TNH TON THIT K CC N V CNG TRNH (( THAM KHO S 1)) Lu lng thit k: QTB = 200m3/ngy = 8.33m3/h.3 h Q max 1.5 8.33 12.5m / h h Qmax 12.5 qS 3.47.10 3 m3 / s max 3600 3600

3.47(l / s)

2.2.2.1. SONG CHN RC Chc nng: Gi li cc tp cht c kch thc ln nh: vi vn, si th, giy c, bao nilng Do cng sut ca nh my x l nc thi nh v lu lng nc thi khng ln nn chn song chn rc lm vic th cng. Tnh ton: - Lu lng nc i qua qua song chn rc l lu lng cc i ca nc thiqS maxh Qmax 3600

12.5 3600

3.47.10 3 (m3 / s)

- Chn cc thng s thu lc ca mng t song chn rc: Tc dng chy trong mng: v = 0.3m/s. dc I = 0.008. Kch thc mng t song chn rc (chiu ngang v chiu su) l: B x H = 0.4m x 0.7m Chiu cao lp nc trong mng l:hh Qmax 3600 v B

12.5 3600 0.3.0.4

0.0289(m)

0.03(m)

Chn kch thc thanh chn rc (rng v dy) l:b x d = 5mm x 25mm v khe h gia cc thanh l w = 25mm. - Kch thc song chn rc: Gi n,m l s thanh chn v s khe h ca song chn rc. Vy s khe h l: m = n + 1.

B n b (n 1) w 400 n 5 (n 1) 25 n 12.5

Vy chn s thanh l n = 12 C th iu chnh khong cch gia cc thanh li nh sau:400 12 5 (12 1) w w 26.2(mm)

- Tn tht p lc qua song chn: + Tng din tch cc khe song chn (A): A = (B - b x n) x h Trong : B: Chiu rng t song chn rc (m). b: Chiu rng thanh song chn rc (m). n: S thanh song chn rc. h: Chiu cao lp nc trong mng (m). A = (0.4 0.005 x 12) x 0.03 = 0.0102 (m2). + Vn tc dng chy qua song chn rc l:V h1 q smax 3.47 0.34(m / s) A 0.0102 1000 V 2 v 2 (0.34)2 (0.3)2 0.0019(m) 0.7 2 9.81 0.7 2g

0.002(m)

Vy tn tht p lc qua song chn rc l:V 2 v2 0.7 2g (0.34)2 (0.3)2 0.7 2 9.81

h1

0.0019(m)

0.002(m)

Qua song chn rc hm lng SS gim 4%. Vy hm lng SS sau khi qua song chn rc l: SS = 180 x (1-0.04) = 172.8 (mg/l). 2.2.2.2. B IU HA Chc nng: iu ho lu lng v nng cht hu c. Bn trong b iu ho thng c b tr cc thit b khuy trn hoc cp kh nhm to s xo trn u cc cht nhim trong ton b th tch nc thi, trnh vic b lng cn trong b. Ngoi ra, n cng gip cho vic oxy ho mt phn cc cht bn hu c. Tnh ton:

Kch thc b: Chn thi gian lu nc trong b iu ho l: t = 5 gi. Th tch b iu ha l: Vh Qmax t 12.5 5 62.5(m 3 ) .

Chn chiu cao ca lp nc trong b l: h = 4m Chiu cao bo v b iu ha: hbv = 0.5m Vy chiu cao tng cng ca b iu ho l: H = h + hbv = 4 + 0.5 = 4.5(m) Din tch mt bng ca b l: FV H 62.5 13.9(m2 ) 4.5

Ta chn kch thc b iu ho l: L x B x H = 4.6 x 3 x 4.5m Tnh ton h thng cp kh cho b iu ho (bng kh nn): - Lu lng kh cn thit: Lkh = Qmax h x a Trong : Qmax h: Lu lng nc thi ln nht theo gi, Qmax h = 12.5 m3/h. a: Lu lng khng kh cp cho b iu ha, a = 3.74 m3kh/m3 nc thi. Vy Lkh = 12.5 x 3.74 = 46.75 (m3/h). Chn h thng cp kh cho b bng ng nha PVC ng knh ng dn kh chnh t my nn kh n ng phn phi kh dchnh =4 Lkhi v

Trong : v l tc chuyn ng ca dng kh trong ng dn v qua h thng phn phi kh 10 15 m/s. Chn v = 10 m/s.d chinh 4 46.75 3600 10 0.041(m) 41(mm).

Tnh ton my bm nc qua b keo t to bng: Cng sut ca bm c xc nh nh sau:N Q. .g.H 12.5 1000 9.81 10 3600 1000 0.75 1000. 0.45(kw) .

Trong :

l hiu sut ca bm,

= 0.75

H l chiu cao ct p ca bm, H = 10 m. Q l lu lng bm nc thi, Q = 12.5 m3/h

l khi lng ring,

= 1000 kg/m3.

g l gia tc trng trng, g = 9.81 m/s2. Vy chn 2 bm ly tm nhng chm (1 hot ng, 1 d phng) cng sut l 1 Hp. Tnh ng dn nc thi t b iu ha sang b keo t to bong: - Vn tc nc thi chy trong ng trong iu kin c bm t 2 3 m/s, chn v = 2 m/s. Lu lng l 12.5 m3/h. - Chn loi ng dn nc thi l ng PVC. - ng knh ca ng l : D4 Q 3600 v 4 12.5 3600 2 0.047(m) 47(mm)

2.2.2.3. B KEO T - TO BNG Chc nng: B c chc nng khuy trn ha cht vi nc thi. S khuy trn lm cho ha cht c ng u trong nc thi v to thnh nhng bng cn c kh nng lng c. Tnh ton: B keo t - to bng c mt bng dng hnh ch nht, lm bng btng ct thp vi thnh dy 100mm. B c chia lm hai ngn: ngn trn v ngn phn ng. Ngn trn: - Chn thi gian lu nc trong ngn t = 10 pht. G = 1000s - Th tch cn thit ca ngn trn l: V Q t 8.33 5 0.69(m3 ) 601

(gradien thy lc).

- Kch thc ca ngn trn: L x B x H = 0.8 x 0.8 x 1.5m. Ngn phn ng: - Chn thi gian lu trong nc 45 pht - Th tch ca ngn phn ng:V Q t 8.33 45 60 6.25m3

Th tch tng cng ca b: 6.25 + 0.69 = 6.94(m3) Chn chiu cao lp nc trong b HL = 1m Chiu cao bo v : Hbv = 0.5m

Chiu cao tng cng: H = 1+0.5 =1.5 (m) Din tch ca b: F =V H 6.94 1.5 4.6m2

Vy kch thc ca b keo t to bng: L x B x H = 2.2 x 2.2 x 1.5m Chn ng c khuy: - Cng sut khuy P V G 20.69 10002

0.656 10

3

452(W )

: nht ng hc ca nc thi - Hiu sut ng c = 0.7P 452 0.7

- ng knh cnh khy: D = 0.25 x 0.8 = 0.2(m) - Cng sut ng c: P dc645.7(W ) 0.6457(KW ) = 0.65 (kw).

- Tnh s vng quay ca cnh khuy l:n P k D51/ 3

645.7 6.3 1000 0.25

1/ 3

6.84 (vng/s) = 410 (vng/pht)

2.2.2.4. B LNG T I Chc nng: Thc hin qu trnh lng cc bng cn t b keo t to bng dn ti. Tnh ton: chn b lng t 1 l loi b lng ly tm, c mt bng hnh trn, nc thi vo t tm v thu nc theo chu vi b lng li tm. - Din tch tit din t ca ng trung tm: f Qtb.s : lu lng trung bnh (m3/s). Vtt : tc chuyn ng ca nc trong ng trung tm (m/s).Qtb.s u0 2.3 10 3 0.0007 3.31(m2 ) Qtb.s vtt 2.3 10 0.033

0.08(m2 )

- Din tch tit din t ca b lng: F

Uo: tc lng ca ht cn uo= 0.0007 0.0022(m/s). - Vy din tch ca b lng l: F1 3.31 0.08 3.39(m2 ) - ng knh b lng l: D4F1 4 3.39 2.1(m)

- ng knh ng trung tm l: d

4 f tt

4 0.08

0.1(m)

- Tng chiu cao vng lng h1= 3.5 (m) t: Thi gian lu nc, t = 2 gi. - Chiu cao bo v hbv = 0.3m - Chiu cao tng cng ca b lng l: Hth1 hbv 3.5 0.3 3.8 (m).

- Kch thc ca b l: D x H = 2.1 x 3.8 m. - Ti trng mng trn: LS200 30.3(m3 / m.ngy). 2.1 t Xc nh hiu qu kh BOD5 v SS : R a b t 2 0.018 0.02 2 34.48% R 2 0.0075 0.014 2 56.33% Q .D

RBOD

Trong : t l thi gian lu nc t = 2 (gi) a, b l cc hng s thc nghim. i vi BOD5 th a = 0.018; b = 0.02; vi SS th a = 0.0075; b = 0.014. Xc nh lng bn sinh ra - Lng bn kh sinh ra mi ngyG G 56.33 653.33mg / l 10 100 73.6 kg ngay G C 73.6 80 0.92 (m3/ngy)6

kg m3 l 200 1000 3 mg ngay m

- Th tch bn sinh ra mi ngy: V bun

Trong : G l lng bn sinh ra mi ngy C: hm lng cht rn trong bn nm trong khon 40 120g/l = 40 120 kg/m3, ly trung bnh C = 80 kg/m3 Sau khi i qua b lng t 1 hm lng SS gim 56.33%, BOD gim 34.48%. Ta c Hm lng SS v BOD sau khi ra khi b lng 1 l: SS = 180 x (100% 56.33%) = 78.6 (mg/l)

BOD = 520 x (100% 34.48%) = 340.7 (mg/l). 2.2.2.5. B AEROTANK Chc nng: Thc hin qu trnh phn hy cc cht hu c ha tan c trong nc thi iu kin hiu kh. Tnh ton: Hm lng cc cht sau khi qua b lng t 1 nh sau: COD = 565 mg/l. BOD = 340.7 mg/l. SS = 78.6 mg/l. mu: 74 Pt Co. Cc thng s tnh ton c bn: Thi gian lu bn:c

5 15 ngy.

T s F/M: 0.2 0.6 kg/kg.ngy. Ti trng th tch: 0.8 1.92 kgBOD5/m3.ngy. Nng MLSS: 2500 4000mg/l. T s th tch trn lu lng gi: WQ 3 5h 0.25 1

T s tun hon bn hot tnh: QthQ

iu kin tnh ton qu trnh bn hot tnh xo trn hon ton: MLVSS: MLSS = 0.8 Hm lng bn tun hon: Xth = 8000mgVSS/l Hm lng bn hot tnh trong b: MLVSS = 3000mg/l. Thi gian lu bn trung bnh:c

10 ngy.

Nc thi c cha y lng cht dinh dng N, P v cc cht vi lng khc. BOD5 : BODL = 0.68 BOD5 : N : P = 100 : 5 : 1 Hm lng cht l lng trong nc thi cn t sau x l: Cs = 40mg/l.

Hm lng ca cc nguyn t dinh dng thch hp cho qu trnh hiu kh l BOD : N : P = 100 : 5 : 1 Kim tra nc thi u vo Aerotank: Ta c: BOD5 : N : P = 340.7 : 1.38 : 0.42 = 811 : 3.3 : 1. Do vy, ta phi b sung thm Nit cho b Aerotank ( b sung bng bm nh lng). Ta c lng Nit cn c l : N340.7 5 17(mg / l) 100 340.7 1 100

Lng Phtpho cn c l :

P

3.41(mg / l)

Vy lng Nit b sung l : Nbs = 17 1.38 = 15.62 (mg/l). Nit s c b sung bng ur. Vy lng ur cn thit l : Lu lng nc thi cn x l l Q = 200 m3/ngy. Lng ur tiu th =33.5 200 1000 6.7(kg / ngay) . 15.62 60 28 33.5(mg / l)

Nng dung dch Ur s dng l 10% hay 100kg/m3. Lu lng dung dch ur cung cp = Thi gian lu dung dch l 1 ngy Th tch b yu cu l 0.067 m3. Chn 1 my bm chm ur, Q = 3(l/h), p lc 1.5 bar. Lng Phtpho b sung l : Pbs = 3.41 0.42 = 3(mg/l). Phtpho c b sung bng H3PO4. Vy lng H3PO4 cn thit l :3 98 31 9.5(mg / l). 6.7 100 0.067(m3 / ngay) .

Lu lng nc thi cn x l l Q = 200 m3/ngy. Lng ur tiu th =9.5 200 1.9(kg / ngay) . 1000

Nng dung dch Ur s dng l 85% hay 850kg/m3.

Lu lng dung dch ur cung cp =

1.9 850

2.2 10 3 (m3 / ngay)

2.2(l / ngay) .

