DAnuoc Thai Cua Vy

8/2/2019 DAnuoc Thai Cua Vy

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n mn hc: X l nc thi GVHD: TS. Trn Vn Quang

LI M U

Qu trnh cng nghip ha, hin i ha t nc to nn mt sc p ln i vi

mi trng.

Trong giai on hin nay, khi m nn kinh t ca nc ta c nhng bc pht trin

mnh m v vng chc,i sng ca ngi dn ngy cng c nng cao th vn mi

trng v cc iu kin v sinh mi trng li tr nn cp thit hn bao gi ht. Trong

cc vn v nc c quan tm nhiu hn c.

Mt trong cc bin php bo v mi trng sng, bo v ngun nc mt, nc

ngm khng b nhim do cc hot ng sinh hot v sn xut ca con ngi l thugom v x l nc thi. Nc thi sau x l s p ng c cc tiu chun thi vo

mi trng cng nh kh nng ti s dng nc sau x l.

Vi ti l thit k mt trm x l nc thi sinh hot, th hin bn v thit k, sau

mt thi gian hng dn ca thy c b mn, n v c bn c hon thnh.

Di y l bn thuyt minh v trm x l nc thi.

Trong qu trnh hon thnh n do s cha hon thin v kin thc v thiu cc

kinh nghim thc t,nn trong qu trnh thc hin n cng nh trong kt qu

cui cng khng th khng c nhng sai st nht nh. Knh xin thy c thng cm

v gip em ch ra nhng thiu st kin thc v kinh nghim ca em ngy

c nng cao hn.

Sinh vin thc hin

Nguyn Th Hng Vy

SVTH: Nguyn Th Hng Vy Lp 10MTLT Trang 1


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I. Nhim v thit k:

Thit k trm x l nc thi cho thnh ph vi cc s liu c s sau:

Nc thi sinh hot:

Dn s : 130000 ngi Tiu chun cp nc trung bnh : 120 l/ng.ng

Nc thi sn xut v dch v:

S liu v nc thiTn nh my, dch v

Bnh vin Bia Thy sn I

Thi gian hot ng,gi/ng

24 24 16

Lu lng, m3/ng 450l/ging 2500 4000

Nhit , 0C

pH

Cht l lng, mg/l 380 4500

BOD5, mg/l 250 850

COD, mg/l 350 1500

Cc s liu v thi tit, a cht thu vn :

Nhit trung bnh nm ca khng kh : 19oC

Nhit trung bnh ca hn hp nc thi sinh hot v cng nghip v mang : 18oC

Hng gi ch o trong nm: ng Bc

Mc nc ngm :

+ Ma kh su di mt t : 5 m+ Ma ma su di mt t : 4 m

Ngun tip nhn : Sng loi B

Yu cu c bn v cht lng nc thi sau khi x l x vo sng khng dngcho mc ch sinh hot theo ct B Quy Chun K Thut Quc Gia V NcThi Sinh Hot (QCVN 14:2008/BTNMT) nh sau :

Nhu cu oxy sinh ho BOD5 (20oC): 50 mg/l

Hm lng cht l lng SS: 100 mg/l



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II. Xc nh cc thng s tnh ton

1 Xc nh lu lng tnh ton ca nc thi

1.1. Lu lng nc thi sinh hot

Tiu chun thot nc trung bnh ly bng 80% tiu chun cp:qtb = 0.8qc = 0.8120 = 96 (m3/ng)

Lu lng nc thi sinh hot trung bnh ngy m tnh theo cng thc:

shngdtbQ =

1000

Nqtb =1000

13000096=12480 (m3/ng)

Lu lng nc thi sinh hot trung bnh gi tnh theo cng thc:

sh

htbq = 241000 Nqtb

= 24100013000096

= 520 (m3

/h)

Lu lng nc thi sinh hot trung bnh giy tnh theo cng thc:

shstbq = 1000

3600

shhtbq = 1000

3600

520 = 144,44 (l/s)

C sh stbq = 144,44 (l/s) th Kch = 1,5

Lu lng nc thi sinh hot gi ln nht

shhmzxq = sh htbq Kch = 5201,5 = 780 (m3/h)

Lu lng nc thi sinh hot giy ln nht:

shsq max =

shstbq Kch = 144,441,5 =216,66 (l/s)

1.2. Lu lng nc thi ca bnh vin:

Bnh vin c 300 ging bnh tng ng c 300 ngi phc v.

