ta chn hai bm ny bm nc vo b iu ha.

Bng 4.3 Cc thng s thit k v kch thc hm bm tip nhnSTT Thng s n v Gi tr

1 Lu lng gi ln nht, Q maxh m3/h 21,35

2 Thi gian lu nc, t pht 533 Th tch thc hm bm, Vb m3 18,94 Chiu su hu ch, h m 25 Kch thc hm bm

Chiu di, L m 3,5Chiu rng, B m 1,8

Chiu su tng cng, H m 3

Trang 40


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4.2.3 B iu ha

4.2.3.1 Nhim v

Do tnh cht nc thi thay i theo tng ca v khng n nh. V vy cn

thit xy dng b iu ha iu ha v lu lng v nng nc thi. ng thi

khi lm thong nh cp kh xy vo nc thi s trnh sinh mi hi thi ti y v

lm gim khong 20 -30% hm lng COD, BOD c trong nc thi.

Vic s dng b iu ha trong qu trnh x l mang li mt s thun li sau:

+ n nh lu lng v nng cc cht i vo cng trnh x l

sinh hc.

+ Tng cng hiu qu x l nc thi ca cng trnh x l sinh

hc pha sau, nh gim thiu hoc loi b hin tng gy sc do tng ti trng

t ngt, pha long cc cht gy c ch cho qu trnh x l sinh hc, n nh

pH ca nc thi m khng cn tiu tn nhiu ha cht.

+ Gip cho nc thi cp vo cc b sinh hc c lin tc trong

giai on cc phn xng khng x nc.4.2.3.2 Tnh ton

Kch thc b:

Thi gian lu nc trong b iu ha 4 8h, Chn t = 6h

Th tch b iu ha33

25,516/54,8 mhhmtQV h ===

Chn b hnh khi ch nht, chiu cao lm vic h = 4m, chiu cao bo v

hbv=1m

Chiu cao xy dng

m5m1m4hhH bv =+=+=

Din tch mt bng b

2

3

8,1 24

25,51m

m

m

H

VF ===

Kch thc b iu ha: L x B x H = 4m x 3,5m x 5m

Trang 41


42/84


Vt liu xy dng

Chn vt liu xy dng b iu ha l b tng ct thp M250, thnh dy

200mm, bn y dy 300 mm, st Nht an thnh hai lp, @200 phi 14, chng thm

sika bn trong 2 lp, bn ngoi qut bentum.

Thng s v kch thc b th hin trong bng 4.4.

Bng 4.4 Thng s v kch thc b iu ho

STT Thng s n v Gi tr1 Thi gian lu nc, t H 62 Th tch thc ca b, V m3 70

3 Chiu cao lm vic, h M 44 Chiu cao bo v, hbv M 15 Chiu cao xy dng, H M 56 B rng ca b, B M 3,57 Chiu di b, L M 4

Dng khuy trn, tnh thit b xo trn b iu ha:

Bng 4.5 Cc dng khuy trn b iu ha

Dng khuy trn Gi tr n v

Khuy trn c kh 4 8 W/m3 th tch b

Kh nn, tc kh nn 10 15 L/m3.ph (m3 th tch b)

Do nhit ca nc thi khong 200C 250C trong khi nhit ca kh t

my thi kh cao hn nhiu (khong 400C) nn khi cp kh vo b iu ha va h a

trn cc dng nc va nng nhit ca nc thi (v yu cu ca nc thi khi

vo cc cng trnh sinh hc l phi c nhit t 28 35oC thch hp cho cc

phn ng sinh hc).Vy chn khuy trn b iu ha bng h thng thi kh

Lng kh nn cn thit cho khuy trn

phLphmmphmmVRq ttk /980/98,070./014,03333 ====

Vi

R: Tc kh nn, R = 10 15L/m3.ph, chn R = 14L/m3.ph

Vtt: Th tch thc t ca b, Vtt = 70m3

Trang 42


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Chn a phn phi kh b tr theo chu vi thnh c lu lng kh 120l/ph.

S a phn phi kh cn thit cho khuy trn

2,8/12 0

/980===

phL

phL

r

qn K ci, chn 9 ci

Chn a phn phi kh tinh loi EPDM, a mn 9, ng knh 270mm

Theo chiu di b t 3 a, a cch thnh b 0,67m, cc a cch nhau:

mn 33,12

267,04=

=

Theo chiu rng b t 3 a, a cch thnh b 0,55m, cc a cch nhau:

mn 2,12

255

,05

,3

=

=

Tnh ton ng dn kh nn:

ng ng chnh:

mmmv

qD

Khi

KK36036,0

14,315

0154,044==

=

=

qKK lu lng khng kh cn thit, qKK=924l/ph = 0,0154m3/s

Vkhi vn tc dng kh 15m/sVy chn ng dn kh chnh phn phi vo b iu ha l ng inox SUS304

42mm

ng ng nhnh

mv

qd

Khi

KK0255,0

14,36

00308,044=

=

=

qKK lu lng khng kh trong ng nhnh, qkk= 924L/ph/5 = 184,8L/ph =

0,00308 m3/s

vKh vn tc khng kh trong ng chn 6m/s

Vy chn ng dn kh nhnh vo b iu ha bng inox SUS304 27mm.

Tnh ton bm nc thi vo b SBR.

Lu lng bm: Q= 25,625m3 vy lu lng mi bm 25,625 m3/3h = 8,542

m3/h = 205m3/ngy

Ct p bm: H = 10 m

Trang 43


44/84


Cng sut bm:

N =

1000

HgQ=

85,01000606024

1 081,91000205

= 0,274 kW.

