THUYET MINH(24-0702010)

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m

Nhm: III

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Mc Lc

Nhm: III

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PHN I. NHIM V N 1. Nhim v: Tnh ton thit k h thng x l nc thi trung tm y t cng sut 150m3/ngy 2. Cc thng s tnh ton (c s thit k):- La chn trong cc ti liu su tm.

3. Nhim v yu cu:- a ra h thng x l nc thi tng. - Thit k chi tit cc cng trnh n v

4. Sn phm phi np:- Bn thuyt minh chi tit n - Bn v

Nhm: III

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PHN II. T VN Hot ng ca cc bnh vin nc ta hin ny ang c ci thin hng ngy c v cht ln v lng. Nhng nm gn y nhu cu khm cha bnh ca ngi dn rt ln. Hn na, vi ch trng a thy thuc n vi tt c cc bnh nhn trn ton quc k c vng su v vng xa. Do , hin ny nh nc u t xy dng, ci to nng cp nhiu bnh vin, trm y t khp c nc nhm phc v ngi dn c tt hn. Bn cnh , ngy ny c rt nhiu bnh vin c nh v va do cc t chc c nhn xy dng ln. Tuy nhin, song song vi vic tng cng kh nng phc v khm cha bnh cho nhn dn, cc hot ng ca bnh vin cng thi ra mt lng rt ln cht thi gy nh hng n con ngi v mi trng. Nh chng ta a bit, cht thi y t c xem l mt trong nhng loi cht thi nguy hi c tc ng trc tip n con ngi v mi trng nu khng c kim sot, qun l v x l tt. V vy, vic kim sot, qun l v x l cht thi y t l mt nhim v cp bch ca ngnh y t v cc ngnh lin quan, nhm bo v mi trng, bo v sc khe cho nhn vin y t, bnh nhn v cng ng. nc ta, cng tc qun l v x l cht thi y t c ban, ngnh cc cp quan tm. Tuy nhin, n ny vn cha c ch trng u t ng mc, qun l cha hiu qu nh cng tc phn loi, vn chuyn... X l cha ng quy nh, ch yu vn cn tp trung x l chung cng vi cc loi cht thi khc ti bi chn lp, cn cc h thng XLNT ca bnh vin th thit k s si, khng hiu qu, ch yu che mt cc c quan c thm quyn hoc khng c h thng XLNT (Vit Nam NET 11/9/2004). Vi s gia tng ngy cng nhiu cc loi cht thi, c bit l cht thi y t nguy hi, cng vi s qun l cn nhiu bt cp nh hin ny, s l mt ngun gy nhim mi trng, nh hng ti sc khe cng ng dn c nghim trng hin ti v trong tng lai, nu nh ngay t bay gi chng ta khng c nhng bin php tch cc hn. Nc thi thng cha nhiu tp cht v vi sinh c bn cht khc nhau. V vy, mc ch ca x l nc thi l sao cho nc sau khi x l t tiu chun t ra. c trng ca nc thi bnh vin tng t nh nc thi sinh hot. Nhng c c im khc l nc thi bnh vin c nhiu vi trng gy bnh, cht ty ra v cc ha cht. Trong phn ny s a ra mt s phng php c bn c th c p dng trong cng ngh x l nc thi bnh vin.Nhm: III Trang: 4


PHN III. TNG QUAN CC PHNG PHP X L NC THI3.1. X l nc thi bng phng php c hc tch cc ht l lng ra khi nc thi, thng ngi ta s dng cc qu trnh thu c. Vic la chn phng php x l tu thuc vo kch thc ht, tnh cht ha l, nng ht l lng, lu lng nc thi v mc lm sch cn thit. Phng php x l c hc c th loi b c n 60% cc tp cht khng ho tan c trong nc thi v gim BOD n 30%. tng hiu sut ca cc cng trnh x l c hc c th dng bin php lm thong s b Hiu qu x l c th ln ti 75% cht l lng v 40 50% BOD [4]. 3.1.1. Lc qua song chn hoc li chn y l bc x l s b, mc ch ca qu trnh l kh tt c cc tp vt c th gy ra s c trong qu trnh vn hnh h thng x l nc thi. - Song chn rc: Nhm gi li cc vt th pha trc. Song chn c chia lm hai loi di ng hoc c nh, thng c t nghing mt gc 60 o 75o theo hng dng chy, c lm bng st trn hoc vung v cng c th l va trn va vung, thanh n cch thanh kia mt khong bng 60 100 mm chn vt th v 10 25mm chn vt nh hn [6,26]. Vn tc dng chy qua song chn thng thng ly 0,8 1 m/s. Trc chn rc cn c khi lp thm my nghin nghin nh cc tp cht [11,6]. - Li lc: Sau song chn rc, c th loi b cc tp cht rn c kch thc c nh v mn hn ta c th t thm li lc. Li c kch thc l t 0,5 1mm. Li lc c thit k vi nhiu hnh dng khc nhau [2]. 3.1.2. Lng ct B lng ct thng c thit k tch cc tp cht rn v c khng tan c kch thc t 0,2 2 mm ra khi nc thi [2]. Da vo nguyn l trng lc, dng nc thi c cho chy vo b lng theo nhiu cch khc nhau: theo tip tuyn, theo dng ngang, theo dng t trn xung v ta ra xung quanh Nc qua b lng, di tc dng ca trng lc, ct nng s lng xung di v ko theo mt phn cht ng t. Theo nguyn l lm vic, ngi ta chia b lng ct thnh hai loi: b lng ngang v b lng ng. 3.1.3. Cc loi b lng Qu trnh lng chu nh hng ca cc yu t chnh sau: lu lng nc thi, thi gian lng, khi lng ring v ti lng tnh theo cht rn l lng,Nhm: III Trang: 5


