TRNG I HC K THUT CNG NGH KHOA MI TRNG & CNG NGH SINH HC BI GING K THUT X L NC THI Th.S. Lm Vnh Sn Dng cho sinh vin ngnh MI TRNG & CNG NGH SINH HC Nm xut bn 2008 H THNG X L NC THI KHU CNG NGHIP VIETNAM-SINGAPORE Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 1 Chng 1: NHNG VN CHUNG V X L NC THI 1.1. PHN LOI NC THIhiuvlachncngnghxlncthicnphiphnbitccloincthikhcnhau.C nhiu cch hiu v cc loi nc thi, nhng trong ti liu ny tc gi a ra 3 loi nc thi da trn mc ch s dng v cch x thi nh sau. 1.1.1. Nc thi sinh hot Nc thi sinh hat l nc c thi b sau khi s dng cho cc mc ch sinh hot ca cng ng : tm,gitgi,tyra,vsinhcnhn,chngthngcthiratcccccnh,cquan, trng hc, bnh vin, ch, v cc cng trnh cng cng khc. Lng nc thi sinh hat ca khu dn c ph thuc vo dn s, vo tiu chun cp nc v c im ca h thng that nc.Thnh phn ca nc thi sinh hat gm 2 lai: -Nc thi nhim bn do chtbi tit ca con ngi t cc phng v sinh -Nc thi nhim bn do cc cht thi sinh hat : cn b t nh bp, cc cht ra tri, k c lm v sinh sn nh. Nc thi sinh hat cha nhiu cht hu c d b phn hy sinh hc, ngai ra cn c cc thnh phn v c, vi sinh vt v vi trng gy bnh rt nguy him. Chthu c cha trong nc thi sinh hat bao gm cc hp cht nh protein (40 50%); hydrat cacbon (40 - 50%) gm tinh bt, ng v xenlulo; v cc cht bo (5 -10%). Nng cht hu c trong nc thi sinh hat dao ng trong khang 150 450%mg/l thoe trng lng kh. C khang 20 40% cht hu c kh phn hy sinh hc. nhng khu dn c ng c, iu kin v sinh thp km, nc thi sinh haat khng c x l thch ng l mt trong nhng ngun gy nhim mi trng nghim trng. Lng nc thi sinh hot dao ng trong phm vi rt ln, ty thuc vo mc sng v cc thi quen ca ngi dn, c th c tnh bng 80% lng nc c cp. Gia lng nc thi v ti trng cht thi ca chng biu th bng cc cht lng hoc BOD5 c 1 mi tng quan nht nh. Ti trng cht thi trung bnh tnh theo u ngi iu kin c vi nhu cu cp nc 150 l/ngy c trnh by trong bng 1.1Bng.1.1.Ti trng cht thi trung bnh 1 ngy tnh theo u ngi Cc cht Tng cht thi (g/ngi.ngy) Cht thi hu c (g/ngi.ngy) Cht thi v c (g/ngi.ngy) 1.Tng lng cht thi 2.Cc cht tan 3.Cc cht khng tan 4.Cht lng 5.Cht l lng 190 100 90 60 30 110 50 60 40 20 80 50 30 20 10 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 2 Bng 1.2: Thnh phn nc thi sinh hat phn tch theo cc phng php ca APHA Mc nhim Cc cht (mg/l) NngTrung bnhThp - Tng cht rn - Cht rn ha tan - Cht rn khng ha tan - Tng cht rn l lng - Cht rn lng - BOD5 - DO - Tng nit - Nit hu c - Nit ammoniac - NO2 - NO3 - Clorua - kim - Cht bo - Tng photpho 1000 700 300 600 12 300 0 85 35 50 0,1 0,4 175 200 40 - 500 350 150 350 8 200 0 50 20 30 0,05 0,2 100 100 20 8 200 120 8 120 4 100 0 25 10 15 0 0,1 15 50 0 - Nc thi sinh hot c thnh phn vi cc gi tr in hnh nh sau: COD=500 mg/l, BOD5=250 mg/l, SS=220 mg/l, photpho=8 mg/l, nit NH3 v nit hu c=40 mg/l, pH=6.8, TS= 720mg/l. Nh vy, Nc thi sinh hot c hm lng cc cht dinh dng kh cao, i khi vt c yu cu cho qu trnh x l sinh hc. Thng thng cc qu trnh x l sinh hc cn cc cht dinh dng theo t l sau: BOD5:N:P = 100:5:1 Mt tnh cht c trng na ca Nc thi sinh hot l khng phi tt c cc cht hu c u c th b phn hy bi cc vi sinh vt v khong 20-40% BOD thot ra khi cc qu trnh x l sinh hc cng vi bn. 1.1.2. Nc thi cng nghip (nc thi sn xut) L lai nc thi sau qu trnh sn xut, phc thhuc loi hnh cng nghip. c tnh nhim v nng ca nc thi cng nghip rt khc nhau ph thuc vo lai hnh cng nghip v ch cng ngh la chn. Trong cng nghip, nc c s dng nh l 1 loi nguyn liu th hay phng tin sn xut (nc cho cc qu trnh) v phc v cho cc mc ch truyn nhit. Nc cp cho sn xut c th ly mng cpncsinhhotchunghocly trctiptngunncngmhayncmtnuxnghipch thng x l ring. Nhu cu v cp nc v lu lng nc thi trong sn xut ph thuc vo nhiu yu t. Lu lng nc thi ca cc x nghip cng nghip c xc nh ch yu bi c tnh sn phm c sn xut. Bng 1.3. lu lng nc thi trong 1 s ngnh cng nghip Ngnh cng nghipTnh cho Lulngnc thi 1.Sn xut bia 2.Tinh ch ng 3.Sn xut b sa 4.sn xut x phng v cht ty ra 5.Sn xut nc khong v nc chanh 6.Nh my hp rau qu 7.Giy 8.Giy trng 9.Giy khng ty trng 10. Dt si nhn to11. X nghip ty trng1 l bia 1 tn c ci ng 1 tn sa - - 1 tn sn phm- 1 tn 1 tn1 tn sn phm 1 tn si 5,65 (l) 10-20(m3)5-6 (l) - - 4,5 - 1,5 - - - 100(m3)1000 - 4000 (m3) Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 3 Ngoira,trnhcngnghsnxutvnngsutcaxnghipcngcnghaquantrng.Lu lng tnh cho 1 n v sn phm c th rt khc nhau. Lu lng nc thi sn xut li dao ng rt ln. Bi vy s liu trn thng khng n nh v nhiu x nghip li c kh nng tit kim lng nc cp do s dng h thng tun hon trong sn xut. Thnh phn nc thi sn xut rt a dng, thm ch ngay trong 1 ngnh cng nghip, s liu cng c th thay i ng k do mc hon thin ca cng ngh sn xut hoc iu kin mi trng. Cn c vo thnh phn v khi lng nc thi m la chn cng ngh v cc k thut x l. Sau y l 1 s s liu v thnh phn nc thi ca 1 s ngnh cng nghip Bng 1.4.Tnh cht c trng ca nc thi 1 s ngnh cng nghip Cc ch tiu Chbin sa Snxut tht hp Dtsi tng hp Snxut clorophenol - BOD5 (mg/l) - COD (mg/l) -Tngchtrn (mg/l) -Chtrnllng (mg/l) - Nit (mgN/l) - Photpho (mgP/l) - pH - Nhit (0C) - Du m (mg/l) - Clorua (mg/l) - Phenol (mg/l) 1000 1900 1600 300 50 12 7 29 - - - 1400 2100 3300 1000 150 16 7 28 500 - - 1500 3300 8000 2000 30 0 5 - - - - 4300 5400 53000 1200 0 0 7 17 - 27000 140 Ni chung,ncthit cc nhmy ch binthc phmc hmlng nit v photphocho qu trnh x l sinh hc, trong khi hm lng cc cht dinh dng ny trong nc thi ca cc ngnh sn xut khc li qu thp so vi nhu cu pht trin ca vi sinh vt. Ngoi ra, nc thi cc nh my ha cht thng cha 1 s cht c cn c x l s b kh cc c t trc khi thi vo h thng nc thi khu vc. C hai loi nc thi cng nghip: -+Ncthicngnghipquicsch:llaincthisaukhisdnglmnguisn phm, lm mt thit b, lm v sinh sn nh. -+Laincthicngnghipnhimbnctrngcacngnghipvcnxlccb trc kjhi x vo mng li that nc chung hoc vo ngun nc tytheo mc x l. 1.1.3. Nc thi l nc ma y l lai nc thi sau khi ma chy trn trn mt t v li ko cc cht cn b, du m, khi i vo h thng that nc.Nhngnicmnglicngthotringbit:mnglicngthotncthiringvimngli cng thot nc ma. Nc thi i v nh my x l gm: nc sinh hot, nc cng nghip v nc ngm thm nhp, nu sau nhng trn ma ln khng c hin tng ngp ng cc b, nu c nc ma c th trn qua np y cc h ga chy vo h thng thot nc thi. Lng nc thm nhp do thm t nc ngm v nc ma c th ln ti 470m3/ha.ngy. Ni c mng cng chung va thot nc thi va thot nc ma. y l trng hp hu ht cc th trn, th x, thnh ph ca nc ta. Lng nc chy v nh my gm nc thi sinh hot, nc thi cng nghip, nc ngm thm nhp v mt phn nc ma. Lu : Trong th : Nc thi sinh hot thng trn chung vi nc thi sn xut v gi chung l nc thi th. Nutnhgnng,ncthithgmkhong50%lncthisinhhot,14%lccloinc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 4 thm, 36% l nc thi sn xut. Lu lng ncthi th ph thuc rt nhiu vo iu kin kh hu v cc tnh cht c trng ca thnh ph. Khong 65-85% lng nc cp cho 1 ngun tr thnh nc thi. Lu lng v hm lng cc cht thi ca nc thi th thng dao ng trong phm vi rt ln. Lu lng nc thi ca cc thnh ph nh bin ng t 20% QTB- 250%QTB Lu lng nc thi ca cc thnh ph ln bin ng t 50% QTB- 200%QTB Lu lng nc thi ln nht trong ngy vo lc 10-12h tra v thp nht vo lc khong 5h sng. Lu lng v tnh cht nc thi th cn thay i theo ma, gia ngy lm vic v ngy ngh trong tun cng cn c tnh n khi nh gi s bin ng lu lng v nng cht gy nhim. 1.2. THNH PHN, TNH CHT CA NC THI VA CC DNG NHIMBN 1.2.1. Lu lng nc thi- Xc nh lu lng nc thi c HTTN dng PP o lu lng ti ca x. - Nu cha c HTTN hon chnh ta tnh theo tng loi sau: 1..2.1.1. Nc thi sinh hotNc thi sinh hot thng chim t 65% n 80% lng nc cp i qua ng h cc h dn, cc c quan, bnh vin, trng hc, khu thng mi , khu gii tr,65% p dng cho ni nng, kh, nc cp dng c cho vic ti cy c. Trongmtstrnghpphidavotiuchunthotnuctnhtonsblulngnc thi.(tham kho bng 1.5) sau y: Bng 1.5. Tiu chun thi nc khu vc dn c SttMc thit b v sinh trong cng trnhTiu chun thi (l/ngi.ng) 1C h thng cp thot nc, c dng c v sinh, khng c thit b tm 80 100 2C h thng cp thot nc, c dng c v sinh v thit b tm thng thng (vi sen) 110 140 3C h thng cp thot nc, c dng c v sinh, c bn tmv cp nc nng cc b 140 180 cc khu thng mi, c quan, trng hc, bnh bin, khu gii tr xa h thng cng thot ca thnh ph,phixydngtrmbmncthihaykhuxlncthiring,tiuchunthinccth tham kho bng 1.6, bng 1.7, bng 1.8. Tuy nhin, c s thay i trong thc t iu kin nc ta. Bng 1.6.Tiu chun thi nc t cc khu dch v thng mi Lu lng (l/n v tnh- ngy) Ngun nc thin v tnh Khong dao ngTr s tiu biu Nh ga sn bay Gara- t, sa xe Qun bar Kho hng ho Khch sn Hiu git l Tim n Siu th C quan Hnh khch u xe Khch hng Ngi phc v Nh v sinh Nhn vin phc v Khch Ngi phc v Cng nhn My git Ngi n Ngi lm Nhn vin 7,5 -15 26 -50 3,8 -19 38-60 1515-2270 30-45 151-212 26-49 26-60 1703-2460 7,5-15 26-50 26-60 11 38 11 50 1900 38 180 38 49 2080 11 38 49 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 5 Bng 1.7: Tiu chun thi nc t cc cng s Lu lng (l/n v tnh-ngy) Ngun nc thin v tnh Khong dao ngTr s tiu biu Bnh vin Bnh vin tm thn Nh t Nh ngh Trng i hc Ging bnh Nhn vin phc v Ging bnh Nhn vin phc v T nhn Qun gio Ngitrongnhiu dng Sinh vin 473 -908 19 -56 284-530 19 -56 284 -530 19 -56 190 -455 56 -133 625 38 378 38 435 38 322 95 Bng 1.8.Tiu chun thi nc t cc khu gii tr Lu lng (l/n v tnh-ngy) Ngun nc thin v tnh Khong dao ngTr s tiu biu Khunghmtckhch sn mini Khunghmtlu,tri, t di ng Qun c ph gii kht Cm tri Nh n B bi Nh ht Khu trin lm, gii tr Ngi Ngi Khch Nhn vin phc v Ngi Xut n Nhn vin Ngi tm Nhn vin Gh ngi Ngi tham quan 189 -265 30 -189 3,8 -11 30 -45 75 -150 15 -38 30 -189 19 -45 30 -45 7,5 -15 15 -30 227 151 7,5 38 113 26,5 151 38 38 11 19 Lu lng nc thi sinh hot: Qtb = N.q Qnmax = Qtb . Kng Qs = Qtb /86400 Qsmax = Qs . Kc Trong :+N: S dn c + q: Tiu chun thot nc + Kng:H s khng iu ha ngy H s khng iu ngy ca nc thi sinh hot khu dn c ly Kng = 1,15 1,3 + Kc: H s khng iu ha chung H s khng iu ha chung Kc = Kng . Kh Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 6 Bng 1.9.H s khng iu ha chung ca nc thi sinh hot Lu lng trung bnh (lit/giy) 510205010030050010005000 Kc max2,52,11,91,71,61,551,51,471,44 Kc min0,380,450,50,550,590,620,660,690,71 1.2.1.2. Nc thi cng nghip Ph thuc vo quy m, tnh cht sn phm, quy trnh cng ngh ca tng nh my. Lu lng sn xut c th dng cng thc sau y: Q = qtc x P Trong : + P : Cng sut sn phm ca nh my + qtc : Tiu chun (nh mc ) s dng nc cho sn xut. C th thamkho s liu nh mc x thi ca nh my trong bng 1.10 Bng 1.10. Tiu chun thi nc ca mt s ngnh cng nghip STTNgnh sn xutnc thi/sn phm (qtc) 1Ch bin m cao su54 lit/tn sn phm crp 2Ch bin thy sn20 100 m3/tn 3Ch bin nng sn 6 60 m3/tn nng sn 4Ch bin tht3 10 m3/tn sn phm 5Thuc da65 100 m3/tn da t 6Git gi33 lit/kg qun o7Ru bia0,3 m3/gi la (36 lit) 8C ph22 m3/tn sn phm 9Luyn du3 m3/thng du th (150 l) 10Luyn cn thp0,1 0,8 m3/tn thp 11Chn nui gia cm15 25 lit/kg gia cm 12Sn xut giy v bt giy60 240 m3/tn sn phm Ngoi ra trong x nghip cncmt lng nc thisinhhot rt lnnn vic xc nhn cng c mt ngha v cng quan trng. Tiu chun nc thi sinh hot ca cng nhn trong cc phn xng s3n xut c th ly theo Bng 1.11 Bng 1.11.. Tiu chun thot nc thi sinh hot trong cc phn xng sn xut Loi phn xngTiu chun thot nc (l/ngi.ng) Kh Phn xng nng ta nhit Phn xng thng 35 25 2,5 3,0 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 7 Lng nc tm cho cng nhn sau gi lm vic theo kp l 40 60 lit/ngi v thi gian tm l 45 pht. Lu lng nc thi trong cc x nghip cng nghip: Qtb = (25N1 + 35N2)/1000, m3/ng Qhmax = (25N3 + 35N4)/T.1000 Qsmax = Qhmax /3,6 S phn b lu lng nc thi sn xut theo ca kp c th ly theo phn trm lu lng ngy nh trong bng 1.12 Bng 1.12. Phn b phn trm lu lng sn xut theo ca BuiLm vic 3 caLm vic 2 ca Bui sng40 5050 65 Bui chiu35 3050 65 Bui m20 25 C ngy100100 Ngoi ra khi khng c s liu c th ca tng nhmy c th tnh lng nc thi chung theo din tchca khu cng nghip nh sau: -KCNgmccnhmySXrasnphmth,tngmnc,lngncthidaongt9-14m3/ha.ngy. -SX sn phm ngm nc trung bnh t 14-28m3/ha.ngy. -Lng nc thi KCN tnh theo lng nc cp: 90-95% 1.2.1.3. Nc ma Vic xc nh lu lng nc ma kh phc tp. Rt nhiu cng trnh x l nc thi sinh hot hin naychacpnhiunvicxcnhlngma.Tiliunytrnhmtphngphpnghc (phng php .) xc nh lu lng nc ma ti mt vng bt k. Vic tnh ton mg li thotnc ma s cp trong mt ti liu khc ca tc gi 1.2.1.3.1. Cc s liu c bn thit k h thng thot nc ma 1.Thi gian ma: L thi gian ko di ca mt trn ma tnh bng pht hoc gi. Thi gian bt u cnmaclngncchyvomnglinhhnlulngtnhton.Hintngnygils chm tr ca dng chy nc ma, do nc ma phi mt thi gian di chuyn t b mt lu vc n mng li thot nc. V vy, trn sut chiu di on ng, lu lng lun nh hn lu lng ti a hin din cui on ng tnh ton. -Thi gian ma tnh ton: ttt = tm + tr + to Trong : + tm : Thi gian tp trung nc ma trn b mt t im xa nht n mng li 9Z,n,i : h s lp ph, h s nhm v dc b mt tp trung nc m 9I :cng ma, mm/pht 9L : chiu di on nc chy phutI i ZL ntm,. .. . 