Chn loi bm nhng chm t ti b iu ha c lu lng Qb = 8,542m3/h.

Ct p H =10 m, cng sut N = 0,5 Hp, hng sn xut Tsurumi Nht.

ng ng dn nc vo b SBR:

Vn tc dng chy trong ng c p l v = 0,7 1,5 m/s. Chn v=1,0 m/s.

ng knh ng dn nc:

D = 60602 40,120544

= x

x

xv

xQ

=0,055 (m).

Kim tra li vn tc nc trong ng:

V= 2,1606024)05,0(

2 0544

22==

xxxx

x

xD

xQ

m/s > v=1m/s

tha iu kin.

Vy chn ng nc sang b SBR l ng nha uPVC c 60mm.

Vt liu xy dngChn vt liu xy dng b iu ha l BTCT M250, thnh dy 200mm, bn y

dy 300 mm, st Nht an thnh hai lp, @200 phi 14, chng thm sika bn trong

2 lp, bn ngoi qut bentum.

4.2.4 B SBR

Cc thng s u vo ca b SBR:

- Cng sut thit k: Q=205m3/ng.

- BOD5 = 215 mg/l.

- COD = 420 mg/l

Cc thng s u ra: (Theo tiu QCVN 14 2008, ct A)

- BOD5 30 mg/l

- COD - mg/l

Cc thng s thit k:

- Nng bn hot tnh u vo ca b X 0 =0.

Trang 44


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- Thi gian lu bn (tui ca bn) c=10 30 ngy, chn 10 ngy

- T s F/M = 0,05-0,2 ngy-1

- Nng bn hot tnh l lng trong b: X=2000 5000 mg/l, chn X=3500

mg/l.

- tro ca cn: Z = 0,3 mg/mg.

- Ch s th tch bn: SVI = 150 ml/g

- BOD5 = 0,65COD

- T s MLVSS: MLSS= 0,68

- Nhit nc thi: t= 25oC

- Nng cn lng trung bnh di y b XS=10000mg/l.

- Cht l lng trong nc thi u ra cha 20mg/l cn sinh hc v 65% cht c

kh nng phn hy sinh hc.

4.2.4.1 Xc nh kch thc b SBR:

Tng thi gian ca mt chu k hot ng

T = tF + tA + tS + tD + t1= 3 + 2 + 0,5 + 0,5 = 6h

Vi:Thi gian lm y: tF = 3h.

Thi gian phn ng: tA = 2h.

Thi gian lng: tS = 0,5h.

Thi gian rt nc: tD = 0,5h.

Thi gian pha ch: t1 = 0,

Chn SBR gm 2 n nguyn, khi n nguyn ny ang lm y

th n nguyn khc ang phn ng.

S chu k hot ng ca 1 n nguyn trong 1 ngy

n =h

h

6

24= 4 (chu k/n nguyn.ngy)

Tng s chu k lm y trong 1 ngy

N = 2xn = 2x4 = 8 (chu k/ngy)

Th tch b lm y trong 1chu k

Trang 45


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VF =8

2 05= 25,625 (m3)

Hm lng cht rn l lng trong th tch bn lng

Xs =SVI

lmlgxmg /1000/1000=

1 50

10001000x= 6666,67 (mg/l)

Xt s cn bng khi lng

VTxX =VSxXS

T

S

V

V=

SX

X=

676666

3500

,= 0,525

Cn cung cp thm 20% cht lng pha trn bn khng b rt ra theokhi rt nc

0,525x 1,2=0,63

T

F

V

V= 1 0,63 = 0,37 chn

T

F

V

V= 0,3

Th tch ca b SBR:

VT =30,

FV =3,0

625,25= 85,42 m3

Chn:

Chiu cao ca b, H = 4,6 m

Chiu cao bo v b, hbv = 0,4 m

Chiu cao xy dng b

Hxd = H + hbv = 4,6 + 0,5 = 5 m

Din tch ca b:

S =6,4

42,85=18,56 m2

Vy kch thc b SBR: L x B x H = 6m x 3m x 5m

Thi gian lu nc trong sut qu trnh:

hQ

VT202 4

2 05

42,8522=

=

= 10 50 h

4.2.4.2 Xc nh hm lng BOD5 ho tan trong nc thi u ra:

Trang 46


47/84


Tng BOD5ra = BOD5ho tan + BOD5 ca cn l lng

Hm lng cht l lng c kh nng phn hy sinh hc u ra:

25,625 x 0,65 = 16,65 (mg/l)

Hm lng BOD ca cht l lng c kh nng phn hy sinh hc u ra:

16,65 mg/l x 1,42 mg O2tiu th/mg t bo b oxi ho = 23,65 mg/l

Hm lng BOD5 ca cht l lng u ra:llBOD

5 = 23,68 x 0,68 = 16,08 (mg/l)

Hm lng BOD5 ho tan trong nc thi u ra:ht

BOD5 =

ra

BOD5 -

ll

BOD5 = 30 16,08 =13,92 mg/l4.2.4.3 Hiu qu x l:

Hiu qu lm sch theo BOD5 ha tan:

( ) ( )%5,931 00

2 1 5

92,1 32 1 51 00 =

=

=

o

o

S

SSE .