ti lng thu lc, s keo t cc ht rn, vn tc dng chy trong b, s nn bn c, nhit ca nc thi v kch thc b lng. B lng ngang B lng ngang c dng hnh ch nht. Thng thng b lng ngang c s dng trong cc trm x l c cng sut 3000 m3/ngy m i vi trng hp x l nc c dng phn v p dng cng sut bt k cho cc trm x l nc khng dng phn [2]. Trong b lng ngang, ngi ta chia dng chy v qu trnh lng thnh bn vng: Vng nc thi vo, vng tch, vng x nc ra v vng bn [2]. B lng ngang thng c chiu sau H t 1,5 4 m, chiu di bng 8 12 ln chiu cao H, chiu rng knh t 3 6 m. Vn tc dng chy trong b lng ngang thng chn khng ln hn 0,01 m/s, thi gian lu 1 3 gi [2,1,4,10]. B lng ng Trong b lng ng nc chuyn ng t di ln trn, cn cc ht cn ri ngc chiu vi chiu chuyn ng ca dng nc. Khi x l nc khng dng cht keo t, cc ht cn c tc ri ln hn tc dang ca dng nc s lng xung y b lng. Khi x l nc c dng cht keo t, th cn c thm mt s cc ht cn c tc ri nh hn tc chuyn ng ca dng nc cng c lng theo. Hiu qu lng trong b lng ng ph thuc vo cht keo t, s phn b u ca dng nc v chiu cao vng lng [2,8]. B lng ng thng c dng hnh vung hoc hnh trn v c s dng cho cc trm x l c cng sut n 3000 m3/ngy m. Nc thi a vo tm b vi tc khng qu 30 mm/s, thi gian lu nc trong b t 45 120 pht [1,2,10]. B lng theo phng bn knh ng knh b t 16 60m. chiu su phn nc chy 1,5 5m, cn t l ng knh/chiu su t 6 30. y b c dc i 0,02 v tm. Nc thi c dn t tm ra thnh b va c thu vo mng ri dn ra ngoi. Cn lng xung y c tp trung li v a ra ngoi. Thi gian nc thi lu trong b 85 90 pht. B lng ny c ng dng cho cc trm x l c lu lng t 20.000 m3/ngy m tr ln, dn quay vi tc dng 2 3 vng/1gi [1,2,9,10]. 3.1.4. Tch cc tp cht ni Du, m trong mt s nc thi sn xut, s to thnh mt lp mng mng ph ln din tch mt nc kh ln, gy kh khn cho qu trnh hp th oxy khng kh vo nc, lm cho qu trnh t lm sch ca ngun nc bNhm: III Trang: 6


cn tr, v nh hng ti qua trnh sng ca sinh vt. V vy, phi x l cc cht ny trc khi x vo ngun tip nhn. 3.1.5. Lc c hc Qu trnh lc c s dng trong x l nc thi tch cc tp cht phn tn nh khi nc m b lng khng lng c. Trong cc b lc thng dng vt liu lc dng tm v dng ht. Vt liu lc dng tm c th lm bng tm thp khng g, nhm, niken, ng thau v c cc loi vi khc nhau. Tm lc cn c tr lc nh, bn v do c hc, khng b trng n v b ph hu iu kin lc. Vt liu lc dng ht l ct thch anh, than antraxit, than cc, si, , thm ch c than nu, than bn hay than g. 3.2. X l nc thi bng phng php ha l Nhng phng php ha l thng c s dng trong x l nc thi l: keo t, hp ph, trch ly, bay hi, tuyn ni X l ha l c th l giai on x l c lp hoc x l cng vi cc phng php c hc, ha hc, sinh hc khc trong cng ngh x l nc thi hon chnh . 3.2.1. Phng php ng t v keo t tch cc cht gy nhim bn dng ht keo v ha tan mt cch hiu qa bng cch lng, cn tng kch thc ca chng nh s tc ng tng h gia cc ht phn tn, lin kt thnh mt tp hp cc ht, nhm lm tng tc lng ca chng. Vic kh cc ht keo rn bng lng trng lc i hi trc ht cn trung ha in tch ca chng, th n l lin kt chng vi nhau. Qu trnh trung ha in tch thng c gi l qu trnh ng t (Coagultion) cn qua trnh to thnh cc bng ln hn t cc ht nh gi l qu trnh keo t (Floccultion) . Phng php ng t Vic la chn cht ng t ph thuc vao thnh phn, tnh cht ha l, gi thnh, nng tp cht trong nc, pH v thnh phn mui trong nc. Trong thc t cht ng t s dng rng ri nht l Al2(SO4)3 v cc mui st Fe2(SO4)3.2H2O, Fe2(SO4)3.3H2O, FeSO4.7H2O v FeCl3. Phng php keo t Keo t l qu trnh kt hp cc ht l lng khi cho cc cht cao phn t vo nc. Khc vi qu trnh ng t, khi keo t th s kt hp din ra khng ch do tip xc trc tip m cn do tng tc ln nhau gia cc phn t cht keo t b hp ph trn cc ht l lng. Vic s dng cht keo t cho php gim cht ng t, gim thi gian ng t v tng vn tc lng [8]. C ch lm vic ca cht keo t da trn cc hin tng: hp ph phn t cht keo trn b mt ht keo, to thnh mng li cht keo t. Di tc ng ca chtNhm: III Trang: 7