5 , 13 , 0 5 , 0 3 , 06 , 0 6 , 0=Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 8 (Cng thc xc nh tm p dng cho cc bmt tp trung ncma c san nn khng c rnh, lung,..) Lu : Tnh ton tm s b c th ly nh sau: 9Trong tiu khu khng c h thng thot nc ma: tm = 10 pht 9Trong tiu khu c h thng thot nc ma: tm = 05 pht + tr : Thi gian nc chy trong rnh: tr = 1,25. lr /vr (giy) 9lr, vr : chiu di (m) v vn tc (m/s) nc ma chy cui rnh 91,25 : h s tnh n s tng tc chy trong thi gian ma + to : Thi gian nc chy trong ng n tit din tnh ton: to = M lo / vo(giy) 9lo, vo : chiu di, vn tc nc ma chy trong ng 9M : h s tnh n s chm tr ca dng chy nc ma M = 2 : a hnh thot nc ma bng phng i < 0,01 M = 1,5 : a hnh thot nc ma c dc =0,01 0,03 M = 1,2 : a hnh thot nc ma c dc > 0,03 2. Cng ma:l lng nc ma ri xung tnh trn mt n v din tch trong mt n v thi gian. Cng ma c biu din di 2 hnh thc: theo lp nc v theo th tch. -Cng ma tnh theo lp nc l t s gia chiu cao lp nc v thi gian ma. i = h/t (mm/pht) -Cng ma tnh theo th tch l lng nc ma tnh bng l/s.ha q = 166,7 i (l/s.ha) -Cng ma c xc nh theo cng thc Lin x c: Trong : + n,C : i lng ph thuc c im kh hu tng vng + q20 : Cng ma trong thi gian 20 pht vi chu k P= 1 nm + P : Chu k ma, nm + t : thi gian ma tnh ton, pht -Cng ma c xc nh theo cng thc Trn Lit Vin: Cc gi tr n, C, b tra trong bng phn b ma tng a phng 3.Chukma:Lthigianlplimttrnmaccngcngvthigianma.nvtnh bng nm 4. Chu k trn cng (P):l thi gian c mt trn mavt qu cng ma tnh ton La chn P :+ Khu dn c, thnh ph nh :0,3 01 nm + Thnh ph ln, khu cng nghip: 01 03 nm + Khu vc c bit quan trng:05 10 nm Bng 1.13. Chu k trn cng i vi khu vc dn c iu kin lm vic ca cngLoi cng Thun liTrung bnhBt liRt bt li Khu vc0,250,350.51 Ph chnh0,350,512 ( ) [ ]nntP C qqlg . 1 . 2020+=( ) ( ) [ ]( )nnb tP C q bq++ + +=lg . 1 2020Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 9 iu kin thun li:a.Din tch lu vc khng ln hn 150 ha, a hnh bng phng, dc trung bnh ca mt t 0,005 v nh hn b.ngcngttheongphnthyhocphntrncasndccchng phn thy khng qu 400m iu kin trung bnh: a.Din tch lu vc ln hn 150 ha, a hnh bng phng, dc trung bnh ca mt t khong 0,005 v nh hn. b.ng cng t pha thp ca sn dc, theo khe t nc, dc ca sn dc nh hn hay bng 0,02, din tch lu vc khng qu 150 ha. iu kin bt li: a.ng cng t pha thp ca sn dc v din tch lu vc ln hn 150 ha. b.ng cng t theo khe t nc ca sn dc, dc trung bnh ca sn dc ln hn 0,02. iu kin rt bt li: ng cng dng thot nc t mt ch trng Bng 1.14.Gi tr P theo q20 Gi tr P khi q20 bngc im vng thot nc ma 50 7070 9090 100> 100 a hnh phng, i< 0,006 khi:F 150 ha F > 150 ha a hnh dc, i> 0,006 khi: F 20 ha F = 20 50 ha F = 50 100 ha F > 100 ha 0,25 0,33 0,33 0,50 0,33 0,5 0,5 1 2 3 5 0,33 0,5 0,5 1,5 0,5 1,5 1 2 3 5 5 0,5 1,5 1,5 2 1 2 1 3 5 10 2 3 4 3 4 5 10 10 10 20 Bng 1.15. Chu k trn cng i vi khu vc cng nghip Hu qu do vic trn cngP (nm) Qu trnh cng ngh khng b h hng Qu trnh cng ngh b h hng1 2 3 - 5 5. H s dng chy: L t s gia lng nc ma chy vo mng li thot nc v lng nc ma ri xung. = qc / qr + qc, qr:Lng nc ma ri trn din tch 1 ha v lng nc ma chy vo mng li thot nc t 1 ha . = Ztb . q0,2 . t0,1 Trong : - q,t: cng ma (l/s.ha) v thi gian ma tnh ton (pht) - Ztb:h s mt ph trung bnh ca ton lu vc Khi din tch b mt khng (hoc t) thm nc ln hn 30% din tch lu vc th h s dng chy cho php ly bng tb l i lng trung bnh chungca h s dng chy o v din tch b mt m khng ph thuc vo cng ma v thi gian ma. Bng 1.16. bng xc nh h s dng chy o v h s lp ph b mt Z Dng b mt H s dng chy oH s Z Mi nh, mt ng btng0,950,240 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 10 3 / 2. 001 , 0 11F += Mt ph dm, o, ng nha0,60,224 ng lt cui, hc0,450,145 Mt ph dm khng c vt liu kt dnh0,40,125 ng si trong vn0,350,09 Mt t0,30,064 Mt c0,150,038 1.2.1.3.2. Tnh ton nc ma Gi thit rng thi gian ma chnh bng thi gian nc ma t im xa nht trong lu vc chy n tit din tnh ton. Xc nh lu lng tnh ton nc ma cn c vo thi gian tp trung nc ma c gi l phng php cng gii hn. Qtt = . . q. F Trong o: + F: din tch lu vc, ha + H s phn b ma ro l h s k n s phn phi ma khng ng u trnton lu vc = qTB / qmax Bng 1.17. Gi tr Din tch lu vc, ha BOD -COD/BOD cng nh th XLSH cng d. -Nc thi sinh hot c BOD ~ 0.86COD (NT cng nghip th thay i) 1.2.4.3. Oxy ha tan (DO) -y l ch s quan trng trong x l SINH HC hiu kh (lun gi 1.5 _ 2mg/l).-DO ph thuc vo nhit , p sut ca nc (nhit tng DO gim, p sut tng DO tng). -Nu k hiu thiu ht oxy: D + D = 0: oxy bo ha hon ton + D = 1: Thiu ht han ton nn khng c oxy. - thiu ht oxy sau thi gian t: Dt = Do*10-K2t Trong : Vi: K2: h s tc ha tan ( ph thuc vo to, S, ) K2Ngun nc 10oC15 oC20 oC25 oC Khng c dng chy-0.110.15- vchy 500 1:1- 5:10.540.720.91.35 5:1 25:10.544.068 25:1 125:110121520 125:1 600:125303550 > 600506070100 1.3.2.Nguyn tc x nc thi vo ngunSau khi x l, vic x vo ngun phi tun theo lut bo v ngun nc: Bng 1.19.Bng ccgi tr cho php tng ln sau qu trnh x thi H cha Cht nhim bn Loi 123 Sau khi x nc thi th SS trong ngun tng ln cho php1. SS 0.25 (mg/l)0.75 (mg/l)1.5 (mg/l) 2. Mi, vSau khi x nc thi th nc ngun khng mi 3. DOD > 4 mg/l Sau khi x th BOD20 khng vt qu 4. BOD20 3 (mg/l)6 (mg/l)Khng quy nh 5. PKhng lm thay i P: 5.5 < pH < 8.5 Khng c mu khi nhn qua ct nc cao6. Mu sc 20 cm10 cm5 cm 7. VKCm x nc thi c VK gy bnh 8. Cht cNc thi x vo khng c tnh c hi Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 16 Ghi ch: - Loi 1: Cp nc th, XN ch bin thc phm - Loi 2: Cp cho Cng nghip , dng chn nui ca, tm git, - Loi 3: Ti tiu, chn nui thy sn 1.3.3.Xc nh mc x l nc thi -Khi b cc cht nhim trong nc thi khng phi lm cho chng bng khngm phi n mc cho php x vo ngun (TC x thi).-Cng trnh x l tt hay khng da vo 2 yu t: + Hiu qu x l (mc x l). + Nin hn s dng. -C 2 cch xc nh mc x l: + Xc nh mc x l theo SS + Xc nh mc x l theo BOD 1.3.3.1.Theo SS Hm lng cht l lng cho php trong nc thi x vo ngun c xc nh nh sau: C2 = p( . Qq + 1) + Cng Trong : - C2: Hm lng cht l lng cho php trong nc thi x vo ngun - p:Hm lng cht l lng tng cho php trong nc ngun sau xo trn (g/m3) (TC SS) - Q: Lu lng nc ngun (m3/h) - q: Lu lng nc thi (m3/h) - Cng: Hm lng cht l lng trong nc ngun (g/m3) - : H s ph thuc c tnh thy lc Eo = 100% (C1 - C2) C1 1.3.3.2. Theo BOD BOD ca nc thi cho php thi vo ngun: L2 = t ktht kt kngt kthLLLqQ1 1'1110 101010 + Vi: - Lng: BOD ngun - k1, k1: Hng s tc tiu th oxy ca nc thi v nc ngun - k1: Theo bng ph thuc nhit To, oC1015202530 k1 0.0630.080.10.1260.158 - k1 : Theo bng sau: Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 17 Gi tr k1, vi nhit nc ngunc tnh ngun nc 100C1050C200C250C Ngun nc khng c dng chy hoc chy chm 0.110.15 Ngun nc c tc dng chy < 0.5 m/s 0.170.1850.020.215 Ngun nc vi dng chy mnh 0.4250.460.050.54 Ngun nc nh vi dng chy mnh 0.6840.740.080.865 - t: Thi gian xo trn =1 - Lth: BOD ti hn ca hn hp nc thi v ngun Suy ra: Mc cn thit x l nc thi: Eo = Lo - L2Lo . 100% V d: Xc nh mc cn thit x l nc thi vi lu lng q= 0.8 m3/s, BOD ban u Lo = 261 mg/l, hm lng cht l lng C1 = 271.6 mg/l. Lu lng nc sng Q = 14 m3/s, tc dng chy VTB = 0.4 m/s, chiu su trung bnh HTB = 2 m, nng cht l lng Cng = 12 mg/l, BOD l Lng = 2 mg/l. Khong cch t ca x ti mt ct tnh ton l L = 30 km, nhit trung bnh ma h to = 15oC. Thi gian ti hn cho bng 2.6 (h). H s cong ca sng = 1.2. Sng thuc ngun loi I. Bi gii Theo SS E = (VTB.HTB)/200 = (0.4 x 2)/200 = 0.004 = 1.2 x 1.5 30.0040.8 = 0.321 = 1 -e- 0.32 3300001 + 140.8 e- 0.32 330000 = 0.85 C2 = 0.25 [0.85(14/0.8) + 1] + 12 =15.98 (mg/l) Eo = [(271.6 15.98)/ 271.6]. 100% = 93.5 (%) Theo BOD L2 = 0.85 14 0.8 (310- 0.08x2.6 - 2 10- 0.185x2.6 10- 0.08x2.6) + 3 10- 0.08x2.6 =28.69 (mg/l) Eo = [(261 28.69)/ 261]. 100% = 89 (%) 1.4. S CNG NGH X L NC THI 1.4.1. C s la chn cng trnh x l nc thi:Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 18 Trong vicquyt nh xy dng cngtrnh x l ncthi, 3 nhn t chnh quantrng c gi l 3E, gm: Mi trng (Environment),K thut (Engineering), Kinh t (Economic) cn phi hi ha vi nhau. Khi kho st thit k mt t hp cng trnh, tin trnh xem xt theo s sau: Cc bc thit k cng trnh x l nc thi Trong cc bc trnh by trong s , vic chn laqui trnh x l thit kcngtrnhmang tnh chtquyt nhquantrng. Mt cng trnh cthit k, xy dng v vn hnh hiu qu phthuc vo nhiu yu t khc nh k nng ca k s thit k, chin lc ca nh qun l, kh nng u t xy dng cng trnh v trang b cc thit b my mc, cht lng thi cng v lp t my mc v chi ph xy dng v vn hnh bo dng. Ngoi ra ta c th da vo mc tiu x l la chn cng trnh cho ph hp. VD: -Tch rn khi lng: song chn rc, lng, lc -Tch lng khi rn: nn bn, tch nc khi bn -Tch lng khi lng: tch du m -Tch kh khi lng: tch kh ammonia, kh sinh hc -Cht hu c: hiu kh (bn hot tnh,sinh trng bm dnh), k kh (UASB) -Cht dinh dng: kh Nit, Photpho Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 19 Tng quan v cng ngh v phng php x l nc thi Cng ngh x l Phng php x l Cng trnh x lMc tiu x l X l s b + Ha L + Ha hc - Tuyn ni- Hp ph- Keo t... - Oxy ha- Trung ha -Tchccchtllng v kh mu -Trunghavkhc nc thi X l tp trung + C hc + Sinh hc + Kh trng + X l bn cn - Song chn rc - B chn rc - B lng t I - H sinh vt - Cnh ng lc, ti - Knh oxy ha - Aeroten - B lc sinh hc - B lng t II - Trm trn Clor - Mng trn - B tip xc - B metan - Sn phi bn - Trm x l c hc bn cn - Tch cc tp cht rn v cn l lng -Tchccchthuc dng l lng v ha tan -Khtrngtrckhix ra ngun -nnhvlmkh ngun cn X l trit + C hc + Sinh hc + Ha hc - B lc ct - B aeroten bc II - B lc sinh hc bc II - H sinh vt - B kh nitrat - B oxy ha - Tch cc cht l lng - Kh nit v phtpho - Kh nit ,phtpho v cc cht khc 1.4.2. Dy chuyn cng ngh trm x l nc thi: 1 dy chuyn x l c th bao gm 5 khi sau: a.Khi x l c hc: tch cc cht khng ha tan v 1 phn dng keo (song chn rc, lng ct, lng, vt du lc) b.Khi x l ha hc (thngt sau cc cngtrnh x l chc, trc cng trnh xlsinh hc): bin i ha hc v kt hp c hc (keo t, hp ph, hp th) c.Khixl sinh hc:dngVSVoxyhachtbnhucdngkeovhatan(iukint nhinvnhnto:cnhngti,hsinhhc,mngoxyha,cnhngti,blcsinh hc, bn hot tnh) d.Khi x l cn: x l cc cht thi to thnh trong qu trnh x l c hc, ho hc, sinh hc (b metan, sn phi bn, trm x l c hc bn cn) e.Khi kh trng: kh trng trc khi x ra ngun (trm trn Clor, mng trn, b tip xc) Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 20 VD: S phn khi x l nc thi sinh hot: 1.4.3.Gii thiu 1 s dy chuyn x l nc thi: 1. XLNT sinh hot: 9Nc thi c a qua song chn rc loi b tp cht l lng th c th lm nght thit b 9Sau NT c a vo b vt du m tch du m ra khi nc. Trn hnh l m hnh b lng ngang kt hp b vt du m nn ta khng cn x dng b lng t I.9B aeroten s x l cc cht hu c phn hy sinh hc c trong nc thi. 9B lng 2 dng lng bn sinh hc c trong nc thi sau qu trnh x l b aeroten. 9Trckhixrangunnguntipnhn,ncthicavobtipxcchlorinekh trng. 9Lngbnphtsinhcavoblngbntchncvbntrckhiavob metan x l cn hu c. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 21 SCRac Be lang t IBe Lang Cat be vt dauX X L Ly y b ba a c c m mo o t t Nc thai Be Lang t IIBe aerotenCl2 X X L Ly y S Si in nh h H Ho o c cBe tiep xucchlorine kh nc Nen bunPhan huy k khcha bun 2.XLNT bnh vin: 9-B iu ha: ieu hoa s bien thien cua lu lng/cng o chat hu c. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 22 9-Besinhhoctiepxucvabelang:Khnhngchathucphanhuysinhhoc (BOD) va can l lng (SS).9-Be sinh hoc tiep xuc c lam thoang bi may thoi thoi kh. 9-Bun tuan hoan: duy tr mat o sinh khoi cao 9-Bun d: bun d c thai en he thong x ly bun va thai bo. 9-Trc khi x ra ngun ngun tip nhn, nc thi c a vo b tip xcchlorine kh trng. 3. XLNT dt nhum: -Keo t-to bng: gip cho vic tp hp ca cc ht cn nh thnh cc ht cn ln hn c th tch ra bng lng trng lc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 23 B keo t to bng nu nh trn hnh l khng ph hp v cht l lng qua b hiu kh v b lng c x l gn ht.B keo t to bng phi t sau b iu ha hiu qu x l t cao nht. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 24 Bm ap lcOng t chayOng t chayOng t chayOng t chayOng t chayOng t chayHo thu nc a x b x c6 x 4 x 3 (m)Be ieu Hoa a x b x c14.1 x 9 x 4.8(m)Be Tao Bong x b x c 10.6 x 2.5 x 1.8 (m)Be Lang Li TamIDx c 11 x 4.7 (m)Be Aeroten a x b x c16.5 x 7 x 4.5 (m)Be Lang Li TamII Dx c 20.6 x 4.7(m)Ho Tiep Xuc a x b x c6 x 4.4 x 3.3 (m)Be Phan ng a x b x c1.8 x 1.25 x 0.6 (m)Mat at-3,74(m)Mat at0(m)-0.8(m)-2.0(m)-2.4(m)-2.0(m)-1.2(m)+3.7(m)+1.9(m)+2.4(m)+1.8(m)+2.4(m)+1.8(m)+2.2(m) Hthng x l nc thi nh my Giy Hthng x l nc thi Bnh vin Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 25 NCTHAI VAOXA RANGUONTENCONGTRNHKCHTHC(Dai*Rong*Cao), mHAMBM4*2,5*3,8BE IEUHOA BE LANGI BE AEROTANK BE LANGII BE KH TRUNG10*5,3*3,5D=4H=6,411*7*4,4D=4,8H=7,23*1,3*2,30.0 0.0+2500+2000+3000+2000+1000- 3800-1000-4400-1300-5200-1300NCTHAIVAOXA RANGUONTENCONGTRNH KCHTHC(Dai*Rong*Cao), mHAMBM2,5*2,2*3,2BE IEUHOA BE LANGI BE UASB BE AEROTANK BE LANGIIBE KH TRUNG15*5*2,7D=2,87H=5,5156*4*3,3 19,1*4*5D=4,7H=5,253*2,08*2,30.0 0.0+200+1700+1500+3300+3000+1400+1000- 3000-1000-4015-1300-3850-1300 Hthng x l nc thi sinh hot Hthng x l nc thi nh my thc phm Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 26 8E hEh 80h x h = 6 x 4,48E X0 LY 8Ihh h0680 x 10 x 68E Lkh hkh16 x 4 x Z,68E kE0 T0, Tk0 80h(M0I hkhZ,8 x Z,8 x Z)8E T0YEh h0I & IE0 h0k x h = 7,4 x 40h kh0h kF0h kh0h kF80M kF L0680M kF L06TkM 80MZ x Z,8 x Z0.00 0.00uong hoa rhaIuong bun6h0 Th6h.Th0h Fhk 0hh [6h 6FoIymarMkY EF 80hh006 8k6hTh0h Fhk 0hh [6hha0hTh0 h Fhk 0hh [6hFk6Th0h Fhk 0hh [6h kIZ(804)8 CB ATHANH GAT BU NkEhh ThkM L00h Hthng x l nc thi nh my vifon Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 27 Chng 2: X L NC THI BNG PHNG PHP C HC 2.1. KHI NIM V PHNG PHP X L NC THI BNG PHNG PHP C HC Phngphpnycsdngtchcctpchtkhnghatanvmtphncccht dng keo ra khi nc thi. Cc cng trnh x l c hc bao gm: 2.1.1. Thit b chn rc: Thitbchnrccthlsongchnrchoclichnrc,cchcnngchngi nhng rc bn th (giy, rau, c, rc), nhm m bo m cho my bm, cc cng trnh v thit b x l nc thi hot ng n nh. Song v li chn rc c cu to bng cc thanh song song, cc tm li an bng thp hoc tm thp c c l ty theokchcccmtlihaykhongcchgiaccthanhmtaphnbitloichn rc th, trung bnh hay rc tinh. Theo cch thc lm sch thit b chn rc ta c th chia lm 2 loi: loi lm sch bng tay, loi lm sch bng c gii. 2.1.2. Thit b nghin rc: Lthitbcnhimvctvnghinvnrcthnhccht,ccmnhnhllng trong nc thi khng lm tc ng, khng gy hi cho bm. Trong thc t cho thy vic s dng thit b nghin rc thay cho thit b chn rc gy nhiu kh khn cho cc cng on x l tip theo do lng cn tng ln nh lm tc nghn h thng phn phi kh v cc thit b lm thong trong cc b (a, l phn phi kh v dnh bm vo cc tuabin. Do vy phi cn nhc trc khi dng. 2.1.3.B iu ha: Lnvdngkhcphcccvnsinhradosbinngvlulngvtilng dng vo, m bo hiu qu ca cc cng trnh x l sau, m bo u ra sau x l, gim chi ph v kch thc ca cc thit b sau ny.C 2 loi b iu ha: B iu ha lu lng B iu ha lu lng v cht lng Cc phng n b tr b iu ha c th l b iu ha trn dng thi hay ngoi dng thi x l. Phng n iu ha trn dng thi c th lm gim ng k dao ng thnh phn nc thi ivocccngonphasau,cnphngniuhangoidngthichgimcmt phn nh s dao ng . V tr tt nht b tr b iu ha cn c xc nh c th cho tng h thng x l, v ph thuc vo loi x l, c tnh ca h thng thu gom cng nh c tnh ca nc thi. 2.1.4.B lng ct: Nhimvcablngctlloibcnth,nmgnh:ct,si,mnhthytinh,mnhkim loi, tro, than vn nhm bo v cc thit b c kh d b mi mn, gim cn nng cc cng on x l sau.

B lng ct gm nhng loi sau: B lng ct ngang: C dng nc chuyn ng thng dc theo chiu di ca b. B c thit din hnh ch nht, thng c h thu t u b. B lng ct ng: Dng nc chy t di ln trn theo thn b. Nc c dn theo ng tiptuyn vi phn di hnhtrvob.Ch dngchy kh phctp, nc va chuyn ng vng, va xontheo trc, va tnh tin i ln, trong khi cc ht ct dn v trung tm v ri xung y. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 28 Blngcttiptuyn:lloibcthitdinhnhtrn,ncthicdnvob theo chiu t tm ra thnh b v c thu v mng tp trung ri dn ra ngoi. B lng ct lm thong: trnh lng cht hu c ln trong ctv tng hiu qu x l, ngi ta lp vo b lng ct thng thng mt dn thit b phun kh. Dn ny c t st thnh bn trong b to thnh mt dng xon c qut y b vi mt vn tc trnh hin tng lng cc cht hu c, ch c ct v cc phn t nng c th lng. 2.1.5.B lng: Lng l phng php n gin nht tch cc cht bn khng ha tan ra khi nc thi. Da vo chc nng v v tr c th chia b lng thnh cc loi: Blngt1:cttrccngtrnhxlsinhhc,dngtchccchtrn, cht bn l lng khng ha tan. Blngt2:ctsaucngtrnhxlsinhhcdnglngcccnvisinh, bn lm trong nc trc khi thi ra ngun tip nhn Cn c vo chiu dng chy ca nc trong b, b lng cng c chia thnh cc loi ging nh b lng ct trn: b lng ngang, b lng ng, b lng tip tuyn (b lng radian). 2.1.6.Lc Lc c ng dng tch cc tp cht phn tn c kch thc nh khi nc thi, m cc b lngkhngthloicchng.Ngitatinhnhqutrnhlcnhccvtliulc,vch ngn xp, cho php cht lng i qua v gi cc tp cht li.Vt liu lc c s dng thng l ct thch anh, than cc, hoc si, thm ch c than nu, than bn hoc than g. Vic la chn vt liu lc ty thuc vo loi nc thi v iu kin a phng. C nhiu dng lc: lc chn khng, lc p lc, lc chm, lc nhanh, lc chy ngc, lc chy xui 2.6.2. Tuyn ni, vt du m Phng php tuyn ni thng c s dng tch cc tp cht ( dng ht rn hoc lng) phntnkhngtan,tlngkmrakhiphalng.Trongmtstrnghpqutrnhny cng c dng tch cc cht ha tan nh cc cht hot ng bmt. Qu trnh nh vy c gi l qu trnh tch hay lm c bt. Trong x l nc thi v nguyn tc tuyn ni thng c s dng kh cc cht l lng v lm c bn sinh hc. Qu trnh tuyn ni c thc hin bng cch sc cc bt kh nh (thng l khng kh) vo trong pha lng. Cc kh kt dnh vi cc ht v khi lc ni tp hp cc bng kh v ht ln s ko theo cc ht cng ni ln b mt, sau chng tp hp li vi nhau thnh cc lp bt cha hm lng cc ht cao hn trong cht lng ban u. Bng . ng dng cc cng trnh c hc trong x l nc thi Cc cng trnhng dng Li chn rcTch cc cht rn th v c th lng Nghin rcNghin cc cht rn th n kch thc nh hn ng nht B iu hoiu ha lu lng v ti trng BOD v SS LngTch cc cn lng v nn bn LcTch cc ht cn l lng cn li sau x l sinh hc hoc ha hc Mng lcTng t nh qu trnh lc, tch to t nc thi sau h n nhVn chuyn khB sung v tch kh Bay hi v bay khBay hi cc hp cht hu c bay hi t nc thi 2.2. TNH TON THIT K CC CNG TRNH C HC 2.2.1. Song chn rc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 29 SCR l cng trnh x l s b nhm loi b mt lng rc bn th chun b cho x l nc thi sau . SCR bao gm cc thanh an sp xp cnh nhau. Khong cch gia cc thanh gi l khe h (mt li) v k hiu l b. Ta c th phn bit cc loi SCR nh sau: SCR th: b = 30 200mm. SCR c tinh:b = 5 25mm. SCR c nh v di ng. SCR th cng v c gii. Cc tit din ca thanh an: TNH TON

8 - 10

h1 hA-A l1lSl2 Bk B sSongchn rc tinh Songchn rc th Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 30 Khong cch gia cc thanh b = 16 25mm. Gc nghing = 60 - 900.Vn tc trung bnh qua cc khe:v = 0,6 - 1 m/s S khe h gia cc thanh zkv h bqn. .1max= + kz: h s tnh n s thu hp dng chy: 1.05 + qmax : lu lng ln nht Chiu di tng cng ca SCR:Bs = s (n - 1) + b.n (s: chiu dy song chn : 8 10 mm) Chiu di on knh m rng trc SCR: tgB Blk s21=( =15-200) Chiu di on thu hp sau:l2 = 0,5l1(m)Tn tht p lc qua SCR: + : h s tn tht cc b: = (s/b)4/3sin. + : h s ph thuc hnh dng thanh an: =2,421,831,67 1,97 0,92 + K: h s tnh ti s tng tn tht p lc do rc mc vo SCR: K = 3. Lng rc c gi li: Wr = a.Ntt /365.1000 (m3/ng.). + a: lng rc tnh cho 1 ngi/nm : 5 6 l/ngi.nm. + Dn s tnh ton: N = Q/q. + q: tiu chun thot nc: Mt s c tnh ca SCR: + m rc: 80%. + tro : 7 8 %. + Trng lng th tch 750 kg/m3. V d p dng: Tnh ton thit k song chn rc ca mt cng trnh x l nc vi cc thong s nh sau: lu lng trungbnh QTBng = 300 m3/ngy. -Lu lng nc thi theo gi ln nht: Qmaxh = QTBh . kh = 12,5 * 2,2 = 31,25 (m3/h) Kgvhs.22max =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 31 Vi kh l h s vt ti theo gi ln nht (k = 1,5 3,5), chn k=2,5. -Chn loi song chn c kch thc khe h b =16 mm. -Tit din song chn hnh ch nht c kch thc: s x l = 8 x 50 mm. a)S lng khe h ( ) khe kh b vQnzl s498 , 9 05 , 11 , 0 016 , 0 6 , 010 68 , 83max= = = Chn s khe l 10 s song chn l 9. Trong : n : s khe h. Qmax : lu lng ln nht ca nc thi, (m/s). vs : tc nc qua khe song chn, chn vs = 0,6 m/s. kz : h s tnh n hin tng thu hp dng chy, chn kz =1,05 b)B rng thit k song chn rc ( ) ( ) ( ) ( ) () m n b n s Bs232 , 0 10 016 , 0 1 10 008 , 0 1 = + = + = Chn Bs = 0,3 m.Trong : s : b dy ca thanh song chn, thng ly s = 0,008 c)Tn tht p lc qua song chn rc kgvhs =22maxTrong : vmax :vn tc nc thi trc song chn ng vi Qmax , vmax = 0,6. k :h s tnh n s tng tn tht p lc do rc bm, k = 2-3. Chn k = 2. : h s tn tht p lc cc b, c xc nh theo cng thc: 83 , 0 60 sin016 , 0008 , 042 , 2 sin04 / 3 4 / 3= = = bs Vi: : gc nghing dt song chn rc, chn= 600. : h s ph thuc hnh dng thnh an,= 2,42 ( )() ( ) cm m hs5 05 , 0 381 , 9 26 , 083 , 02= = =d)Chiu di phn m rng trc SCR () mtg tgB BLk s13 , 020 22 , 0 3 , 0201===

Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 32 Chn L1 = 0,2 Trong : Bs : chiu rng song chn. Bk : b rng mng dn, chn Bk = 0,2m. : gc nghin ch m rng, thng ly = 200. e)Chii di phn m rng sau SCR () m L L 1 , 0 2 , 0 5 , 0 5 , 01 2= = =f)Chiu di xy dng mng t SCR () m L L L Ls8 , 1 5 , 1 1 , 0 2 , 02 1= + + = + + =Trong : Ls : chiu di phn mng t song chn rc, L = 1,5m g)Chiu su xy dng mng t SCR () m h h Hs65 , 0 5 , 0max= + + =Trong : hmax = hl : y ng vi ch Qmax. hs : tn tht p lc qua song chn. 0,5 : khang cch gia ct sn nh t SCR v mc nc cao nht. Tm tt thng s thit k mng v song chn rc STTTn thng sn vS lng 1Chiu di mng (L)m1,8 2Chiu rng mng (Bs)m0,3 3Chiu su mng (H)m0,7 4S thanh song chnThanh9 5S khe (n)Khe10 6Kch thc khe (b)mm16 7B rng thanh (s)mm8 8Chiu di thanh (l)mm50 2.2.2. B lng ct B lng ct thng dng lng gi nhng ht cn ln c cha trong nc thi (chnh l ct). C nhiu loi b lng ct. 2.2.2.1. B lng ct ngang Blngctngangncchythngthngchthucnub.Ctccovhthu bng co st v ly ra bng bm phun tia. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 33 A A Tnh ton: Chiu di ca b: L = vmax.t (t = 30 - > 60s) = kuh vom 11000 -Vmax : vn tc khi Qmax: 0,3 m/s. -k: h s ly ph thuc u0. ou0= 18mm/s: k = 1,7. ou0 = 24 m/s:k = 1,3. (ng knh ht ct thng 0,2 0,25 mm). -h1: chiu su cng tc ca b: 0,25 1 m. -u0 = ln thu lc ca ht ct vi ng knh 0,2 0,25 gi li trong b: u0 = 18 24 mm/s. -Tit din t ca b : mvQFmax=-Chiu rng ca b :. 1.h vqb =S ngn trong b: 1.h bFn =Vn tc ln nht: vmax 0,15 m/s. Th tch ct trong b: 1000. . T p NWttc =-Nttdn s tnh ton. -p: lng ct vi m 60%, 0,02 l/ngi. ng.. -T: thi gian gia 2 ln x ct khi b : 2 4 ngy. Chiu su lp cn ct: n b LWhc. .2 =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 34 Chiu su tng cng: H xd = h1 + h2 + h3. (h3 = 0,2 0,4 m: chiu cao bo v t nc n tng). 2.2.2.2. B lng ct ng: Nc chy t di ln dc theo thn b: Tnh ton: Din tch tit din ngang: v nQF.max=Chiu cao cng tc: h1 = v.t. Chiu su tng cng: H = h1+ h2 + h3 + h4.