T s F/M:

M

F=

XV

SQ

T

o

=

350042,85

2 1 52 05

= 0,147 ngy-1 [0,05-0,2] ngy-1

Ti trng th tch ca b phn ng:

42,85

1 020521 53

=

=T

o

V

QSL = 0,52 kgBOD5/m3.ngy

4.2.4.4 Tnh ton lng bn sn sinh ra mi ngy.

Tc tng trng ca bn:

35,01 00 1 46,01

4,0

K1

YY

cdb =+=+=

Lng bn hot tnh sinh ra do kh BOD5 theo VSS trong 1 ngy:

( ) 42 7,1 41 092,1 321 520535,0)( 3 === SSQYP obX kg/ngy

Ta chn:

Y=0,4 g VSS/g bBOD

Kd.T = k20 x (T-20) = 0,12 g/g.ngy (1,04)25-20 = 0,0146 g/g.ngy

Bng 4.6 H s ng hc bn hot tnh 20o

C.

Trang 47


48/84


H s n v Gii hn Gi tr in hnh

m g VSS/g VSS.ngy 3-13,2 6

Ks g bCOD/m

3

5-40 20Y g VSS/g bCOD 0,3-0,5 0,4kd g VSS/g VSS.ngy 0,06-0,2 0,12fd Khng th nguyn 0,08-,02 0,15

Tng lng bn sinh ra theo SS trong 1 ngy:

61,203,01

427,14

1

=

=

=

z

PP XSS kg/ngy

Tng lng bn d cn x lmi ngy:

Lng bn d cn x ly(Gd) = tng lng bn lng cn tri ra khi b

= 20,61 20x205x10-3 = 16,51 kg/ngy.

Th tch cn chim ch sau 1 ngy:

62,1

1000

1000002,1

51,1 6

02,1=

=

=

S

db X

GV

m3/ngy.

Chiu cao cn lng trong b:

mxS

Vh bb 045,0

1 82

62,1

2

=

==

Th tch bn phi x mt b ( li 20%):

Vb = 0,8hb F =0,80,04536 = 0,648m3

Vy lng bn phi bm b hai b SBR mi ngy l:

Vtcb = 0,648x2 = 1,296 m3/ngy

4.2.4.5 Xc nh lng khng kh cn thit cho mt n nguyn:

Lng oxi cn thit cung cp cho mi b theo iu kin cn lm sch BOD,

oxy ha amoni NH+4 thnh NO3-, kh NO3- .

OCo = Q(So-S) - 1,42xPx + 4,57Q(N0 N)

= (102,5m3/ngy)(215-13,92)g/m3(1kg/103g)-1,42x(14,427kg/ngy)/2 +

4,57 x 102,5 (32,5 2) g/m3 (1kg/103g)

= 24,65 kg/ngy

Thi gian thi kh ca mt b: ti thiu mt na thi gian lm y nn thi kh

Trang 48


49/84


2

3H+2h = 3,5 h

Tng thi gian sc kh mt ngy ca mt b:3,5hx4 = 14h

T l chuyn ho oxi trung bnh:

1 4

/65,2 42

ngakgO= 1,76kg/h

Lng oxi thc t:

1,76 kg/h x2 = 3,52 kg/h

Ta chn:Hiu sut chuyn ho oxi l 9%

Khng kh c 23,2% trng lng O2

Khi lng ring khng kh l 1,2 kg/m3

Lng khng kh cn cp:

Mkk= )2 32,0)(/2,1(09,0/52,33mkg

hkg= 140,48 m3/h

Kim tra lng khng kh cn thit cho xo trn hon ton mt b:

q =V

Mkk =ngaphut/1 440, m8 5 4 2

L/m1 0 0 0/ngay, m1 4 0 4 83

33

= 1,142L/m3.pht

Tr s ny nm ngoi khong cho php: q = 20-40 L/m3pht

Vy ta chn q = 25L/m3.pht

Lng khng kh cn thit cho qu trnh:

Mkk= 25l/m3pht85,42m3= 2135,5L/pht = 0,0356m3/s

S lng a thi kh cn lp t trong b SBR

N =q

Mkk =phut.

u, L/ph2 1 35 5

/1 2 0l= 17,79 a

Vy s a thi kh cn lp t trong mi b SBR l: 18 a.

4.2.4.6 Cch phn phi a thi kh trong b

Kh t my thi kh c dn qua ng chnh i vo b SBR (t dc theo

chiu di b). Mi ng ng dn vo mi b SBR c chia lm 3 ng ng ph

Trang 49


50/84


cp 1 b tr dc theo thnh b xung y b phn phi kh cho cc a t ti y

mi b SBR. Theo tiu chun cc u rng ca a thi kh l rng phi 27 nn chn

ng nhnh cp 2 l ng phi 27 dn kh vo cc a.

Ti mi b SBR dc theo chiu di b tr 6 a, mi a cch nhau 1m v cch

thnh b 0,5m.

Khong cch gia 2 ng ng dn kh ph t gn nhau l 2m

Khong cch gia 2 ng ng ngoi cng n thnh b l 1m

4.2.4.7 Tnh ton ng ng, bm bn ra khi b SBR

ng ng dn nc ra khi b SBR:


ng knh ng dn nc:

D =6060240,1

20544

=

x

x

xv

xQ

=0,055 (m).

Theo kinh nghim thc t trnh trng hp b tt nghn v gim thi gian

thu nc ra khi b SBR ta chn ng thot nc ra khi b SBR l ng uPVC c

114.

Thu nc ra khi b SBR bng phao ni, chn thit b Decanter ca nh cung

cp Cng ty TNHH Cng Ngh Mi Trng Thng Long. Thit b gm mt phao

ni lm bng vt liu si thy tinh, pha trn l h thng c in t t ng iu

khin vic ht nc, c bao quanh bi mt lp bo v, phn ny c ni vi

phn cha nc chm di nc, gia hai phn ny c bt kn hon ton bng

mt vng m nm di y ca phao ni. Cc h thng ny c ni vi ngdn nc ra bng nha do c th un cong theo s ln xung ca thit b. Sau

cng, ng dn nha do ni vi ng dn nc ra c nh bng nha PVC 114mm.