Chm bng bm nh lng. Cc bc tnh ton cho aerotank khuy trn hon ton - Xc nh BOD5 ca nc thi u vo v u ra ca b aerotank : Ta c BODvo = 340.7 (mg/l). Chn hiu qu x l BOD ca b aerotank l 90% Vy BOD5ra = 340.7 x (1 0.9) = 34.7 (mg/l). - Tnh BOD5 ho tan trong nc u ra Phng trnh cn bng vt cht: BODra = BOD5 ho tan trong nc u ra + BOD5 ca cht l lng trong nc u ra Trong BOD5 u ra l 34.7 mg/l BOD5 ha tan i ra t b Aerotank l S, mg/l - SSra = 20 mg/l (65% l cn c th phn hy sinh hc ) - BOD5 cha trong cn l lng u ra: 0.65 x 20 = 13 mg/l. Vy lng oxy cn thit l: 13(mg/l) x 1.42( mgoxy/ mg t bo )= 18.46 (mg/l) Chuyn i t gi tr BOD20 sang BOD5 BOD5 = BOD20 x 0.68 = 18.46 x 0.68 = 12.55 (mg/l) Vy 34.7( mg/l) = S + 12.55(mg/l) S = 22.15(mg/l) Tnh hiu qu x l: + Hiu qu tnh theo BOD5 ha tan:E So S 100 So 340.7 22.15 100 93.5% 340.7

+ Hiu qu x l ca ton b s E 340.7 34.7 100 89.8% 340.7

- Xc nh th tch b aerotank:V Q Y (So X (1 K dc

S) c)

10 200 0.5 (340.7 22.15) 3000 (1 0.05 10)

71(m3 ) .

Vic

c

: thi gian lu bn

= 10 ngy.

Q: Lu lng trung bnh ngy Q = 200 m3/ngy. Y: H s sn lng bn Y = 0.5 mg VSS/mgBOD5 La: BOD5 ca nc thi dn vo b La = 340.7 mg/l. Lt: BOD5 ho tan ca nc thi ra khi b aerotank Lt = 22.15mg/l. X: Hm lng bn ho tan X = 3000 mg/l Kd: H s phn hu Kd = 0.05mg-1 + Thi gian lu ca b:V Q 71 200 0.36 (ngy) = 8.64(h).

Chn chiu cao hu ch H = 3m, chiu cao bo v h = 0.5m. Vy chiu cao tng cng ca b l: Ht = H + h = 3 + 0.5 = 3.5(m). Chn chiu rng b B = 4m Chiu di L ca b: LV B H 71 4 3.5 5.1(m) .

Vy kch thc ca b Aerotank l L x B x H = 5.1 x 4 x 3.5m. Tnh ton lng bn d thi ra mi ngy H s sn lng quan st (Yobs) l:Y obs V 1 Kd 0.5mgVSS / mgBOD5 1 0.05mg 1 10g 1 0.333mgVSS / mgBOD 5 .

c

Lng bn sinh ra mi ngy theo VSS l: PVSS = Yobs x Qx (BODv BODr) = 0.333mgVSS/mgBOD5 x 200m3/ngy x (340.7 22.15)gBOD/m3 x 10-3kg/g.= 21(kg/ngay) Tng lng bn sinh ra mi ngy theo SS l: PSS + Lng cn d hng ngy phi x i: Px = Pss Q x 20 x 10-3 = 30 200 x 20 x 10-3 = 26 (kg/ ngy) Xc nh lng bn tun hon S lm vic ca h thng: Q, So B aerotank Qr, Xr, S B lng 2 Qe, S, XeP VSS 0.7 21 0.7 30(kgSS / ngy).

+ Xc nh lu lng bn d x ra hng ngy (Qw) t b lng theo ng tun hon bn :c

V.X Qw.X r Q.Xe

Q

V .Xw

Q.X e . Xr. c

c

Trong : X l nng bn hot tnh trong b X = 3000mg/l. Xr l nng cht rn bay hi c trong bn tun hon Xth = 0.7 x 200 = 140 (mg/l) Xe: nng cht rn bay hi u ra : Xe= 20 x 0.7 =14 (mgVSS). Qw l lu lng bn d cn x l (m3/ngy). Q l lu lng nc thi (m3/ngy).Qw V Xc c

Q Xe

Xr

71 3000 10 200 14 10 8000

2.66 (m3/ngy).

+ Lng oxy cn thit cho qu trnh bn hot tnh Khi lng BOD L tiu th trong qu trnh sinh hc bn hot tnh l:M BODL Q (So S ) 0.68 200 (340.7 22.15) 10 0.683

93.69 (kg/ngy).

Nhu cu oxy cho qu trnh l:M O2 M BODL 1.42 21.2 93.69 1.42 21.2 63.6 (kgO2/ngy).

Gi s rng khng kh c 23.2% trng lng oxy v khi lng ca khng kh l 1.2 kg/m3. Vy Lng khng kh l thuyt cho qu trnh l:M kk M O2 0.232 1.2 63.6 0.232 1.2 228.4 (m3/ngy).

Kim tra lng khng kh cn thit cho xo trn hon ton l:q M kk E V 228.4 1000 0.093 71 1440 24(l / m3 . pht).

Trong : V l th tch aerotank (m3). E l hiu qu x l BOD (%) Tr s q nm trong khong cho php q = 20 40 l/m3.pht. Nh vy lng khng kh cp cho qu trnh hot tnh cng cho nhu cu xo trn hon ton. Lng kh cu thit ca my thi kh l:Qkk f M kk E 2 228.4 0.093 1440 3.4 (m3/pht).

2.2.2.6. B LNG T II Chc nng: Lng hn hp nc bn t b aerotank dn qua. Tnh ton: Chn loi b lng c mt bng l hnh trn - Din tch tit din t ng trung tm ca b lng l: f Q: lu lng tnh ton vtt tc dng chy trong ng trung tm - Din tch tit din t ca phn lng ca b lng l: F0v2 : tc chy trong b lng ng Qtt v2 2.3 10 3 0.0005 4.6(m2 ) Qtb vtt 2.3 10 0.033

0.08(m2 )

- Din tch tng cng ca b lng l: F - Chn ng knh ca b lng: D - ng knh ng trung tm l: d4F

F0

f

4.6 0.08

4.68(m2 )

4 4.68

2.45(m). Chn D = 2.5 (m).

4 f

4 0.08 v2 t

0.32(m) 2.7(m)

- Chiu su lp nc trong b lng l: h1 - Chn chiu cao bo v: hbv = 0.3 m.

0.0005 1.5 3600

t : thi gian lu nc trong b lng (t = 1.5h).

- Chiu cao tng cng ca b lng l: H = 2.7 + 0.3 = 3 (m). Vy kch thc b l D x H = 2.5 x 3m. Tnh bm nuc thi t b lng 2 qua b lc p lc: Chn 2 bm nc thi (1 hot ng, 1 d phng) nh b iu ha, Q bm = 12.5 (m3/h), cng sut 1 Hp. 2.2.2.7. B LC P LC Chc nng: Gi li lng cn l lng cn trong nc thi bng lp vt liu lc. Kt qu ca qu trnh lc l sau khi ra khi thit b lc p lc nc thi khng c mu c, hiu qu ca qu trnh lc t 70 85% theo hm lng cn cn li trong nc thi. Tnh ton: - Chn tc lc l v = 8m/h. - Din tch b mt b lc:Atb Qh v

8.33 1.04(m2 ) . 8 4 1.04 1.15(m) . Vy chn D = 1.2m.

- ng knh b lc p lc: D

4A

- Khong cch t b mt vt liu lc n phu thu nc ra: h = HVL.e + 0.25 Trong : HVL l chiu cao vt liu lc. e l gin n vt liu lc khi ra ngc, e = 0.25 0.5 Chn: - i vi ct: + Chiu cao lp ct h1 = 0.3m. + ng knh hiu qu de = 0.5mm. + H s ng nht U = 1.5. - i vi than: + Chiu cao lp than h2 = 0.5m + ng knh hiu qu de = 1.2mm. + H s ng nht U = 1.6.h (0.3 0.5) 0.4 0.25 0.57(m)

- Chiu cao tng cng ca b lc p lc: H = h + HVL + hbv + h + hthu = 0.57 + (0.3 + 0.5) + 0.5 + 0.2 + 0.3 = 2.4(m) Trong :

hbv: chiu cao an ton, hbv = 0.5m. hd: Chiu cao lp si , h = 0.2m. hthu: Chiu cao phn thu nc, hthu = 0.3m. - Vy th tch b lc p lc l: VF.H .D2 .H 4 (1.2) 2 2.4 4 2.7(m3 ) .

- Vy kch thc b lc l: D x H = 1.2 x 2.4m - Tn tht p lc qua lp vt liu lc sch (u chu k lc):h 1 60 L V . h o 2 C 1.8t 42 d10

Trong : C: H s nn, C = 600 1200 ty thuc vo tnh ng nht v sch. Chn C = 1000. to: Nhit ca nc (oC), t = 30 (oC). d10: ng knh hiu qu ca vt liu lc (mm). v: Tc lc (m/h), v = 8 (m/h). L: Chiu dy lp vt liu lc (m). + i vi lp lc ct: h11 60 0.2 8 0.004(m) . 1000 1.8 30 42 (0.5) 2 1 60 0.4 8 0.001(m) . 2 1000 1.8 30 42 (1.2)

+ i vi lp lc than hat tnh: h2

- Vy tn tht p lc qua hai lp vt liu lc l: h = 0.004 + 0.001 = 0.005(m). - Chn th tch si l 0.2m2 - Th tch lp ct: Vc = A x h1 = 1.04 x 0.3 = 0.312 (m3). - Th tch lp than: Vt = A x h2 = 1.04 x 0.5 = 0.52 (m3). Tnh ton qu trnh ra lc (ra ngc) - Chn tc ra nc vnc = 0.35(m3/m2.pht) - Ra ngc bng nc trong thi gian t = 4 5 pht vi tc vnc = 0.35 (m3/m2.pht). - Lng nc cn thit ra ngc cho b lc (Wn):

Wn = A x vnc x t = 1.04 x 0.35 x 5 = 1.82 (m3). - Lu lng bm nc ra ngc cho b lc (Qn): Qn = A x vnc x 60pht = 1.04 x 0.35 x 60 = 21.84 (m3/h) 22 (m3/h). - Cng sut ca bm: NQ.H . .g 1000. 22 8 1000 9.81 3600 1000 0.8 0.6(kW ).

- Vy chn bm ly tm c cng sut l 1 Hp ca Ytalia. 2.2.2.8. B KH TRNG Chc nng: Ph hy, tiu dit cc loi vi khun gy bnh c trong nc thi trc khi x ra ngun tip nhn. ng thi tp trung nc sau lc vi thi gian lu l 30 pht. Tnh ton: - Th tch ca b kh trng l:V 8.33m3 / h 30 phut 60 4.2(m3 )

- Chn chiu cao lp nc trong b l 1.4m. Kch thc b: B x L x H = 1.5 x 2 x 1.4m 2.2.2.9. B NN BN Chc nng: Tch bt nc do mt phn bn hot tnh t b lng 2 v cc bng cn t b lng 1 a vo, lm gim s b m ca bn, to iu kin thun li cho cc qu trnh x l bn phn tip theo. Tnh ton: Chn loi b nn bn ng, bn t b lng t 2 v lng 1 c a n b nn bn nhm lm gim m xung cn khong 96 97%. Thng s thit k b nn bn ng: - Lng bn a n b nn bn: Q = 3.2 (m3/ngy) = 0.13 (m3/h) - Din tch b mt yu cu: FQh qo 0.13m3 / h 0.3m3 / m2 .h 0.43(m2 ) .

Trong : qo l ti trng tnh ton ln din tch mt thong ca b nn bn v c chn ph thuc vo nng bn hot tnh dn vo b nn bn, m3/ m2.h

- ng knh ca b nn bn:D

4 F

4 0.43

0.74(m).

- Th tch bn sau nn: V - Nng bn sau p 12%

99.6kg / ngay 1 0.98 1000kg / m3

3 4.98(m3 / ngy) = 0.21(m /h)

- Khi lng bn sau nn: 99.6kg/ngy 0.12 = 12(kg/ngy) - Chiu cao cng tc ca vng nn: H = qo x t = 0.3 x 10 = 3 (m). Trong : t l thi gian nn, t = 10h. qo l ti trng tnh ton ln din tch mt thong ca b nn bn v c chn ph thuc vo nng bn hot tnh dn vo b nn bn m3/m2.h. - Chiu cao tng cng ca b nn bn: HT = H + hb + hd + hbv = 0.3 + 0.7 + 0.3 + 0.3 = 4.3 (m). Trong : hb l chiu cao lp bn, hb = 0.6 2.4m, chn hb = 0.7m. hbv l chiu cao bo v, hbv = 0.3m. - dc y b l 100m2/m. - Tc thanh gt bn l 0.03 vng/pht. - Kch thc ca b nn bn (ng knh v chiu cao): D x H = 1.5 x 4.3m. Bn c bm t b nn sang sn phi bn vi thi gian l 8 gi/ngy. Vy chn bm c lu lng l Q = 5m3/ngy. 2.2.2.10. SN PHI BN Chc nng: Lm ro nc trong cn t n m cn thit thun li cho vn chuyn v x l cn tip theo. Tnh ton: - Lng cn a n sn l: Qc = 4.98(m3/ngy). - Din tch hu ch ca sn phi bn: FQc 30 qo n 4.98 30 18.7(m2 ) 2 4

Vi qo: Ti trng cn ln sn phi bn, chn q o = 2 m3/m2/ngy (xt trng hp cn ti v bn hot tnh ln men vi nn nhn to c h thng rt nc). n: H s ph thuc vo iu kin kh hu, chn n = 4.