Lu lng nc thi trung bnh ngy m ca bnh vin:

phvungtbQ = =

1000

nqtb1000

300450= 135 (m3/ng)

Trong : n = 300: s ging bnh.

Lu lng nc thi trung bnh gi ca bnh vin:

bvhtbq =

24

bvngdtbQ =

24

135= 5,625 (m3/h)

Lu lng nc thi trung bnh giy ca bnh vin:



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bvstbq =

36001000

bvhtbq =

3600

1000625,5 = 1,56 (l/s)

1.3. Lu lng nc thi ca nh my bia:

Lu lng nc thi trung bnh ngy m ca nh my bia:

biangdtbQ = 2500 (m3/ng)

Lu lng nc thi trung bnh gi ca nh my bia:

biahtbq =

24

biangdtbQ =

24

2500= 104,17 (m3/h)

Lu lng nc thi trung bnh giy ca nh my bia:

biastbq = 36001000

bia

htbq = 3600100017,104 = 28,94 (l/s)

1.4. Lu lng nc thi ca nh my thy sn 1:

Lu lng nc thi trung bnh ngy m ca nh my Thy sn 1:

tsngdtbQ = 4000 (m3/ng)

Lu lng nc thi trung bnh gi ca nh my Thy sn 1:

tshtbq = 16

ts

ngdtb

Q = 16

4000= 250 (m3/h)

Lu lng nc thi trung bnh giy ca nh my Thy sn 1:

tsstbq =

36001000

tshtbq =

3600

1000250= 69,44 (l/s)

Bng 2. Bng phn b lu lng tng cng nc thi sinh hot v nc thi cngnghip theo tng gi trong ngy m.

Ccgi

Nc thi sinhhot

Nc thinh my bia

Nc thibnh vin

Nc thiThy sn

Lu lng

tng cng

%Qsh m3 m3 m3 m3 m3 %Qtc

0-1 1.5 187.2 104.17 5.625 0 297 1.55

1-2 1.6 199.68 104.17 5.625 0 309.48 1.62

2-3 1.6 199.68 104.17 5.625 0 309.48 1.62

3-4 1.6 199.68 104.17 5.625 0 309.48 1.62



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4-5 1.6 199.68 104.17 5.625 0 309.48 1.62

5-6 1.6 199.68 104.17 5.625 0 309.48 1.62

6-7 4.28 534.14 104.17 5.625 250 893.94 4.68

7-8 5.87 732.58 104.17 5.625 250 1092.4 5.71

8-9 5.8 723.84 104.17 5.625 250 1083.6 5.67

9-10 6.27 782.5 104.17 5.625 250 1142.3 5.98

10-11 6.27 782.5 104.17 5.625 250 1142.3 5.98

11-12 6.27 782.5 104.17 5.625 250 1142.3 5.98

12-13 4.93 615.26 104.17 5.625 250 975.06 5.10

13-14 4.07 507.94 104.17 5.625 250 867.73 4.54

14-15 5.67 707.62 104.17 5.625 250 1067.4 5.58

15-16 5.92 738.82 104.17 5.625 250 1098.6 5.75

16-17 5.92 738.82 104.17 5.625 250 1098.6 5.75

17-18 5.7 711.36 104.17 5.625 250 1071.2 5.60

18-19 5.68 708.86 104.17 5.625 250 1068.7 5.59

19-20 4.25 530.4 104.17 5.625 250 890.2 4.66

20-21 4.55 567.84 104.17 5.625 250 927.64 4.85

21-22 4.23 527.9 104.17 5.625 250 887.7 4.64

22-23 2.6 324.48 104.17 5.625 0 434.28 2.27

23-24 1.6 199.68 104.17 5.625 0 309.48 1.62

Tng 100 12480 2500 135 4000 19115 100

T bng thng k ta c:

Lu lng tng cng trung bnh ngy mtcngdtbQ = iQ =

shngdtbQ +

bvngdtbQ +

bngdtbQ +

tsngdtbQ

= 12480 + 135 + 2500 + 4000 = 19115 ( m3/ng)



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Lu lng tng cng trung bnh gi :

tchtbQ =

24

tcngdtbQ =

24

19115= 796,46 ( m3/h)

