TRNG I HC TI NGUYN V MI TRNG THNH PH H CH MINH

N MN HCCNG NGH X L NC CP

Tn ti :TNH TON THIT K H THNG X L NC MT CP CHO SINH HOT CNG SUT 5000 m3/ngy m.

GVHD: ThS. NGUYN VN SNGSinh vin thc hin: NG NG DNG

CHNG 1: TNG QUAN V NGUN NC MTNc mt bao gm cc ngun nc ao, m, h cha, sng sui. Do s kt hp t cc dng chy trn b mt v thng xuyn tip xc vi khng kh nn cc c trng ca nc mt l: Cha kh ha tan c bit l oxy Cha nhiu cht l lng, ring trng hp nc cha trong cc ao, m, h nn xy ra qu trnh lng cn nn cht l lng lng li trong nc c nng tng i thp v ch yu dng keo. C hm lng cht hu c cao. C s hin din ca nhiu loi to. Cha nhiu vi sinh vt.Cht lng nc thin nhin c th c phn loi v nh gi theo cc ch tiu sau:Ch tiu l hc: Nhit : Nhit ca nc l mt i lng ph thuc vo i lng mi trng v kh hu. Nhit c nh hng khng nh n cc qu trnh x l nc v nhu cu tiu th.Nc mt thng c nhit thay i theo nhit mi trng. mu: mu thng do cc cht bn trong nc to ra. Cc cht st, mangan khng ha tan lm nc c mu nu , cc chat humic to ra mu vang. Cc cc loi thy sinh to nc mu xanh l cy. Nc c mu (PtCo). mu biu kin trong nc thng do cc cht l lng trong nc to ra v d dng loi b bng phuonh php lc. c: Nc l mi trng truyn nh sng tt, khi trong nc c cc vt l nh: cc cht huyn ph, cc ht cn t ct, cc vi sinh vtkh nng truyn sang b gim i. N c c ln chng t nc nhiu cn bn. n v o c thng l mg SiO2/l, NTU, FTU. Hm lng cht l lng cng l i lng tng quan n c ca nc. Mi v: Mi v trong nc thng do cc hp cht ha hc, ch yu lafc c hp cht hu c, hay cc sn phm t qu trnh phn hy vt cht gy nn. Nc thin nhin c th c mi t, mi tanh, mi thi. Nc sau khi kh trng vi hp cht clo c th b nhim mi clo hay clophenol. Tuy theo thnh phn v cc mui khong ha tan nc c th c cc v mn, ngt, cht, ng Cc ch tiu ha hc: pH: ph l ch s c trng cho nng ion H+ c trong dung dch, n c ng dng kh cc hp cht sunfua v cacbonat v khi tng pH c thm c nhn oxy ha, cc kim loi ha tan trong nc c th chuyn thnh dng kt ta v d dng tch ra khi nc bng bin php lng lc kim: kim l tng hm lng ca cc ion bicacbonat, hydroxit v anion ca cc mui v cc axit yu. Do hm lng cc cht ny c trong nc rt nh nn b qua. nhit nht nh kim phc thuc vo pH v hm lng kh CO2 c trong nc. cng: cng ca nc l i lng biu th cc ion canxi v magie c trong nc. Dng cng cao trong sinh hot s gy x phng do cacxi v magie pahnr ng vi cc axit bo to ra cc hp cht kha tan. Cc ch tiu sinh hc: Vi khun thng dng n bo. T bo c cu to n gin so vi cc sinh vt khc. Vi khun c trong nc c th gay ra cc bnh l, vim ng rut v cc bnh tiu chy khc.