= h1+ 0,5+ h3 + h4. Nu trn : FD4=Nu vung :F D =Tc nc : v = 0,4 m/s. Thi gian lu: t = 2 3,5 pht. 2.2.2.3. B lng ct tip tuyn: C mt hnh trn. Mng dn nc vo tip tuyn vi b. Chu tc dng ca 2 lc, lc bn thn P, v lc ly tm. Ti trng nc b mt : 100m3/m2.h. Tc nc trong mng: 0,8 0,6 m/s. Hiu qu gi ct: 90%. h D/2. 2.2.2.4. B lng ct lm thong: L bc pht trin ca b lng ct tip tuyn. Nh thi kh m dng chy nc thi trong b va quay va tnh tin to nn chuyn ng xoc c. Tnh ton Hiu sut 90 95%. ng knh ng thi kh: 2,5 6 mm. Din tch tit din ngang: tv nQF.max= . Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 35 -vt: vn tc thng: 0,01 0,1 m/s. -n: s ngn ca b. Chiu su cng tc: totovubhvu bh = =11. -Chiu rng b b. -uo : ln thu lc u0 ph thuc vo kch thc d ca ht ct theo bng di y: d(m)0.10.120.150.20.30.4 uo(mm/s)5.127.2711.217.229.140.07 Thi gian lu 1 vng:vvbt 2 . 11 = (vv: vn tc vng theo chu vi tit din ngang: 0,25 0,3 m/s.) Thi gian nc lu li: t = 1,1 .m.t1. (m: s vng nc trong 1 b: m = 1/ lg(1 2h/H).) Chiu di ca b L = vt . t. Lng khng kh cn thit: Lk = I .F. (I: cng kh: 25m3/m2.h.) V d p dng: Tnh b lng ct ngang cho mt cng trnh x l nc thi vi cng sut 4000m3/ngy, hm lng SS = 254mg/l, COD~ Chiu di ca b lng ct ngang c xc nh theo cng thc: oUv H KLmax* * * 1000=Trong : -K: h s ph thuc v loi b lng ct v th thy lc ca ht ct, K = 1,3 -H: su tnh ton cab lng ct, H = 0,25 1m, chn H = 0,3m -vmax: tc ln nht ca nc thi trong b lng ct ngang, vmax = 0,3 m/s. -Uo = th thy lc ca ht ct, Uo = 18,7 24,2 mm/s. ng vi ng knh ca ht ct d = 0,25 mm. Chn Uo = 24,2 mm/s. Vy:2 , 243 , 0 * 3 , 0 * 3 , 1 * 1000= L =4,83m ~ Chiu rng ca b lng ct ngang: H vQB*maxmax=Trong : -Qmax: Lu lng ln nht giy, Qmax = 417 m3/h = 116 l/s = 0,116 m3/s -vmax = 0,3 m/s -H = 0,3 m Chn 4 b lng ct ngang dng mng. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 36 Vy : Chiu rng mi ngn l: 4 * 3 , 0 * 3 , 0116 , 0= B =0,3m ~ Chiu rng mng: 2 / 33 / 2max112=KKQBvg mBvbTrong : -B = 1,3m -v = 0,3m - m : h s lu lng ca ca trn ph thuc v gc ti. Chn g ti1 cot , 450= = ag , chn m = 0,352. -Qmax = 0,116 m3/s. -K = 1,3. Vy: 2 / 33 / 23 , 1 13 , 1 1116 , 03 , 0 * 3 , 181 , 9 * 2 352 , 03 , 0 * 3 , 1= b =0,2m ~ chnh y: 3 / 23 / 2max1.KK KBvQP= Trong : -Qmax = 0,116 m3/s -B = 1,3. -v = 0,3m/s. -K = Qmin/Qmax = 167/417 = 0,4 Vy: 3 / 23 / 14 , 0 14 , 0 1.3 , 0 * 3 , 1116 , 0= P= 0,2m ~ Th tch phn cha cn ca b lng ct ngang: 1000*o tbq QW =Trong : -Qtb = 4000 m3/ng -q0: lng ct trong 1000 m3 nc thi, q0 = 0,15 m3 ct/1000 m3 nc thi Vy: 100015 , 0 * 4000= W = 0,6 m3/ngay.d Phn lng ct c b tr pha trc ca b lng ct ngang. Trn mt bng c dng hnh vung, kch thc 1,1 x 1,1m, su H + 0,64m = 0,3 + 0,64 = 0,94m Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 37 Phn lp m rt nc c su 0,64m. ~ Hm lng cht l lng, COD v BOD ca nc thi sau kh qua b lng ct gim 5% v cn li -CSS2 = CSS1 (100 5)% -CSS1 = 245 mg/l, hm lng cht l lng khi qua chn rc CSS2 = 245 (100 5)% = 233 mg/l -CCOD2 = CCOD1 (100 5)% -CCOD1 =540 mg/l, hm lng COD ban u CCOD2 = 540 (100 5)% =513 mg/l -CBOD2 = CBOD1 (100 5)% -CBOD1 = 259 mg/l, hm lng BOD khi qua chn rc CBOD2 = 259 (100 5)% = 246 mg/l 2.2.3. B vt du m Ncthicamtsxnghipnung,chbinbsa,cclm,xnghippdu... thng c ln du m. Cc cht ny thng nh hn nc v ni ln trn mt nc. Nc thi sau x l khng c ln du m mi c php cho chy vo cc thy vc. Hn na, nc thi c ln du m khi vo x l sinh hc s lm bt cc l hng vt liu lc, phin lc sinh hc v cn lm hng cu trc bn hot tnh trong aerotank... Ngoi cch lm cc gt n gin bng cc tm si qut trn mt nc, ngi ta ch to ra cc thit b tch du, m t trc dy chuyn cng ngh x l nc thi. Tnh ton: Chiu di cng tc: L = K.(v/umin).h. -K: h s ph thuc dng chy, ph thuc (v/umin). Hnh Thit b tch du, m lp mng 1. Ca dn nc ra;2. ng gom du, m;3. Vch ngn;4. Tm cht do x5. Lp du;6. ng dn nc thi vo;7. B phn lng lm t cc tm gn 8. Bn cn Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 38 v/umin 101520 K1.51.651.75 -Cng thc Stock xc nh umin:( )2.181h n h md g u =9d: ng knh du. 9pn, pd: t trng ring ca du v nc. (g/cm3). 9: nht nc thi ( 200c: =0,01). Din tch tit din ngang: f = Q/v. Chiu su cng tc: h = f/B. (B: b rng b) Dung tch: W = B. L .h. Thi gian lng: t = L/v. V d p dng: Hy tnh ton b vt du m cho h thng x l nc thi c cng sut 200 m3/ngy,Chn thi gian lu nc l 2h( ) h 3 5 . 1 Ti trng b mt 40 (m3/m2.ng.) Chn kiu thit k di : rng l 1 : 4 Th tch ca b lng: V =Q*T = 200*2 = 400 (m3/m2.ng.) = 16.67 (m3/h) Din tch b mt: ( )2540200mUQFo= = =Chiu rng b mt: ( )() m Bm B B B L B F12 . 15 * 4 * 4 * *2 2= = = = = Ly B = 1.2 mChiu di L = 4*B = 4.8 mDin tch F = 5.76 m2 Ti trng b mt 72 . 3476 . 5200= = =FQUo(nmtronggiihnchophpbng4-3schtnhtonthitkcccngtrnh XLNT) Chiu cao b: 98 . 276 . 567 . 16= = =FVhm Chn h = 2.9m Th tch b lng: V = F*h = 5.76*2.9 = 16.7 m3 Thi gian lu nc trong b hQVT 2242007 . 16= = =Vn tc nc chy trong vng lng: ( ) s mh BQv / 0007 . 09 . 2 * 2 . 1 * 86400200*= = =Hiu qu kh BOD % 48 . 342 * 02 . 0 018 . 02=+=+=bt atRBOD Hm lng BOD cn li sau khi qua b lng 1 ( ) ( ) ( ) l mg BOD BODdv/ 5 . 314 % 48 . 34 100 480 % 48 . 34 100 * = = =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 39 Hm lng COD cn li sau khi qua b lng 1: BOD = BODv*( 100 34.48)% = 672*( 100-34.48)% = 440.3( mg/l) 2.2.4. X l bng phng php lng 2.2.4.1. C s l thuyt lngLng l qu trnh tch khi nc cn l lng hoc bng cn hnh thnh trong giai on keo t to bng hoc cc cn bn sau qu trnh x l sinh hc Trong cng ngh x l nc thi qu trnh lng c ng dng : Lng ct, sn, mnh kim loi, thu tinh, xng, ht st,.. b lng ct. Loi b cht l lng b lng t 1. Lng bn hot tnh hoc mng vi sinh vt b lng t 2. Hai i lng quan trng trong vic thit k b lng chnh l tc lng v tc chy trn. thit k mt b lng l tng, u tin ngi ta xc nh tc lng ca ht cn c loi v khi t tc chy trn nh hn tc lng. Tnh cht lng ca cc ht c th chia thng 3 dng nh sau : Lng dng I: lng cc ht ri rc. Qu trnh lng c t trng bi cc ht lng mt cch ri rcvtclngkhngi.Cchtlngmtcchringlkhngckhnngkeot, khng dnh bm vo nhau sut qu trnh lng. c th xc nh tc lng dng ny c thngdngnhlutcincaNewtonvStoketrnhtcn.Tclngdngny hon ton c th tnh ton c. Lng dng II:lng bng cn. Qu trnh lng c t trng bi cc ht ( bng cn) kt dnh vi nhau trong sut qu trnh lng. Do qu trnh bng cn xy ra trn cc bng cn tng dn kch thc v tc lng tng. Khng c mt cng thc ton hc thch hp no biu th gi tr ny. V vy c cc thng s thit k v b lng dng ny, ngi ta th nghim xc nhtcchytrnvthigianlnghiuqukhbngcnchotrctctlngth nghim, t nhn vi h s quy m ta c tc chy trn v thi gian lng thit k. Lng dng III: lng cn tr. Qu trnh lng c t trng bi cc ht cn c nng cao (> 1000mg/l). Cc ht cn c khuynh hng duy tr v tr khng i vi cc v tr khc, khi c khi ht nh l mt th thng nht lng xung vi vn tc khng i. Lng dng ny thng thy b nn bn. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 40 VVIV12345III67VI III8910M HNH TH NGHIM CC BC TIN HNH. Chun b thng cha nc thi v khuy trn u nc thi. Chun b ct lng hnh hpBm nc th vo ct lng : V lng 1 pht. Ly mu nc kim tra c (SS) cc su khc nhau ng vi thi im khc nhau (5, 10, 15, 20, 40, 60, 90 pht, cho n khi SS = 0) cc su khc nhau: 1.8, 1.4, 1.0, 0.6, 0.4 m Sau khi o c ta tnh ton hiu qu lng theo cng thc sau: R% =( 1-C1 / C0 ) x 100%. 9R%:hiu qu mt chiu su tng ng vi mt thi gian lng%. 9C1 :hm lng SS thi gian t su h, mg/L. 9C0 :hm lng SS ban u, mg/L. Lp bng kt qu o SS Cao (m) Co (mg/l) 5 (pht)101520406090 0.2 0.6 1.0 1.4 1.8 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 41 Lp bng hiu qu sau khi lng tnh ra % (R) Cao (m) 5 (pht)101520406090 0.2 0.6 1.0 1.4 1.8 KT QU THNGHIM Dng th vi trc honh biu th thi gian ly mu, trc tung biu th chiu su. V biu hiu qu lng. Ni suy cc ng cong hiu qu lng bng cch ni cc im c cng hiu qu lng nh m hnh gi sau: h T giao im gia ng cong hiu qu lng v trc honh, xc nh tc chy trnV0 = H / ti . Trong H l chiu su ct (2m), ti l thi gian ly mu c xc nh t giao im ng cong hiu qu lng v trc honh. Vngthngngtti.chiucaoH1,H2 .Tngngvicctrungimonthng gia ng thng ti v cc ng cong hiu qu. Hiu qu lng tng cng thi gian ti c tnh nh sau: RTi=Ra + H1/ H ( Rb- Ra ) +H2 ( Rc-Rb ) + .. 2.0 m1.8 m1.6 m1.4m1.2 m1.0 m0.8 m0.6 m0.4 m0.2 m0.0 m5. 10 15 20 40 60 90100 pht su (m) 25 3540 Ra = 55% 80 95100%HaHbHc HdHe t2 = 30 t1 = 18 t3 = 37.5 t4= 50 t5 = 62.5t6 = 82.5 t7 = 100 21b aH HH+=Rb = 65%BIU HIU QU LNG NI SUY NG CONG Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 42 0204060801000 0.02 0.04 0.06 0.08 0.1 0.12Van toc lang (van toc chay tran) (m/p)Hieu qua lang (%) oth bie u die n mo i quan hegi a hie u quala ng vato c ocha ytra n o th bieu dien moi quan he gia hieu qua lang va thi gian lang 0204060801000 20 40 60 80 100Thi gian lang (phut)Hieu qua lang (%)T cc s liu tnh ton trn xy dng biu hiu qu lng theo thi gian lu nc v hiu qu lng theo tc chy trn. Thaibiutrnvihiuqulngyucucthxcnhthigianluncvtc chy trn thit k. 2.2.4.2. Cc loi b lng 2.2.4.2.1. B lng hnh trn Trongblnghnhtrn,ncchuynngtheohngbnknh.Tutheocchchyca dng nc vo v ra m ta c cc dng b lng trn khc nhau. a)B lng trn phn phi nc vo bng bung phn phi trung tm b)B lng trn phn phi vo bng mng quanh chu vi b v thu nc ra bng mng trung tm Nc ra Nc voX cn Nc raX cnNc vo Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 43 c) B lng trn phn phi nc vo v thu nc ra bng mng t vng quanh theo chu vi b. Tuy nhin, trng hp a thng dng hn v ngi ta thch dng hn. Trong trng hp a c th a nc t y hay t thnh b. Bung trung tm c d= 15-20% Db. Chiu cao tr: 1-2,5m. y b c dc : 1/12. 2.2.4.2.2. B lng ngang (HCN) Ncthiivovngphnphinctublng,quavchphnphi,nc chuyn ng u nc vo vng lng, thng cu to dng mng c l. Vi:- h1: chiu su lm vic. - h2: chiu cao lp cha cn. - h3: chiu cao lp nc trung ho (=0,4m). - h4: chiu cao thnh b cao hn mc nc(0,25-0,4m). Hxd = h1 + h2 + h3 + h4 - i = 0,01-0,001. - dc h thu khng nh hn 45o. - B lng t 1 c chiu cao p lc x cn >=1,5m. - Tm chn cao hn mt nc 0,15-0,2m v su hn so vi mc nc langV HQ 5 Trong -Qtbngy: lu lng tnh ton trung bnh theo ngy. -hcng tc : chiu cao cng tc, hcng tc = 2(m).-Vlng : vn tc vng lng (m/s) Vlng = B LQ= 86400 4 141500 = 0.0003 (m/s) L >) ( 7 , 586400 0003 . 0 2 51500m L = (*) Theo gio trnh TTTKXLNT-TXLai, th : L = 2nl (**) Vi n : s mng trong b. l = 4(m) : chiu di mng.T (*) & (**) : 2nl > 5,7 n > 87 , 5= 0,71 chn n = 1 Th tch mng: Chn s b : DRC = 40,50,3 = 0,6 (m3) Ti trng mng : qmng = lQ= 41500= 375 (m3/m ngy ) Tha k qmng = 124 490 (m3/m ngy) Vn tc nc chy vo mng : Vmng (m/s) ) ( 10 065 , 7403 , 0 14 , 342 42 2mdSl === ) ( 9810 065 , 7069 , 04loSSnlpp== =) ( 330 ) ( 33 , 012412mm mBed= = = =) ( 310 ) ( 31 , 085 , 0 385 , 0mm mHen= ===Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 50 Vmng = FQ ViF:din tch mng, F = D R = 4 0.5 = 2 (m2) Vmng =86400 21500= 0,0086 (m/s) Theo (1), trang 50 th Vmng < VH : vn tc ti hn M( )2 / 11 8 =fd g KVH Vi-K : hng s thuc tnh cht cn, nc thi cng nghip vi K = 0,06 - : t trng ca ht, chn = 1,25 -g : gia tc trng trng, g = 9,8 (m/s2) -d : ng knh ht cn, d = 10-4(m) -f : h s ma st, f = 0,025 VH = 2 / 1425 , 010 8 , 9 ) 1 25 , 1 ( 06 , 0 8 = 0,0685 (m/s) Vng nn cn. Th tch vng nn cn. Vi: -T : thi gian gia hai ln x cn, ( theo quy phm 6 24 h) chn T = 8 h. -C : hm lng cn cn li sau khi lng, (theo quy phm 1012 mg/l), chn C = 10 (mg/l). - : nng trung bnhcacn nn,trabng3.3/78schXLNC ca PTSNguyn NgcDung chn= 25.000( mg/m3) -Cv: hm lng cn trong nc a vo b lng, Cv = 194 (mg/l) ( theo tnh ton phn b tuyn ni). -H : hiu qu lng, H = 75%. Chiu cao vng nn cn. H thng x cn. Th tch cn cn x sau 8h.Vx = Wc = 2,91 (m3). Lng nc cn c pha long trong khi x. V = K Vx