Lu lng tng cng trung bnh giy :tc

stbQ = 36001000.tc

htbq

= 36001000.46,796

= 221,24 (l/s)

Lu lng tng cng ln nht gi :tc

hQ max = 1142,3 ( m3/h)

Lu lng tng cng ln nht giy :tc

sQ max =3600

1000.maxtc

hQ =3600

1000.3,1142= 317,31 (l/s)

Lu lng tng cng nh nht gi:tc

hQ min = 297 ( m3/h)

Lu lng tng cng nh nht giy:tc

sQ min =3600

1000.mintc

hQ =3600

1000.297= 82,5 (l/s)

2. Xc nh nng cht bn nc thi theo cht l lng (SS) v theo BOD

2.1. Xc nh nng cht bn theo cht l lng (CSS):

Hm lng cht l lng ca 65% h dn c s dng b t hoi:

CSS1 = 1000961005565

1000100

=

tb

SS

q

hn= 372,4 (mg/l)

Hm lng cht l lng ca 35% h dn khng c s dng b t hoi:

CSS2 = 10009665

1000 =tb

SS

q

n= 677,08 (mg/l)

Hm lng cht l lng trong nc thi sinh hot:

=> Csh =130000

4550008,677845004,372 += 479,04 (mg/l)

Trong :

% s ngi s dung b t hoi l 65%

nSS : hm lng cht l lng ca nc thi sinh hot tnh cho 1 ngitrong mt ngy m, nSS = 60 - 65 g/ng.ng (theo bng 25-TCVN7957:2008), chn nSS =65 (g/ng.ng)

h: Hiu sut gim SS khi dng b t hoi h=55-65% (theo ch thch bng25-TCVN 7957:2008) chn h=55%

Hm lng cht l lng trong nc thi sn xut:

Nh my bia: Cbia= 380 (mg/l)



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Nh my thy sn 1: Cthy sn 1 = 450 (mg/l)

Nc thi t cc nh my mun thi ra h thng x l chung ca thnh ph th theo

tiu chun ti thiu phi x l s b t yu cu cht lng nc loi C-TCVN 5945-

2005. Hm lng cht l lng ti a l 200mg/l. Hm lng cht l lng trong nc thi bnh vin:

Cbv = Nqn

tb

SS 1000

= 60010.135

1000653

= 289 (mg/l)

Trong :

qtb: lu lng thi nc trung bnh ca bnh vin

qtb = 135 m3/ng = 135.103 (l/ng)

N: s ngi trong bnh vin (ngi bnh v nhn vin), quy c c 1 gingbnh c 1 phc v:

N = 300 + 300 = 600 ngi

Hm lng cht l lng trong hn hp nc thi c tnh:

Css =bvbiaThssh

bvbvbiabiaThsThsshsh

QQQQ

QCQCQCQC

++++++ ....

=1352500400012480

135289250020040002001248004,479+++

+++

= 356,79(mg/l)

2.2. Xc nh nng cht bn theo BOD5:

Nc thi sinh hot:

L sh = 1000)( 55

+

tb

CLBOD

LBOD

q

nbna(mg/l)

Trong :

a l % s ngi s dung b t hoi, a = 65%

b l % s ngi khng s dng b t hoi, b = 35%

L

BODn 5 : ti lng cht bn theo BOD5 lng ca nc thi sinh hot tnh cho

mt ngi trong ngy m ly theo bng 25 TCVN 7957-2008, LBODn 5 = 30-35

(g/ng.ng), chn LBODn 5 = 35 (g/ng.ng).

CL

BODn

5 : ti lng cht bn theo BOD5 cha lng ca nc thi sinh hot tnhcho mt ngi trong ngy m ly theo bng 25 TCVN 7957-2008, CLBODn 5 =65(g/ng.ng).



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L sh = 100096)3565,06535,0(

+

= 473,96 (mg/l)

Nc thi bnh vin:

Lbv = Nq

n

tb

CLBOD

10005= 60010135

1000653

= 288,89 (mg/l)

Trong :

qtb: lu lng thi nc trung bnh ca bnh vin

qtb = 135 m3/ng = 135.103 l/ng

N: s ngi trong bnh vin (ngi bnh v nhn vin)

N = 300 + 300= 600 ngi

Nc thi sn xut:

Nh my bia: 250 mg/l Nh my thy sn 1: 850 mg/l

Hm lng BOD5 trong hn hp nc thi:

LBOD5 =bvbiaThssh

bvbvbiabiaThsThsshsh

QQQQ

QLQLQLQL

++++++ ....