CHNG 2 : CHNG 2: TNH TON H THNG X L NCnh:inh

M T CNG NGH Nc t sng qua cng trnh thu v trm nc th, ti y c li chc rc gi li nhng cn th, kch thc ln, rong ru, ti nilongNc c bm ln cao v t chy vo cc cng trnh tip theo.u tin nc c bm ln v chy qua trm b c kh, cht keo t v keo ha trn sn cc cng trnh chun b phn, b trn vi c vo nc v khuy trn u gip cho qu trnh to bng. Nc tip tc chy qua b to bng, bng cn hnh thnh s c loi b bng b lc. Nc sau lc s c chm chlor kh trng v chy vo b cha. T y nc c phn phi vo khu dn c thong qua trm bm cp II v mng li cp nc.Phn cn ca b lng s c x l qua cc cng on: nn bn v kh 2.1 CNG TRNH THU NC: Cng trnh thu t lng sng, bun thu t st b, tm bm tch ring Trong trng hp dng sng c dc thoi, lng sng xa b, ta b tr hng thu v trm thu bm xa nhau, cng trnh thu t lng sng, trm bm t xa b. u hng thu t li chn, mt li 5 x 5mm, bng si dy ng, ng knh 2mm, khung thp hn c th tho lp d dng lm sch v thay th khi cn. Vn tc chy qua li v 0,6m/s trnh hin tng ko rao vo ng. Din tch li chn xc nh theo cng thc: F1=K1Trong : Q: lu lng cn thu Q= 0,058m3/s V : vn tc qua li < 0,6m/s, nn chn v = 0,5m/s K1 : h s thu hp din tch do cc dy lm li chon ch v rc bm, K= 1,5 1,6, chn K= 1,5 F1 =1,5 = 0,174 m2 Vy kch thc li chn l 0,42m x 0,42m

Trm bi:Cng sut ca trm bi: N = = = 14,2 kWTrong : Q : cng sut Q = 0,122m3/s H : p lc ca bm chn H = 20m : th tch ca nc, = 1000kg/m3 : hiu sut ca bm, ly = 80%Trong ngn thu b tr hai bm cng cng sut 14,2kW, mt bm hot ng cn bm kia d phng, hai bm ny mc song song vi nhau 3.2 CC CNG TRNH CHUN B DUNG DICH PHN:3.2.1 B trn phn: C th cho phn vo nc di dng bt, ht kh hoc di dng dung dch. nh lng c phn vo nc di dng bt hoc dng kh th phi c dng phn sn xut ra di dng bt, nhng vic nh lng phn di dng phn dng kh th thng khng chnh xc v khng bo v sinh v nhiu bi, nn c th loi tr vic dung phn bt. Thng nh lng phn vo nc di dng dung dch c nng 1 5%.Vic tng nng c dung dch phn s lm gim chnh xc khi nh lng, v vy u tin dng cc thng ha trn ha trn phn c nng cao, ng thi lng bt cc cn, tp cht khng tan trong nc b ha tan, sau mi chuyn qua b tiu th pha long nng 1 5% ri nh lng vo nc Tc ha tan phn cc trong nc tng nhanh khi kch thc cc c phn cng nh, tng cng tun hon ca nc trong b ha tan v tng nhit ca nc. V vy m bo thi gian ha trn phn ph hp vi yu cu ca cc nh my qun l ra cho nh my ca mnh, th phi cn p nh phn trc khi cho vo b ha trn.Nhim v ca b ha trn l ha tan phn cc v lng cn bn. Nng dung dch phn trong b thng cao nhng khng vt qu nng bo ha. Theo TCXD 33:1985 c th ly nng dung dch phn trong b ha trn trong khong 10 17% . ha tan phn trong b c th dung khng kh nn, my khuy hoc bm tun hon.Nhng i vi trng hp ny th ta dng my khuy, b xy bng b b tng ct thp, b phn khuy trn gm: ng c in, b phn truyn ng v cnh khuy. n gin ta chon cnh khuy kiu phng.Ta chn b ha trn phn dng cnh khuy kiu phng c 02 cnh qut, s vng quay l 60 vng/pht.Liu lng x l nc c theo bng sau:

ng vi hm lng cn nc sng SG N vo khong 270mg/l, chn lng phn P = 50mg/l.Cn c vo c ca nc mt sng SG N vo khong 150Pt.Co, ta xc nh c lng phn nhm Al2(SO4)3 cn thit kh mu theo cng thc :PAl = 4. = 49mg/lVy chn lng phn l P = 50mg/lDung tch b ha trn phn tnh theo cng thc:Wh= = Trong :Q : lu lng nc x l (m3/h ). Q = 208 m3/hN : thi gian gia hai ln ha tan phn, ly n = 24hpp : liu lng phn d tnh cho vo nc (g/m3). pp = 50mg/l = 50g/m3 bh : Nng dung dch phn trong thng ha trn (%). Chn bh= 10% (Theo TCXD 33: 1985 c th ly nng dung dch phn trong b ha trn trong khong 10 17%.) : Khi lng ring ca dung dch = 1 tn/m3Trong bi tnh ton ny loi phn s dng lm cht keo t l phn nhm Al2(SO4)3 khng cha nc.Vy dung tch b ha trn phn l:Wh = = 2,5m3Vic khuy trn c tin hnh trong b trn hnh vung vi t l gia chiu cao v chiu rng l 2:1. Vy ta chn kch thc b 1,08 x 1,08 x 2,2m= 2,5m3Chn chiu cao an ton cho b ha trn phn l: 0,4m ( Theo tiu chun chn chiu cao an ton m trong khong 0,3 0,5 m) 3.2.2 Tnh ton thit b khuy trn phn: B c bng my trn cnh qut, dung tch b khuy trn c tnh trn l: Wh = 2,5 m3B c thit k hnh vung vi t l kch thc nh sau: a x b x h =1,08 x 1,08 x 2,2m. Chon s vng quay cnh qut l 60 vng/pht (quy phm 40 vng/ pht ). Chiu di cnh qut ly bng 0,45 b ngang b (quy phm = 0,40,45b) .Icp = 0,45x1,08 = 0,486 mVy chiu di ton phn ca cnh qut l: 0,486 x 2 = 0,972 mDin tch mi cnh qut thit k trung bnh l 0,15 m2/cnh qut/ 1 m3 phn trong b.fcp = 0,15 x Wh = 0,15 x 2,5 = 0,375 m2

Chiu rng mi cnh qut:bcp = 0,3750,486 = 0,77 mNng lng khuy trn cn thit:P = k..n.D5kh (W)Trong :k : h s sc cn ca nc ph thuc vo kiu cnh khuy, k = 1,08 vi cnh khuy kiu phng hai cnh. : khi lng ring ca dung dch, ly = 1000 kg/m3 n : s vng quay trong 1 giy, n = 60 vng/pht = 1 vng/giy.Dkh : ng knh cnh khuy, Dkh = 0,972 mP = k..n.D5kh = 1,08.1000.1.0,9725 = 937 WCng sut ca ng c:N = = = 1171 W = 0,8 h s hu ch ca c cu truyn ng ( hiu sut) 3.3 THIT B PHA CH VIVi dc dng kim ha nc, lm mm nc hoc n nh nc. Vi cho vo nc c th dng vi sa hay vi bo ha.Cng thc xc nh liu lng cht kim ha : Pk = e1.( mg/lTrong :Pk : hm lng cht kin ha (mg/l)Pp : hm lng phn cn thit dng keo t (mg/l), tnh Pp = 30mg/le1, e2 : ng lng ca cht kim ha v ca phn (mg/mgl). Trong trng hp ny s dng cht kim ha l CaO nn e1 = 28; v i vi cht keo t l Al2(SO4)3 nn e2 = 57Kt : kim nh nht ca nc ngun (mgl/l) 1 : kim d phng ca nc (mgl/l)c : T l cht kim ha nguyn cht c trong sn phm s dng (%). (Trng hp ny c = 80% )Vy ta c :Pk = e1.( = 28. (Dung tch b pha vi sa c xc nh theo cng thc :Wv = (m3)Trong :

Q : Lu lng nc tnh ton (m3/h), Q = 208 (m3/h)n : s ln gia hai ln pha vi ( theo quy phm 6 12h ), ly n = 12Pk : Liu lng vi cho vo nc (mg/l), Pk = 11,42 mg/lbv : Nng vi sa (5%) : Khi lng ring ca vi sa 1 tn/m3Wv = = = 0,57(m3)Ti trm b tr hai b, mt lm vic, mt d phng.Dung tch 5% b tiu th c nh lng u vi lu lng khng i bng bm nh lng a vo b trn ng, tng t ta cng b tr hai bm nh lng hai b.Tnh ton thit b khuy trn vi sa:B dc khuy trn bng my trn cnh qut; dung tnh b pha vi sa c tnh trn : Wv = 0,57 (m3)B c thit k hnh trn, ng knh ca b phi ly bng chiu cao cng tc ca b d = h, chiu cao xy dng ca b l h + 0,4 m