- Chia sn phi bn ra lm 2 ngn, din tch mi ngn l 9.4 m2. Kch thc mi ngn l L x B = 3.5 x 2.7 m. - Din tch ph ca sn phi bn ly bng 20% din tch sn phi bn: F2 = 0.2 x 18.7= 3.74 (m2). - Din tch tng cng ca sn phi: F = 18.7+ 3.74 = 22.5 (m2). - Chia sn phi bn ra lm 2 ngn, din tch mi ngn l 11.25 m2. - Chn sn phi bn hnh ch nht - Kch thc mi ngn l L x B = 4 x 2.8m. - Chiu cao sn phi bn: H = h1 + h2 + h3 + h4 Trong : h1 l b dy y btng, h1 = 250 mm. h2 l b dy lp si , h2 = 200 mm. h3 l b dy lp ct, h3 = 250 mm. h4 l chiu cao cha bn v chiu cao an ton, h4 = 500mm Vy H = 250 + 200 + 250 + 500 = 1 200 (mm) = 1.2 (m). Lm 2 n nguyn c kch thc ging nhau. Khong 20 30 ngy x bn mt ln, bn kh c thu gom bng gu hoc my. Tnh ton lng ha cht + Lng ha cht cho vo b keo t: B cha dung dch axit sunfuric H2SO4 v bm chm H2SO4. - Lu lng cn thit Qtbh = 8.33m3/h. - Nng dung dch H2 SO4 20%, trng lng ring ca dung dch l 1.84 - Lng axit chm vo b keo t: Mc ch: a pH ca nc thi v 6.5. pH = 9, gi s K = 5.5x10-6mol/l.5.5 10 6 98 200 1000 Liu lng axit chm vo (ly d 10%): 20% 1.84 10 0.3 (l/ngy).

Vy chn 2 bm nh lng (1 vn hnh, 1 d phng) c Q = 0.0125(l/h), p lc 1.5bar. B trn dung dch phn v bm chm dung dch phn. Lu lng thit k Q = 200m3/ngy.

Lng phn nhm cn thit l 600mg/l. Khi lng phn l 600 x 200 x 10-6 = 0.12 (kg/ngy). Dung dch phn c nng 40 % (tc 400kg/m3). Lu lng phn l120 400 0.3 (m3/ngy) = 300(l/ngy)..

Chn b trn phn bng nha compositte c th tch 1000l. Chn 2 bm nh lng (1 vn hnh, 1 d phng) c Q = 12.5(l/h), p lc 1.5bar. + B cha PAC v bm chm PAC: Lu lng thit k Q = 200m3/ngy. Lng cht tr keo t PAC l 0.4mg/l. Khi lng PAC l 0.4 x 200 x 10-3 = 0.08(kg/ngy). PAC c nng 2% (20kg/m3). Lu lng PAC l0.08 203 0.004 (m /ngy) = 4 (l/ngy) = 0.17 (l/h).

Thng cha lng ha cht s dng cho 15 ngy. Vy chn thng cha c th tch l 4 x 15 = 60 (l). Chn 2 bm nh lng (1 vn hnh, 1 d phng) c Q = 0.17(l/h), p lc 1.5bar. + Lng Cl dng kh trng Chc nng: Kh trng nc nhm mc ch ph hy, tiu dit cc loi vi khun gy bnh Tnh ton: - Lng Clo hot tnh cn thit kh trng nc thi. Chn Clo dng l dung dch Javen 10%. Lu lng thit k: Q = 200m3/ngy Liu lng clo: 8mg/l Lng clo chm vo b kh trng l:8 x 200 x10-3 = 1.6 (kg/ ngy) Nng dung dch NaOCl:10% Lng NaOCl 10% chm vo b kh trng: Chn bm nh lng l 1 l/h.1.6 16 (l/ ngy) = 0.7 (l/h). 0.1

TNH TON THIT K CC N V CNG TRNH ( THAM KHO S 2)

1 Song chn rcNhim v song chn rcSong chn rc l cng trnh x l s b, mc ch ca qu trnh ny l kh cc tp cht th (gi, rc, l cy, ) c th gy ra s c trong qu trnh vn hnh x l nc thi nh lm tc bm, tc ng ng hoc knh dn y l bc quan trng bo m an ton v iu kin lm vic thun li cho c h thng.

Tnh ton kch thc song chn rcNc thi sau khi qua ngn tip nhn s c dn ti song chn rc bng mng dn.

Bng 2: Cc thng s thy lc mng dn nc thiThng s Qd QhTB Qhmax Qgi ymax dc i Chiu ngang B Vn tc Vmax y H m m/s m n v m3/d m3/h m3/h m3/s Gi tr

60025 40 0.0083 0,001 0.3 0.38 0.12

Chiu su ca lp nc song chn rc ly bng y ca mng dn ng vi QmaxH1 = Hmax = 0,12 m

S khe h ca song chn rc c tnh theo cng thc:n Trong : n : s khe h Qmax K V l H1 0.0083 1, 05 11.376 12 0, 38 0, 016 0,12

Qmax Vmax l k

: lu lng ln nht ca nc thi, Qmax = 0,0083m3/s : vn tc nc chy qua song chn rc, Vmax = 0,38 m/s : khong cch gia cc khe h, l = 16mm = 0,016 m : h s tnh n mc cn tr dng chy, k = 1,05

Chiu rng ca song chn rc c tnh theo cng thc: Bs = s(n 1) + (l n) = 0,008(12 1) + (0,016 12) = 0.28 mTrong : s : b dy ca thanh song, chn s = 0,008 m

Tn tht p lc qua song chn rc:

hs Trong :Vmax m/s K1

2 Vmax K1 2g

0,628

0,382 3 2 9,81

0,014 m

: vn tc ca nc thi trc song chn ng vi Qmax, Vmax = 0,38 : h s tnh n s tng tn tht do vng rc, K1 = 3 : h s sc cn cc b,

s l

4/3

sin

1,83

0,008 0,016

3/ 4

sin60 0

0,628

: h s ph thuc vo tit din thanh song, ly theo bng 3-7 sch X l nc thi th v cng nghip (Lm Minh Trit), ly = 1,83 : gc nghing song chn so vi hng dng chy, = 600

Chiu di phn m rng ca song chn:

L1Trong : Bs Bm

Bs Bm 2tg

0,5 0,3 2tg20 0

0,275m

: chiu rng ca song chn rc, Bs = 0,5 m : chiu rng ca mng dn, Bm = 0,3 m : gc nghing phn m rng, = 200

Chiu di xy dng song chn rc:L=2 Trong : L2 : chiu di phn cng tc song chn rc, L2 = 1 m L1 + L2 = 2 0,275 + 1 = 1,55 m

Chiu su xy dng ca song chn rc: H = H1 + hs + 0,3 = 0,12 + 0,014 + 0,3 = 0,434 mTrong : hs SSr = SSv : tn tht p lc qua song chn rc, hs = 0,014 m (100% - 5%) = 664 (100% - 5%) = 630 mg/l

Hiu sut kh SS t 5%, vy SS ra khi song chn rc l:

Bng 3: Nng cht bn ra khi song chn rcCh s BOD5 COD SS n v mg/l mg/l mg/l Gi tr Dng vo 1610 2300 Dng ra 1610 2300 630

664

B iu ho lu lngChc nng b iu hoNc thi cng nghip c thi ra vi lu lng thng bin i theo gi, thi v sn xut, ma (ma, nng). Trong khi cc h thng sinh hc phi c cung cp nc thi u n v th tch cng nh v cc cht cn x l 24/24 gi. Do s hin din ca mt b iu ho l ht sc cn thit. B iu ho lu lng c dng duy tr dng thi vo gn nh khng i, khc phc nhng vn vn hnh do s dao ng lu lng nc thi gy ra, gim c kch thc cc cng trnh sinh hc sau v nng cao hiu sut ca cc qu trnh cui dy chuyn x l.

Tnh ton kch thc b iu hoChn thi gian lu l 4gi Th tch ca b iu ho

V

Q max t 160m3 V h

max Qh t 160m3

B iu ho c hnh dng ch nht, chn chiu cao cng tc ca b H ct = 4 m, chiu cao phn bo v hbv = 0,4 m, vy chiu cao xy dng b iu ho:H = Hct + hbv = 4 + 0,4 = 4,4 m Din tch b: F Vh (tt ) H ct 160 4 40 m2 B L 5m 8m

Chn chiu di L = 8 m ; chiu rng B = 5 m Vy th tch thc ca b: Vtt L B H XD 8 5 4.4 176m3

Lng kh nn cn thit cho khuy trn:

qkh = R

Vh(tt) = 0,012

160 = 1.92 m3/pht = 115.2 m3/gi

R: tc kh nn, R = 10 15 l/m3.pht, theo bng 9-7 sch X l nc thi th v cng nghip (Lm Minh Trit), chn R = 12 l/m3.pht = 0,012 m3/m3.pht B iu ha khuy trn bng kh nn s dng ng c l, b tr theo dng li. Theo bng 9-8 sch X l nc thi th v cng nghip (Lm Minh Trit), chn: Lu lng kh qua mi l l = 40 l/pht.l ( quy phm t 28 133 l/pht.l) Chn hiu sut chuyn ho oxy S l khuch tn kh: n qkh 1000 l = 26%.( quy phm t 22 29%). 115.2 1000 48 l 40 60

V ta c 5 ng phn phi kh nn chn n = 50 l

Lu lng kh qua mi l khuch tn thc t:ltt qkh n 115.2 24 50 100 0.6m3 / h

Chn s l trn 1 ng=10 l, nh vy khong cch gia cc l theo chiu di l:ll L n 7 0.7m 10

Khong cch gia cc l theo chiu rng b:L= 1m

Chn ng phn phi kh chnh c

=0.075m

Vn tc kh trong ng chnh lvc qkh 4 3,14 D 2 7.25m/s

Chn ng phn phi kh nhnh cvnh qkh 4 3,14 D 2

=0.034m7.05m/s

Bng 4: Thng s k thut b iu ho lu lngThng s Vh(lt) Vh(tt) t F H Hct hbv B L n v m3 m3 Gi m2 Gi tr 160 176 4 40 4.4 4 0,4 5 8

mm m m m

Bng 5: Thng s k thut v cp kh cho b iu ho lu lngThng s qkhi n Vng chnh Dng chnh vnhnh Dnhnh n v m3/gi Gi tr 115.2 50 7.25 0,075

Lm/s

m m/sm

7.050,034

Tnh ton my thi kh p lc cn thit ca my thi khH=4.4m=0.44atm

Nng sut yu cuG Qkh= 115.2m3/h

Trng lng ca dng khng khqkhikhi

0.0416kg / s

Cng sut my thi khPmay

GRT P2 29.7 n e1

n

1 P

1.92kw Pmay

GRT 29.7 n e

n

P2 P1

1

1.92kw

Trong

R l hng s kh=8.314KJ/Kmol T l nhit tuyt i T=3000K P1: p sut tuyt i ca khng kh u vo=1atm P2: p sut tuyt i u ra=0.44+1=1.44atm N=(k-1)/k=0.283 (k=1.395 i vi khng kh) 29.7 h s chuyn i E l hiu sut ca my, chn e= 0.7 Nc thi sau khi qua b iu ha s c lu lng khng i theo thi gian : Q = 25 m3/h

Hiu sut kh BOD5 v COD t 15%, nng cc cht ra khi b iu ho cn li l:BOD5(ra) = BOD5(v) (100% - 15%) = 1610 COD(ra) = COD(v) (100% - 15%) = 2300 (100% - 15%) = 1368.5 mg/l (100% - 15%) = 1955 mg/l

Bng 6: Nng cht bn ra khi b iu haCh s BOD5 n v mg/l Gi tr Dng vo 1610 Dng ra 1368.5

COD SS

mg/l mg/l

2300

1955 630

664

B lng 1 ( lng ly tm) Chc nng ca b lng 1B lng 1 dng loi b cc ht cn l lng c kh nng lng c gip cc cng trnh ph sau hot ng hiu qu hn v cng trnh lm h hng my bm bi cc ht cn c kch thc ln

Tnh ton b lng 1B lng 1 c dng hnh trn, nc thi vo t tm b ri i ra, thu nc theo chu vi b.