Tnh ton bm bn ra khi b SBR v b nn bn.

- Lu lng bn cn thi b ti mt b SBR trong: QVb=0,648 m3/ngy. Lng

bn ny c chia iu cho bn chu k hot ng ca b SBR.

- Lng bn cn x b ti mt chu k:

Trang 50


51/84


Qck4

648,0= 0,162 m3/ngy = 1,875.10-6 m3/s.

- Chiu cao ct p: H=10m.- Cng sut ca bm:

N =

1000

hgQck =8,01000

1081,9108010875,1 6

= 2,48.10-4 kW

Vi:

+ : khi lng ring ca bn thi ly bng khi lng ring ca bn,

=1080kg/m3.

+ : hiu sut hu ch ca bm. Chn =0,8.Ngoi th trng khng c loi bm trn, chn loi bm nhng chm cnh h.

S lng bn ci, mi b SBR t hai ci c ct p H =10 m, cng sut bm 0,5Hp,

hng sn xut Tsurumi Nht.

ng ng dn kh vo b SBR:

- ng ng chnh:

ng knh ng dn kh chnh (cung cp cho 2 b SBR)

Dk =k

k

xv

xQ

4

=

9

0356,04= 0,07 m.

Vi:

vk: Vn tc kh trong ng dn chnh

vkh=9m/s.

Chn ng dn kh chnh l ng inox SUS30475mmKim tra li vn tc kh trong ng:

22 )075,0(

0356,044

=

= D

xQv Kkh =8,06m/s

- ng ng nhnh:

Lng kh qua mi ng nhnh:

qk =6

kQ =6

0356,0= 0,0059 m3/s

Trang 51


52/84


ng knh ng nhnh dn kh:

dk =v

qk

4=

9

0059,04

=28,89mm

Vi: vn: Vn tc kh trong ng nhnh

vn = 9m/s.

Chn ng nhnh dn kh l ng inox SUS304, ng knh 34mm.

Kim tra li vn tc kh trong ng:

22

)034,0(

0059,044

=

=

D

qv Kkh = 6,5 m/s.

4.2.4.8 Tnh ton my thi kh

p lc cn thit ca h thng phn phi kh:

Hk= hd + hc + hf+ H

= 0,4 + 0,4 + 0,5 + 4,7 = 6,0 m.

Vi:

hd: Tn tht p lc do ma st dc chiu di ng; hd 0,4 m;

chn hd =0,4mhc: Tn tht cc b; hc 0,4 m, chn hc = 0,4 m

hf: Tn tht qua thit b phn phi kh; hf 0,5 m, chn hf = 0,5 m

H: Chiu su hu ch ca b SBR, H = 4,7 m

Cng sut my thi kh:

Pk=

1

729

2830

1

21

,

, P

P

en

TRGk

=

1

1

593,1

8,0283,07,29

2 9831 4,808372,0283,0

= 4,345 kW.

Vi:

e : Hiu sut my thi kh; e = 0,7 - 0,8, chn e = 0,8

Gk: Trng lng dng kh

Gk= Qkx k = (0,0356 + 0,0288) x 1,3 = 0,08372 kg/s

R : Hng s kh; R = 8,314 KJ/KmoloK (i vi khng kh)

Trang 52


53/84


T1: Nhit khng kh u vo T1 = 25 + 273 = 298oK

P1: p sut tuyt i ca khng kh u vo P1 = 1 atm

P2: p sut tuyt i ca khng kh u ra:

P2 = 1 +1 2,1 0kH = 1 +

1 2,1 0

0,6= 1,593 atm

n: h s n, n =K

K 1=

395,1

1395,1 = 0,283 (K = 1,395)

in iu khin

iu khin cc pha hot ng ca hai b SBR bng cc van in t ng vi

s iu khin ca time thi gian. c thit k vi mc ch ti u ha cc qu trnh

vn hnh hot ng ca h thng SBR

Vt liu xy dng

Chn vt liu xy dng b SBR l BTCT M250, thnh dy 200mm, bn y

dy 300 mm, st Nht an thnh hai lp, @200 phi 14, chng thm sika bn trong 2

lp, bn ngoi qut bentum.

Bng 4.7 Thng s kch thc SBRSTT Thng s n v Gi tr1 Lu lng thit k, Q tbnga m

3/ngy 205

2 Thi gian lm y, tF = 3h. h 33 Thi gian phn ng, tA = 2h. h 24 Thi gian lng, tS = 0,5h. h 0,55 Thi gian rt nc, tD h 0,56 Thi gian ch, tI h 07 S n nguyn 2

8 S chu k /ngy.b 49 Chiu cao b m 4,610 Chiu cao bo v, hbv m 0,411 Chiu cao xy dng, Hxd m 512 Chiu di b, L m 613 Chiu rng b, B m 314 Thi gian lu nc h 2015 T s F/M ngy 1 0,14716 Ti trng th tch kgBOD/ngy 0,52

4.2.5 B trung gian

Trang 53


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4.2.5.1 Nhim v

Nc sau lng t b SBR theo ng dn chy vo b trung gian ri c bm

vo 2 b lc p lc.

4.2.5.2 Tnh ton

Kch thc b

Thi gian lu nc t = 15 pht (qui phm 10 15 pht).

Th tch b:

)(;135,260

15.54,8. 3mt

h

tbQV ===

- Chn b trung gian c kch thc nh sau

- Chiu di D x R x H = 2x1,1x2 m.