Wv = = Vy ng knh b :d = = = 0,9 mChn s vng quay ca cnh qut l 60 vng/pht (quy phm 40 vng/pht ), chiu di cnh qut ly bng 0,45 ng knh b (Quy phm = 0,4 0,45d).lcp = 0,45*d = 045*0,9 = 0,405 mVy chiu di ton phn ca cnh qut : 0,405*2 = 0,81mDin tch mi cnh qut thit k 0,15 m2 cnh qut/1m3 vi sa trong b.fcp = 0,15*Wh = 0,15*0,57 = 0,09 m2Chiu rng mi cnh qut :bcp = fcp lcp = 0,09*0,045 = 0,22 mNng lng khuy trn cn thit :P = k..n.D5kh (W)Trong :k : h s sc cn ca nc ph thuc kiu cnh khuy, k = 1,08 vi cnh khuy phng 2 cnh. : khi lng ring ca dung dch, = 1000 kg/m3n : s vng quay trong 1 giy, n = 60/60 vng/sDkh : ng knh cnh khuy, Dkh = 0,81 mVy :P = 1,08.1000.(6060). 0,815 = 377 WCng sut ng c :N = = = 471 W3.4 B TRN C KHMc ch:So vi lng nc cn x l, lng hoc cht s dng ch thng chim t l rt nh. Mt khc phn ng ca chng xy ra rt nhanh khi chng tip xc vi nc. V vy cn phi khuy trn phn phi nhanh v u ha cht ngay sau khi chng vo nc nhn t c hiu qu x l cao nht. Chn b trn trn, vi Q = 5000m3/ngy m = 0,058 m3/s, t = 30 0CChn Gradient vn tc G = 800 s-1 Thi gian khuy trn HRT = 40sChiu su lp nc H = DTh tch b trn :V = HRT*Q = 40*0,058 = 2,32 m3M V = H* = D* = 2,32 m3Nn H = D = 1,44 mChn chiu cao bo v hbv= 0,3 mVy chiu cao b : Hb= 1,44+0,3= 1,74 mNng lng khuy :P= *V*G2 = 0,8*10-3*2,32*8002 = 1187,84 WVi : nht ng lc ca nc, 30 0C nn = 0,8*10-3Cng sut ca ng c :N = = = 1484,8 W3.5 B TO BNG :Trong qu trnh x l nc bng cc cht keo t, sau khi phn c trn u vi nc v kt thc giai on thy phn s bt u hnh thnh bng cn. Cn xy dng b phn ng vi mc ch p ng cc yu cu kt dnh to ra bng cn.Nguyn l lm vic ca b l qu trnh to bng kt ta din ra nh s xo trn ca dng nc trong b bng bin php c kh. B phn chnh ca b l cc cnh khuy, cnh khuy thng c dng bn phng, t i xng qua trc quay. Kch thc bn cnh khuy c tnh vi t l tng din tch bn cnh vi mt ct ngang b 15-20%. Cc cnh khuy c lp vo trc quay to thnh gung khuy. Mi ngn t mt gung khuy. Tc ngn ca gung khuy t 3-5 vng/pht. Ly tc cho ngn du v gim dn nhng ngn sau. Nh s iu chnh tc ny s to iu kin thu li cho cc bng cn to thnh ngy cng ln.Chn b to bng khuy trn bng cnh gung, trc ngang, dng chy ngang.Dung tch ca b c tnh theo cng thc :W = = = 104 m3 Trong :Q : Lu lng cn x l. Q = 5000 m3/ngy m = 208 m3/ht : Thi gian lu nc trong b, chn t = 30 pht ( qui phm 10-30 pht ).Chia b lm 2 ngn, mi ngn chia lm 3 bung, chn kch thc chiu rng v chiu cao ca mi bung l :h = b = 3,6 mTit din ngang ca mt ngn :f = h*b = 3,6*3,6 = 12,96 m2 Chiu di b :L = = = 4 mTrong :n : l s ngn phn ngf : tit din mi ngnChiu di mi ngn : l =42 = 2 mCc ngn c ngn cch vi nhau bng cc vch hng dng thng ng.Dung tch mi bung :3,6*3,6*3 = 38,88 m2Cu to gung khuy gm trc quay v bn bn cnh khuy t qua trc, ton b t theo phng ngang. Tng din tch bng cnh ly bng 17% din tch mt ct ngang b ( qui phm 15-20%)fc = f*0,17 = 12,96*0,17 = 2,2 m2Din tch mi bn cnh ly :fc 4 = 2,24 = 0,55 m2Chn chiu di cnh l lc= 3 mNn chn chiu rng cnh la bc= 0,18 mCc bn cnh t khong cch t mp ngoi n tm trc quay : R1= 0,9 m v R2= 0,6 mChn tc quay ca gung khuy ngn u l 5 vng/pht, ngn gia l 4 vng/pht, ngn cui l 3 vng/pht.Tc chuyn ng ca bn cnh khuy so vi mt nc bng 75% vn tc ca bn thn u bn cnh khuy.vp= 0,75*vk = = 0,0785 R*n (m/s) Nhu cu nng lng cho xo trn :P = (W)Trong :CD : H s tr lc ca nc, ph thuc vo t l gia chiu di v chiu rng bn cnh :Vi = = 20 CD =1,5A : Din tch cnh khuy, A = fc= 0,9 m2 : Khi lng ring ca dung dch, 1000 kg/m3Vi 2 bn cnh, R1=0,9 m v R2=0,6 mP = = =0,3086*n3 ngn th nht, n=5 vng/phtP1= 0,3086*53= 38,58 WNgn th hai, n=4 vng/phtP2=0,3086*43= 19,75 W ngn th cui, n=3 vng/phtP3=0,3086*33= 8,33 W Gi tr gradient vn tc :G = (s-1)Trong :P : Nhu cu nng lng (W)Vng : Th tch ca mt ngn to bng, Vng= 10,6 m3 : nht ng hc ca nc, 30 0C, = 0,798.10-3Vy ngn u, P1=38,58 W, ta c :G1 = = 67,53 s-1Ngn gia, P2=19,75 W G2 = = 48,3 s-1Ngn cui, P3= 8,33 WG3 = = 31,4 s-13.6 B LI TM:

Nguyn tc lm vic :Nc cn x l vo ng trung tm ca b, ri c phn phi vo vng lng. Trong vng lng nc chuyn ng chm dn t tm b ra ngoi v t di ln trn. y, cn c lng xung y, nc trong th c thu vo mng vng v theo ng ng sang b lc.So vi mt s b kiu lng khc, b li tm c mt s u im sau : nh c thit b gt bn, nn y c dc nh hn so vi b lng ng, do chiu cao cng tc ca b nh, thch hp cho vic xy dng nhng khu vc c mc nc ngm cao. B va lm vic va x cn lien tc nn khi x cn b vn lm vic bnh thng.Tnh ton : Din tch b mt b xc nh theo cng thc :

F = 0,21.+ f (m2)Trong :Q : lu lng x l, Q = 208 m3/hu0 : Tc lng cn tnh ton, u0= 0,5 ( quy phm 0,4 1,5 mm )f : Din tch vng xoy ca b, y l din tch nm gia b do chuyn ng xoy ca dng nc, cn khng lng xung c: f = .rx2 (m2)rx : Bn knh vng xoy, rx=rp+1 rp : Bn knh ngn phn phi nc hnh tr, chn rp= 2 m ( quy pham 24)rx=rp+1= 2+1 = 3 mf = .rx2 = 3,14.32 = 28,25 m2Vy F = 0,21.+ 28,25 = 161,49 m2Bn knh ca b l :R = = = 7,17 mChn chiu su ti thnh b : h = 2,4 mChn dc y b l : i = 0,06 ( qui phm 58%)Chiu cao ca b lng s l :H = h + i.R = 2,4 + 0,06.7,17 = 2,83 mChn chiu cao o v l : 0,3 mKim tra li ti trng mng trn :Lm = = = 110 m3/m.ngy, t yu cuTnh ngn phn phi nc :Ngn phn phi nc c thit k hnh tr c khoan l trn vch ngn ngp di mc nc trong b su bng chiu su b lng ti thnh b (h = 1,5 m) Din tch xung quang ca ngn phn phi :fp = = 3,14.4.1,5 = 18,84 m2Tng din tch cc l trn vch ngn : m2Chn ng knh dl = 36 mm ( qui phm 3640mm), fl= 0,00102 m2S l : n = = = 196 lXp thnh 6 hng ngang: Khong cch gia cc tm l theo chiu ng :e =h/6 = 1500/6 =250 mmChu vi ngn phn phi :l = 2.rp = 2.2 =12,56 mKhong cch gia cc tm l theo chiu ngang :en = = = 385 mmT s din tch cc l vi din tch b mt xung quanh ngn phn phi nc :K = .100% = 1,08%