-Theo quy phm lu lng x = 30% 60% Vx, 100) ( = = vtbgio vtbgiocC H Q T C C Q TW) ( 91 , 2100 000 . 25194 75 5 , 62 83m Wc= = ) ( 05 , 05691 , 2mFWhcc = =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 51 Chn lu lng x l 50%Vx -Theo quy phm thi gian x = 20 40 pht, Chn thi gian x l 20 pht. -K : h s pha long khi x cn bng thu lc ( iu 6.5.4 TCXD -51-84) K =0,5. V = 0,5 2,91 =1,455( m3). Lu lng cn x. Tng tit din ng x. Chn vn tc nc qua l vx = 1,5 (m/s). ng knh ng x. Chn ng x c ng knh Dx = 35(mm). dc y b chn i = 0,02. H thng thu nc b mt. Tit din ng thu. Chn-Tit din ng thu ln hn lu lng tnh ton t 20 30% chn tit din ng thu ln hn lu lng tnh ton 20%. -Vn tc nc chy qua ng thu vo theo quy phm 0,6 0,8 m/s vo = 0,6 (m/s). ng kinh ng thu. Chn Do = 200 (mm). Cc thng s ca b. Chiu di b. Lb = L + Lpp = 14 + 1 = 15 (m) Vi-Ll: chiu di vng lng, Ll = 14 (m) -Lpp :chiu di t u b n vch phn phi. Chiu cao b:H = 3(m). Chiu rng b: B = 4(m). ) / ( 0012 , 020 60455 , 13s mtVQx== =) ( 0008 , 05 , 10012 , 02mvQSxxx= = =) ( 032 , 014 , 30008 , 0 4 4mSDxx===) ( 164 ) ( 164 , 014 , 3021 , 0 4 4mm mSDoo= ===) ( 021 , 0 0174 , 010020 0174 , 0100202m SSSo= += +=Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 52 2.2.5. Xl bng phng php lc 2.2.5.1. Nguyn l ca qu trnh lc 2.2.5.1.1. Khi nim Lc l qu trnh tch cc cht lng l lng ra khi nc khi hn hp nc v cht rn l lng i qua lp vt liu l ( lp vt liu lc), cht rn l lng s c gi li v nc tip tc chy qua. y l giai on (cng trnh) cui cng lm trong nc. 2.2.5.1.2. Phn loi b lc Theo tc : 9B lc chm: c tc lc 0.1 0.5 m/h 9B lc nhanh: vn tc lc 5 15 m/h 9B lc cao tc: vn tc lc 36 100 m/h Theo ch lm vic: 9B lc trng lc: h, khng p. 9B lc c p lc : lc kn, Ngoi ra cn chia theo nhiu cch khc nhau theo chiu dng chy, lp vt liu lc, theo c ht vt liu lc, cu to ht vt liu lc, 2.2.3.1.3. Vt liu lc 9Ct thch anh nghin. 9Than antraxit (than gy) 9Si, 9Polime xc nh vt liu lc phi da vo mt s ch tiu: bn c hc bn ho hc: trnh tnh xm thc. Kch thc ht Hnh dng ht. H s khng ng nht:K= d80/d10 (Trong : d80, d10 : kch thc c ht sng lt qua 80%, 10% tng s ht). 2.2.5.2. Tnh ton cc loi b lc 2.2.5.2.1. B lc Biu thnh phn vt liu lc qua sng S v nguyn tc lm vic ca b lc chm 1.B lc 2.Ngun nc 3.p ly nc 4.Ca a nc vo 5.Ca thu nc ra 6.B cha bc sch 7.Ct lc 8.Si 9.Sn thu nc 10.Van iu chnh tc lc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 53 Nc t mng phn phi i vo b, qua lc (nh hn 0.1 0.5 m/h). lp ct lc trn lp si , di lp si l h thng thu nc lc. Lp ct lc : thch anh c chiu dy ph thuc vo c ht: 0.3 1 mm=>h = 800 mm 1 2 mm => h = 50 mm Ngoi ra cn dng si hoc dm: 2 20 mm => h = 100 mm 20 40 mm => h = 150 mm Tm li: c 6 lp: Chiu caolp vt liu lc (mm) Tn vt liu lcKchthcvt liu lc (mm) 800Ct thch anh0.3 1 50Ct thch anh1 2 100Si hoc dm2 5 100Si hoc dm5 10 100Si hoc dm10 20 100Si hoc dm20 -40 Lp nc trn lp ct : 1.5 m u im : To lp mng gip lc tt. Dng x l nc khng phn Khng dng my mc. Qun l n gin Nhc im: Din tch ln Vn tc lc thp B lc chm s dng vi cng sut nh hn hoc bng 1000 m3/ngy m; SS nh hn hoc bng 50 mg/l; M < 50o B lc chm c dng hnh vung, n 2; i 5% TNH TON 1.Din tch b mt b lc chm: F = Q / v ( m2) Q : lu lng nc x l (m3/h) V : vn tc lcph thuc vo SS vo b: SS 25 mg/l v = 0.3 0.4 m/h SS 25 mg/l v = 0.2 0.3 m/h Nc ngm v = 0.5 m/h 2.S b lc c xc nh theo phng trnh sau: Trong : Vtc : vn tc lm vic ca b khi c mt ngn ngng hot ng. (Tc lc tng cng ph thuc vo SS ) SS 25 mg/l : vtc= 0.4 0.5 m/h SS 25 mg/l : vtc = 0.3 0.4 m/h X l nc ngm : vtc = 0.6 m/h 3.Chiu cao: H = ht + hd + hn + h c + hp tcv vNN 1Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 54 ht: chiu dy lp sn y thu nc lc 0.6- 0.5 m hd : chiu dy lp si 0.45 m hc: chiu cao lp ct lc 0.85 m hn : chiu cao lp nc (0.8 1.8 m) hp : chiu cao d phng (0.3 0.5m) 4.Cng ra lc: qo: lng nc lc qua 1 m2 b trong 1 gi (m3/m2.h). (qo = Q/F) n: tng s ngn tp trung. 5.Dung tch nccho mt ln ra mt ngn: fn: din tch1 ngn (b, l : chiu rng v chiu di ca mt ngn) 6.Thi gian ra: 10 20 pht. 2.2.5.2.2. B lc nhanh Nguyn tc hot ng Nclct b lng ngang, quamng phn phi vo blc, qua lp vt liu lc, lp si vo h thng thu nc trong v c a v b cha nc sch. TNH TON: B lc phi tnh theo hai ch lm vic, ch bnh thng v tng cng. Khi n 20 b d tr mt b n 20 b d tr 2 b 1.Tc lc : Ph thuc ng knh ht. a. B lc 1 lp lc : (ct thch anh) ( )2. / 26 . 31 m s ln qqor = ) (1000. .3mt f qWn n rr =( )3.mnl bfn =Hnh : B lc nhanh trng lc 1.ng dn nc t b lng sang 2.H thng thu nc lc v phn phi nc ra lc 3.ng dn nc lc 4.ng x nc ra lc 5.Mng phn phi nc lcv thu nc ra lc 6.ng dn nc ra lc 7.Mng thot nc 8.Mng phn phi nc lc 9.ng x nc lc u 10.Van iu chnh tc c lc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 55 dt H s khng ng nht K hlc vtb Vtc(m/h) 0.7 0.8 8 1.0 1 1.2 2 2.2 1.8 -2 1.5 1.7 700 800 1200 1300 1800 2000 5.5 6 7.0 8 8 10 6 7.5 8 10 10 12 b. B lc ct hai lp (ct thch anh v angtraxit) dt Hskhngng nht K hlc vtb Vtc(m/h) 7.0 8.02 2.2700 8008 1010 12 1 1.22 2.2400 -500 2.Thi gian ca mt chu k lc ch tng cng Ttc( N 20) Ttc [ N (N1 + a)].t2 N: s b lc N1: s b ngng sa cha a: s b lc ra ng thi t2 : thi gian ngng b lc ra: (t2 = 0.35 gi) 3.Din tch trm x l: T : thi gian lm vic ca trm /ngy(h) a: s ln ra 1 b / ngy m t1 : thi gian ra lc (h) (3 7 pht) W : cng nc ra lc ( l/s.m2) 4. S lng b lc cn thit : N = 0.5 (F)0.5 5.Ttc lc tng cng: + vtc theo (1) vtc cho theo bng 6. Chiu cao b lc: H = h + hv + hn + hp (m) h : chiu cao lp : ( ph thuc vo c ht 50 100mm) hv: chiu dy lp vt liu lco1 lp : 700 2000 mm o2 lp : 1100 1300 mm hn : chiu cao lp nc trn lp vt liu lc (m) (2 m) hp : chiu cao d phng (m) ( 0.3 m) 7.lng nc ra lc cn thit: f : din tch b lc f = F/N W : cng nx ra lc. ( )22 1. . . . 6 , 3 .mv t a t W v TQFtb tb =) 1 (1 =NNv vbt tb) / (1000.3h mW fQr =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 56 220040015040035010008.c Qr chn ng knh tnh phn phi s ng Xc nh tng din tch l, trn c s tit din ngang ca ng: = (30 40%) Chn ng knh l ng nhnh s l ng nhnh . 2.2.5.2.3. B lc p lc B lc p lc l mt loi b lc khp kn, thng c ch to bng thp c dng hnh tr ng v hnh tr ngang. Blcplccsdngtrongdychuynxlncthi(cuidychuyncng ngh ). Do b lm vic di p lc, nn nc cn x l c a vo trc tip t trm bm vo b, ri a trc tip vo ngun tip nhn. Cu to: ging b lc nhanh Nguyn tc lm vic:Nc a vo b qua 1 phu b tr nh b, qua lp ct lc, lp vo h thng thu nc trong, i vo y b v vo ngun tip nhn. Khi ra b, nc t ng ng p lc chy ngc t di ln trn qua lp ct lc v vo phu thu, chy theo ng thot nc ra xung ng thu nc ra lc V d p dng: Tnh b lc chm cho cng trnh x l nc cng sut 90m3/ngy B lc c cu to nh hnh, bao gm Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 57 a.Tnh tan kch thc b lc chm Theo kt qu th nghim, vn tc nc trong b lc chm ly bng vlc = 0.64m/h Din tch mt ct ngang ca b lvQF =Trong : Q: lu lng nc x l, Q = 3.75 m3/h vl: tc lc, vl = 0.64m/h ) ( 86 . 564 . 075 . 32mvQFl= = =Chn b hnh ch nht c kch thc L x B = 2.5m x 2.4m = 6m2. Vt liu lc l , si, ct thch anh, than hot tnh. Chiu cao lp vt liu lc Ct c d = 1-2mm, chiu cao hc = 40cm. Si c d = 1-2mm, chiu cao hs = 20cm. c d = 1-2mm, chiu cao h = 20cm. Than c chiu cao hth = 20cm. Vy chiu cao tng cng ca lp vt liu: Hvl = 100cm = 1.0m Chiu cao lp sn y thu nc lc, h = 0.3m Chiu cao lp nc pha trn (0.8 1.8m), chn hn = 0.8m Chiu cao bo v (0.3 0.5m), chn hbv = 0.3m Vy chiu cao tng cng ca b lc H = hvl + h + hn + hbv = 1 + 0.3 + 0.8 + 0.3 = 2.4 m b.Tnh ton h thng phn phi nc ra lc i vi b lc hai lp th ct v than rt d xo trn ln nhau do ch dng bin php ra bng nc thun ty. Cng ra lc: Wr = 15 l/sm2 Thi gian ra lc: tr = 6 pht Chu k ra lc: T = 45h Lu lng nc ra lc 1234561.Ong dn nc t b lng 2.Ong x nc ra lc 3.Mngphnphinclcv thu nc ra lc 4.Ong dn nc ra lc 5.Mng tp trung nc 6.vt liu lc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 58 ) / ( 88 ) / ( 0879 . 0100015 * 86 . 51000*3s l s mW FQrr = = =Vi: F: din tch mt b lc Wr: cng ra lc Chn ng knh ng chnh dc = 300mm bng thp th tc nc chy trong ng chnh l vc = 1.25m/s (nm trong gii hn cho php 2m/s). Vi ng knh ng chnh l 300mm th tit din ngang ng chnh l: ) ( 07 . 043 . 0 * 14 . 3422 2mdfc= = = Chnkhangcchgiacc ng nhnhl 0.25m(quyphmchophp0.250.3m)thsngnhnh ca b lc l: 2 . 19 2 *5 . 2 . 04 . 22 *25 . 0= = =Bn(ng)Chn n = 20 ng Lu lng nc ra lc chy trong mi ng nhnh ) / ( 4 . 42088s l qnh= =Chnngknhngnhnhdnh=55mm=0.055mbngthpthtcncchytrongngnhnhvnh= 1.85m/s (nm trong gii hn cho php 1.8 2m/s). Tng din tch l ly bng 35% din tch tit din ngang ca ng (quy phm cho php 30 35%), tng din tch l tnh c l fl = 0.35 * 0.07 = 0.0245 (m2) Chn l c ng knh 10mm (quy phm 10 12mm), din tch mt l s l fl = 401 . 0 * 14 . 32 = 7.85.10-5 (m2) Tng s l 31210 . 85 . 70245 . 050= ==loloffn (l) S l trn mi ng nhnh =6 . 1520312= (l), chn 16 l. Trn mi ng nhnh, cc l xp thnh hai hng so le nhau, hng xung pha di v nghing mt gc 450 so vi mt phng nm ngang. S l trn mi hng ca ng nhnh l 8 l. c.Tnh tan mng thu nc ra lc B lc c chiu di 2.5m, b tr 2 mng thu nc ra lc c y hnh tam gic. Khang cch gia cc mng d = 2.5/2 = 1.25m. Lu lng nc ra thu vo mi mng qm = Wr*d*l (l/s) trong : Wr: cng ra lc, Wr = 15 l/sm2 d: khang cch gia cc tm mng, d = 1.25m. l: chiu di ca mng, l = 1.9m qm = 15 * 1.25 * 1.9 = 35.625(l/s) = 0.035625 (m3/s) Chiu rng mng thu nc ra lc Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 59 532) 57 . 1 ( aqK Bmm+=(m) Trong :a: t s gia chiu cao phn ch nht (hCN) vi na chiu rng ca mng, ly a = 1.1 (quy phm a = 1 1.5). K: h s i vi tit din mng hnh tam gic, K = 2.1 ) ( 307 . 0) 1 . 1 57 . 1 (035625 . 01 . 2 532m Bm=+= ) ( 16885 . 021 . 1 * 307 . 02*2ma BhBhamCNmCN= = = =Vy chiu cao phn mng ch nht l: hCN = 0.16885m.Ly chiu cao phn y tam gic l h = 0.1m. dc y mng ly v pha mng tp trung nc l i = 0.01.Chiu dy thnh mng ly l m = 0.06m. Vy chiu cao tan phn ca mng thu nc ra l Hm = hCN + h +m = 0.16885 + 0.1 + 0.06 = 0.3289m Khang cch t b mt lp vt liu lc n mp trn ca mng nc xc nh theo cng thc ) ( 25 . 0100*me LHm+ = Trong : L: chiu dy lp vt liu lc, L = 0.6m. e: gin n tng i ca lp vt liu lc, ly theo bng (4-5) (sch X l nc cp), e = 50% ) ( 253 . 0 25 . 0100% 50 * 6 . 0m Hm= + = Theo quy phm, khang cch gia y di cng ca mng dn nc ra phi nm cao hn lp vt liu lc ti thiu l 0.07m. Chiu cao tan phn ca mng thu nc ra l Hm = 0.3289m, v mng dc v pha mng tp trung i = 0.01, mng di 2.4m nn chiu cao mng pha mng tp trung l: 0.3289 + 0.024 = 0.353m. Vy mH = 0.353 + 0.07 = 0.423(m) Nc r lc t mng thu trn vo mng tp trung nc. Khang cch t y mng thu n y mng tp trung xc nh theo cng thc ) ( 2 . 0*75 . 