=1352500400012480

13589,288250025040008501248096,473

+++

+++

= 522,05 (mg/l)

Hm lng BOD20 trong hn hp nc thi

LBOD20= 85,005,522

85,05 =BOD

L=614,18 (mg/l)

3. Xc nh dn s tnh ton:

Dn s tng ng theo cht l lng:sstdN =

ss

biabiathsths

n

QCQC .. +

=65

1353804000450 += 28482 (ngi)

Dn s tnh ton theo cht l lng:

Nss = N +sstdN + Nbv = 130000 + 28482 + 600 = 159082 (ngi)

Dn s tng ng theo BOD5:



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BODtdN

5

..

BOD

thsthsbiabia

n

QLQL +=

=65

85040002500250 += 61923 (ngi)

Dn s tnh ton theo BOD5 :

NNOS = N +BODtdN + Nbv= 130000+61923 + 600 = 192523 (ngi)

4. Mc lm sch nc thi cn thit:

Nc thi sau khi x l thi ra sng loi B, theo quy chun14:2008/BTNMT th phi p ng c cc yu cu c bn sau:

Hm lng cht l lng SS 100 mg/l.

Nhu cu oxy sinh hc BOD5 50 mg/l.

Mc cn thit x l nc thi thng c xc nh theo:

Hiu sut x l theo SS:

ESS = %100.SS

tss

C

CC

Trong :

tC : Hm lng ti a cht l lng ca nc thi sau x l cho php x vo sng,

t

C= 100 mg/l

ssC : Hm lng cht l lng ca hn hp nc thi

SSC = 458,67 mg/l.

ESS = %10067,45810067,458

=78,2 %

Hiu sut x l theo BOD5:

%10020

=hh

ThhBOD L

LLE

Trong : LT: Hm lng BOD5 ti a ca nc thi sau x l cho php x vosng,

LT = 50 (mg/l)LT.BOD20= 85,050

= 58,82 (mg/l)

Lhh: Hm lng BOD20 ca hn hp nc thiLhh = 1267,18 (mg/l)

20BODE = %10018,61482,5818,614

=90,42 %

Kt qu tnh ton v mc cn thit x l nc thi cho thy cn thit phi xl sinh hc khng hon ton.

III. La chn cng ngh ca trm x l



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Da vo:- Cng sut ca trm x l.- Thnh phn v c tnh ca nc thi.- Mc cn thit x l nc thi.- Tiu chun x nc thi vo cc ngun tip nhn tng ng.

- Phng php s dng cn.- iu kin mt bng v c im a cht thy vn khu vc xy dng trmx l nc thi.

- Cc ch tiu kinh t k thut khc.Chn cng ngh x l nh sau: X l c hc:

- Ngn tip nhn.- Song chn rc + my nghin rc.- B lng ct + sn phi ct- B lng ngang t I

X l sinh hc- Aeroten (vi sinh vt l lng bn hot tnh)- B lng ngang t II.

X l cn:- B nn bn ng.- B mtan.- Sn phi bn.

S dy chuyn cng ngh

Nc c bm ln ngn tip nhn t chy qua cc cng trnh x l tip theo.

Nc thi i qua song chn rc v b lng ct nhm loi b cc loi b ct si v rc.Tip theo nc qua b lng ngang t I loi b bt cc cht l lng c trong nc.Sau khi c x l c hc, nc thi c a sang cc cng trnh x l sinh hc tiptheo, m y c th l Aeroten y c ti sinh bn hot tnh . Nc thi ra khi bAeroten c a sang b lng ngang t II nhm lng bt bn hot tnh, mt phn bnc a tun hon v b aeroten, phn bn d cn li c a sang b nn bn.

Cui cng nc thi c x vo ngun tip nhn l sng loi B. Nc sau khix l t Quy chun k thut quc gia v mi trng 8:2008/BTNMT . Phn bn d ca

b lng II c a vo b nn bn nhm gim th tch bn v m. Sau lng bnny c a qua b mtan phn hu v n nh. Cn sau khi phn hy c x vosn phi bn n khi t m khong 80% s c vn chuyn i chn lp.