keo t gia cc ht keo to thnh cu trc 3 chiu, c kh nng tch nhanh v hon ton ra khi nc. 3.2.2. Phng php tuyn ni Phng php tuyn ni thng c s dung tch cc tp cht phn tn khng tan, t lng km ra khi pha lng v cung c dng tch mt s tp cht ha tan nh cc cht hot ng b mt . u im ca phng php tuyn ni so vi phng php lng l c th kh c hon ton cc ht nh, nh v lng chm trong mt thi gian ngn . Qu trnh tuyn ni c thc hin bng cch sc cc bt kh nh vo trong pha lng, cc bt kh kt dnh vi cc ht cht bn v ko chng ni ln trn b mt, sau chng tp hp li vi nhau thnh cc lp bt. C hai hnh thc tuyn ni: Sc kh p sut kh quyn v bo ha khng kh p sut kh quyn sau thot kh ra khi nc p sut chn khng [4]. 3.2.3. Phng php hp ph Tch cc cht hu c v kh ha tan khi nc thi bng cch tp trung cc cht trn b mt cht rn hoc bng cch tng tc gia cc cht bn ha tan vi cc cht rn. Phng php hp ph c dng loi ht cc cht bn ha tan vo nc m mt s phng php khc khng loi b c. Thng thng y l cc hp cht ha tan c c tnh cao hoc cc cht c mi, v v mu rt kh b phn hy sinh hc. Cc cht hp ph thng dng l than hot tnh, t st hot tnh, silicagen, keo nhm, mt s cht tng hp khc hoc cht thi trong sn xut, nh x tro, x mt st, Trong s ny than hot tnh c s dng nhiu nht [7,8]. 3.2.4. Phng php trao i ion Trao i ion l mt qu trnh trong cc ion trn b mt ca cht trao i vi ion c cng in tch trong dung dch khi tip xc vi nhau. Cc cht ny gi l ionit, chng hon ton khng tan trong nc. Phng php trao i ion c dng lm sch nc cp hoc nc thi khi cc kim loi nh Zn, Cu, Cr, Ni, Pb, Hg, Cd, Mn cng nh cc hp cht ca asen, photpho, xyanua. Phng php ny cho php thu hi cc cht c gi tr v cho hiu sut x l cao. Cc cht trao i ion c th v c hoc hu c, c ngun gc t nhin hay nhn to [7,9]. 3.2.5. Phng php tch bng mng Mng c nh ngha l mt pha, ng vai tr ngn cch gia cc pha khc nhau. Vic ng dng mng tch cc cht, ph thuc vo thm qua ca cc hp cht qua mng. Qu trnh phn tch bng mng ph thuc vo p sut, iu kin thy ng, kt cu thit b, bn cht v nng ca ncNhm: III Trang: 8


thi, hm lng tp cht trong nc thi cng nh nhit . [10]. - Thm thu ngc: Phng php ny l lc nc qua mng bn thm, mng ch cho nc i qua cn cc ion ca mui ha tan trong nc c gi li. lc c nc qua mng ny phi to ra p lc d ngc vi hng di chuyn nc bng thm thu [7,9]. Hiu sut ca qua trnh thm thu ph thuc vo tnh cht ca mng bn thm [8]. - Siu lc: Siu lc v thm thu ngc u ph thuc vo p sut, ng lc ca qu trnh v i hi mng cho php mt s cu t thm qua v gi li mt s cu t khc. Lu lng cht lng i qua mng siu lc ph thuc vo chnh lch p sut [10]. - Thm tch v in thm tch: Dng loi mng cho php i qua mt loi ion chn lc, khng cho nc i qua[7]. Nhc im ca phng php ny l tiu hao in nng ln [10]. 3.2.6. Cc phng php in ha Ngi ta s dng cc qu trnh oxy ha cc anot v kh ca catot, ng t in lm sch nc thi khi cc tp cht ha tan v phan tn. Tt c cc qu trnh ny u xy ra trn cc in cc khi cho dng in mt chiu i qua nc thi. Hiu sut ca phng php ny c nh gi bng mt lot cc yu t nh mt dng in, in p, h s s dng hu ch in p, hiu sut theo dng, hiu sut theo nang lng. Nhc im ca phng php ny l tiu hao in nng ln. [8]. 3.2.7. Phng php trch ly Trch ly pha lng c ng dng lm sch nc thi cha phenol, axit hu c, cc ion kim loi phng php ny c ng dng khi nng cht thi ln hn 3 4 g/l [5,8]. Lm sch nc thi bng phng php trch ly bao gm ba giai on [5,7,8]: Giai on th nht: Trn u nc thi vi cht trch ly, gia cc cht lng hnh thnh hai pha lng. Giai on th hai: Phn ring hai pha lng ni trn Giai on th ba: Ti sinh cht trch ly

3.3. X l nc thi bng phng php ha hc Cc phng php ha hc thng c ng dng trong x l nc thi: trung ha, oxi ha v kh. Cc phng php ny c ng dng kh cc cht ha tan v trong cc h thng cp nc khp kn. Ty theo tnh cht nc thi v mc ch cn x l m cng on x l ha hc c a vo v tr no. Chi ph s dng phng php ny thng cao. 3.3.1. Phng php trung haNhm: III Trang: 9


Nc thi cn c trung ha (a pH = 6,5 8,5) trc khi thi vo ngun tip nhn hoc s dng cho cng ngh x l tip theo. Ty thuc vo th tch, nng ca nc thi, ch thi, kh nng sn c v gi thnh ca tc nhn ha hc la chn phng php trung ha. Trung ha nc thi c th c thc hin bng nhiu cch khc nhau [8,7,8,11]: Trung ha bng trn ln cht thi Trung ha bng b sung cc tc nhn ha hc Trung ha nc thi axit bng cch lc qua vt liu Trung ha bng cc kh axit