Vt liu xy dng

Chn vt liu xy dng b SBR l BTCT M250, thnh dy 200mm, bn y

dy 300 mm, st Nht an thnh hai lp, @200 phi 14, chng thm sika bn trong 2

lp, bn ngoi qut bentum.

Bm nc ln b lc p lc

Chn 2 bm trc ngang loi ly tm chu c mi trng

nc thi.

Ct p tng cng m bm thng c l : H = 10 m.

Cng sut bm :

)(;

.1000

...Kw

HgqN b

=

Trong :

qb : Lu lng bm, qb = 0,0023 (m3/s).

: Khi lng ring ca dung dch; chn p = 1050 kg/m3

g : Gia tc trng trng, g = 9,81 m/s2.

H : Ct p bm, H =10 m.

: Hiu sut chung ca bm = 0,65 0,8. Chn

= 0,65.

Trang 54


55/84


)(;5,075,0.65,0.1000

10.81,9.1050.0023,0

.1000

...HP

HgqN b ===

Ta chn bm c cng sut: N = 0,5 HP

ng ng dn nc vo b lc p lc


ng knh ng dn nc:

D =6060240,1

20544

=

x

x

xv

xQ

=0,055 (m).

Kim tra li vn tc nc trong ng:

V= 2,1606024)05,0(

20544

22==

xxxx

x

xD

xQ

m/s > v=1m/s

tha iu kin.

Vy chn ng dn nc vo b lc p lc l ng nha uPVC c 60mm.

Bng 4.8: Bng tm tt kt qu tnh ton b trung gian

Thng s K hiu n v Gi tr

Th tch thc ca b V m3 4,4

Chiu di ca b D m 2

Chiu rng ca b R m 1,1

Chiu cao tng cng H m 2

4.2.6 B lc p lc

4.2.6.1 Chc nng

B lc c dng gi li mt phn hay ton b cn bn c trong nc,

kh cc ht mn v c v hu c. Nc c bm t b trung gian qua ng phn

phi vo b lc, qua lp vt liu lc, lp si vo h thng thu nc trong v

c a v b kh trng.

4.2.6.2 Tnh ton

Dng b lc p lc vi 1 lp vt liu lc l ct thch anh, c:

ng knh ht: d = 0,5 1,25 (mm).

Trang 55


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Chiu dy lp vt liu lc 0,8 (m),

H s khng ng nht K = 2 2,2 ;

ng knh tng ng 0,7 0,8 mm.

Vt liu dng si c:

ng knh d = 5 2 mm, chiu dy d = 0,15 m.



Tng din tch ca b lc:

btbt vatWtTvQF

216,3 =

Trong :

+ Q: Cng sut trm x l 205 (m3/ngy m)

+ T: Thi gian lm vic ca trm trong mt ngy m (gi), T = 24 gi

+ btv : Tc lc tnh ton ch lm vic bnh thng (m/h), [ly theo

bng 4-10 trang 153 X L Nc Cp TS.Nguyn Ngc Dung] btv =

15 m/h

+ a : S ln ra mi b trong mt ngy m lm vic ch bnh

thng, a=1

+ W : Cng nc ra lc, [ly theo bng 4-5 trang 128 X L Nc

Cp TS.Nguyn Ngc Dung] W = 8 (l/sm2)

+ 1t : Thi gian ra lc, [ly theo bng 4-5 trang 128 X L Nc Cp

TS.Nguyn Ngc Dung] 1t = 0,1 (gi)

+ 2t : Thi gian ngng b lc ra, 2t = 0,35 gi

1 535,011,086,31 524

2 05

xxxxxF

= = 0,58 (m2)

S b lc cn thit, [Theo cng thc 4-51 trang 140 X L Nc Cp

TS.Nguyn Ngc Dung]

N = F5,0 = 0,5 58,0 = 0,38 b

Trang 56


57/84


Chn s b lc cn thit l N = 1 b, chn 2 b (Mt b hot ng mt b d

phng).

Din tch 1 b lc:

1

58,0==

N

Ff = 0,58 (m2)

Bn knh ca b lc:

===

14,3

58,0

14,3

fr 0,43m

ng knh ca b:

D = 0,86m = 860mm, chn ng knh ca b lc D=900mm

Chiu cao ton phn ca b lc xc nh theo cng thc:

H = h0

+ h1

+h2

+h3

+h4

=0,25+0,4+0,8+0,6+0,25=2,3 (m)

Trong :

+ 1h : Chiu cao lp si , [theo bng 4-7 trang 141 X L Nc Cp

TS.Nguyn Ngc Dung] 1h = 0,4 m

+ 2h : Chiu dy lp vt liu lc, ly theo bng 4-6 trang 139 X L Nc

Cp TS.Nguyn Ngc Dung 2h = 0,8 m

+Chn khong cch t phu thu n np trn thit b lc l: h

4

= 0,25 (m)

+Chn gin n lp vt liu khi ra ngc: e = 0,5 (m); [theo XLNT LVS

trang 60]

+ Khong cch t mt trrn lp vt liu n phu thu nc ra lc.

Trang 57

)(;6,0)8,04,0.(5,0).(213 mhheh =+=+=


58/84


Chn thit b c 3 chn, ng knh chn: dc

=114 mm, dy 3 mm; khong

cch t b mt t thit b n y di thit b: h0

= 0,25 (m)

Xc nh h thng phn phi nc ra lc

Cng ra lc cho mt b :

Qra =1000

. nuocWf =1000

1 5.58,0= 0,0087 m3/s

Thi gian ra lc l 8 pht. [theo bng 4-5 trang 128 X L Nc Cp

TS.Nguyn Ngc Dung]

Lng nc mt ln cho mt b :

q = Qra.t = 0,0087.8 .60 = 4,178 m3/ln

Chn tc nc chy trong ng dn theo quy phm l 2 m/s.