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IV. TNH TON CNG NGH X L NC THI:


Sng loi C

Bnd

Cn

CtVnchuyn

Vn chuyn

Lm ro nc,rc vi, vn

chuyn

Nc thi

Bntunhon

Cp kh

B lng ly tmt I

Aeroten

B mtan

Sn phi bn

B lng ly tmt II B nn cn

Ngn tip nhn

Song chn rc

B lng ct ngang


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1. Ngn tip nhn nc thi:

- Nc thi c bm theo ng ng p lc n ngn tip nhn ca trm x l.Ngn tip nhn c t v tr cao nc thi t c th t chy qua tng cngtrnh n v ca trm x l.

- Da vo lu lng tnh ton c xc nh,tc

hQ max =1139.8 m3/h, chn ngntip nhn vi thng s mi ngn nh sau:

Lu lng

nc thi Q

(m3/h)

ng knh ngp lc, d (mm)

Kch thc ca ngn tip nhn

2 ng A B H H1 h h1 b

1142,3 300 2000 2300 2000 1600 750 900 600

Mng dn nc thi t ngn tip nhn ti cc cng trnh tip theo c tit dinhnh ch nht.

Kt qu tnh ton thu lc mng dn nc thi sau ngn tip nhn:

Thng s thu lcLu lng tnh ton, L/s

qtb = 221,24 qmax = 317,31 qmin = 82,5

dc i 0,001 0,001 0,001

Vn tc v (m/s) 0,75 0,79 0,59

y h/B (m) 0,82 1,1 0,38

B rng (mm) 600 600 600


B

b

h

A

Ngn tip nhn

H

Nc thi vo

Ngn tip nhn


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- Chiu cao xy dng mng : H = hmax + hbv (m)

Trong : hmax ly bng y tnh ton ca mng dn tng ng vi Qmax

hmax = 1,1 6,0 = 0,66 m

hbv - chiu cao bo v, hbv = 0,3 m Chiu cao xy dng mng H = 0,66 + 0,3 = 0,96 (m)

2. Tnh ton song chn rc:

Chn 2 song chn rc trong 1 song chn lm vic, 1d phng.

L3

Lp

L1

ht

L5

Bs

L4 L2

h

hs

>20

- Chiu cao lp nc song chn rc ly bng chiu cao lp nc ca mngdn nc h = hmax = 1,1 0,6 = 0,66 m

- S khe h ca song chn rc:

n = khbv

q

s

max

max= 05.1

66,0016.079,0

31731,0

= 40 (khe)

Trong : n - l s khe h

qmax - lu lng ln nht giy: qmax = 0,31731 (m3/s)

vs - tc nc chy qua song chn: vs = 0,79 (m/s)

b - khong cch gia cc khe h b = 16 mm = 0,016 m

k - h s tnh n mc cn tr ca dng chy do h thng co rc,

k = 1,05

- Chiu rng ca song chn rc c tnh theo cng thc sau:

Bs = s (n +1) + (bn) = 0,008 (40+1) + (0,01640) = 0,97 (m)

Trong : s l b dy ca thanh song chn rc, thng ly 0,008 m.



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- Kim tra vn tc dng chy phn m rng ca mng trc song chn ngvi Qmin khc phc kh nng lng cn ti , vn tc ny phi ln hn 0,4 m/s :

vmin =min

min

hBQ

s =

23,097,0

0825.0

= 0,4 (m/s) tha mn.

vi hmin = h/DB = 0,38 0,6 = 0,23 m

Trong : Qmin l lu lng nh nht chy qua song chn rc.

- Tn tht p lc song chn rc :

hs = gKv

.2

.. 1

2max (m)

Trong : vmax vn tc ca nc thi trc song chn rc ng vi ch Q max.

vmax = 0,79 (m/s)

Kl h s tnh n s tng tn tht do vng mc rc song chn.

Kl = 23, chn K1 = 3.

- h s sc cn cc b ca song chn rc:

= 04

3

4

3

60sin016,0

008,083.1)sin(

=

l

b = 0,63

- h s phc thuc vo tit din ngang ca thanh song chn.

Tra bng 3-7, [TTTKCT], chn = 1,83.