3.3.2. Phng php oxi ha kh lm sch nc thi ngi ta c th s dng cc cht oxy ha nh clo dng kh v ha lng, cc hp cht ca clo nh NaOCl, Ca(OCl)2 v KMnO4, K2Cr2O7, H2O2, oxy ca khng kh, O3 [8]. Trong qu trnh oxy ha, cc cht c hi trong nc thi c chuyn thnh cc cht khng c hi hoc t c hi hn v tch ra khi nc. Qu trnh ny tiu tn mt lng ln cc tc nhn ha hc [3,7]. Cc cht oxy ha thng c dng trong x l nc thi: clo, hydro peoxyt, oxy trong khng kh, ozon, tia UV [7,11]. 3.3.3. Kh trng nc thi Dng cc ha cht hoc cc tc nhn c tnh c i vi vi sinh vt, to, ng vt nguyn sinh, giun, sn trong mt thi gian nht nh, m bo cc tiu chun v sinh. Tc kh trng ph thuc vo nng ca cht kh trng, nhit nc, hm lng cn v cc cht kh trong nc v vo kh nng phn ly ca cht kh trng. Cc cht thng s dng kh trng: kh hoc nc clo, nc javel, vi clorua, cc hipoclorit, cloramin B [22,25]. Mt s phng php kh khun thng c ng dng hin nay: Phng php Chlor ha: Lng Clor hot tnh cn thit cho mt n v th tch nc thi l: 10 g/m3 i vi nc thi sau x l c hc, 5 g/m3 i vi nc thi sau x l sinh hc hon ton. Clor phi c trn u vi nc thi v thi gian tip xc gia ha cht v nc thi ti thiu l 30 pht [3,7]. Phng php Chlor ha nc thi bng clorua vi: Phn ng c trng l s thy phn ca clo to ra axit hypoclorit v axit clohyric. Clorua vi c trn vi nc sch n lc t nng

Nhm: III

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khong 10 15%. Sau , c bm nh lng bm dung dch clorua vi vi liu lng nht nh ti ha trn vi nc thi. Kh trng nc thi bng iod: L cht kh ha tan nn iod c dng dng dung dch bo ha. ha tan ca iod ph thuc vo nhit ca nc. Khi pH 7, iod s dng ly t 0,3 1 mg/l, nu s dng cao hn 1,2 mg/l s lm cho nc c mi v iod [7,6]. Kh trng nc bng ozon: Tc dng dit trng sy ra mnh khi ozon ha tan liu lng, mnh v nhanh gp 3100 ln so vi clo. Thi gian kh trng xy ra trong khong t 3 8 giy [4]. Lng ozon cn kh trng nc thi t 0,2 0,5 mg/lt, ty thuc vo cht lng nc, cng khuy trn v thi gian tip xc (thng thi gian tip xc cn thit 4 8 pht) [3,6,7]. u im khng c mi, gim nhu cu oxy ca nc, gim nng cht hu c, gim nng cc cht hot tnh b mt, kh mu, cht rn, nit, pht pho, phnol, xianua... Nhc im ca phng php ny l tiu tn nng lng ln v chi ph u t ban u cao [6,7,9]. Kh trng nc bng tia t ngoi Dng cc n bc x t ngai, t trong dng chy ca nc, cc tia cc tm pht ra s tc dng ln cc phn t protit ca t bo vi sinh vt, ph v cu trc v lm mt kh nng trao i cht, v th chng b tiu dit. Hiu qu kh trng cao khi trong nc khng c cc cht hu c v cn l lng. S dng tia cc tm kh trng khng lm thay i mi v ca nc [4]. 3.4. X l nc thi bng phng php sinh hc Ngi ta s dng phng php sinh hc lm sch nc thi khi cc hp cht hu c v mt s cht v c nh H2S, cc sunfit, amoniac, nit [8]. Phng php ny da trn c s s dng hot ng ca vi sinh vt, ch yu l vi khun d dng hoi sinh c trong nc thi, phn hu cc cht hu c gy nhim bn trong nc thi. Cc vi sinh vt s dng cc hp cht hu c v mt s cht khong lm cht dinh dng v to nng lng. Kt qu l cc cht hu c gy nhim bn c khong ha v tr thnh cc cht v c, cc cht kh n gin v nc. Trong qu trnh dinh dng, chng s dng cc cht dinh dng ti to t bo, sinh trng v sinh sn nn sinh khi, ng thi c th lm sch cc cht hu c ha tan hoc cc ht keo phn tn nh[13,21]. Nguyn l chung ca qu trnh oxy ha sinh ha: thc hin qu trnh oxy ha sinh ha cc hp cht hu c ha tan, cc cht keo v phn tn nh trong nc thi cn c di chuyn vo bn trong t bo ca vi sinh vt, tm liNhm: III Trang: 11