Tit din ng dn nc ra n b lc :

Sng =2

1Qra =

2

1. 0,0087 = 0,00435 m2

ng knh ng dn nc ra ti b lc

Dng =

S.4=

00435,0.4= 0,0744 m = 7,4 mm.

Chn ng dn c ng knh 75 mm.

Kim tra li vn tc nc chy trong ng dn chnh

v = orua

S

Q

= 4.

2D

Qrua

= 40075

,0

.

0087,02

= 1,47 m

(nm trong gii hn cho php 2 m/s)

Cu to h thng phn phi kiu c lp si gm: gin ng phn phi c

ng chnh v cc ng nhnh u vi nhau theo hnh xng c. Gin ng phn phi

c t trong lp si st y b. Cc ng nhnh c khoan hai hng l phn

phi so le na bn di v c hng to thnh 450 so vi phng thng ng.

ng knh l chn 10 mm. Din tch ca mt l Sl = r2

= 3,14.52

=0,0000785m2

Trang 58


59/84


Tng din tch cc l:

Stl = 35% Sng = 35%.0,00435 = 0,00152m2

S l cn thit:

0000785,0

00152,0==

l

tl

s

SN = 19,36 l

Chn s l cn thit l 20 l

Khon cch gia cc trc ca ng 200mm v gia cc tim l l 200mm

Tnh bm nc ra lc

Da vo hai thng s c bng l: lu lng nc ra lc (Qr) v p lc cn

thit ca my bm (Hr)

Lu lng nc ra lc Qr= 0,0087m3/s

p lc cn thit ca my bm xc nh theo cng thc sau:

Hr=hhh+ h + hp+ hs + hc +bbm +hcb= 4 + 0,5 + 7,76 + 0,18 + 0,14 + 2 + 2,4 = 16,98m

Trong :

- hhh: cao hnh hc tnh t mc nc thp nht n mp thu phu thu nc ra

lc, hhh=4m- h : Tn tht p lc trn ng ng dn nc t trm bm n b ra lc, chn

h = 0,5m

- hp: Tn tht p lc trong h thng phn phi nc ra lc, c tnh theo cng

thc sau:

mgg

hpvv n

76,781,9.2

2

81,9.2

2.03,19

22

.22

22

0=+=+=

Vi:

+ v0 tc nc chy u ng chnh: 2m/s

+ vn: Tc nc chy u ng nhnh: 2m/s

+ g; Gia tc trng trng: 9,81m/s2

+ :h s sc cn, tnh theo cng thc sau

03,19112 2,0

2,21

2,22

=+=+=

w

K ,

Trang 59


60/84


( Kw: t s gia tng in tch cc l trn ng (0,00152m2) v din tch tit din

ngang ca ng chnh (0,00435m2), Kw= 0,35)

- hs: Tn tht p lc qua lp si : 24...42.8,1

60.

1

2v

d

L

tChs

+= (m/ngy)

)/(;18,024.9..10

4,0.

4225.8,1

60.

600

1

2ngymhs =

+

=

-h

c

: Tn tht p lc qua lp ct lc:

)/(;14,024.9..2,1

8,0.

4225.8,1

60

.600

1

2 ngymhc =+

=

- hbm: p lc ph v kt cu ban u, ca lp ct lc; 2,0m

- hcp: Tng tn tht cc b cc b phn ni ng v van kha, xc nh theo

cng thc: mg

vhcb 4,2

81,9.2

2)].592,0()526,0()698,0[(

2

22

=++==

+ : Tn tht p lc qua ct = 0,98; kha=0,26; t=0,92.

+ v: Vn tc nc chy trong ng; v=2m/s

Cng sut bm:

N =

.1000

... gHQ= kW2

7,01000

81,999898,160087,0=

Trong : Q = 0,0087 m3/s : lu lng nc dng ra lc

H = 16,98 m: ct p ca bm

= 998 kg/m3: khi lng ring ca nc nhit lm vic

= 0,7 : hiu sut chung ca bm

Vy chn bm c cng sut 2 kW, vi lu lng l 32 m3/h v ct p l 17m, hng

sn xut Tsurumi Nht

Bng 4.9 Thng s kch thc b lc

STT Thng s n v Gi tr

1 Lu lng bn,Qtbgi m3/gi 8,54

2 Chiu cao b lc m 2,3

Trang 60


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3 ng knh b lc m 0,94 Chiu cao lp si m 0,45 Chiu cao lp cat m 0,86 Lu lng nc ra lc m3/s 0,00877 Ct p bm ra lc m 17

4.2.7 B kh trng

Nc thi sau khi qua b lc p lc c dn n b tip xc kh trng

bng dung dch NaOCl 10%

Thi gian tip xc gia dung dch NaOHCl vi nc l 30 pht

4.2.7.1 Tnh ton th tch bTh tch hu ch ca b tip xc c tnh theo cng thc:

3

27,45,054,8 mth

tbQV ===

Trong d:

Q: lu lng nc thi, Q = 205 m3/ngy = 8,54 m3/h

t: thi gian tip xc gia nc thi v dung dch Clorua vi, t = 30 pht =

0,5h

Vn tc nc chy trong b tip xc, v = 2 4,5 m/pht. Chn v = 2

m/pht

Din tch b tip xc:

2

1,67,0

27,4m

h

VF ===

h: chiu cao mc nc b, h = 0,7m

B xy dng hnh ch nht c 4 ngn:

2

525,14

1,6

4

mF

f ===

Kch thc mi ngn:

+ Chiu di : L = 1,3m

+ Chiu rng : B = 1,3m

Chiu di b:

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( ) mbnnBL 5,51,0143,14)1( =+=+=

b: b dy vch ngn, b = 0,1m

Chiu cao bo v: hbv = 0,3m

Chiu cao b: H = h + hbv = 0,7 + 0,3 = 1m

4.2.7.2 Tnh ton lng ha cht:

Lng Clo chm vo:

ngykgngygaQX /05,2/205010205 ====

Trong : Q: lu lng nc thi Q = 205 m3/ngy = 8,54m3/h

a: liu lng clo hot tnh, a = 10 g/m3

= 10.10-3

kg/m3

Lng NaOCl cn chm vo b tip xc:

ngaykgM

MXM

Cl

NaOCl /3,45,35

5,7405,2=

=

=

Lng dung dch NaOCl 10% cn chm vo b tip xc

hlngylC

MVt /79,1/43

1,0

3,4====

Chn thi gian lu ca dung dch NaOCl l 1 tunTh tch thng ha cht: ltVV 3017431 ===

Chn bm nh lng chm NaOCl lu lng 1,79 l/h

4.2.7.3 ng knh ng dn nc thi:

mmmv

QD 66066,0

14,37,03600

54,84

3600

4==

==

Trong : v: vn tc chy trong ng v = 0,7m/s

Q: lu lng nc thi, Q = 8,54 m3/h.

Chn ng uPVC mm90=

Bng 4.10 Thng s kch thc b kh trng.


1 Lu lng bn,Qtb

gim3/h 8,54

2 Chiu di b kh trung m 5,53 Chiu rng b kh trung m 1,3

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4 Chiu cao b kh trung m 1,0

4.2.8 Tnh ton b nn bn4.2.7.1Nhim v

Bn d t b lng t II c a v b nn bn. Di tc dng ca trnglc, bn s lng v kt cht li. Sau khi nn, bn c ly ra y b.

4.2.7.2Tnh ton

Khi lng cn t b cha bn chuyn ti b nn

ngykgPSVm swbunhhbun /93,16%3,11000005,1296,1 ===

Trong :

Vhh: L hn hp nc v bn x t b lng 2. Vhh = Qb = 1,296 m3/ngy.

Sbun : L t trng bn so vi nc. Sbun= 1,005

w : L khi lng ring ca nc. w =1000kg/m3

Ps : Nng cn tnh theo cn kh, %. Ps = 0,8 2,5%. Chn Ps = 1,3%

Lng bn cc i dn ti b nn bn

ngykgmkM bun /32,2093,162,1max ===

Trong: k l h s khng iu ha thng ca bn hot tnh d. k =1,15-1,2.Chn k = 1,2.

Din tch b nn bn

2max58,0

35

32,20m

U

MS ===

Trong : U: Ti trng cht rn, U = 29 49 (kg/m 2.ngy) chn U = 35(kg/m2.ngy)

Din tch b nn bn tnh lun phn ng trung tm2

7,058,02,12,1 mSSt ===

ng knh b nn bn

mS

D t 94,014,3

7,044=

=

=

Chn D = 1,0 m

ng knh ng trung tmmDd 15,0115,015,0 ===

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Chn d = 0,15m

ng knh phn loe ca ng trung tm

d1 = 1.35d = 1.35 x 0.15 = 0.2m ng knh tm chn

dch= 1.3d1 = 1.3 * 0.2 = 0.26m

Chiu cao phn lng ca b

mtvHlang 8,13600101005,03

===

Trong :

t: L thi gian lu bn trong b nn. Chn t= 10h.

v : L vn tc bn dng. v = 0,5mm/s ( )/1,0 smv

Chiu cao phn nn vi gc nghing 45o, ng knh b D = 1.0m v chnng knh ca y b 0.3m s bng:

h2 = D/2 0.3 /2 = 1.0/2 0.3 = 0.35m

- Chiu cao ng trung tm

Hng = 60% x Hlng = 60% x 1,8 = 1,08m

Chiu cao tng cng ca b nn bnHtc = Hlng + h2 + h3 = 1,8 + 0,35 + 0.4 = 2,55m

Trong :

Hlng: L chiu cao phn lng ca b

h2: L chiu cao phn nn vi gc nghing 45o

h3: L khong cch t mc nc trong b n thnh b , h3 = 0.4m

Nc tch ra trong b nn bn c a v b iu ho tip tc x l.

Mng thu nc Vn tc nc chy trong mng: 0.6 0.7 m/s, chn v = 0.7 m/s.

Din tch mt ct t ca mng:

A = 23

0034.0/86400*)/(7.0

)/(205m

ngayssm

ngaym

v

Q==

Mng b tng ct thp dy 100mm, c lp thm mng rng ca inox SUS304, dy1mm.

Mng rng ca

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ng knh mng rng ca c tnh theo cng thc:

Drc = D (0,1 + 0,1 + 0,003)*2 = 1.0 0,406 = 0,594m, chn 0,6m

Trong D: ng knh trong b lng I, D = 1,0m

0.1: B rng mng trn = 100mm = 0.1m

0.1: B rng thnh b tng = 100mm = 0.1m.

0.003: Tm m gia mng rng ca v mng b tng = 3mm

Mng rng ca c thit k c 6 khe/m di, khe to gc 90o.