- gc nghing ca song chn so vi hng dng chy = 600.

hs = 0,63 =

81.92

379,0 20,06 (m)

- Chiu di phn m rng trc thanh chn rc L1 vi gc m rng ca mng l200

L1 =tg

BB ms

2= 0202

6,097,0

tg

= 0,51 (m)

Vi: Bm chiu rng mng dn

- Chiu di phn m rng sau thanh chn rc L2

L2 =2

1L =2

51.0= 0,255 (m)

- Chiu di phn mng m rng t song chn rc Ls = 1,5m- Vy chiu di xy dng l :



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L = L1 + L2 + Ls= 0,51 + 0,255 + 1,5 = 2,27 (m)

- Chiu cao xy dng t song chn rc

Hxd = hmax + hs + 0,5 = 0,66 + 0,06 + 0,5 = 1,22 (m)

Trong : 0,5: Khong cch gia ct sn nh t song chn rc v mc nc cao nhths: Tn tht p lc song chn rc

- Khi lng rc ly ra trong mt ngy m t song chn rc:

Wr =1000365

llNa =1000365

1590828

= 3,49 (m3/ng)

Trong : a - lng rc tnh cho u ngi trong nm

Vi chiu rng khe h ca cc thanh trong khong 15 20mm, a = 8 L/ng.nm

Nss dn s tnh ton theo cht l lng.

- Trng lng rc ngy m:

P = Wr G = 3,49 750 = 2615,05 (Kg/ng) = 2,615 (T/ng)

Trong : G khi lng ring ca rc, G = 750 kg/m3 (iu 6.14 Tiu chun xydng TCXD 51 - 2008)

- Trng lng rc tng gi:

Ph = hKP 24= 2

24615,2 = 0,22 (T/ng)

Vi : Kh h s khng iu ha gi ca rc, ly bng 2.

- Lng nc cn cung cp cho my nghin rc 40m3 /1 tn rc (Theo iu 6.2.4TCVN 51-84):

Qn = 40P = 402,615 = 104,6 (m3/ng)

Hm lng cht l lng (Css) v NOS (L 20NOS ) ca nc thi sau khi qua song chn rcgim 4%, cn li :

'ssC = )%4100( ssC = 458,67 (100 - 4)% = 440,32 (mg/l)

== 18,614)%4100(2020

'BODBOD LL (100 4)%= 589,61 (mg/l)

3. Tnh ton b lng ct ngang:

B lng ct c chc nng lng cc khong cht v c, ch yu l ct.

- Chiu di b lng ngang c tnh theo cng thc sau:

L =0

max ...1000u

HvK tt



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Trong : Htt - chiu su tnh ton, Htt = 0,66 (m)

vmax - vn tc dng chy trong b ng vi qmax, vmax= 0,3 m

u0 - th thu lc ca ht ct, u0 = 24,2 mm/s

K - h s ly theo bng 27 TCVN 7957- 2008Vi b lng ct ngang K = 1,3

=> L =2.24

66.03.03.11000 10,64 (m)

- Din tch mt ct t ca b tnh theo cng thc:

A =max

max

vn

q s

=

3.02

31731,0

= 0,53 (m2)

Trong : n - s n nguyn cng tc, n = 2

- Din tch mt thong ca nc thi trong b lng ct ngang:

F =0

max

U

q

Trong : u0: vn tc lng tnh, U0 = 24,2 (mm/s).

qmax = 317,31 l/s

=> F =0

max

Uq =

2,2431,317 = 13,11 (m2)

- Chiu ngang tng cng ca b lng ct :

B =L

F=

64,10

11,13= 1,23 (m)

- Chn b lng ct ngang gm 3 n nguyn, trong 2 n nguyn cng tc v1 n nguyn d phng, chiu ngang mi n nguyn:

b =3

B =223,1 = 0,62 (m)

- Th tch phn nn cn ca b lng ct ngang c tnh theo cng thc sau:

Wc =1000

TPNss =1000

102.0159082 = 3,18 (m3)

Trong : P - lng ct gi li trong b lng ct cho 1 ngi trong mt ngy m,

theo bng 28 TCVN 7957- 2008 ng vi h thng thot nc ring hon

ton, a = 0,02 l/ngi.ng.



17/45


T - chu k x ct : t 2 ngy m, m bo cho cn ct khng kp phnhy, chn T = 1 ngy m.

Nss dn s tnh ton theo cht l lng.