qua trnh x l sinh hc gm cc giai on sau [2, 3,8]: - Chuyn cc hp cht nhim t pha lng ti b mt ca t bao vi sinh vt do khuch tn i lu v phn t. - Di chuyn cht t b mt ngoi t bao qua mng bn thm bng khuch tn do s chnh lch nng cc cht bn trong v bn ngoi t bo - Qu trnh chuyn ha cc cht trong t bo vi sinh vt vi s sn sinh nng lng v qu trnh tng hp cc cht mi ca t bo vi s hp th nng lng. 3.4.1. Cc cng trnh x l sinh hc nc thi trong iu kien t nhin C s ca phng php ny l da trn kh nng t lm sch ca t v ngun nc. Vic x l nc thi trn cnh ng ti, bi lc din ra do kt qu t hp ca cc qu trnh ha l v sinh ha phc tp. Thc cht l khi cho nc thi thm qua lp t b mt th cn c gi li y, nh c oxy v vi khun hiu kh m qu trnh oxy ha c din ra. Thc t cho thay rng qu trnh x l nc thi qua lp t b mt din ra su ti 1,5m [4]. Cho nn cnh ng ti, bi lc thng c xy dng nhng ni c mc nc ngm thp hn 1,5m tnh n mt t. Nh vy ngi ta xy dng cnh ng ti phi tun theo hai mc ch: V sinh v kinh t nng nghip. Nc thi sinh hot cha nhiu vi khun gy bnh v trng giun sn, v vy, khi xy dng v qun l cnh ng ti phi tun theo nhng yu cu v v sinh nht nh. C hai loi cnh ng ti: 3.4.1-1. Cnh ng ti cng cng v bi loc Trong nc thi sinh hoat c cha cc cht dinh dng cho cy trng nh : m, kali, ln hm lng ca chng ph thuc vo tiu chun thi nc. Nc thi trc khi a ln cnh ng ti, bi lc cn phi x l s b trc. Cnh ng ti v bi lc c xy dng ti nhng ni t ct, t ct tuy nhin cng c th xy dng nhng ni st. Cnh ng ti v bi lc l nhng c san bng hoc dc khng ng k v ngn cch bng nhng b t, nc thi c vo cc nh h thng ng ng trong cc phn phi. Kch thc ca cc ph thuc vo a hnh, tnh cht ca t ai v phng php canh tc [2]. 3.4.1-2. Canh ong ti nong nghiep T lu ngi ta ngh ti vic s dng cc cht thi phn bn c cha trong nc thi, khng ch bng cch ti ln nhng cnh ng cng cng, m cn ti ln nhng cnh ng nng nghip thuc nng trng v nhng vng ngoi th Ty theo ch ti nc m ngi ta phn ra: cnhNhm: III Trang: 12


ng ti thu nhn nc thi quanh nm v thu nhn nc thi theo ma. Chn loi no l ty thuc vo c im thot nc ca vng v loi cy trng hin c. Trc khi thi vo cnh ng, nc thi cn phi c x l s b. Tiu chun ti nc ln cnh ng nng nghip ly thp hn tiu chun ti nc ln cnh ng cng cng. Hiu sut x l nc thi trn cnh ng ti t rt cao [2, 3]. 3.4.1-3. Ho sinh hoc H sinh hc l h cha khng ln lm, dng x l nc thi bng sinh hc ch yu da vo qu trnh t lm sch ca h. Trong cac cng trnh sinh hc t nhin th h sinh hc c p dng rng ri nhiu hn ht. Ngoi vic x l nc thi h sinh hc cn cn c th em li nhng li ch sau [2, 3]: Nui trng thy sn; Ngun nc ti cho cy trng; iu ha dng chy nc ma trong h thng thot nc thi th. Cn c vo c tnh tn ti v tun hon ca cc vi sinh v c ch x l m ngi ta phn ra ba loi h [2, 3,7]: H k kh: Dng lng v phn hy cn bng phng php sinh ha t nhin da trn c s sng v hot ng ca cc vi sinh vt k kh, loi h ny thng c s dng x l nc thi cng nghip c nhim bn ln[2]. H ty tin: Trong loi h ny thng xy ra hai qu trnh song song: qu trnh oxy ha hiu kh v qu trnh oxy ha k kh. Ngun oxy cung cp cho qu trnh ch yu l oxy do kh tri khuch tn qua mt nc v oxy do s quang hp ca rong to, qu trnh ny ch t hiu qu lp nc pha trn su khong 1m. Qu trnh phn hy k kh lp bn y h ph thuc vo iu kin nhit . Chiu su ca h c nh hng ln ti s xo trn, ti cc qu trnh oxy ha v phn hy trong h. Chiu su ca h ty tin thng ly trong khong 0,9 1,5 m [2,3]. H hiu kh: Qu trnh oxy ha cc cht hu c nh cc vi sinh vt hiu kh. Ngi ta thng phn loi h ny thnh hai nhm: h lm thong t nhin v h lm thong nhn to. H lm thong t nhin l loi h c cung cp oxy ch yu nh qu trnh khuch tn t nhin. m bo nh sng c th xuyn qua, chiu su ca h khong 30 40 cm. Thi gian lu nc trong h khong 3 12 ngy. H hiu kh lm thong nhn to, l loi h c cung cp oxy bng cc thit b thi kh nhn to, hoc my khuy c hc. Chiu su ca h c th t 2 4,5 m [2,11]. 3.4.2. X ly sinh hoc hieu kh nc thai trong ieu kien nhan tao X l nc thi bng phng php hiu kh trong iu kin nhn to da trn nhu cu oxy cn cung cp cho vi sinh vt hiu kh trong nc thi hot