Bng 7: Cc thng s nc u vo ca b lng1Ch s Lu lng BOD5 COD SS n v m3/ng mg/l mg/l mg/l Gi tr

6001368.5 1955 630

Chn ti trng b mt V0=40m3/m2.d (quy phm 32 48 m3/m2.d) Qtbd = 600m3/d Din tch b mt b lng 1 F1=Qtb/V0=15m2 Chn ng knh ng trung tm Dtt=20%D (quy phm 15 20%) ng knh b D4(F1 f tt )

D

4.4m

Chn Db = 4.5 m

Dtt = 0.9 m

Tnh li din tch cn thit

R

Xc nh li ti trng b mt ca b lng 1V0 Q 24 F1

t 1.83 t a b 1.83 0.0075 0.014

55.25%

37.736m3 / m2 .d

Chn : chiu su b lng H=3m Chiu cao lp bn lng hbn=0.7m Chiu cao lp trung ho hth=0.2m Chiu cao bo v hbv=0.3m Chiu cao tng cng Htc=4.2m Chiu cao ng trung tm h=60%=1.8mKim tra

Th tch phn cng tc b V ct thi gian lu ca b 42 (Dbe 2 d tt ) H

45.78m3

t = Vct /Q = 1.83 gi

Tng chiu di mng rng ca :L= D = 14.13m

Ti trng thu lc ca mng trngLs = Q/L = 42.46m3/m2.d

Hiu qu kh BOD5 :

t 1.83 t a b 1.83 0.018 0.02 Trong a,b l cc hng s thc nghim RHiu qu kh SS

33.52%

R

t t a b

1.83 1.83 0.0075 0.014

55.25%

Nng cc cht ra khi b lng 1

BOD5=BODV(100%-33.52%)= 909.78 mg/l CODR=1299.68 mg/l

SSr=279.14 mg/lLng bn ti sinh ra mi ngy Th tch bn sinh ra mi ngy

Mbun=(664 - 279.14)600.10-3=231kg/d Vbun = Mbun/C = 2.9 m3/d

Trong C l hm lng cht rn trong bn ly = 80kg/m3

Bng 8: Nng cht bn ra khi b lng 1Ch s BOD5 COD SS n v mg/l mg/l mg/l Gi tr Dng vo 1368.5 1955 Dng ra

909.78 1299.68 279.14

630

B UASBC s chn phng nX l sinh hc bng vi sinh vt ym kh l qu trnh phn hu cc cht hu c, v c c trong nc thi trong mi trng khng c oxy. Quy trnh ny c p dng x l n nh cn v x l nc thi cng nghip c nng BOD5, COD cao ( 500 mg/l) p dng quy trnh x l hai bc, bc mt x l ym kh, bc hai x l hiu kh.

Tnh ton thit k b UASB

Bng 9 : cc thng s thit k b UASBCh s Lu lng BOD5 COD SS Yu cu sau b UASB: CODr chn CODr = 450 mg/l. n v m3/ng mg/l mg/l mg/l Gi tr

600909.78 1299.68 279.14

500 mg/l a qua quy trnh x l hiu kh tip theo,

Hiu qu lm sch cn t ca b UASB:

ETrong :

CODv CODr CODv

1299.68 450 1299.68

65.38%

CODv : nng COD dn vo b UASB, CODv = 1299.68 mg/l. CODr : nng COD dn ra khi b UASB, CODr = 450mg/l.

Lng COD cn kh 1 ngy:G Qng COD CODr v 103

600

1299.68 450

10

3

509.808kg/d

Ti trng kh COD hng ngy (ly theo bng 12-1 sch Tnh ton thit k cc cng trnh x l nc thi TS. Trnh Xun Lai): a = 8 kgCOD/m3.ngy

Dung tch phn x l ym kh:Vk G a 509.808 8 63.73 m3

Tc nc i ln trong b:

0,6 0,9 m / h chn v = 0,8 m/h

Din tch mt bng b cn thit:

FTrong :

Q tbh v

25 0,8

31,3 m 2

Qtbh v

: lu lng nc thi dn vo b UASB tnh theo gi, Qtbh : vn tc i ln ca nc trong b, v = 0,8 m/s

= 25 m3/h.

Chiu cao phn x l ym kh:H1 Vk F 63.73 31, 32 2, 04m

Chn chiu cao vng lng: H2 = 1,2 m Chn chiu cao phn d tr:H3 = 0,3 m.

Chiu cao xy dng b UASB:H = H1 + H2 + H3 = 2,1 + 1,2 + 0,3 = 3.6 m

Th tch ton b b UASB:Vt = H F = 3.6 31,4 = 112.75 m3

Kim tra thi gian lu nc trong b: F (H H 3 ) 31, 4 3, 6 0, 3 4,13h Qtbh 25 Kch thc b UASB: ta c din tch mt bng b F = 31,4 m2, chn chiu t di ca b L = 5.8 m vy chiu rng ca b B = 5,4 m. Tnh ton phn mng lng cn: chn gc nghing ca mng lng nghing mt gc = 500 so vi tng ca b UASB B c chia lm 2 ngn lng, chiu rng mi mng:B 2 Chiu cao phn mng lng: b 5, 4 2 2, 7m

HLcao xy dng b phi 30%

B : tg 4

5, 4 : tg500 4

1, 4m

Kim tra chiu cao ngn lng: t s gia chiu cao mng lng so vi chiu

HC H

30%

1, 4 39% 30% 3, 6

Nh vy chiu cao phn mng lng m bo chiu cao thit k. bo Kim tra thi gian lu nc trong ngn lng, thi gian lu nc trong ngn lng phi m 1gi

Kim tra thi gian lu:tlTrong : tl Vl Qgi F HL H3 : thi gian lu nc trong ngn lng, (gi) : th tch ngn lng, Vl = F (H1 + H3) : lu lng nc thi theo gi, Qgi = 25 m3/h : din tch mt bng b, F = 31,32 m2 : chiu cao ngn lng, HL = 1,4 m : chiu cao phn bo v, H3 = 0,3 m

Vl Qh

F (H L H 3 ) Qh

31, 32

1, 4 0, 3 25

1, 4h

Nh vy thi gian lng trong mng lng m bo yu cu thit k. Tnh ton tm chn kh v tm hng dng

Khong cch gia 2 tm chn kh: vn tc nc chy qua khe vo ngn lng nm trong khong 9 10 m/h, chn v = 10 m/hTa c:

v

Qh Skhe

25 4 5, 8 bk

10m / h

bkTrong : bk Skhe

25 4 5, 8 10

0,108m

: khong cch gia hai tm chn kh, m : tng din tch tit din ngang ca cc khe,

Skhe = 4

L

bk (m2)

Tnh ton lng kh mtan sinh ra

Lng kh sinh ra khi phn hu 1 kg COD l: m = 0,5 m3/kg COD Vy lu lng kh sinh ra trong mt ngy l:Qkh = m G = 0,5 509.808 = 255 m3/ng

Trong : G : lng COD kh mi ngy, G = 509.808 kgCOD/d

Trong tng ton b th tch kh sinh ra th kh CH4 chim 75% th tch, nh vy lng kh mtan do b UASB sinh ra trong ngy l:

QCH4

Qkh

75%

255 75%

191, 25 m3 /d

Tnh ton dn ng phn phi nc voPhn phi nc vo b UASB bng dn ng xng c. Chn vn tc nc trong ng chnh vc = 1 m/s, vn tc nc trong ng nhnh vn = 1 m/s, vn tc trong ng xng c vx = 1 m/s, ng knh l phn phi d l = 15 mm. Tra bng tnh ton lu lng ta c:

ng knh ng phn phi chnh: Dc = 100 mm. ng knh ng nhnh: Dn = 60 mm. ng knh ng xng c d = 27 mm.Tnh ton lng bn sinh ra

Lng sinh khi hnh thnh mi ngy:Y COD v CODr Qd 1 kd Y 0, 04 1299, 68 450 600 1 0, 025 60c 3

Px

10

8,17kgVS / d

Trong :

: h s sn lng bn, Y = 0,04gVSS/gCOD = 0,04kgK/S/kgCOD

CODv : nng COD dn vo b UASB, CODv = 1299,68mg/l. CODr : nng COD dn ra khi b UASB, CODr = 450 mg/l Qng kdc

: lu lng nc thi, Qng = 600 m3/ng : h s phn hu ni bo, kd = 0,025ngay-1 : thi gian lu bn trong b, c = 60 ngy

Lng bn bm ra mi ngy:Wb Px CSS 8,17 40 0, 204m3 / d

Trong : CSS : nng bn trong b UASB, Css = 40kg/m3.

Bng 10: Nng cc cht vo v ra khi b UASBCh s BOD5 COD SS n v mg/l mg/l mg/l Gi tr Dng vo 909.78 1299.68 279.14 Dng ra 273 450 97.7 Hiu sut kh cht bn(%) 70 65.4 65

Bng 11: Cc thng s cu to b UASBThng s B L bk H1 H2 H3 H Thi gian lu nc t n v m m m m m m m Gi Gi tr 50 5,4 5,8 0,108 2,1 1,2 0,3 3,6 4.13

B AerotenC s la chn phng nNc thi sau khi qua cc cng trnh x l c hc v sinh hc bc I nng ca cc cht bn vn cn kh cao v vy nu p dng b aeroten c in thng thng x l s khng m bo tiu chun p dng v khng t hiu qu cao. Aeroten xo trn hon ton l mt gii php kh thng dng v phng php ny cho php nng BOD 5 vo b x l ca cng trnh vn m bo yu cu. 1000 mg/l m hiu sut

Tnh ton thit k b aeroten xo trn hon toni vi b aeroten xo trn hon ton th hm lng cht rn l lng u vo khng quy nh v nng BOD5 cho php di 1000mg/l

Bng 12:Ch s Lu lng BOD5 COD SS

Cc thng s u vo ca b aeroten n v m3/ng mg/l mg/l mg/l Gi tr

600273 450 97.7

Xc nh lu lng bn tun hon cho b aeroten

Q, X0

AEROTEN

Q+Qth, X

Be Lan g

Q, Xr

Qth, Xth

Qb, Xth Hnh 1: S thit lp cn bng sinh khi quanh aerotenTrong Q, Qth, ln lt l lu lng nc u vo, lu lng bn tun hon, (m3/d) S,S0 l nng cht nn ( tnh theo BOD5) u vo v nng cht nn sau khi qua b aeroten v b lng 2 (mg/l) X, Xr, Xth l nng cht rn bay hi trong b aeroten, nng bn tun hon v nng bn sau khi qua b lng 2 (mg/l)

-

Chn: BOD5 ra = 20 mg/l Cn l l lng u ra SSr=28 mg/l gm c 65% l cn c th phn hu sinh hc Nc thi khi vo b Aerotank c hm lng cht rn l lng d bay hi 0 T s gia cht rn bay hi vi cht rn l lng l 0.8 X0 =

-

-

Lng bn tun hon 9000mg/l Nng bn hot tnh c duy tr trong b aerotank l: X=3000 mg/l Thi gian lu bn trong h thng H s BOD5:BOD20 = 0.68 H s phn hu ni bo kd=0.06 ngy-1 H s sn lng ti a Y=0.5mgVSV/mgBOD5c

=10 ngy

Tnh kch thc b aecrotankTa c : Phng trnh cn bng vt cht BOD5 u ra bng BOD5 ha tan i ra t b aeronten + BOD5 cha trong lng cn l lng u ra.

Ta c : SSra = 28 mg/lLng BOD20 cha trong cn l lng ra khi b lng II : 0.65 28 18.2(mg / l)

Lng BOD20 khi b oxy ha ht chuyn thnh cn tng ln 1.42 ln (1 mg BOD20 tiu th 1.42 mg O2.)18.2(mg / l) 1.42 (mgO2/mg t bo) = 25.84 (mg/l)

Chuyn i gi tr BOD20 sang BOD5BOD5 = BOD20 x 0.68 = 25.84 x 0.68 = 17.6 (mg/l)

Lng BOD5 ha tan ca nc thi sau lng II : 20 S 17.6 S 20 17.6 2.4(mg / l)

Hiu qu x l BOD5 ca b aerotenE 273 20 100% 92.7% 273

Da vo cn bng sinh khi quanh b aerotanic ta c phng trnh cn bng sinh khi :

QX 0Trong :

QTh XTh

(Q QTh ) X

- X0 = hm lng cn l lng u vo, mg/l - Q = lu lng vo b : Q = 600m3/ngy. - QTh : Lu lng bn tun hon; m3/ ngy - XTh : Hm lng SS ca lp bn lng hoc bn tun hon, X Th = 9000mgSS/l - X : Hm lng bn hot tnh trong b aeroten, X = 3000mg/l Hm lng bn hot tnh trong b : MLVSS 3000(mgVSS / l ) MLSS 3750mgSS / l 0.8 0.8Gi s X0 = 0 v QTh = nh sau :.Q , chia 2 v cho Q, biu thc trn c th khai trin

X X ThTrong :

X

3750 9000 3750

0.71 (tha gii hn 0.25 1)

= h s tun hon

QTh Q

QTh

.Q 0.71 600 426 m3/ngy= 17.75m3/h

Th tch cng tc ca b aerotank (Q QTh ) Y (S0 S ) V X (1 Kd C) (600 426) 10 0.5 (2.73 2.4) 3000(1 0.06 10) Din tch b mt b : F V H1 289.2 3.5 82.63m2289.2m3

Trong : Chiu cao cng tc ca b chn H1 = 3,5m

Chn s n nguyn b n = 2, chiu rng mi b b = 4.1 mChiu di ca b aerotank l :

F 82.63 10(m) 2 b 2 4.1 Chiu rng ton b b B = 2 x b = 2 x 4.1 = 8.2 (m) LChn chiu cao bo v ca b hbv = 0.5 (m) Chiu cao tng cng ca b aerotanic :

H H1 hbv 3.5 0.5 4(m) Vy kch thc ca mi b aerotank (c 2 b) : L b H 10 4.1 4 Tnh thi gian lu nc trong b : t V Q QTh 289.2 24 6.8(h) (600 426)

Tnh lng bn d mi ngy : H s sn lng quan st (Yobs)Tnh theo phng trnh :

Yobs

Y 1 K d Oc

0.5 1 0.06 10

0.3125

Lng bn d sinh ra mi ngy theo VSS

P

X (VSS )

Y

obs

Q(S

0

S ) 103

3

0.3125 600(273 2.4) 10

50.7kgVSS / ngy

Tng lng bn sinh ra mi ngy theo SS PX (VSS ) 50.7 62.5kgSS / d 0.8 0.8 Lng bn d c kh nng phn hy sinh hc cn x l : Lng bn d cn x l = tng lng bn lng SS tr ra khi lng II.