- Chiu cao lp ct trong b lng ct ngang trong mt ngy m:

hc =nbL

cW =262,064,10

18,3

= 0,24 (m)

- Chiu cao xy dng ca lng ct ngang:

Hxd = H + hc + 0,5 =0,66 + 0,24 + 0,5 = 1,4 (m)

0,5: Khong cch t mc nc n thnh b, m

* Kim tra li tnh ton vi iu kin vmin 0,15 m/s

vmin =min

min

2 hbQ

= 23,062,020825,0

= 0,29 0,15 m/s

Ct b lng ct c gom v h tp trung u b lng bng thit b co cgii, t thit b nng thu lc s a hn hp ct - nc n sn phi ct.

dn ct n sn phi ct bng thit b nng thy lc cn pha long ct vinc sau x l vi t l 1:20 theo trng lng ct.

- Thi gian mi ln x ct di 30 pht.

- Trng lng th tch ca ct 1,5 T/m3

- Nc cng tc do my bm vi p lc 2- 3 at

- Lng nc cn thit cho thit b nng thu lc

Qct = Wc 1,5 20 = 3,18 1,5 20 = 95,4 (m3/ngy)

Hm lng cht l lng (Css) v NOS (L 20NOS ) ca nc thi sau khi qua b lng ctgim 5%, cn li :

''

ssC = )%5100('

ssC = 440,32 (100 - 5)% = 418,3 (mg/l)== 61,589)%5100(2020

'''BODBOD LL (100 5)%= 560,13 (mg/l)

4. Sn phi ct

- Din tch ca sn phi ct c tnh theo cng thc:

F =h

PNss

1000

365=

51000

36502.0159082

= 232,26 (m2)

Trong : P lng ct tnh theo u ngi, P = 0,02 (l/ngi.nm)Nss dn s tnh ton theo cht l lng.



18/45


h chiu cao lp bn ct trong nm, h = 3 5 m/nm.

Chn sn phi ct gm 2 , din tch mi bng 232,26 : 2 = 116,13(m2).

- Kch thc mi trong mt bng: 10,8 m 10,8m.

5. Thit b o lu lng.

S mng parsal

m bo cho cc cng trnh x l nc hot ng t hiu qu, ta cn bit lulng nc thi chy vo tng cng trnh v s dao ng lu lng theo cc gi trongngy.

xc nh lu lng nc ta dng mng Parsal. Kch thc mng c nhhnh theo tiu chun v c chn tu thuc vo lu lng nc.

Vi gi tr lu lng tnh ton ca trm l:

qmax = 317,31 l/s.

qtb = 221,24 l/s.

qmin = 82,5 l/s.

Theo bng 3-37/[TTTKCT-Lm Minh Trit], ta chn mng Parsal c cc kchthc sau:

Lu lng max: 500 l/s

b = 7,5 cm L 1 = 135 cm W = 60 cmA = 84 cm L2 = 60 cm C1 = 100 cm

B = 30 cm L3 = 90 cm C2 = 100 cm

6. B lng ly tm t I:

- Th tch tng cng ca b:

W = Qmax,h t = 1142,32 = 2284,6 m3

Trong : Qmax,h : lu lng ln nht gi.t thi gian lng ca b, thng ly bng 2h.


B

l1 l2 l3

A WE


19/45


- Chn 2 b cng tc, th tch mi b l:

3,11422

6,2284

2===

WWb m3

- Din tch mi b trong mt bng :

F =3

3,1142=

H

Wb = 380,77 m2

Trong :

H : chiu su vng lng ca b lng ly tm (1,5 5m). T l gia ng knhD v chiu su vng lng ly trong khong t 6 n 12, chn H = 3 m.

- ng knh mi b :

D =14,3

77,38044 =F = 22m

Kim tra: 3,73

22==

H

Dtha mn (quy phm 6 )12

- ng knh ca ng trung tm: d = 15%D = 0,1522 = 3,3 m

- Tc lng ca ht cn l lng trong b lng

42,026,3

3

6,3=

=

=

t

Hu (mm/s)

- Hiu sut b lng ly tm l 50 65%. Chn E = 60%

- Nng cht l lng sau khi qua b lng s l:

32,167100

)60100(3,418

100

)100("1 =

=

=

ECC ss mg/l

Theo quy phm nng cht l lng trc khi vo cng trnh x l sinh hc C

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