Nhm: III

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ng v pht trin, qu trnh ny ca vi sinh vt gm c hai qu trnh [3,7,10,11]. Dinh dng s dng li cc cht hu c, cc ngun nit v pht pho cng nhng ion kim loi khc vi mc vi lng xy dng t bo mi, pht trin tng sinh khi. Phn hy cc cht hu c cn li thnh CO2 v nc. C hai qu trnh dinh dng v oxy ha ca vi sinh vt c trong nc thi u cn oxy. p ng c nhu cu oxy, ngi ta thng phi khuy o, hoc sc kh vo trong khi nc. 3.4.2-1. Be phan ng sinh hoc hieu kh B Aeroten v b FBR l nhng dng b phn ng sinh hc hiu kh. Qu trnh hot ng sng ca qun th vi sinh vt trong b thc cht l qu trnh nui vi sinh vt trong cc bnh phn ng sinh hc hay cc bnh ln men thu sinh khi. Cc cht l lng trong nc thi hay cc gi th c nh l ni c ng cho cc vi sinh vt sinh sn v pht trin. Khi x l nc thi b aeroten c gi l qu trnh x l vi sinh trng l lng ca qun th vi sinh vt. Cc bng cn tn ti trong b chnh l bn hot tnh. Cn khi x l nc thi trong b FBR c gi l qu trnh x l sinh trng bm dnh, cc loi vi sinh vt sng bm dnh ln ga th to thnh lp mng vi sinh, lp mng vi sinh ny tp hp thnh qun th vi sinh sng trn . Bn hot tnh l loi bn xp cha nhiu vi sinh vt c kh nng oxy ha v khong ha cc cht hu c cha trong nc thi. Tng t nh vy i vi b FBR th cc gi th l mi trng thun li cho cc vi sinh vt dnh bm (mng vi sinh), cc vi sinh vt dnh bm ln b mt vt liu mt cch c chn lc nn kh nng hp ph cc cht hu c trong nc thi cao hn trong b Aroten. Trong qu trnh x l hiu kh trong b aeroten, cc vi sinh vt sinh trng dng huyn ph, qu trnh lm sch trong b din ra theo mc dng chy qua hn hp nc thi v bn hot tnh c sc kh. Vic sc kh y m bo cc yu cu: lm cho nc c bo ha oxy v duy tr bn hot tnh trng thi l lng. 3.4.2-2. Loc sinh hoc B lc sinh hc l mt thit b phn ng sinh hc trong cc vi sinh vt sinh trng c nh trn lp mng bm trn lp vt liu lc. Nc thi c ti t trn xung qua lp vt liu lc bng hoc cc lp vt liu khc, to ra lp mng nht gi l mng sinh hc, ph ln b mt lp vt liu m, v vy ngi ta cn gi loi b ny l b lc nh git (trickling filter), c ch ca qu trnh lc sinh hc c minh ha trn hnh 2.1. [8]. Khi dng nc

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thi chy trm ln mng nht ny, cc cht hu c c vi sinh vt chit ra cn sn phm ca qa trnh trao i cht CO2 s c thi ra qua mng cht lng [8]. 3.4.3. X l nc thi bng sinh hc k kh Qu trnh phn hy cc cht hu c trong iu kin k kh do mt qun th vi sinh vt hot ng khng cn s c mt ca oxy khong kh, sn phm cui cng l mt hn hp kh CH4, CO2, N2, H2S trong c ti 65% l CH4 [11,13]. Ngi ta c th coi qu trnh ln men mtan gm ba pha: pha u l pha phn hy, pha th hai l pha chuyn ha axt, pha th ba l pha kim (mtan ha)[4]. 3.4.3-1. Phng php k kh vi sinh trng l lng Trong cc qu trnh phn hy k kh cc cht hu c, x l nc thi bng phng php k kh sinh trng l lng c dng ph bin. nhit 35 37oC, khi nguyn liu trong b khng th c gia nhit v xo trn do vy thi gian ln men l kh di 30 60 ngy. Nu khi nguyn liu c gia nhit ti 50 55oC v khuy o trong iu kin k kh, th thi gian ln men cn rt ngn li cn 15 ngy hoc t hn [13,21]. B phn ng c bn hot tnh nng cao cho php b lm vic vi ti lng cao. m bo b lm vic vi nng bn cao, ngi ta phi cy ging vi sinh vt ca pha axt v pha sinh metan. B phi vn hnh vi ch thy lc cng sut thit k, sau 2 3 thng mi t c nng cn thit. Nu khng cy ging t nhin, b hot ng 3 4 thng mi t c nng bn cn thit [8]. 3.4.3-2. Phng php k kh vi sinh trng gn kt y l phng php x l k kh nc thi da trn c s sinh trng bm dnh vi vi khun k kh trn cc gi mang. Hai qu trnh ph bin ca phng php ny l lc k kh v lc vi lp vt liu trng n, c dng x l nc thi cha cc cht ccbon hu c. Qu trnh sinh trng gn kt cng c s dng x l nitrat [3,11]. - Lc k kh vi sinh trng l lng gn kt trn gi mang hu c Phng php ny l ng dng kh nng pht trin ca vi sinh vt thnh mng mng trn vt liu lm gi th, c dng nc y chy qua. Vt liu c th l cht do dng tm sp xp hay bng vt liu ri hoc ht, nh ht polyspiren c ng kh 3 5 mm. Nc thi i t di lp vt liu lc i ln v tip xc vi lp vt liu. Trn mt cc lp vt liu c cha cc vi sinh vt k kh v ty tin pht trin thnh mng mng, khi cc cht hu c trong nc thi tip xc vi mng dnh bm trn mt vt liu s c hp th v phn hy. Bn cn c gi li trong khe rng ca lp lc, sau 2 3 thng lm vic x bn mt ln, thau ra lc [3,11].Nhm: III Trang: 15


- X l nc thi bng lc k kh vi lp vt liu gi lng trng n Theo phng php ny, vi sinh vt c c nh trn lp vt liu ht c gin n bi dng nc dng ln sao cho s tip xc ca mng sinh hc vi cc cht hu c trong mt n v th tch l ln nht. Nc ra c quay li pha long nc thi u vo, v cn gi lu lng 5 10 m/h gi cho vt liu trng thi xp trng n. Nng sinh khi c th t ti 15.000 40.000 mg/l [3,2]. S dng loi lc ny cn lu thu hi cc ht vt liu theo dng, nu cn loi b huyn ph cn phi t thm thit b lng trong tip theo. Ti lng COD trong nc thi c th gim t 30 60 kg/m3.ngy v hiu sut lc t 70 90% [4]. 3.4.3-3. H k kh trong h k kh, vi sinh vt k kh phn hy cc cht hu c thnh cc sn phm cui dng kh, ch yu l CH4, CO2, v cc sn phm trung gian sinh mi nh H2S, axit hu c H k kh c th s dng x l nc thi c hm lng cht hu c cao, nh protein, du m, khng cha cc cht c c tnh i vi vi sinh vt, cc cht dinh dng v nhit nc tng i cao (trn 20oC). Ty thuc vo lng BOD trong nc thi, c th xay h k kh kt hp vi h ty tin v h hiu kh. Nh vy ta c mt chui h v mi h c th lm gim mt lng BOD ng k [2, 3].