1322mA gqhMm+ =Trong : qM: lu lng nc chy vo mng tp trung nc, qM = 0.088 m3/s. A: chiu rng ca mng tp trung, chn A = 0.5m. g: gia tc trng trng, g = 9.81m/s2 ) ( 457 . 0 2 . 05 . 0 * 81 . 9088 . 075 . 1322m hm= + = d.Tnh tn tht khi ra b lc Tn tht p lc trong h thng phn phi bng gin ng khoan l Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 60 ) (2 22 20mgvgvhnp+ = Vi: v0: tc nc chy u ng chnh, v0 = 1.25m/s. vn: tc nc chy u ng nhnh, vn = 1.85m/s. g: gia tc trng trng, g = 9.81m/s2. : h s sc cn 12 . 22 + =kWkW: t s gia tng din tch cc l trn ng hoc mng v din tch tit din ngang ca ng hoc mng chnh, kW = 0.35. 96 . 18 135 . 02 . 22= + = ) ( 68 . 181 . 9 * 285 . 181 . 9 * 225 . 196 . 182 2m hp= + = Tn tht p lc qua lp si ) ( * * 22 . 0 m W L hr s d =Trong :Ls: chiu dy lp si , Ls = 0.4m. Wr: cng ra lc, Wr = 15l/sm2. ) ( 32 . 1 15 * 4 . 0 * 22 . 0 m hd= = Tn tht p lc qua lp vt liu lc ) ( * * ) ( m e L aW a hr VL+ =Vi kch thc ht d = 1mm, a = 0.76 v b = 0.017 ) ( 3 . 0 % 50 * 6 . 0 * ) 15 * 017 . 0 76 . 0 ( m hVL= + = Tn tht p lc trong ni b b ) ( 3 . 3 3 . 0 32 . 1 68 . 1 m h h h hVL d p= + + = + + = Thng s thit k b lc chm STTTn thng sS liu dng thit kn v 1Chiu cao b tng cng2.4m 2Kch thc b lcL*B=2.5*1.9m2 3ng knh ng phn phi nc0.05m 4S mng thu nc ra lc2mng 5S ng phn phi nc ra lc20ng 6Chiu cao mng thu0.345m 7Chiu rng mng0.337m V d p dng 2: Tnh ton b lc p lc cho cng trnh x l nc thi thy sn cng sut 300m3/ngy (thi gian hot ng ca nh my l 8 gi) Chn b lc p lc hai lp than Anthracite v ct thch anh. Cc thng s thit k c chn: Chiu cao lp ct: h1 = 0,3 (m). ng knh hiu qu ca ht ct de = 0,5 mm, h s ng nht U = 1,6 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 61 Chiu cao lp than: h2 = 0,5 (m). ng knh hiu qu ca ht ct de = 1,2 mm, h s ng nht U = 1,5 Tc lc v = 9 (m/h) v s b lc n = 2. Din tch b mt lc: ( )22 , 495 , 37mvQAhtb= = = ng knh bn lc p lc: () mnAD 6 , 114 , 3 22 , 4 4 4=== Chn D = 1,6 m Khong cc t b mt vt liu lc cho n ming phu thu nc ra lc: ( ) () m e H hvl65 , 0 25 , 0 5 , 0 5 , 0 3 , 0 25 , 0 = + + = + = Trong : Hvl: chiu cao lp vt liu lc: bao gm chiu cao lp ct v chiu cao lp ct (m) e: gin n ca vt liu khi ra: e = 0,25 0,5, chn e = 0,5 Chiu cao tng cng ca bn lc p lc H= h + Hvl + hbv + hthu = 0,65 + 0,8 + 0,25 + 0,3 = 2 (m) Trong : hbv: chiu cao bo v t mng thu nc n np y pha trn (m), hbv = 0,25 (m) hthu: chiu cao phn thu nc (m), hthu= 0,3 (m). Tnh lu lng kh: Da vo bng9 14 (trang 427 XLNT cng nghip v th Lm Minh Trit) Tc ra nc vn = 0,35 m3/m2.pht Tc ra kh vk = 1 m3/m2.pht Ra ngc chia lm 3 giai on (1) Ra kh vi vk = 1 m3/m2.pht trong 1 2 pht (2) Ra kh v nc trong 4 5 pht (3) Ra ngc bng nc trong 4 5 pht vi vn = 0,35 m3/m2.pht. Lng nc ra lc cn thit cho 1 bn lc/1 ln ra: ) / ( 35 , 7 10 35 , 022 , 43be m t v A Wn n= = = Lu lng bm nc ra ngc: ) / ( 1 , 44 ) / ( 60 35 , 022 , 43h m h phut v A Qn n= = =

Lu lng my thi kh ra ngc: ) / ( 126 ) / ( 1 , 2 ) 122 , 43 3h m phut m v A Qk k= = = =

Tnh tn tht p lc qua lp vt liu lc; Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 62 heovdLT ch + =242 8 , 160 1 Trong : C: h s nn p, C = 600 1200, chn C = 1000 To: nhit nc (oC) de: ng knh hiu qu (mm) vh: tc lc (m/ngy) L : chiu dy lp vt liu lc (m) i vi lp ct: ) / ( 18 , 01) ( 2495 , 03 , 042 25 8 , 160100012ngay mngayhhc= + = i vi lp than:) / ( 052 , 01) ( 2492 , 15 , 042 25 8 , 160100012ngay mngayhhth= + = Tn tht qua 2 lp vt liu lc: htt = hc+ hth = 0,18 + 0,052= 0,232 (m/ngy) Sau b lc p lc hm lng cn l lng SS cn li khong 7 mg/l, tng ng BOD5 ca cn l lng: ( ) l mg SS BODsau ll/ 6 , 4 72 , 0 42 , 1 65 , 05= = Lng BOD5 sau b lc p lc: ( ) l mg BOD BOD BODll ht sau/ 97 , 22 6 , 4 37 , 185 5 5= + = + = 2.3. B iu ha 2.3.1. B iu ho lu lng v cht lng 9t sau b lng ct, trc b lng t 1 9B iu ho c nhim v iu ho lu lng v cht lng nc thi. 9Trong b c h thng khuy trn m bo ho tan v san u nng , trnh lng cn. 9Nng cht bn sau khi ra khi b iu ho tng thi im: Vi: - Q: lu lng TB ca nc thi (m3/h). - Ct, Ct+1: nng bn ra khi b thi im t v t+1 (mg/l). - Ct, qt: nng v lu lng chy vo b trong thi gian t (t = 1h). - Wt+1: dung tch nc trong b thi im t+1. 9Lu lng khng kh cn:Qkk = n . qkk . L Vi:Qe Q C e q CCttttWQtWQt tt1 1. . 1 .1+ ++= +Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 63 -n: s b -qk: cng thi kh 2-4m3/mh. -L: chiu di ng thi bng chiu di b (m). 2.3.2. B iu ho ch yu lm nhim v iu ho lu lng 9t sau SCR, khng i hi c thit b khuy trn. - Th tch: xc nh nh b cha nc sch. - Vt liu: BTCT. V d p dng: Tnh b iu ha lu lng cho cng trnh x l nc thi 4870m3/ngy cho mt th trn Gii: Th tch tch lu b iu ho c xc nh da vo th tch tch lu vo b qua cc gi v th tch tch lu bm i qua tng gi vi lu lng bm bng lu lng trung bnh gi.Th tch tch lu dng vo gi th I c xc nh: Vv(i) = Vv(i-1) + Qi Trong :Vv(i-1) Th tch tch lu dng vo ca gi trc , m3;Qi Lu lng nc thi ca gi ang xt, m3/h;Th tch tch lu bm i ca gi th i:Vb(i) = Vb(i-1) + Qb(i) Trong :Vb(i-1) Th tch tch lu bm i ca gi trc Qb(i) Lu lng bm ca gi ang xt, m3/h;Kt qu tnh ton c th hin qua bng sau: Cc gi Q (m3/h) Th tch tch lu vo b (A), m3 Th tch tch lu bm i (B), m3 Hiu s th tch (A) (B), m3 0 192,858392,8583232,629139,771 1 292,8583185,7166465,258279,541 2 392,8583278,5749697,887419,312 3 - 492,8583371,4332930,516559,083 4 5106,5995478,03271.163,145685,112 5 6155,3055633,33821.395,774762,436 6 7322,233955,57121.628,403672,832 7 8243,43581.199,0071.861,032662,025 8 9337,6111.536,6182.093,l661557,043 9 10337,6111.874,2292.326.29452,061 10 11337,6112211,842.558,919347,079 11 12333,12422.544,9642.791,548246,584 12 13289,41752.834.3823.024.,177189,795 13 14258,1273.092,5093.256.,806164,297 14 15277,8553.370,3643.489,435119,071 15 16281,783.652,1443.722,06469,9203 16 17321,18453.973,3283.954,693-18,6352 17 18393,01554.366,3444.187,322-179,0217 18 19335,67354.702,0174.419,951-282,0662 19 20277,534.979,5474.652,58-326,9672 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 64 1.206301.54WFh= = =20 21239,3025.218,8494.885,209-333.6402 21 22155,23055.374,085.117,838-256,2417 22 23115,1625.489,2425.350,467-138,7747 23 2493,85835.583,15.583,10 Th tch l thuyt b iu ho bng hiu i s gi tr dng ln nht v gi tr m nh nht ca ct hiu s th tch tch lu:Vh(lt) =(762,436) ( -333,6402) = 1.096,076 (m3)Th tch thc t ca b iu ho:Vh(tt) = (1,1 1,2)* Vh(lt) Vh(tt) = 1,1 * 1.096,076 = 1.206 (m3) Chn chiu cao ca b l h = 4 (m) Din tch ca b : (m2)

Chn kch thc b iu ho l : L x B = 20m x 15mChiu cao xy dng ca iu ho:H = h + 0,5 = 4 + 0,5 = 4,5 (m)Vi 0,5 l chiu cao an ton.Vy th tch xy dng b iu ho:W = L*B*H = 20 * 15 *4 = 1.200 (m3) Lu lng kh cn cung cp cho b iu ho: trnh hin tng lng cn v ngn chn mi trong b iu ho cn cung cp mt lng kh thng xuyn.Qkk = qkk * W = 0,013* 1.200 = 15,6 (m3/pht)ViqkkLngkhcnthitxotrn,qkk=0,010,015m3/m3.pht,chnqkk=0,013 m3/pht, (Ngun: Tnh ton thit k cc cng trnh x l nc thi Trnh Xun Lai, 2000) ;Khng kh c phn phi qua h thng ng chm l vi ng knh 4 mm, khong cch gia cc tm l l 150 mm. Khi , s l phn phi trn mi ng nhnh l: (l)Vi din tch y b l 20 m x 15 m, ta cho cc ng sc kh t dc theo chiu di b, cc ng c t trn cc gi cao 20 cm so vi y b.Khong cch gia cc ng nhnh l 1,5 m, cc ng cch tng l 0,75 m. Khi , s ng nhnh c phn b (n ng) l: Vn tc kh ra khi l thng t5 20 m/s, chn vlo = 15 m/s. Lu lng kh i qua tng ng nhnh:(m3/pht) Lu lng kh i qua cc l sc kh: (m3/pht) Khi ng knh l :Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 65 (mm) Chn ng knh ca ng nhnh l 65 mm. Khi , vn tc kh trong ng nhnh l:(m/pht) Chn ng knhng chnh l 170 mm, khi vn tc kh trong ng chnh l: (m/pht) p lc cn thit cho h thng kh nn:Hc = hd + hf + hc +H Trong : hd Tn tht p lc theo chiu di trn ng ng dn, m; hc Tn tht qua thit b phn phi, m;Tn tht hd, hc khng vt qu 0.4 m. hf Tn tht cc b ca ng phn phi kh, m;Tn tht hf khng vt qu 0.5 m. Vy p lc tng cng l:Hc = 0,4 + 0,5 + 4 = 4,9 (m) p lc kh nn: Cng sut my nn: kwTrong : q Lu lng khng kh cn cung cp, q = 32,76 m3/pht = 0,546 m3/s;- Hiu sut ca my bm,= 0,7; S h thng sc kh b iu ho Cc thng s thit k b iu ho STT Tn thng s S liu dng thit k n v1 Chiu di b iu ho (L) 20 m2 Chiu rng b iu ho (B) 15 m3 Chiu cao b (H) 4,5 m4 S ng nhnh phn phi kh 10 ng5 ng knh ng nhnh 65 mm6 S l phn phn phi trn 1 ng nhnh 132 l7 ng knh ng chnh170 mmVdpdng2:Tnhtonthitkbiuhachocngtrnhxlncthinhmycaosucngsut 12,5m3/gi -Th tch b iu ha:Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 66 ( )3max5 , 62 5 * 5 , 12 * m t Q Vh= = = Trong : t: Thi gian lu nc thi trong b iu ha, chn t = 5h -Kch thc b iu ha:Chn b hnh ch nht. Chiu di b: Chn D = 6m Chiu rng b: Chn B = 4m Chiu cao b: () mD BVH 6 , 24 * 65 , 62*= = = Chn chiu cao bo v ca b l Hbv = 0,4m chiu cao tng cng (chiu cao xy dng): 2,6 + 0,4 = 3 (m) Th tch thc ca b iu ha: D B H = 6 4 3 = 72 (m3) -Lu lng kh cn cung cp cho b iu ha: = = =hm V qkk325 , 56 5 , 62 * 60 * 015 , 0 * Trong :qkk: tc cp kh trong b iu ha, v = 0,01 0,015 m3/m3.pht, chn qkk = 0,015 m3/m3.pht (Theo Tnh ton thit k cc cng trnh x l nc thi -Trnh Xun Lai 1999) V- dung tch b iu haChn h thng cp kh bng nha PVC c c l, h thng gm 1 ng chnh, 4 ng nhnh vi chiu di mi ng l 6m, t cch nhau 0,8m. -ng knh ng chnh dn kh vo b iu ha: () () m mVQongkkcD 045 , 0 0446 , 03600 * 10 * 14 , 325 , 56 * 43600 * ** 4 = = = Chn cD= 0,045m Trong : Vng: vn tc kh trong ng, Vng = 10 15m/s,chn Vng =10m/s-ng knh ng nhnh dn kh vo b iu ha: D = 6 mHbv= 0,4 m H = 2,6 m B = 4 m 0,8 mBi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 67 () () m mVqDongongn023 , 0 0223 , 03600 * 10 * 14 , 30625 , 14 * 43600 * ** 4 = = = Chn Dn = 0,023m Trong : qng: lu lng kh trong mi ng, ( )hmQqkkong30625 , 14425 , 564= = =-ng knh cc l phn phi kh vo b iu ha: dl = 2 5 mm Chn dl = 3 mm -Vn tc kh qua l phn phi kh: Vl = 15 20 (m/s) Chn Vl = 15 mm -Lu lng kh qua 1 l phn phi kh:= = =hdV qmlo lo32 238151 , 0 3600 *4003 , 0 * 14 , 3* 15 3600 *4** -S l trn 1 ng: N =86 , 3638151 , 00625 , 14= =loongqql Chn N = 36 l -S l trn 1 m chiu di ng: n = 66366= =Nl -Xc nh cng sut thi kh: N =) / ( 62 , 03600 75 , 0 10225 , 56 ) 1 34 , 1 ( 34400102) 1 ( 3440029 , 0 29 , 0h KWQ pk= = Cng sut bm: Nb = 1,2*N = 1,2*0,62 = 0,744 (Kw/h) 1,2: H s an ton. Chn 2 bm c cng sut 1 Kw/h, 1 bm chy, 1 bm ngh lun phin Trong : Qk: Lu lng kh cung cp. Qk = 56,25 (m3/h) : Hiu sut my bm, chn = 75% = 0,75 p- p lc ca kh nn 23 mm 1000 mm3 mm125mmBi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 68 p = ) ( 34 , 133 , 105 , 3 33 , 1033 , 10) 33 , 10 (atmHd=+=+ Vi: Hd: p lc cn thit cho h thng ng kh nn c xc nh theo cng thc:Hd = hd + hc + hf + H Trong : hd: Tn tht p lc do ma st dc theo chiu di ng dn, (m) hc: Tn tht cc b ca ng phn phi khTn tht hd + hc khng vt qua 0,4(m), chn hd + hc = 0,4 hf: Tn tht qua thit b phn phi, khng vt qu 0,5(m) Chn hf = 0,5 (m) H: Chiu cao hu ch. H = 2,6 (m) Vy: Hd = 0,4 + 0,5 + 2,6 = 3,5 (m) Cc thng s thit k b iu ha STTTn thng sS liu dng thit kn v 1Chiu di b (L)6(m) 2Chiu rng b (B)4(m) 3Chiu cao b (H)3(m) 4Thi gian lu nc5gi 5Cng sut my nn kh1KW/h 6Th tch xy dng b72m3 7Din tch xy dng24m2 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 69 Chng 3: X L NC THI BNG PHNG PHP HA L 3.1. PHNG PHP KEO T TO BNG 3.1.1. Keo t v cc ha cht dung trong keo t Trong nc tn ti nhiu cht l lng khc nhau. Cc cht ny c th dng phng php x l khc nhau ty vo kch thc ca chng: d > 10-4 mm : dng phng php lng lc. d < 10-4 mm : phi kt hp phng php c hc cng phng php ho hc. Tc l cho vo cc cht to kh nng dnh kt ko cc ht l lng lng theo => gi l phng php keo t trong x l nc. thc hin qu trnh ny ngi ta cho vo nc cc cht phn ng thch hp : Al2(SO4)3; FeSO4; hoc FeCl3. 