PX (SS )

M d (SS) = 62.5 kgSS/ngy - 600 (m3/d) X = 45.7kgSS Lng bn d c kh nng phn hy sinh hc cn x l : M d (VSS) Ta c cng thc : = 45.7 x 0.8 = 36.6 kgSS/ngy m

c Qw Qw

V0 X X Th Qe X e Qe X e Qe X Th c V : Th tch b aerotank ; V = 289.2m3 X : Nng cht rn bay hi; X = 3000 mgVSS/l c : Thi gian lu bn : c = 10 ngy. Qe : lu lng nc a ra ngoi b lng t 2 : Qe = Q = 600 m3/ngy Xe : nng , cht rn bay hi u ra ca h thng : Xe = 28 mgSS/l x 0.8 = 22.4 mgVSS/l XTh : nng cht rn bay hi trong bn hot ng tnh tun hon XTh = 9000 mgSS/l x 0.8

Vx

Trong :

Qw

289.2 3000 600 22.4 10 10.2m3 /d 7200 10

Kim tra ti trng th tch LBOD v t s F/M . Ti trng th tch : LBOD Q.La V 600.401, 5.10 289.2 0.83

T s ny nm trong khong cho php LBOD = 0.8 1.9Trong : La l hm lng BOD20 i vo b : La T s F/M : F /M La T0 X 401.3 6.8 3000 124 0.47 ngyBOD5 273 0.68 0.68

401.3 mg/l

Tr s ny nm trong khong cho php (F/M = (0.2

0.6) ngy -1

Tnh lng oxy cn cung cp cho b aeroten da trn BOD20 Lng oxy cn thit trong iu kin tiu chun :OC 0 Q(S0 S) 1.42PX

600(273 2.4) 1.42 50.7 ngy 068 1000 Vi = 238.7 kgO2/ngy l h s chuyn i gia BOD5 v BOD20 : Lng oxy thc t cn s dng cho b : OC4 Trong : CS : nng bo ha oxy trong nc nhit lm vic ; Cs = 9.08 mg/l CL : lng oxy ha tan cn dng nc trong b ; CL = 2mg/l Lng khng kh cn thit : Qk Trong : f : h s an ton f = 1.2 chn f = 1.5 OU = Ou.h b phn phi tnh theo gam oxy cho 1m3 khng kh Qu : cng sut ha tan oxy vo nc su 1m, theo bng 7.4 TTXLNT Trnh Xun Lai, Chn Qu = 4.5gO2/m3.d h : su ngp nc ca thit b phn phi kh chn 3.5m Qkhi 306 4.5 3.5 1 3 1.5 1.5 OCt OU f OC0 Cs CS CL 238.7 9.08 9.08 2 = 0.68

306 kgO2/ngy

: cng sut ha tan oxy vo nc thi ca thit

= 29413 m3 kk/ ngy = 1214.3 m3kk/h

Tnh ton my thi kh : p lc cn thit ca my kh : Hm = hL + hd + H = 0.5 + 0.5 + 3.5 = 4.5m Chn Hm = 4.5m = 0.45atm Trong : hL :tn tht trong h thng ng vn chuyn h = 0.5m H : su ngp nc ca ming vi phun H = 3.5m

Nng sut yu cu : QTT =12 3 m /h = 0.34m3/s 4.3

Cng sut ca my thi kh : GRT0.283

P2

0.442 8.314 298 1.45 1 29.7 0.283 0.7

0.283

20.64Kw

1

P 29.7ne P 1 Trong :

1

P : cng sut yu cu ca my nn kh kw G : trng lng ca dng khng kh G = QTT xKK

= 0.34 x 1.3 = 0.442 kg/s

R : Hng s kh R = 8.314 T1 : Nhit tuyt i T1 = 273 + 25 = 2980K P1 : p sut tuyt i ca kh u vo P1 = 1 atm. P2 : p sut u ra P2 = Hm + 1 = 0.45 + 1 = 1.45 atmn (K 1) K 0.283 (K = 1.395 i vi kk)

29.7 : h s chuyn i e : hiu sut ca my, chn e = 0.7 Tnh ton h thng phn phi kh.

Kh c cung cp bng h thng ng PVC c gn cc a phn phi kh c ng knh 0.3m, din tch b mt f = 0.07m2. Cng kh qua mi a l 1.2 l/s, ng knh bt kh ra khi thit b khong t 1 6 mm. S lng a cn dng cho b aerotank l : N QTT 1.2 0.34 103 1.2 284 a

Nh vy mt b cn : 142 a Gi s s lng a theo chiu rng : Nb S lng a theo chiu di : NL N Nb 284 18 a 16 16dia = 8 a/b 2be

Khong cch gia cc a theo chiu rng : mb B Nb L NL 8.2 16 0.5(m)

Khong cch gia cc a theo chiu di b : mL 10 18 0.5m

Vy s lng a thc t cn s dng l : 16 x 18 = 288 a

Bng 13: Cc thng s cu to b aerotenThng s B L H N Nl Nb n v m m m a Gi tr 8.2 10 4 284 18 16

aa

ml mb

m m

0.5 0,5

B lng IIC s la chn phng nB lng ng thng c p dng cho cc trm x l nc thi c cng sut va v nh. Khi s dng b lng ng sau b aeroten cn c tc dng nn bn trc khi a bn n cc cng trnh x l cn.

3.6.2 Tnh ton thit k b lng ngCc thng s tnh ton b lng ng (theo bng 9-12 sch X l nc thi th v cng nghip (Lm Minh Trit))

-

i vi nc thi sau khi x l bng bn hot tnh : Ti trng b mt : LA = 25m3/m2 ngy Ti trng bn : LS = 5kg/m2.h. Din tch b mt lng theo ti trng b mt:AL =

Q

TB ngay

L

A

600m3 / ngay = 24 m2. = 25m3 / m 2 ngay

Din tch b mt lng tnh theo ti trng cht rn :AS = (Q Qth )x MLSS (25 17, 5)x 3750 = 5 x 1000 LS 32,1m2

Do AS > AL, vy din tch b mt theo ti trng cht rn l din tch tnh ton.

ng knh b lng : chn s n nguyn ca b lng ng 2 b.D= 4 x A 2 4 x 32,1 2 4, 5(m)

ng knh ng trung tmd = 20% D =0.2 x 4.5 = 0.9 m 0,5 mm/s (theo iu 7.11.1 Sch 20 Kim tra vn tc i ln ca nc trong b lng. v TCN 51 84).

v=

Q Qth F

(600 426)x 1000 32,1 x 3600 x 24

0, 37mm / s (tha iu kin).

Chiu cao hu ch ca b lng chnhL = 3 m (hL = 2,7 3,8m)

Chiu cao phn cha bn lng.

hb =Trong :

D dn x tg 2

=

4, 5 0, 5 tg500 2

2, 4(m)

hb : chiu cao phn cha bn lng D : ng knh b lng ng, D = 4,5 m = 500 (theo dn : ng knh y phn cha bn, dn = 0,5m : gc nghing y b lng so vi phng ngang, iu 5.9.c Sch 20 TCN 51 84)

Chiu cao bo v : hbv = 0,3m.Chiu cao tng cng ca b lng: H = hL + hb + hbv = 3 + 2,4 + 0,3 = 5,7 (m)

Chiu cao ng trung tm :h = 60% hL = 0.6 x 3 =1.8m

Kim tra li thi gian lu nc b lng : Th tch phn lng mi b :VL = (D 2 d 2 ) x hL 4 = 4 (6, 52 0, 9 2 ) x 3= 45.8m3

Thi gian lu nc :t = 2V Q Qth 2x 45,8 25 17, 75 2, 2(h)

Th tch phn cha bn mi b :Vb = (AS x hb)/2 = (32,1 x 2,4)/2 = 38,52 m3

Thi gian lu bn trong b :

tb = 2 x

Vb 2x 38,52 = 10, 2 Q Qth 17, 75 24

4, 2(h)

Ti trng mng trn :LS = (Q Qth ) / 2 D (600 426) / 2 3,14x 4,5 36,13m3 / m.ngay

Bng 14 : Cc thng s cu to b lng ngThng s h1 n D d n v m B m m hb hbv H Gi tr 3 2

4,50,9 50 2,4 0,3 5,7

mm m

B tip xcChc nng:Lm nhim v kh trng nc thi trc khi x ra ngun tip nhn.B c chc nng l lm tng s tip xc ca vi khun vi cht kh trng.

Tnh ton b tip xcThit k b tip xc dng b trn c cc vch ngn nhm to ra s i chiu lin tc ca dng nc. B c cu to hnh ch nht, bn trong c vch ngn. Thi gian tip xc khng nh hn 30 pht (Lm Minh Trit,1978), chn thi gian lu nc trong b tip xc l 30 pht

Dung tch b tip xc:

V = Q t = 12.5 m3Din tch mt bng ca b

S = V/H1 = 12.5/2 = 6.25 m2

Trong : H1 l chiu cao cng tc ca b chn bng 2m

Chiu cao bo v H2 = 0.2m Chiu cao ca b H = 2.2m B tip xc c 3 vch ngn. Kch thc mi vch ngn l

L B H = 1m 2.1m 2.2m

Bng 15: Bng thng s cu to b tip xcThng sH1 H2 H n L B

n vm m m Vch ngn m M

Gi tr2 0.2 2.2 3 3 2.1

B mtanLng bn dn n b mtan Bn t b lng I:

Wb1 = 2.9 m3/dBn t b UASB: Wb UASB = 0.204 m3/d Bn t b lng II: bn trong b lng II s c nn trc khi dn ra, m ca bn trc khi nn P1 = 99,7%, m sau khi nn t P2 = 97%, vy lng bn dn vo b mtan l:

Wb 2

Qb

100 P1 100 P2

10.2

100 99,7 100 97

1,02m 3 / d

Lng bn tng cng:

W = 2.9+0.204+1.02 = 4.124 m3/d

Dung tch b mtan:

WmTrong : d

W 100 d

: liu lng cn ngy m dn vo b mtan (%), d = 11% (ly theo bng 42-TCN-51-84)

4.124 100 37.5m 3 11 Chn chiu cao cng tc b mtan H1 = 3m, Din tch mt bng b: Wm

Fng knh mi b:

Wm H1

37.5 3

12.5m 2

4 12.5 4m 3.14 Chn chiu cao chp trn H2 = 1m, chiu cao chp y: H3 = 1m. Chiu cao tng cng Htc= H1+H2 +H3 = 5m Bn thi sau khi b x l b mtan th lng bn cn li khong 70%:Wc = 70% W = 70% 4.124 = 2.9 m3/d

D

4 F

Bng 16: Thng s cu to b mtanThng s H1 D H2 H3 H n v m m m m m

Gi tr3 4 1

15

Sn phi bnChc nng:Sau khi qua b metan lng cn s c a n sn phi bn lm ro nc, sau bn cn s c chuyn i theo chu k

Tnh ton sn phi bnLng bn vo: Wv= 2.9m3/d Chu k ly bn ra l 2 thng Th tch bn m sn phi cha c lV = Wvt = 174 m3

Chiu cao hu ch ca sn phi : H1= 0.5m Chiu cao lp si H2=0.3m Chiu cao lp ct H3=0.2m Chiu cao tng cng H=1m Din tch sn phi :F = V/H = 174m2

Sn phi bn chia lm 2 ngn mi ngn l 87m2 Kch thc mi ngn : L B = 10m 8.7mTNH TON THIT K HTXLNT ( THAM KHO S 3)