Nh vy tng s khe dc theo mng b tng l : 0,0594 * * 6 =

11,2 khe (chn 12 khe)

Lu lng nc chy qua mi khe:

Qkhe = smngayskhe

ngaym

Sokhe

Q/1097,1

)/(86400*12

)/(20534

3

==

Mt khc ta li c

Qkhe = .2..15

8gCd smHtgH /1097,142.1

2

. 3425

2

5

==

Trong :Cd: H s lu lng, Cd = 0,6

g: Gia tc trng trng (m/s2).

: Gc ca kha ch V, o90=

H: Mc nc qua khe (m)

Gii phng trnh trn ta c H = 0.028m = 28,63 mm < 50 mm chiu suca khe t yu cu.

Bng 4.11 : Tng hp tnh ton b nn bn.Thng s Gi tr

Lng bn cc i dn ti b nn bn(kg/ngy) 20,32

ng knh b nn bn, D(m) 1.0

ng knh ng trung tm, d(m) 0.15

ng knh phn loe ca ng trung tm, dl(m) 0.2

ng knh tm chn, dch(m) 0.26

Chiu cao phn lng, hl(m) 1,8

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Chiu cao tng cng b nn bn, H tc(m) 2,55

4.2.9 Sn phi bn

Sn phi bn c nhim v lm ro nc trong cn t n m cn thitthun li cho vn chuyn v x l cn tip theo.

Din tch hu ch ca sn phi bn

2

0

172

3,32

3652648,0365m

nq

QF tc =

=

= [Theo trang 164 Sch X L

Nc Thi Th V Cng Nghip ca Lm Minh Trit]

Vi 0q : Ti trng cn ln sn phi bn c th ly theo bng di y.

Trong trng hp xt cn ti v bn hot tnh ln men vi nn nhn to c

h thng rt nc, chn na./ 230 2 mmq =

n: H s ph thuc vo iu kin kh hu, tm thi c th ly :

- i vi cc tnh pha Bc : n = 2,2 2,8

- i vi cc tnh min Trung : n = 2,8 3,4

- i vi cc tnh pha Nam : n = 3,0 4,2 (v cn lu n 6 thng ma

ma, khi cn c bin php rt nc nhanh)'nentc QQ = Lng cn tng cng dn n b nn bn, Qtc= 0,6482 m3/ngy

Bng 4.12 Ti trng cn trn 1 m2 sn phi bn.

Cn dn n sn phi bn Ti trng cn, m3/m2.nm

Nn t nhin khng cng rt nc

Nn nhn to c ngrt nc

Cn ti v bn hot tnh chaln men

1 1,5

Cn ti v bn hot tnh lnmen

1,5 2

Cn ln men lng 1,5 3,5

Ta chn 2 n nguyn kch thc sn phi bn: LxBxC = 9mx4mx1m

Din tch ph ca sn phi bn: ly bng 20% din tch sn phi bn:

F2 = 0,2 x 72 = 14,4 m2 , lm trn =14 m2

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Din tch tng cng sn phi bn:

F = F1 + F2 = 72 + 14 = 86 m2

Lng bn phi t m 96% n 75% trong mt nm l:

W = 365Q751 00

961 00

= 3650,64825

4= 37,84 m3

Khong 20-30 ngy x mt ln, bn kh c thu gom bng th cng v bn lm

phn vi sinh

Bng 4.13 Thng s kch thc sn phi bn.


1 Lu lng bn,Q tbnga m3/ngy 0,648

2 Chiu di sn phi bn M 93 Chiu rng sn phi bn M 4

4 Chiu cao sn phi bn M 1

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CHNG 5: KHI TON GI THNH X L

5.1 Chi ph xy dng, cung cp, lp t trm x l nc thi

Xy dng trm x l nc thi theo cng ngh la chn th tng chi ph thc

hin c khi qut nh sau (p theo biu gi mi thng 02/2011).

Bng 5.1: Bng khi ton chi tit cc hng mc thc hinBng I: Chi ph xy dng b (VN) 229,995,280

STT Thng s k Thut SL VTXutx

n gi(VN)

Thnh tin(VN)

1

Hm bm tip nhn:kch thc:D x R x H = 3,5 x 1,8 x 3,0 mVt liu:BTCT dy 200 mm, st Nht phi

14 an st thnh 2 lp @200,betong M 250.Qut chng thm Sika bn trong 2lp, bn ngoi sn nc loi snngoi tri.

9,31

2

M3b

tng

VitNam(B

hinhu)

0 0

Trang 68


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2

B iu ha:Kch thc:D x R x H = 4,0 x 3,5 x 5,0 m

Np b BTCT, dy 100 mm, dngst Nht phi 12 ly.Vt liu:BTCT dy 200 mm, st Nht phi14 an st thnh 2 lp @200,

betong M 250.Qut chng thm Sika bn trong 2lp, bn ngoi sn nc loi snngoi tri.

26,25

M3btng

VitNam

2,480,000 65,100,000

3

B SBR: 02 bKch thc 01 b:D x R x H = 6,0 x 3,0 x 5,0 m

Vt liu:BTCT dy 200 mm, st Nht phi14 an thnh 2 lp @200, betongM 250.Qut chng thm Sika bn trong 2lp, bn ngoi sn nc loi snngoi tri.

54.5M3btng

VitNam

2,480,000 135,160,000

4

B trung gian:Kch thc:D x R x H = 1,1 x 2,0 x 2,0 m

Np b BTCT, dy 100 mm, dngst Nht phi 12 ly.Vt liu:BTCT dy 200 mm, st Nht phi14 an thnh 2 lp @200, betongM 250.Qut chng thm Sika bn trong 2lp, bn ngoi sn

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