9Phn nhm: cho vo nc chng phn ly thnh Al3+ ----------------> Al(OH)3 Al3+ + 3H2O == Al(OH)3 + 3H+ pH ca nc nh hng trc tip n qu trnh thu phn:pH > 4.5 : khng xy ra qu trnh thu phn. pH = 5.5 7.5 : t tt nht. pH > 7.5 : hiu qu keo t khng tt. Nhit ca nc thch hp vo khong 20-40oC, tt nht 35-40oC. Ngoi ra cc yu t nh hng khc nh : thnh phn Ion, cht hu c, liu lng 9Phn st : gm st (II) v st (III): a.Phn Fe (II) : khi cho phn st (II) vo nc th Fe(II) s b thu phn thnh Fe(OH)2. Fe2+ + 2H2O == Fe(OH)2 + 2H+ Trong nc c O2 to thnh Fe(OH)3 pH thch hp l 8 9=> c kt hp vi vi th keo t tt hn. Phn FeSO4 k thut cha 47-53% FeSO4. b.Phn Fe (III):Fe3+ + 3H2O = Fe(OH)3 + 3H+ Phn ng xy ra khi pH > 3.5 Hnh thnh lng nhanh khi pH =5.5 - 6.5c. So snh phn st v phn nhm: ho tan Fe(OH)3 < Al(OH)3 T trng Fe(OH)3 = 1.5 Al(OH)3 Trng lng i vi Fe(OH)3 = 2.4; Al(OH)3 =3.6 Keo st vn lng khi nc c t huyn ph. Lng phn FeCl3 dng = 1/3 1/2 phn nhm Phn st n mn ng ng. Tuy nhin vic ng dng c th phi xc nh liu lng v loi phn thch hp. Mc d vychng ta c th xc nh theo tiu chun TCXD 33 1985 nh sau:1)X l nc c: Hm lng cn (mg/l)Al2(SO4)3 khan (mg/l) < 10025 35 101 200 30 45201 40040 60 Thy phn Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 70 401 60045 70 601 80055 80 801 100060 90 1001 140065 105 1401 180075 115 1801 220080 125 2201 250080 130 2)X l nc mu:Lng phn nhm : M PAl4 =+ M: mu ca nc ngun (Co pt)3)X l nc va c va mu: - Ta ly gi tr max { (1) v (2)} - Nu ta dng phn st th ly bng 1/3 1/2 ng vi nhm. - Khi kim nc thp => lng cht kim ho : Pk = e1(Pp/e2 Kt+ 1 )100/C ( mg/l) Trong : oPk : hm lng cht km ho (mg/l). oPp: hm lng phn cn dng keo th(mg/l). oe1, e2: trng lng ng lng ca cht km ho v phn. oKt kim nh nht ca nc ngun. o1: kim d phng ca nc. oC: t l cht km ho nguyn cht(%). i khi cn phi dng cc tc nhn ph tr keo t : gi l cht tr lng: axit silix, oliacrilamit, (PPA); polialuminun clorua(PVC) 3.1.2.Cc thit b v cng trnh ca qu trnh keo3.1.2.1.Cc cng trnh chun b dung dch phn:(nh liu lng phn): bao gm: Thng ho trn, thng tiu th, thit b nh liu lng cht phn ng. Cc cng trnh trn u dung dch cht phn ng vi ngun: ng trn, b trn. Cccngtrnhtoiukinchophnngtobnglngxy rahonton:ngn phn ng b phn ng. Mt s s b tr cc cng trnh chun b phn. i vi cng trnh c cng sut x l nh: 1Thng ho trn Thng tiu th phnncnc Bm nh lng bm vo b ho trn Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 71 i vi cng trnh x l c cng sut ln: i vi cng trnh x l nc c cngsut va v ln. 3.1.2.1.1. B ho trn phn: nhim v lng cn, ho tan phn cc. Nng dung dch phn trong b l 10-17% Dng kh nn hoc cnh khuy ho tan phn Cng sut : ln hn 20.000 m3/ng. Gch hoc b tng ct thp. Sn bng g trn ng khng kh nn Thng tiu th nc Thit b nh lng phn T chy Thng ho trn phnnc Nc Thng ho trn phnnc 1Thng tiu th nh lng T chy xung trn 12845Ghinh 21: Be ha hen suc bang khong khi nen.1 voi nuJc2 0ng gio8 Fhen40hi dJ hen5 0ng dan dung dich hoa chat sang be dinh luJngG ong xaBi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 72 Lp sn cch: 0.5 0.6mm Ong khng kh nn chu axt: ng nha, thp n mn, Vn tc ng: 10 15m/s Ap lc khng kh nn:8 10l/s.m2 Lu lng gi thi vo b Qgi = 0.06 .W.F (m3/pht) W: cng sc kh(l/s.m2) F : din tch b mt b (m2) Thi gian pha: 2 3 gi, thi gian lng 2 3 giTng y nghing 45-50o. ng ng dn nc chn trong 1 gi phi y b. ng knh ng x cn nh hn 150mm. Mt trong ph lp chng axt. Cng sut :5000 20000 m3/ngy ==> trn bng my khuy. Cu to b pha phn qut vi cnh khuy phng Vt liu: g, nha hoc b tng. Cnhkhuy:kiuphngcsvngquayl20-30vng/pht,scnhkhuynh nht l 2 cnh. Chiu di cnh lcnh = (0.4 0.45)Bb. Din tch bn: Sbn = 0.1 0.2 (m2/m3 din tch b). i vi cng sut nh ==> trn bng phng php th cng. Cng sut nh hn 500 m3/ng: dng chum vi v khuy bng tay. Dung tch b ho trn: 9n: thi gian gia hai ln ho tan phn. Cng sut (m3/ng)n (h) < 120024 1200 1000012 10000 500008 12 > 500006 8 10000003 ) (. . 10000. .3my bP n QWhph =Cu to b pha phn ht vi cnh khuy phng Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 73 Pp : phn d tnh cho vo nc (g/m3). bh : nng dung dch phn ho trn(%). y :khi lng ringbng 1 tn/m3 3.1.2.1.2. B tiu th: Nhim v pha long Nng phn 4 10%. Dng khng kh nn hoc my khuy, cng sc 3 5 l/s.m2 y c nghing i = 0.005 v pha ng x. ng knh ng x c d > 100 mm. Dung tch b : 9bt:nng dung dch phn trong thng ho trn. S lng cng trnh nn ln hn hoc bng 2 . 3.1.2.2.Thit b nh lng phn: Nhim v iu chnh t ng lng phn cn thit a vo nc cn x l. C th phn loi: Theo chc nng: nh liu lng khng i: dng cng sut khng i. nh liu lng theo s thay i tnh cht nc x l. Theo ch chy ca phn: nh liu lng t chy. nh liu lng c p: phn vo ng nc c p lc Cc loi thit b: Khi H khng i, ng knh l mng khng i ==>lu lng khng i Cng sut : 47 408 l/h. H = 130 160 mm ng dng cng sut nh. Lu lng phn (l/h)ph thuc vo H(mm)ng knh l mng bng Pb (mm)H = 130 mmH = 140 mmH=150 mmH=160mm ) (.3mbb WWtn ht =Cu to phao Khavanshi. 1.B nh lng 2.Phao nh lng 3.Ong cao su 4.Vi dn dung dch 5.Ong dn dung dch vo b nh lng 6.Ong thng hi 7.Ong thu dung dch 8.Mn chn c l thu. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 74 4 5 6 7 8 47 73.5 105.5 144.0 188 49 76 109.5 149.5 195.5 50.5 79 113.5 154.5 202 52 81.5 117.5 159.5 208 3.1.2.3. Thit b pha ch vi: Cng sut nh c lng vi ln => dng vi sa. Nng vi ti b pha vi nh hn 5%. B thng c din tch cho 30-45 ngy. C th xy bng gch hoc b tng ct thp. Theo c ch vn hnh: Theo m: a vo mt ln, thng quay 30 40 pht. Thng lin tc : a vo thng xuyn timt u. Trng hp dng vi sa: khuy trn khng ngng vi khng lng. Khuy bngthu lc:Tc vi< 5mm/s, bc y hnh chp,nghing450, ng knh ng x nh hn 100 mm. Khuy bng my trn: n > 40 vng/pht. Trn bng kh nn: Cng tiu chun cn ly l 8 10 l/s.m2. Ap lc kh nn: 1 5atm. Tc vi > 0.8 m/s. Bm phi t di mc nc, khng t van 1 chiu. Dung tch b: Qtt : lu lng tnh ton. n: s ln gia hai ln pha vi (6 12 h) Pv : liu lng vi cho vo nc (mg/l). bv:nng vi sa(5%) y: khi lng ring ca vi sa(1tn/m3) 3.1.2.3. Kho ho cht: Cc yu cu:phn, vi, clo cn c d tr vo bo v pha ho cht. Din tch sn pha: Q: cngxut trm x l (m3/ng) P: liu lng ho cht tnh ton. T: thi gian gi ho cht trong kho. : tn s tnhn s i li trong kho: =1.3 G0:khi lng ring ho cht:(1.1tn/m3) Pk: tinh khit ho cht. h: chiu cao cho php ca lp ho cht: 9Phn Al cc: 2m 9Vi cc cha ti: 1.5m y bP n QWvv tt. . 10000. .=) (. . . 10000. . .20mG h PT P QFkkh=Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 75 9FeSO4 trong bao giy: 2m 9Mui n: 2 5 m 3.1.3. Thit b ha trn cht phn ng 3.1.3.1. Phng php trn c hc: Thi gian trn: 30 60 giy. B trn hnh vung: 3.1.3.2. Phng php trn thu lc: Dng cc loi vt cn xo trn. Th hin ngay trn ng y ca bm CI. Chiu di ng y phi to ra 1 tn tht p lc = 0.3 0.4 m. C cc loi b trn. 3.1.3.2.1. B trn ng: Dng trong trng hp c dn vi sa kim ho nc S ti a ca b trn < 15m2 Nguyn tc: nc a x l t di ln (v = 1 1.5m/s) -> chuyn ng ri lm cho nc xo trn cng ho cht. Nc dng ln vi vn tc vd = 25mm/s. Sau theo mng -> cng trnh tip theo (vmang = 0.6m/s), thi gian lu: 2 pht. 3.1.3.2.2. B trn c tm chn khoan l L 1 mng c 3 tm chn thng ng, khoan nhiu l dng chy xoy. S cho cng sut va v ln. Vl = 1m/s. Vcui mng = 0.6 m/s. Hng l trn cng phi ngp trong nc t 0.1 0.15 m; dl = 20 100mm. Chiucao mc nc ngn cui cng = 0.2 0.5 m. Tn tht: thuc(dl/). Trong :dl: ng knh l : chiu di tm chn dl/1.01.52.03.0 0.750.710.650.62 3.1.3.2.3.B cha vch ngn c ca thu hp. Cng xut nh. Vmng = > 0.6m/s V hp = 1m/s (tc qua ca hp). Tn tht p lc qua tm chn h = 0.13m. nh ca thu hp nm su trong nc l 0.1 0.15m. Khong cch hai vch ngn ly = 2 ln chiu rng. 3.1.3.2.4.B trn c kh Dng nng lung cnh khuy -> dng chy ri. 12=BHgvh2 .22=Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 76 Dng b: hnh vung hoc hnh trn c: Tc quay: 500 1500 v/pht. Cnh thng: 50 500 v/ pht 3.1.4.B phn ng to bng kt ta3.1.4.1.B phn ng xoy3.1.4.1.1. B phn ng xoy hnh tr ng hnh tr t tm b lng ng( cng sut < 3000m3/ng). Nc c trn u cht phn ng t b trn chuyn qua. Nc ra khi ming vf = 2 3 m/s. ng knh vi phun: chn theo tc . Khong cch t ming phun n thnh bphn ng l 0.2Db. Trong :t: thi gian lu, t = 15 20 pht H: 2.6 5 mn: s b phn ng. Tn tht p lc do vi phun: h= 0.06 vf 3.1.4.1.2. B phn ng xoy hnh phu: B c dng nh mt ci phiu ln, gc nghing gia 2 thnh b cn ly trong khong 50o -70o tu theo chiu cao b. Thi gian lu nc trong b ngn t 6 -10 pht (nc cly gii hn di v nc mu ly gii hn trn). Tc nc vo b pha di ly bng 0.7 1.2 m/s. Tc nc i ti ch ra khi b lng 4 5 mm/s. B phn dn nc t b phn ng sang b lng phi tnh n tc nc chy trong mng, trong ng v qua l khng c ln hn 0.1 m/s i vi nc c v 0.05 m/s i vi nc mu m bo bng cn c hnh thnh v khng b ph v. Khong cch dn nc sang b lng cng ngn cng tt. Trongqutrnhncdngln,dotitdindngchytngdn,nntcncs gim dn. Tc nc phn b khng u trn tit din ngang, tc nc cng ln khi cng gn tm b v dng nc lun c xu hng phn tn dn dn ra pha thnh b.u im: hiu qucao,tnthtp lc trong b nh, dung tch b nh (thi gianlu nc ngn). Nhc im: kh tnh cu to ca b phn thu nc trn b mt theo hai yu cu: thu nc u v khng phv bng cn, kh xy dng khi dung tch ln. 12=BHn HQDtb. . . 60. 4=Hnh : B phn ng xoy hnh phu 1. ng dn nc t ngn tch kh vo b phn ng 2. B phn ng xoy hnh phu 3. ng thu nc sang b lng 4. Mng vng c l chy ngp Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 77 3.1.4.2.B phn ng kiu vch ngn: Nguynlcutocbncabldngccvchngntorasichiulintcca dng nc. B c cu to hnh ch nht, bn trong c cc vch ngn hng dng nc chuyn ng zic zc theo phng nm ngang hoc phng thng ng. Pha sau u b phn ng c mtngnchoncchythngvoblngngangkhicnsachabphnnghaykhi khng cn keo t. S lng vch ngn c tnh theo hai ch tiu: dung tch b ph thuc vo thi gian lu nc v tc chuyn ng ca dng nc gia hai vch ngn. Thi gian lu nc trong b ly l 20 pht khu x l nc c v 30 -40 pht khi x l nc c mu. Tc chuyn ng ca dng nc gim dn t 0.3m/s u b xung 0.1m/s cui b. Chiu su trung bnh ca b l 2 -3m. dc y b l 0.02 -0.03 x cn. Tn tht : h = 0.15 V2 m (m: s ngoc). B c vch ngn ngang : cng sut 30.000 m3/ng. B c vch ngn ng 6.000 m3/ng. Thng Kt hp b lng ngang. Khong cch gia cc vch ngn khng c nh hn 0.7m nu b c vchngn ngang v c th nh hn 0.7m i vi b c vch ngn thng ng. u im: n gin trong xy dng v qun l vn hnh. Nhc im: khi lng xy dng ln do c nhiu vch ngn v b c chiu cao tho mn tn tht p lc trong ton b Hnh : B phn ng c vch ngn ngang 1. Mng dn nc2. Mng x cn3. Ca a nc vo 4. Ca a nc ra5. Van x cn6. Vch ngn hng dng Hnh : B phn ng c vch ngn ngang 1. Mng dn nc2. Mng x cn3. Ca a nc vo 4. Ca a nc ra5. Van x cn6. Vch ngn hng dng Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 78 3.1.4.3.B phn ng c lp cn l lng: t ngay phn u b lng ngang. C B = Blng. Chia thnh thnh nhiu ngn dc. y hnh phu.Tc nc chy trn qua mng : 0.5 0.6 m/s. Dintchl(lcamnghngngang>25mm)lybng3040%dintchca mng hoc ng phn phi. Vn tc i ln ph thuc vo SS SS (mg/l)Vn tc nc ln (mm/s) < 200.9 20 50 1.2 50 250 1.6 250 25002.2 Chiu cao lp cn 3 m. Thi gian lu: 20 pht Nc chy t phn ng - > lng phi c thi gian trn (vtrn 0.05m/s) 3.1.4.4. B phn ng c kh y l chu trnh hay s dng. B c chia thnh nhiu ngn, mi ngn c b cnh khuy ring bt. Cc ngn (bung) thng c kch thc: 3.6 x 3.6; 3.9 x 3.9; 4.2 x 4.2 Thi gian lu: 10 - > 30 pht. Trng thi lm vic ca b phn ng c trng bi: Gradien vn tc Trong :z: nng lng tiu ph cho 1m3 nc (KGm2/s3). : nht ca nc (KGm2/s) 250C: =0.0092 9G = 80 -> 100 l/s 9Gc = 30 -> 40 l/s Tc chuyn ng cnh khuy: Cng sut cn thit quay cnh: N= 51.C.F.v3 (w) c: h s tr lc ph thuc chiu di v chiu rng bn cnh khuy. 9L/b = 5 -> c = 1.2 9L/b = 20 - > c =1.5 9L/b 20 -> c =1.9 F: dung tch bn cnh (m2) Tc tng i ca quay: V= 0.75 Vk zG 10 =60. 