I. SONG CHN RCI.1 Chc nng: Nc thai a ti cong trnh lam sach trc het phai qua song chan rac. Tai song chan rac, cac tap chat tho nh rac, tui nylon, vo trai cay, gie, go va cac vat khac c gi lai nham am bao cho may bm va cac cong trnh, thiet b x ly nc thai hoat ong on nh. ay la bc quan trong nham am bao o an toan he thong x ly nc thai. Da vao khoang cach gia cac thanh chan co the chia song chan rac thanh cac loai nh: song chan rac loai tho, khoang cach gia cac thanh t 60 100 (mm) va song chan rac mn co khoang cach gia cac thanh t 10 25 (mm). Song chan rac c lam bang kim loai, lam sach bang thu cong hoac

c gii va at nghieng mot goc 45 600. Van toc nc chay qua thanh chan rac c gii han trong khoang 0.6 1.0 (m/s). Van toc cc ai dao ong trong khoang 0.75 1 (m/s) nham tranh ay rac qua khe cua song chan rac va van toc nho nhat qua khe la 0.4 (m/s) nham tranh qua trnh phan huy cac chat ran. Song chan rac tho: Nc thai a en cong trnh lam sach trc het phai qua song chan rac. Song chan rac co the at co nh hoac di ong, cung co the la to hp vi may nghien rac. Thong dung hn ca la cac song chan co nh. Cac song chan c lam bang kim loai at ca vao cua kenh dan. Thanh song chan co the co tiet dien tron, vuong, hoac hon hp. Song chan rac mn: e kh cac chat l lng co kch thc nho thng s dung song chan rac mn co kch thc lo t 0.5 1 (mm). I.2 Cc thng s thit k song chn rc: Lu lng qmaxs = 0,074 m3/s. o doc i = 0,008. Chieu ngang B = 0,3 m. Van toc vmax = 0,8 m/s. o ay h = 0,3 m = Chieu sau lp nc song chan rac hmax = 0,3 m - So khe h cua song chan rac c xac nh theo cong thc:ns qmax K0 V b h

0,074 1,05 21(khe) 0,8 0,016 0,3

Trong o: qmaxs : Lu lng ln nhat giay q maxs = 0,074m3/s - b : Khoang cach gia cac khe h b = 16 mm = 0,016 m. - h : Chieu sau lp nc qua song chan hmax = 0,3 m. - V : Van toc nc chay qua song chan V = 0,8 m/s - K0 : He so tnh en mc o can tr dong chay do he thong can rac K0 = 1,05 - Chieu rong cua song chan rac: Bs = S x (n 1) + b x n = 0,008 x (21 1) + 0,016 x 21 = 0,5 (m) Trong o: S : Chieu day song chan S = 0,008 m.

n : So khe h cua song chan rac n = 21 khe b : Khoang cach gia cac khe h b = 16 mm = 0,016 m - Kiem tra van toc dong chay phan m rong cua mng trc song chan, ng vi lu lng nc thai q = 0,074 m3/s van toc nay khong nho hn 0,4 m/sVkt q Bs h 0,074 0,5 0,3 0,493 (m / s) 0,4 (m / s)

- Ton that ap lc qua song chan:hS2 Vmax K 2 g

Ma:S b4 3 4

sin

2,42

0,008 0,016

3

sin 60 0

0,832

Trong o : Vmax : Toc o chuyen ong cua nc thai trc song chan ng vi lu lng ln nhat V max = 0,8 m/s. K : He so tnh en s tang ton that do vng mac rac song chan. K = 2 3. Chon K = 2. : He so sc can cuc bo cua song chan : He so phu thuoc tiet dien ngang cua thanh. Tiet dien ch nhat = 2,42 0 : Goc nghieng at song chan so vi phng ngang = 60 .hS 0,8 2 0,832 2 2 9,81 0,05 (m)

- Chieu dai ngan m rong trc song chan:I1 Bs B 2 tg 20 0 0,5 0,3 2 tg 20 0 0,275 (m)

Chon L1 = 0,28 m - Chieu dai ngan thu hep sau song chan rac :L2 L1 2 0,28 2 0,14

- Chieu dai xay dng cua mng at song chan rac: L = L1 + L2 + 1 = 0,28 + 0,14 +1 = 1,42 (m) - Chieu cao xay dng mng at song chan rac: H = hmax + hs + hbv = 0,3 + 0,05 + 0,3 = 0,65 (m)

II. HAM BM TIEP NHAN:Ham bm tiep nhan at chm di mat at, co tac dung tap trung, thu gom nc thai t cac nguon trong nha may e tiep chuyen len be ieu hoa nh bm Noi dung tnh toan : Kch thc ham bm Chon bm The tch ham bm tiep nhanVb Qh,max t 266,56m 3 / h 10 ph 60 ph / h 44,43m 3

Vi t : Thi gian lu nc ham bm t = 10 30ph, chon t = 10ph Chon kch thc cua ho thu nc: L x B x H = 4,5 x 4 x 2,5m III. BE LANG CAT THOI KH: Vai tro cua be lang cat la bao ve cac thiet b may moc khoi b mon, giam s lang ong cua cac vat lieu nang trong ong, kenh dangiam so lan suc ra cac be phan huy can do tch tu qua nhieu cat. Cac thong so tnh toan thiet ke be lang cat thoi kh c lay t bang 10-6 sach XLNT o th va cong nghiep cua thay Lam Minh Triet: Gia s chon: Thi gian lu nc trong be lang cat thoi kh t = 5phut T so rong : sau =1:1 Chieu sau be H = 2m Chieu cao bao ve hbv = 0,3m Chieu cao vung cha cat hcat = 0,6m Lng khong kh cung cap qk = 0,2m3/m.phut - The tch be lang cat thoi kh:W Qhmax t 266,6 5 60 22,2m 3

- Chieu rong be bang chieu sau cua be B = H = 2m - Chieu dai be:L W B H 22,2 2 2 5,6m

- T le chieu dai tren chieu rong:

L B

5,6 2

2,8

2,5 5 1 1

Nh vay viec chon kch thc la hp ly. Lng khong kh can thiet:Qkk qk L 0,2 5,6 1,12m 3 / ph

IV. BE IEU HOA:IV.1. Muc ch: Do tnh chat va lu lng cua nc thai thay oi theo tng gi. V vay, that can thiet e xay dng be ieu hoa. Be ieu hoa co nhiem vu ieu hoa nc thai ve lu lng va nong o, lam giam kch thc cac hang muc va tao che o on nh cho cac cong oan x ly tiep theo pha sau, tranh cac hien tng qua tai he thong. Trong be ieu hoa, he thong phan phoi kh c s dung e cap kh nham on nh chat lng nc thai, tranh trng hp xay ra qua trnh phan huy k kh (phat sinh mui hoi thoi).IV.2. Kch thc be

Thi gian lu nc trong be ieu hoa 4 8h chon t = 5h The tch be ieu hoaV Qh,max t 266,6m 3 / h 5h 1333m 3

Chon chieu cao lam viec h = 4.5m, chieu cao bao ve hbv = 0.5m Chieu cao xay dngH h V H hbv 4,5 0,5 5m

Dien tch mat bang beF 1333m 3 5m 266m 2

Chia be ieu hoa lam 02 nganKch thc cua moi ngan: L x B x H = 15 x 9 x 5

IV.3. Tnh toan he thong cap kh cho be ieu hoa: Cac dang khuay tron be ieu hoa (trang 418 sach X ly nc thai o th va cong nghiep tnh toan thiet ke cong trnh Lam Minh Triet , Nguyen Phc Dan, Nguyen Thanh Hung) Bang 3: Dang khuay tron Gia n v tr C kh 48 W/m3 the tch be

Kh nen, toc o kh nen

10 15

L/m3.ph(m3 be)

the tch

Khuay tron be ieu hoa bang he thong thoi kh Lng kh nen can thiet cho khuay tronqk R Vtt 0.012m 3 / m 3 . ph 1333m 3 16m 3 / ph 16000L / ph

Vi R : Toc o kh nen, R = 10 15L/m3.ph, chon R = 12L/m3.ph Vtt : The tch tnh toan cua be, Vtt = 1333m3 So a phan phoi kh can thiet cho khuay tronn qK r 16000L / ph 200L / ph 80dia

V. BE TUYEN NOI:Bang thong so thiet ke be tuyen noi kh hoa tan: (trang 450 sach X ly nc thai o th va cong nghiep tnh toan thiet ke cong trnh Lam Minh Triet , Nguyen Phc Dan, Nguyen Thanh Hung) Bang 4: Thong so Ap suat kN/m T so kh:ran Chieu cao lp nc, m Tai trong be mat, m /m .ngay Thi gian lu nc, phut + Be tuyen noi + Cot ap lc Mc o tuan hoan, %3 2 2

Gia tr Trong khoang 170 - 475 0,03 0,05 1 3 20 325 20 60 0,5 - 3 5 - 120 ac trng 270 - 340 0,01 0,2

Chon: Be tuyen noi hnh ch nhat Chieu sau phan tuyen noi: hn = 2,5m Chieu sau phan lang bun: hb = 0,7m Chieu cao bao ve: hbv = 0,3m Ty le chieu dai/chieu rong: L/B 3 1 Ty so chieu rong/chieu sau: B/H = 1,5:1 (1:1 en 2,25:1) - Dien tch be tuyen noi:

A

Q LA

2000m 3 / ngd 48m 3 / m 2 .ngd

41,7m 2

Vi: LA la tai trong be mat tuyen noi 48m3/m2.ng - Chieu sau tong cong be tuyen noi: H = hn + hb + hbv = 2,5+ 0,7 +0,3 = 3,5 m - Chieu rong be tuyen noi: B = 1,5hn = 1,5 x 2,5 = 3,75m. Chon B = 4m - Chieu dai be tuyen noi:L A B 41,7 4 10,5m

Gia s Chieu dai vung phan phoi vao: l vao = 1m Chieu dai vung thu nc: lthu = 1m - Chieu dai tong cong Ltc = L + Lvao + Lra = 10,5 + 1 + 1 =12,5m Kiem tra t so L:B = 12,5:4 > 3:1 - The tch vung tuyen noi W = B x L x hn = 4 x 10,5 x 2,5 = 105m3 - Thi gian lu nc cua vung tuyen noi:t W Qh 105m 3 83,3m 3 / h 1,26h

Ham lng COD sau tuyen noi: 2700 mgCOD/l x (1 0,4) = 1620 mgCOD/l Ham Lng BOD5 sau tuyen noi: 1800 mgBOD5/l x (1 0,3) =1260 mgBOD5/l Ham lng SS sau tuyen noi: 780 mgSS/l x (1 0,8) = 156mg/l Ham lng dau m sau tuyen noi: 180/l x (1 0,9) = 18mg/l - Lng chat SS va dau m thu c moi ngay MV(SS) = (780 x 0,8 + 180 x 0,9) x 2000m3/ng x 1kg/1000g MV(SS) = 1572 kgSS/ngay Gia s bun ti(hon hp vang noi va can lang) co ham lng chat ran la TSv = 3,4%, VSv = 65% va khoi lng rieng la Sv = 1,0072- Dung tch bun ti can x ly moi ngay: M ( SS) Qv 3,4% 1,0072 1572kgSS / ngay 1m 3 46 m / ngay3

0,034 1,0072kg / L 1000L

- Lng VS cua bun ti can x ly moi ngay: MV(VS) = MV(SS) x 0,65 = 1572 kgSS/ngay x 0,65 = 1022kgVS/ngay

VI. BE UASB:VI.1 Chc nang: ay la mot trong nhng qua trnh k kh c ng dung rong rai nhat tren the gii do hai ac iem chnh sau: Ca 3 qua trnh, phan huy lang bun tach kh, c lap at cung 1 cong trnh. Tao thanh cac loai bun hat co mat o vi sinh rat cao va toc o lang vt xa so vi bun hoat tnh dang l lng. Ben canh o, qua trnh x ly sinh hoc k kh s dung UASB con co nhng u iem so vi qua trnh bun hoat tnh hieu kh nh: t tieu ton nang lng van hanh. t bun d, nen giam chi ph x ly bu. Bun sinh ra de tach nc. Nhu cau dinh dng thap nen giam c chi ph bo xung chat dinh dng. Co kha nang thu hoi nang lng t kh methane sinh ra trong qua trnh. Co kha nang hoat ong theo mua v k kh co the phuc hoi va hoat ong c sau mot thi gian ngng khong nap lieu. He thong UASB (Up flow Anaerobic Slugle Blanked) c phat trien t he thong x k kh oi vi cac loai nc thai co nong o cac chat o nhiem hu c cao. Trong nhng nam gan ay UASB a c nghien cu chuyen sau va trien khai ap dung rong rai tren the gii do cac u iem sau: Tai trong phan huy hu c cao do o mat bang yeu cau cho he thong x ly nho. Nhu cau tieu thu nang lng thap do khong can cung cap oxygen. Co kha nang thu hoi nang lng.VI. Tnh toan:

- Dien tch be mat phan lang:A Q LA 2000m 3 / ngay 12m 3 / m 2 .ngay 166,7m 2

LA: Ti trng b mt phn lng i vi dng bng LA = 12m3/m2.ngy - The tch ngan phan ng be UASB:

Vr

Q.C o LCOD A n Vr A

2000m / ngay 1620COD / m 3kgCOD / m 3 .ngay 166,7 8 1080m 3 166,7m 2

3

3

1kg 1000g

1080m 3

- Chon 8 n nguyen hnh vuong, vay moi canh n nguyen la:B 4,6m

- Chiu cao phn phn ng:H 6,5m

Gi s chiu cao phn thu kh hp = 1,5m (hp = 1,5 2m), chiu cao bo v hbv = 0,3m - Chiu cao tng cng ca b UASB: Htc = H + hp + hbv = 6,5 + 1,5 +0,3 = 8,3m Gi s mi n nguyn c hai phu thu kh, mi phu c chiu cao 1,5m, y phu thu kh c chiu di bng cnh n nguyn: l = B = 4,6m v chiu rng b = 1,9m - Vy phn din tch b mt khe h h gia cc phu thu kh l:AKh A A Ap A 100 4,6m 4,6m 2 4,6m 1,9m 4,6m 4,6m 17,4%

Trong : A: Din tch b mt b Akh : Din tch khe h gia cc phu kh Ap: Din tch y phu thu kh Gia tr nay nam trong khoangAkh/A =15 20% Gia s moi n nguyen co 6 ong phan phoi vao, dien tch trung bnh cho mot au phan phoi:an 4,6m 4,6m 6 C SS Vr TS 3,53m 2 / dau 2 5m 2 / dau

- Lng bun nuoi cay ban au cho vao be (TS = 5%) Mb 30kgSS / m 3 1080m 3 0,05 1tan 1000kg 648 tan

Trong o: CSS: Ham lng bun trong be (30kg/m3) Vr : The tch ngan phan ng TS: Ham lng chat ran trong bun nuoi cay ban au, % - Ham lng COD cua nc thai sau x ly k kh: CODra = (1 0,6) x 1620mg/l = 648 mg/l - Ham lng BOD cua nc thai sau x ly k kh: BODra = (1 0,7) x 1260 = 378 mg/l

- Lng sinh khoi hnh thanh moi ngay:Px Px VCH4 VCH4 Y Q S0 Sc

0,04gVSS / gCOD 1

1620 648 gCOD / m 3 2000m 3 / ngd1

1 Kd

0,015ngay

90ngay

1000g / kg

33KgVS / ngay 159 350,84 ngay S0 S Qb 1,42Px 1620 648 gCOD / m 3 2000m 3 / 1kg 1,42 33 1000g

- The tch kh metan sinh ra moi ngay:

VCH4

665592,6l / ngay

302m / ngay

3

Trong o:0 VCH 4 : The tch kh metan sinh ra ieu kien chuan (nhiet o 0 C va ap

suat 1atm) Q: Lu lng bun vao be k kh, m3/ngay Px: Sinh khoi te bao sinh ra moi ngay, KgVS/ngay 350,84: He so chuyen oi ly thuyet lng kh metan san sinh t 1kg BODL chuyen hoan toan thanh kh metan va CO2, lit CH4/kg BODL - Lng bun d sinh ra moi ngay:QW Px 0,75 C SS QW C SS 33KgVS / ngay 1,47m 3 / ngay 3 0,75kgVS / kgSS 30kgSS / m 1,47m 3 / ngay 30kgSS / m 3 44kgSS / ngay

- Lng chat ran t bun d:M SS

VII. BE AEROTEN:VII.1. Chc nang: Be co nhiem vu x ly triet e cac chat hu c con lai trong nc. Trong be bun hoat tnh dien ra qua trnh oxy hoa sinh hoa cac chat hu c hoa tan va dang keo trong nc thai di s tham gia cua vi sinh vat hieu kh. Trong be co he thong suc kh tren khap dien tch be nham cung cap oxy, tao ieu kien thuan li cho vi sinh vat hieu kh hoat ong, phat trien va phan giai cac chat o nhiem. Vi sinh vat hieu kh se tieu thu cac chat hu c dang keo va hoa tan co trong nc thai e tang trng va tang sinh khoi. Ban chat cua phng phap la phan huy sinh hoc hieu kh vi cung cap oxy cng bc va mat o sinh vat c duy tr cao (2,000 5,000 mg/l). Do vay, tai trong phan huy chat hu c cao va can t mat bang cho he thong x ly. Tuy nhien he thong co nhc iem la can nhieu thiet b va tieu hao nhieu nang lng.

Qua trnh x ly sinh hoc hieu kh nc thai bao gom 3 giai oan sau: - Oxy hoa cac chat hu c:Enzyme

CxHyOz + O2 - Tong hp te bao mi: CxHyOz + NH3 + O2 - Phan huy noi bao: C5H7 HO2 + 5 O2

CO2 + H2O +Enzyme

H CO2 + H2O + 5CO2 + 5H2O + NH3 H H

Enzyme

Cac chat au tien b oxy hoa e tao thanh nang lng la cacbonhydrat va mot so chat hu c khac. Qua trnh nay c thc hien tren te bao vi khuan nh xuc tac men ngoai bao. Mot phan chat ban c van chuyen qua mang te bao vi khuan (mang ban tham) vao ben trong va tiep tuc oxy hoa e giai phong ra nang lng can thiet cho hoat ong song. VII.2. Tnh toan: - Lu lng trung bnh cua nc thai trong mot ngay em: Q = 2000 m3/ng - Ham lng BOD5 trong nc thai dan vao be aeroten: La = 378mg/l - Ham lng chat l lng trong nc thai dan vao be aeroten: C = 156mg/l - Ham lng BOD5 trong nc thai can at sau x ly: Lt = 50mg/l - Ham lng chat l lng trong nc thai can at sau x ly: C = 60mg/l S o lam viec cua he thong

Q, S0

Be Aeroten

Be lang II

Qe, S,

Qr, Xr, S

Qw, Xe

Trong o: Q, Qr, Qw, Qe : Lu lng nc au vao, lu lng bun tuan hoan, lu lng bun xa va lu lng nc au ra, m3/ngay.

So, S : Nong o chat nen (tnh theo BOD5) au vao va nong o chat nen sau khi qua be Aeroten va be lang, mg/l. X, Xr, Xe : Nong o chat ran bay hi trong be Aeroten, nong o bun tuan hoan va nong o bun sau khi qua be lang II, mg/l. - Phng trnh can bang vat chat BOD5 au ra = BOD5 hoa tan+ BOD5 cha trong lng can l lng au ra Trong o: BOD5 au ra : 50 mg/L BOD5 hoa tan i ra t be Aeroten la S, mg/L SSra = 60 mg/l (65% la can co the phan huy sinh hoc) BOD5 cha trong can l lng au ra c xac nh nh sau: 0,65 x 60 = 39 (mg/L). Vay lng O2 can thiet: 39 (mg/L) x 1,42 (mg O2/mg te bao) = 55,38 mg/L. - Qua trnh tnh toan da theo phng trnh phan ng: C5H7O2N + 5O2 5CO2 + 2H2O + NH3 + Nang lng 113 mg 160 mg 1 mg 1,42 mg Chuyen oi t gia tr BOD20 sang BOD5 BOD5 = BOD20 x 0,68 = 55,38 x 0,68 = 37,66 (mg/L) Vay : 50 (mg/L) = S + 37,66 (mg/L) S = 12,34 (mg/L Tnh hieu qua x ly - Hieu qua x ly tnh theo BOD5 hoa tanE So S 100 So 378 12,34 100 97 % 378

- Hieu qua x ly cua toan bo s o:EO 378 50 100 87 % 378

Xac nh the tch be Aeroten:

- The tch aeroten c tnh theo cong thc sau:V QY c (La X (1 k d Lt ) 10 2000 0,5 378 12,34 3200 (1 0,06 10) c)c

714 (m 3 )

Trong o: c : Thi gian lu bun, chon

= 10 ngay

Q : Lu lng trung bnh ngay, Q = 2000 m3 /ngayem Y : He so san lng bun, chon Y = 0.5mgVSS/mgBOD5 La : BOD5 cua nc thai dan vao aeroten, La = 378mg/L Lt : BOD5 hoa tan cua nc thai ra khoi aeroten, Lt = 50mg/L X : Ham lng bun hoat tnh trong be aeroten, MLVSS = 3200mg/L Kd : He so phan huy noi bao, Kd = 0.06 ngay-1 Tnh toan lng bun d thai bo moi ngay - He so san lng quan sat tnh theo cong thc:Yobs Y 1d cK

0,5 1 10 0,06

0,315

- Lng sinh khoi gia tang moi ngay tnh theo MLVSS: Px = Yobs x Q x (BODvao - BODra) = 0,3125 x 2000 x (378 12,34) x 10-3= 288,5 (kgVSS/ngay) - Tong lng can l lng sinh ra trong mot ngay:Pxl Px 0,8 288,5 0,8 360,6 (kgSS/ngay )

- Lng can d hang ngay phai xa i: Pxa = Pxl (Q x 60 x 10-3) = 360,6 2.000 x 60 x 10-3 = 240,6 (kgSS/ngay) - Lng VS cua mang vi sinh can x ly moi ngay:MVSS

240kgSS / ngay 0,7

168kgVS / ngay

- Tnh lng bun xa ra hang ngay (Qw) t ay be lang theo ng tuan hoan bun VX Q e X e c VXc

Q w X th

Qe X e

QW

X th c

Trong o: V : The tch be Aeroten V = 714 m3 X : Nong o chat ran bay hi: X = 3200 mg/L c : Thi gian lu bun c = 10 (ngay)Qe : Lu lng nc a ra ngoai t be lang t II (lng nc thai ra khoi he thong). Xem nh lng nc that thoat do tuan hoan bun la khong ang ke nen Qe = Q = 2.000 (m3/ngay)

Xe : Nong o chat ran bay hi au ra cua he thong Xe = 0,8 x SSra = 0,8 x 60 (mg/L) = 48(mg/L)

Xth : Nong o chat ran bay hi co trong bun hoat tnh tuan hoan Xth = 8.000 (mg/L)QW 714 3.200 2000 48 10 16.56 (m3/ngay ) 8.000 10

- Xac nh ty so tuan hoan

Q,X0 Aeroten

Q+Qth,X Lang II

Qra,Xra

Qth,Xth

Qb,Xth

Phng trnh can bang vat chat oi vi be aerotenQX 0 Qth X th Q Qth X

Vi Q : Lu lng nc thai Qth : Lu lng bun hoat tnh tuan hoan X0 : Nong o VSS trong nc thai dan vao Aeroten, mg/L X : Nong o VSS be Aeroten, X = 3200mg/L Xth : Nong o VSS trong bun tuan hoan, X = 8000mg/L Do X0 thng rat nho so vi X va Xth, do o trong phng trnh can bang vat chat tren co the bo qua ai lng QX0 . Khi o phng trnh can bang vat chat se co dang :Qth X th Q Qth X Qth Q

Chia hai ve cua phng trnh nay cho Q va at ty so ty so tuan hoan), ta c :

(

: c goi la

X th

X X X th

X X 3200 8000 3200 0,67 va Qth Q

Hay

Lu lng bun tuan hoanQth Q 0,67 16,56m3 / ngay 11,1m 3 / ngay

Vi X : Nong o VSS be aeroten, X = 3200mg/L Xth : Nong o VSS trong bun tuan hoan, Xth = 8000mg/L Xac nh thi gian lu nc cua be aerotenW Q 714m 3 2000m 3 / ngay 0,357ngay 8,568h 8,6h

Tnh lng oxy can cung cap cho be Aeroten da tren BOD20 - Lng oxy can thiet trong ieu kien tieu chuanOCO OCO Q(S o S ) 1,42Px f

Vi f la he so chuyen oi gia BOD5 va BOD20 f = 0,682000 (378 12,34) 1,42 288,5 0,68 1.000 665,8 (kgO2 / ngay)

- Lng oxy thc te can s dung cho beOCt OCO Cs Cs CL 665,8 9,08 9,08 2 853,88 (kg O2/ngay )

Trong o: Cs : Nong o bao hoa oxy trong nc nhiet o lam viec Cs = 9,08 mg/L CL : Lng oxy hoa tan can duy tr trong be CL = 2 mg/L Kiem tra ty so F/M va tai trong the tch cua be : Ch so F/MF M S0 X 378 0,357 3.200 0,33(mg BOD5/mg VSS ngay )

Gia tr nay nam trong khoang cho phep cua thong so thiet ke be (0,2 0,6) - Tai trong the tch cua be aerotenL

Gia tr nay nam trong khoang thong so cho phep khi thiet ke be (0,8 19) - Tnh lng khong kh can thiet e cung cap vao be

S0 Q V

378 10 3 2.000 714

1,06 (kg BOD5/m3ngay)

QKK OU

OCt f' OU Ou H 7gO2 / m 3 .m 4.6m'

32.2gO2 / m 3 2

Vif ' : He so an toan , chon f

OCt : Lng oxy thc te can s dung cho be , OCt = 853,88kgO2/ngay OU : Cong suat hoa tan oxy vao nc thai cua thiet b phan phoi Ou: Cong suat hoa tan oxy vao nc thai cua thiet b phan phoi , g O2/m3 khong kh Tra bang 7.1 trang 112 Tnh toan thiet ke cac cong trnh x ly nc thai_Trnh Xuan Lai , ta co Ou = 7 gO2/ m3.mQKK 853,88kgO2 / ngay 32.2gO 2 / m 3 10 3 kg / g 2 26518m 3 / ngay 18415,3L / ph

Chon thiet b khuech tan kh dang a xop , ng knh 170 mm , dien tch be mat F=0,0227 m2, cng o thoi kh 200 L/phut.a = 12 m3/gi.a o sau ngap nc cua a phan phoi kh lay bang chieu sau hu ch cua be H = 4.6m (at sat ay be) - So a can phan phoi trong ben QKK I 18415,3L / ph 200L / ph.dia 92dia

e thuan li cho viec bo tr eu , ta chon so a n = 112 a ma van am bao hieu suat x ly cua be - Ap lc can thiet cho he thong nen kh xac nh theo cong thcH ct hd hc hf H 0,4 0,5 4.6 5.5m

Vi hd : Ton that ap lc do ma sat doc theo chieu dai ong dan, m hc : Ton that cuc bo, m hf : Ton that qua thiet b phan phoi, m H : Chieu sau hu ch cua be, chon H = 4.6m Ton that hd va hc thng khong vt qua 0,4m ; ton that hf khong qua 0,5m - Ap lc khong khP 10,33 H ct 10,33 10,33 5.5 10,33 1,5324at

- Cong suat may nen kh tnh theo cong thc

N Vi

34400(P 0, 29 1) q 102

34400(1,5324 0, 29 1) 0,528 102 0,8

29.33KW

q : Lu lng khong kh, q = 0,528m3/s : Hieu suat may nen kh; = 0,7 0,9 chon- Tnh toan ng ong dan kh

= 0,8

ng knh ong phan phoi chnhD 4 QKK v Khi 4 0.307 15 3,14 0.1615m 161,5mm

Chon ong sat trang kem D = 170 mm Vi v Kh i : Van toc kh trong ong dan kh chnh , chon vKhi 15m / s Q KK : Lu lng kh can cung cap , Q KK 18,415m 3 / ph 0.307m3 / s T ong chnh ta phan lam 14 ong nhanh cung cap kh cho be , moi nhanh at 8 au phan phoi kh. - Lu lng kh qua moi ong nhanh ( Khoang cach gia cac nhanh 1107mm).Qnhanh QKK 14 18415L / ph 14 1315L / ph

- ng knh ong nhanhd 4 Qnhanh v' khi 4 0.022 3.14 15 0.0432m

Chon loai ong sat trang kem d = 45 mm Vi ' ' v kh i : Van toc kh qua moi ong nhanh vkhi 15m / s Qnhanh : Lu lng kh qua ong nhanh Qnhanh 1315L / ph - Kiem tra lai van toc Van toc kh trong ong chnhv khi 4 QKK D2

0.022m 3 / s

4 0.307 3.14 0.17 2

13.53m / s

v kh i nam trong khoang cho phep (10 -15 m/s)

Van toc kh trong ong nhanhv 'khi 4 Qnhanh d2

4 0.022 3.14 0.045 2

13.84 m / s

' v kh i nam trong khoang cho phep (10 -15 m/s)

10) Kiem tra t so F/M va tai trong hu c

F/M

La X

378mg / L 0,357ngay 3200mg / L

0,33kgBOD5 / kgVSS.ngay

Vi : Thi gian lu nc cua aeroten 0,357 ngay - Tai trong the tchLa Q 10 W3

378mg / L 2000m 3 / ngay 10 714m 3

3

1,059kgBOD5 / m 3 .ngay

Ca hai gia tr nay eu nam trong gii han cho phep oi vi aeroten xao tron hoan toan nh a e cap tren. Kch thc be aeroten - Dien tch cua aeroten tren mat bangF W H 714m 3 4.6m 155m 2

Vi H : Chieu cao cong tac aeroten, H = 4.6m Cac kch thc ien hnh cho aeroten xao tron hoan toan (trang 433 - sach X ly nc thai o th va cong nghiep tnh toan thiet ke cong trnh Lam Minh Triet , Nguyen Phc Dan, Nguyen Thanh Hung) Bang 5: Thong so Gia tr Chieu cao hu ch, m 3.0 4.6 Chieu cao bao ve, m 0.3 0.6 Khoang cach t ay en au khuech 0.45 0.75 tan kh, m T so rong : sau 1.0 : 1 2.2 : 1 - Chieu dai cua aerotenL F B 155m 2 10 15.5m

Vi B : Chieu rong aeroten, chon B = 10m (B : H = 10 : 4.6 = 2,174 : 1) - Chieu cao xay dng cua aerotenH xd H hbv 4.6 0.4 5m

Vi hbv : Chieu cao bao ve, chon hbv = 0.4m Vay be aeroten co kch thc nh sau : L x B x H = 15,5 x 10 x 5 m

VIII.BE LANG T II: Chon tai trong be mat thch hp cho loai bun hoat tnh nay la 3 20m /m2.ngay va tai trong chat ran la 3,4kg/m2.h. (Cac thong so thiet ke cho be lang t II c lay trong bang 9-12) - Dien tch be mat be lang theo tai trong be mat la:AL Trong o:TB Qngay

LA

2000m 3 / ngay 20m 3 / m 2 .ngay

100m 2

TB Qngay :Lu lng trung bnh ngay, m3/ngay

LA:Tai trong be mat, m3/m2.ngay - Dien tch be mat be lang theo tai trong chat ran:Q MLSSQr AS LS 2000 11,1 m / ngay 3200 gSS / m3 3 2

78,9m

3,4kg / m 2 .h 24h / ngay 1000g / kg

Trong o: LS la tai trong chat ran,kgSS/ngay. Chon LS = 3,4kg/m2.h Do AL > AS, Vay dien tch be mattheo tai trong be mat c tnh toan - Chon: + So be lam viec ong thi n=2 be + Chieu sau vung lang hL= 3,5m + Chieu sau cua vung bun hb = 1,5m + Chieu cao bao ve hbv=0,3m - ng knh be lang:D 4 F 4 50 3,14 8m

- ng knh ong trung tam: d = 20%D = 0,2 x 8 = 1,6m - Chieu cao tong cong cua be lang II: Htc = hL + hb + hbv = 3,5 + 1,5 +0,3 = 5,3m - Chieu cao ong trung tam: h = 60%hL = 0,6 x 3,5 = 2,1m Kiem tra thi gian nc lu be lang - The tch phan lang:V hL 4 D2 d2L

8 2 1,6 2 4

3,5 168,81m 3

- Thi gian lu nc:

t

V QW Qth

168,8m 3 2000 11,1 m 3 / ngay

0,084ngay

2,016h

- The tch phan cha bun:Vb A hb Vb Q Qth 100 1,5 150m 3 150m 3 2000 11,1 m 3 / ngay 1ngay / 24h

- Thi gian lu gi bun trong be:t 1,8h

- Tai trong mang tran:2000 11,1 m 3 / ngay 80,06m 3 / m.ngay 8 Gia tr nay nam trong khoang cho phep LS 500m3 / m.ngay LS Q QW D

Gia s bun sinh hoc co ham lng TSm = 5%, VSm = 70% va khoi lng rieng bun Sm = 1,0091 - Dung tch bun can x ly moi ngay:Qw MSS

5% 1,0091

1 240,6 5% 1,0091 1000L

4,77m 3 / ngay

IX. BE PHAN HUY BUN K KH: IX.1. Muc ch: Be cha bun co nhiem vu cha bun sinh hoc tach ra t be Aerotank, va tao ieu kien co ac giup on nh bun. Phan bun d c thai bo theo nh ky hoac co the s dung vi muc ch lam phan bon cho cay xanh. IX.2. Tnh toan: Lng bun can x ly bao gom: - Bun sinh hoc t be lang t II co Qw = 4,77m3/ngay, MSS = 240,6kgSS/ngay va MVSS = 168kgVSS/ngay - Bun d t be UASB co:Qw(UASB) = 1,47m3/ngay, MSS(UASB) = 44kgSS/ngay, MVS(UASB) = 33kgVS/ngay - Bun ti t be tuyen noi: QV = 46m3/ngay, MV(SS) = 1572kgSS/ngay, MV(VS) = 1022kgVS/ngay. Vay tong lng bun vao be phan huy k kh moi ngay co: - Khoi tch bun:QS 46 m 4,77 1,473

/ ngay

52,24m 3 / ngay

- Lng chat ran:M SS 240,6 44 1572 kgSS / ngay 1856,6kgSS / ngay

- Lng chat ran de bay hi:

M VSS

168 33 1022 kgVS / ngay

1223kgVS / ngay

Ket qua thc nghiem cho thay: sach X ly nc thai o th va cong nghiep tnh toan thiet ke cong trnh Lam Minh Triet , Nguyen Phc Dan, Nguyen Thanh Hung) - tai trong chat de bay hi LVS = 0,6kgVS/m3.ngay va nhiet o van hanh ngoai tri 280C, hieu qua kh VS at 50% - San lng kh metan 0,55m3/kgVS vao - Ham lng chat ran cua bun a phan huy TSph = 6% - The tch can thiet cho qua trnh phan huy bun:Vt M VS LVS Vt QS 1223kgVS / ngay 0,6kgVS / m 3 .ngay 2038m 52,24m 3 / ngay3

2038m 3

- Thi gian phan huy:td 39ngay

- Lng chat hu c con lai sau qua trnh on nh:SVS SS ST M VSS 1 E% M SS SVS SVS ST M VSS SS 1223kgVS / ngay 1 0,5 611,5kgVS / ngay

- Lng chat vo c con lai:1856,6 1223 633,6 633,6kgSS / ngay

- Tong lng chat ran con lai:611,5 1245,1kgTS / ngay

- Ham lng chat ran de bay hi cua bun phan huy:VS ph 100% 611,5 100% 1245,1 49,1%

Da vao TSph va VSph co the xac nh khoi lng rieng cua bun a phan huy Sph = 1,019 - Toc o bun tch luy:Qa ST TS%S ph 1245,1kgTS / ngay 0,06 1019kg / m 3 20,4m 3 / ngay

Gia s thi gian tr bun phan huy ts = 30ngay - The tch be phan huy xac nh theo cong thc sau:V QS 2 Qa t p Qa t s 20,4m 3 / ngay 30ngay 2028,5m 3

52,24 20,4 m 3 / ngay 39ngay 2

Trong o: QS: Toc o bun vao be phan huy, m3/ngay Qa: Toc o bun tch luy, m3/ngay

tp: Thi gian phan huy bun, ngay ts: Thi gian tr bun a phan huy, ngay Gia s chieu cao hu ch cua be H = 8m, chieu cao phan thu kh h kh = 1,5m va be n=4. Vay ng knh mot be phan huy la:D V nH QS 4 2028,5m 3 4 8m 52,24m 3 / ngay 4 9m

Toc o tren mat tr ve au he thong x ly la:Qn Qa 20,4m 3 / ngay 31,84m 3 / ngay

X. THIET B LY TAM BUN: Dung tch bun a phan huy vao thiet b ly tam moi ngay la Qa = 3 20,4m /ngay co ham lng chat ran TS = 6%, M TS(vao) = 1245,1kgTS/ngay, MVS = 611,5kgVS/ngay. Gia s bun kh nc bang thiet b ly tam co tao ieu kien bang polymer - Banh bun co ham lng TS = 23% va khoi lng rieng 1,076 - Hieu qua giu bun E = 85% - Lieu lng polymer s dung 4,5kg/tan DS - Lng chat ran trong nc tach bun:MF M DS M TS (vao) M TS (vao) M DS TS Qb Mw Sb QS MF QF 1 E% E% 1245,1kgTS / ngay 1 0,85 186,77kgTS / ngay

- Lng chat kho cua banh bun:1245,1kgTS / ngay 0,85 1058,3kgDS / ngay

- Lng banh bun sinh ra moi ngay:Mw 1058,3kgDS / ngay 23% 4601,5kg / ngay 4,28m 3 / ngay 3 1076kg / m Qb 52,24 4,28 47,96m 3 / ngay 4601,5kg / ngay 4,6 tan/ ngay

- Khoi tch banh bun sinh ra moi ngay:

- Lu lng tach bun:QF

- Ham lng can l lng trong nc tach bun:SS 186,77kgSS / ngay 47,96m 3 / ngay 3,894kg / m 3 3894mgSS / L

- Lng Polymer s dung trong ngay:Mp M TS (vao) C polymer 4,5kg / tan DS 1245,1kg / ngay 1tan 1000kg 5,6kg / ngay

XI. BE KH TRUNG: XI.1 Muc ch: Nc thai qua qua trnh x ly sinh hoc se gan nh sach ve mat chat hu c. Song vi lng nc thai ay th ham lng vi sinh vat, vi khuan cho con ngi van con. Chnh v the, cong oan nay se tien hanh qua trnh kh trung bang ozone ket hp vi ch61t oxy hoa nham tieu diet vi khuan gay benh. XI.2. Tnh toan: - Chon thi gian lu cho be la 15 phut. - The tch be la: V=2000 x 15phut/(60phutx24h)= 20,83m3 Vay kch thc be la:L x B x H = 4m x 3,5m x 1,5m - Lng clo hoat tnh can thet e kh trung nc thai. Chon clo dung la dung dch clo 10%. V = a . Q, Trong o: a : lng clo hoat tnh, chon a =8 mg/L Q: lu lng nc thai m3/h V= 8 x 2000 x 10-3 = 16 kg/ng