2 n RVk=Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 79 V d p dng 1. Tnh b phn ng c kh cho cng trnh x l nc thi dt nhum vi cc thng s Qtbng-= 150 m3/ng, COD = 10830 mg/l,BOD = 5956 mg/l, SS= 640 mg/l,Mu = 16000 Pt Co . B phn ng -Th tch b:V = t* sQmax =0,0035*20*60 = 4,2 (m3) Trong :sQmax: Lu lng tnh ton ln nht, sQmax = 0,0035 m3/s t: Thi gian lu nc, t = 20 pht (Thc nghim) - Kch thc be: Chn chiu cao b: H = 1,3 (m) Tit din b: F = HV=3 , 12 , 4= 3,23 (m2) Chn b c dng hnh vung.) ( 8 , 1 79 , 1 23 , 3 m F a = = =Chiu rng b (B) = Chiu di b (D) =) ( 8 , 1 m a =Chn chiu cao bo v b: hbv = 0,2 (m) Chiu cao tng cng (chiu cao xy dng): Hxd = 1,3 + 0,2 = 1,5 (m) Th tch thc ca b phn ng: D * B * H = 1,8 * 1,8 *1,5 = 4,86 (m3) -Loi cnh khuy: Chn loi cnh khuy 2 bn, i xng qua trc, khuy quanh trc thng ng -Nng lng: CZG 10 =Vi VNZ =Trong : : nht nc thi:= 0,0092 (N/cm2) N: Nng lng cho khi nc thi V: Th tch nc thi. V = 4,2 (m3) Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 80 G: Gradien s bin i vn tc ca nc trong 1 dn v thi gian. G khng ln hn 800 (s-1). Chn G = 800 (s-1) ) ( 2471000092 , 0 * 2 , 4 * 800100* *2 2WV GN = = = -Din tch cnh khuy: C: 3* * * 51 v F c N = ) ( 034 , 0953 , 4 * 2 , 1 * 51247* * 5123 3mv cNF = = =Trong : c: H s ph thuc kch thc bn cnh. Chn5 =BL c = 1,2 F: Din tch tit din cnh khuy v: Vn tc cnh khuy,v = 0,75*vk = 0,75*6,594 = 4,95 (m/s) Vi:vk: Vn tc tuyt i ca cnh khuy ) / ( 594 , 660140 * 45 , 0 * 14 , 3 * 260* * 2s mn Rvk= = = Vi:R: Bn knh vng khuy. Chn 2R = 50 60% chiu rng b Chn R = 0,45 (m) n: S vng cnh khuy, n = 140 vng/pht (Thc nghim) -Din tch 1 bn cnh khuy: ) ( 017 , 02034 , 022mFf = = =C: B * L =) ( 017 , 02m f=v 5 =BL Vy: Chiu rng bn cnh khuy: B = 0,06 (m) Chiu di bn cnh khuy: L = 0,3 (m) Cnh khuy b phn ng 0,3 0,45 0,06 0,15 Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 81 Cc thng s thit k b phn ng STTTn thng sS liu dng thit kn v 1Chiu di b (L)1,8m 2Chiu rng b (B)1,8M 3Chiu cao b (H)1,5m 4Thi gian lu nc20pht 5Th tch xy dng b4,86m3 6Chiu rng 1 bn cnh khuy0,06m 7Chiu di 1 bn cnh khuy0,3m 8Bn knh vng khuy0,45m B to bng B to bng c xy dng gm 3 ngn vi kch thc bng nhau -Thi gian lu nc 1 ngn: t = 15 (pht) (Thc nghim)-Th tch 1 ngn:V = t* maxQs=0,0035*15*60 = 3,15 (m3) Trong :sQmax: Lu lng tnh ton ln nht, sQmax = 0,0035 m3/s t: Thi gian lu nc, t = 15 pht (Thc nghim) - Kch thc 1 ngn: Chn chiu cao: H = 1,2 (m) Tit din: F = HV=2 , 115 , 3= 2,625 (m2) Chn ngn c tit din vung.() m F a 62 , 1 625 , 2 = = =Chiu rng ngn (B) = Chiu di ngn (D) =) ( 62 , 1 m a =Chn chiu cao bo v b: hbv = 0,2 (m) chiu cao tng cng (chiu cao xy dng): Hxd = 1,2 + 0,2 = 1,4 (m) Th tch thc ca 1 ngn b to bng: D * B * H = 1,62 * 1,62 *1,4 = 3,675 (m3) -Xy dng b to bng gm 3 ngn c cng kch thc: V = D * B * H = 1,62 * 1,62 *1,4 = 3,675 (m3) -Loi cnh khuy: Chn loi cnh khuy gm trc quanh v 4 cnh khuy t i xng nhau qua trc. Tng din tch bn cnh khuy = 15% din tch mt ct ngang ca b. ) ( 34 , 0100268 , 2 * 15100* 152mffnc= = =Vi: ) ( 268 , 2 4 , 1 * 62 , 1 *2m H B fn= = =Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 82 -Din tch 1 bn cnh khuy: ( )2085 , 04034 , 04mFf = = =Chn chiu di cnh khuy: L = 1,2 (m) Chn bn knh vng khuy R1 = 0,45 (m) 2B < 0,45, B < 0,225Chn20 =BL) ( 06 , 0202 , 120mLB = = =B = 0,06 < 0,225 Chn R2 = 0,225 (m) Cnh khuy b to bng -Mi bung t 1 ng c in, tc quay l: Bung 1: 40 vng/ pht Bung 2: 20 vng/ pht Bung 3: 10 vng/ pht -Kim tra cc ch tiu khuy trn c bn: Bung phn ng 1: - Dung tch: V1 = 3,675 (m3) - Tc chuyn ng ca cnh khuy 40 vng/ pht. - Tc chuyn ng ca bn cnh khuy so vi nc:V1 = 0,75 6040 45 , 0 14 , 3 275 , 06021 = n R = 1,413 (m/s) V2 = 0,75 6040 225 , 0 14 , 3 275 , 06022 = n R = 0,7065 (m/s) Trong :R1, R2: Khong cch t mp cnh khuy n tm trc quay n: s vng quay, n = 40 vng / pht - Nng lng cn quay cnh khuy:N1= 51 * C * Fc * (V13 + V23 ) = 51 * 1,9 * 0,288 * (1,413 3 + 0,70653) = 88,57 (W) Trong :C = 1,9 v L / B = 20 Fc: Tit din ca bn cnh khuy Fc = 1,2*0,06*4 = 0,288 (m2) 0,165B = 0,06R2= 0,225R1= 0,45Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 83 - Gi tr Gradien vn tc: G1 = 10 *) ( 82 , 511675 , 3 * 0092 , 057 , 88* 10** 101 = = = SVN Z

Bung phn ng 2: - Dung tch: V2 = 3,675 (m3) - Tc chuyn ng ca cnh khuy 20 vng/ pht. - Tc chuyn ng ca bn cnh khuy so vi nc:V1 = 0,75 6020 45 , 0 14 , 3 275 , 06021 = n R = 0,7065 (m/s) V2 = 0,75 6020 225 , 0 14 , 3 275 , 06022 = n R = 0,35325 (m/s) Trong :R1, R2: Khong cch t mp cnh khuy n tm trc quay n: s vng quay, n = 20 vng / pht - Nng lng cn quay cnh khuy:N2= 51 * C * Fc * (V33 + V43 ) = 51 * 1,9 * 0,288 * (0,70653 + 0,353253) = 11,07 (W) - Gi tr Gradien vn tc: G2 = 10 *) ( 95 , 180675 , 3 * 0092 , 007 , 11* 10** 101 = = = SVN Z

Bung phn ng 3: - Dung tch: V3 = 3,675 (m3) - Tc chuyn ng ca cnh khuy 10 vng/ pht. - Tc chuyn ng ca bn cnh khuy so vi nc:V1 = 0,75 6010 45 , 0 14 , 3 275 , 06021 = n R = 0,35325 (m/s) V2 = 0,75 6010 225 , 0 14 , 3 275 , 06022 = n R = 0,1766 (m/s) Trong :R1, R2: Khong cch t mp cnh khuy n tm trc quay n: s vng quay, n = 10 vng / pht - Nng lng cn quay cnh khuy:N3= 51 * C * Fc * (V13 + V23 ) = 51 * 1,9 * 0,288 * (0,353253 +0,1766253) = 1,3 (W) - Gi tr Gradien vn tc: G3 = 10 *) ( 62675 , 3 * 0092 , 03 , 1* 10** 101 = = = SVN Z

Cc thng s thit k b to bng STTTn thng sS liu dng thit kn v 1Chiu di b (L)1,62m 2Chiu rng b (B)1,62M Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 84 3Chiu cao b (H)1,4m 4Thi gian lu nc (t)15pht 5Bn knh vng khuy (R1)0,45m 6Bn knh vng khuy (R2)0,225m 7Chiu di cnh khuy1,2m 8Chiu rng 1 bn cnh khuy0,06m 3.2. PHNG PHP TRUNG HA Ncthisnxutcanhiungnhcngnghipcthchaaxithockim.ngn ngahintngxmthcvtrnhchoqutrnhsinhhacccngtrnhlmschv ngunnckhngbphhoi,tacnphitrunghancthi.Trunghacnnhmmc ch tch loi mt s ion kim loi nng ra khi nc thi. Mt khc mun nc thi c x l tt bng phng php sinh hc phi tin hnh trung ha v iu chnh pH v 6.6 -7.6 Trung ha bng cch dng cc dung dch axit hoc mui axit, cc dung dch kim hoc oxit kim trung ha dch nc thi. Mtshachtdngtrungha:CaCO3,CaO,Ca(OH)2,MgO,Mg(OH)2, CaO0.6MgO0.4,(Ca(OH)2)0.6(Mg(OH)2)0.4,NaOH, Na2CO3, H2SO4, HCl, HNO3, Ngoi ra, c th tn dng nc thi c tnh acid trung ha nc thi c tnh kim hoc ngc li.V d nh trong dy chuyn cng ngh sn xutxim, doc 2 cng on:lmsch b mt nguyn liu cn m (y l cng on to ra nc thi c tnh kim mnh) v cng an ty r kimloi (cng on ny lito ra ncthic tnhacidmnh). Tac thtn dng 2 loi nc thi ny trung ha ln nhau. 3.2.1. Trung ho bng trn nc thi cha axit v nc thi cha kim. Phng php ny cho x l nc thi cha axit hoc cha kim trong khu cng nghip c tp trung lai x l v ch thi ca cc nh my khng ging nhau. Nc thi cha axit thng c thi mt cch iu ho ngy m v c nng nht nh. Nc thi cha kim li thi theo chu k, mt hoc hai ln trong mt ca tu thuc vo ch cng ngh.3.2.2. Trung ho bng cch cho thm ho cht vo nc thi. Phng php ny dng trung ho nc thi c cha axit. Ngi ta phn bit ba loi nc thi c cha axit nh sau : Nc thi cha axit yu(H2CO3, CH3COOH) Nc thi cha axit mnh (HCl, HNO3), cc mui canxi ca chng d tan trong nc. Ncthichaaxitmnh (H2SO4, H2CO3) ccmuicanxica chng khtan trong nc. Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 85 3.2.3.Trung ho nc thi cha axit bng cch lc qua lp vt liu lc trung ho. ivincthichaHCl,HNO3vcncthiH2SO4vihmlngdi5mg/lv khng cha mui kim loi nng c th dng phng php lc qua lp vt liu lc l vi magiezit, hoa cn, lmit... 1 21 28 739 10 11125 4Nc thai axitNc thai kiemDan nc thaia c trung hoaBun thaiBa thai6Hnh . S nguyn l trm trung ha nc thi bng s b sung tc nhn ha hc 1. B lng ct 2. B iu ha3. Kho tc nhn 4. B dung dch tc nhn 5. B phnnh lng6. Thng khuy trn 7. Thit b trung ha 8. B lng9. B c c bn 10.Thit b lc chn khng11. Kho cha b cn tch nc12. Sn cha bn 1234756810911Hnh 3.3.3 : S o cong nghe tram x ly vi be loc trong hoa1. Van chuyen phe lieu sau kho loc ; 2. Nc axit t be ieu hoa ; 3. Be loc trung hoa : 4. Phong th nghiem ; 5. May nghien ; 6. ng ray ; 7. Kho olomit ; 8. Be lang; 9. Xa nc trung hoa vao he thong thoat nc ; 10. Ong dan bun can ; 11. San phi bun.S cng ngh trm x l vi b lc trungha 1.Vn chuyn ph liu sau khi lc; 2 Nc axit t b iu ha; 3. b lc trung ha; 4. phng th nghim; 5. my nghin; 6. ng ray; 7. Kho lomit; 8. B lng; 9. X nc trung ha vo h thng thot nc; 10. ng dn bn cn; 11. Sn phi bn Bi ging K thut x l nc thi Thc s Lm Vnh Sn Trang 86 3.3. X L NC THI BNG PHNG PHP TUYN NI 3.3.1.Gii thiu chung. Phngphptuynnithngcsdngtchcctpchtrnkhngtanhoctan hoc lng c t trng nh hn t trng ca cht lng lm nn. Nu s khc nhau v t trng tch, gi l tuyn ni t nhin. Trong x l cht thi tuyn ni thng c s dng kh cc cht l lng v nn bn cn. u im ca phng php ny so vi phng php lng l c th kh hon ton cc ht nh nh,lngchmtrongthigianngn.Khicchtnilnbmt,chngcthcthu gom bng b phn vt bt. 3.3.2.Phn loi3.3.2.1. Tuyn ni phn tn khng kh bng thit b c hc. Cc trm tuyn ni vi phn tn khng kh bng thit b c hc (tuabin hng trc) c s dng rng ri trong lnh vc khai khong cng nh trong lnh vc x l nc thi. Cc thit b kiu ny cho php to bt kh kh nh. 3.3.2.2. Tuyn ni phn tn khng kh bng my bm kh nn (qua cc vi phun, qua cc tm xp). Tuynniphntnkhngkhquaccviphun:Thngcsdngxl nc thi cha cc tp cht tan d n mn vt liu ch to cc thit b c gii (bm, tuabin) vi cc chi tit chuyn ng. Tuyn ni phn tn khng kh qua tm xp, chp xp. 9Tuynnikhngkhquatmxp,chphtcuimsoviccbinphp tuyn ni khc , cu to cc ngn tuyn ni ging nh cu to ca aeroten, t tn innng,khngcnthitbcgiiphctp,rtclikhixlncthic tnh xm thc cao. 9Khuyt imcabinphp tuyn ni ny l:cclcacc tmxp,chp xp chng b ttlm tng tn tht p lc, kh chn vt liu xp p ng yu cu v kch tht cc bt kh.3.3.2.3.Tuynnivitchkhngkhtnc(tuynnichnkhng;tuynnikhng p; tuyn ni c p hoc bm hn hp kh nc). Bin php ny c s dng rng ri vi nc thi cha cht bn kch tht nhv n cho php to bt kh rt nh. Thc cht ca bin php ny l to ra mt dung dch (nc thi) bo ho khng kh. Sau khng kh t tch ra khi dung dch dng cc bt kh cc nh. Kh cc bt kh ny ni ln b mt s ko theo cc cht bn.Tuyn ni vi tch khng kh t nc phn bit thnh : tuyn ni chn khng, tuyn ni khng p, tuyn ni c p hoc bm hn hp kh - nc. 3.3.2.4. Tuyn ni in, tuyn ni sinh hc v ho hc. Tuy