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PHN IV. LA CHN V TNH TON THIT K PHNG N X L NC THI4.1. Tnh cht nc thi Qua nghin cu s liu thc t t cc trm x l nc thi bnh vin ti mt s bnh vin Tnh c quy m tng t (Kin giang, Ph Quc, An giang, Nha Trang) cho thy mt s ch tiu chnh c trong nc thi cn x l nh sau: Stt 1 2 3 4 5 6 7 Cc ch tiu chnh PH BOD COD SS PO Nitrat (NO3- ) Tng Coliform Mu nc th n v Kt qu 7.2 mg/l 250 mg/l 350 mg/l 120 mg/l 9 mg/l MPN/100ml 20 105

Thnh phn nc thi sau x l, nc thi sau x l phi t tiu chun Vit Nam TCVN 7382 : 2004 Mc II vi cc thng s chnh nh sau Stt 1 2 4 5 6 Cc ch tiu chnh PH BOD SS Nitrt tnh theo nit Tng Coliform Nc sau x l n v Kt qu 6.5-8.5 mg/l 20 mg/l 50 mg/l 30 MPN/100ml 1000

4.2. La chn phng n x l nc thi S cng ngh v thnh phn cc cng trnh n v ca trm x l nc thi c la chn ph thuc vo:Nhm: III Trang: 17


- Cng sut ca trm x l; - Thnh phn v tnh cht ca nc thi; - iu kin c th ca a phng; - Mc cn thit x l nc thi; - Tiu chun x nc vo ngun tip nhn tng ng; - Phng php s dng cn; - iu kin mt bng v a cht thy vn khu vc xy dng cng trnh; - Cc ch tiu kinh t k thut khc => Phng n x l: Gm cc giai on x l v cc cng trnh x l n v nh sau: 4.2.1 Phng n 1: - X l c hc + Ngn tip nhn. + Song chn rc + B iu ha - X l sinh hoc: + Aerotank (vi sinh vt l lng bn hot tnh) + B lng ly tm (t II) - X l cn: + B cha bn - Kh trng v lm sch nc + B tip xc + B lc p lc Thuyt minh phng n 1 Nc thi t bnh vin c thi ra t cc b phn khc nhau: Phng chiu X-Quang, ra phim, phng m, phng tr x, phng iu ch thuc Nn tnh cht nc thi ti cc b phn ny cng khc nhau. Tuy nhin lng nc thi ra cc b phn ny thng kh nh so vi tng lng nc thi ra ca ton bnh vin (thng nc thi ra cc nh bnh nhn, cc nh n, nh git, khu dch v c lu lng rt ln) Nc thi v sinh c s l bng hm t hoi 3 ngn trc ri dn

Nhm: III

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vo trm x l nc thi Nc t ngn th 3 ca hm t hoi s c dn sang b iu ho cng vi nc thi t cc phng khm v cc b phn khc nh nh n, khu dch v Ti b diu ho c t song chn rc th, rc b gi li s c ly hng ngy v c n v dch v vn chuyn i x l Nc sau khi qua b iu ho s c bm qua b Aerotank. Ti y qu trnh x l sinh hc din ra cc vi sinh tn ti trong bn hot tnh s oxy ho cc cht hu c c trong nc thi. Kt thc qu trnh x l sinh hc, nc thi s qua b lng lng bn hot tnh v cc cht l lng. Mt phn bn s c tun hon li b Aerotank, cn phn bn d sinh ra trong qu trnh x l s c bm sang b cha bn. Ti y bn s c qua my p bn lm gim th tch cn. Sau b lng, hm lng cn v BOD trong nc thi m bo yu cu x l xong vn cn cha mt lng nht nh cc vi khun gy hi nn ta phi kh trng. V lng nc sau khi x l s c dng li lm ngun nc ti cy cho khu vc nn ta cho qua b lc p lc kh mi ri mi x vo h cha nc ti cy. 4.2.2 Phng n 2: - X l c hc + Ngn tip nhn. + Song chn rc + B iu ha - X l sinh hoc: + Biofin cao ti + B lng ngang - X l cn: + B nn bn + Sn phi bn - Kh trng v lm sch nc + B tip xc + B lc p lc Thuyt minh phng n 2

Nhm: III

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Nc thi t bnh vin c thi ra t cc b phn khc nhau: Phng chiu X-Quang, ra phim, phng m, phng tr x, phng iu ch thuc Nn tnh cht nc thi ti cc b phn ny cng khc nhau. Tuy nhin lng nc thi ra cc b phn ny thng kh nh so vi tng lng nc thi ra ca ton bnh vin (thng nc thi ra cc nh bnh nhn, cc nh n, nh git, khu dch v c lu lng rt ln) Nc thi v sinh c s l bng hm t hoi 3 ngn trc ri dn vo trm x l nc thi Nc t ngn th 3 ca hm t hoi s c dn sang b iu ho cng vi nc thi t cc phng khm v cc b phn khc nh nh n, khu dch v Ti b diu ho c t song chn rc th, rc b gi li s c ly hng ngy v c n v dch v vn chuyn i x l Nc sau khi qua b iu ho s c bm qua b Biofin cao ti v b lng. Sau b lng, hm lng cn v BOD trong nc thi m bo yu cu x l xong vn cn cha mt lng nht nh cc vi khun gy hi nn ta phi kh trng. V lng nc sau khi x l s c dng li lm ngun nc ti cy cho khu vc nn ta cho qua b lc p lc kh mi ri mi x vo h cha nc ti cy. 4.2.3 Nhn xt: Hai phng n trn u t hiu qu x l. V nc thi bnh vin cha nhiu vi sinh gy bnh nn hm lng cn bn x ra cn c x l trit trnh ly lan mm bnh, do ta chn phng n 1. Cn phng n 2, tuy c hiu qu x l tt hn nhng lng cn cha c x l trit v din tch mt bng phi tng i ln. Do ta chn phng n 1 lm phng n tnh ton. 4.2.3.1 S cng ngh:

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NC THI

LC RC

H THU GOM Nc d B IU HA Kh Bn hon lu

B AEROTANK Bn d

B LNG

B CHA BN

Clorine

B TIP XC KH TRNG

BN LC P LC

MI TRNG

4.2.3.2 M t cng ngh: Nc thi sinh hot v y t t cc phng v sinh, phng m, phng xt nghim , nh bp, nh git, v.v. sau khi qua cc cng trnh x l s b nh b t hoi, b tch du m, tch cn ln ra khi nc thi, theo h thng cng ring c a v trm x l. Tai trm x l nc, trc tin nc thi chy qua thit b lc rc tch cn th ( giy, bao nilong, mu g ...), v chy vo ging thu nc thi. T y chng c bm nc thi bm vo b cn bng. B iu ha c tc dng iu ho lu lng v nng cc cht nhim

Nhm: III

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trong nc thi. Tip tc nc thi c bm vo b aerotank vi mt lu lng c nh. Ti b aerotank s xy ra qu trnh phn hy cc cht bn hu c trong nc thi nh cc vi sinh hiu kh l lng qu trnh bn hot tnh. Di ti trng thp, nh oxy cung cp t thit b lm thong, cc vi sinh vt hiu kh s phn hy cc cht hu c trong nc thi thnh CO2, H2O, mt phn c chuyn ho lm pht trin sinh khi - Biomass. Tip tc, nc + bn sinh hc chy sang b lng cp II. Ti y, cn bn s c tch ra khi nc v lng xung y b. Nc sau lng s chy qua b tip xc kh trng tiu dit cc vi trng trong nc bng clor, t tiu chun yu cu trc khi thi ra mi trng. Tip tc nc thi sau b tip xc kh trng c bm qua bn lc p lc loi b cn v xc vi sinh vt trit hn trc khi ra mi trng. Bn tch ra trong b lng mt phn s c bm hon lu v b lm thong gi nng bn trong b ti mc c nh, lng bn d cn li c bm sang b cha bn. Ti y, di tc dng ca qu trnh phn hy k kh, cn s b phn hy thnh CH4, NH3, H2S, H2O v cc cht khong, kt qu l th tch cn gim i ng k. Nc d t b phn hy bn s c a v b iu ha. Bn d trong b cha bn s c a qua my p bn trnh mi hi thi c th pht sinh ra trong qu trnh x l, cc b x l c cu to kn, v c h thng ht v khuych tn kh gy mi c th pht sinh trong qu trnh x l. + u im : H thng x l s dng bin php bn hot tnh hiu kh, sn phm phn hy cui cng ca cc cht hu c trong nc thi l CO2, H2O,v vy khi h thng hot ng bnh thng khng gy mi hi trong khu vc. Hiu sut ca h thng x l tng i cao, kh nng kh BOD ca h thng loi ny c th t n 90-95%, m bo cht lng nc sau x l lun t yu cu. Din tch ca ton b h thng mc trung bnh. C th nng cng sut ca h thng x l khi cn thit bng cch s dng cc gi th vi sinh bm. Vn hnh d dng v chi ph bo tr rt thp v hu nh khng phi bo tr bn trong cc thit b, b x l. H thng c thit k kn, c h thng ht v khuych tn kh gy mi, m bo khng gy mi hi thi cho khu vc bnh vin v khu vc ln cn.

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4.3. Tnh ton cc cng trnh n v. 4.3.1 Song chn rc: Nhim v ca song chn rc l gi li cc tp cht c kch thc ln (ch yu l rc). y l cng trnh u tin trong trm x l nc thi. Khi lng rc thi ly ra trong mt ngy m [1] t thit b lc rc l:W1 = a N tt 365 .1000

Trong : a: Lng rc tnh cho u ngi (theo TCVN 51-2007) vi chu rng khe h ca li chn rc ly trong khong 6-20mm th lng rc ly ra t r chc rc ly cho mt ngi l a = 8 lt/nm Ntt: Dn s tnh theo cht l lng, c tnh nh sau: Cho rng tiu chun cp nc bnh vin l 250 lt/ngi th vi lu lng nc thi l 150m3/ngy tng ng vi 600 ngi Vy khi lng rc ly ra trong mt ngy m l:W1 = a N tt 8 600 = = 0.013 m3/ngy m 365 .1000 365 .1000

Trng lng rc thu c trong mt ngy m tnh theo cng thc P = W1.G = 0,013 . 750 = 9,75 kg/ngy m Trong : G: Trng lng ring ca rc ly G = 750 kg/m3 [1] Trng lng rc trong tng gi trong ngy m l:Ph = P 9,75 .k = .2 = 0,82 kg/h 24 24

Trong : k: L h s khng iu ho gi ca rc a ti trm bm ly s b bng 2 ng ng dn nc thi tp trung t cc phng khoa v b pht n r lc rc c tit din hnh trn DN200. Do lu lng nc thi nh 150m3/ngy m, nn li lc rc c thit k dng r khi lp phng c hai tai treo hai bn. Cc tm li c gn vo nm mt ca khung hnh lp phng bng thp khng g. Vy c mi gi lng rc thu c t thit b lc gic l 0,82 kg rc. Do lng rc ly ra khi r chn rc trong mt ngy m l P = 0,013m3. Do vic ly rc ra t h thng ny c thc hin bng phng php th cng. Chn tit din r chn rc nh sau: D x R x C = 2 x 0,3 x 0,3Nhm: III Trang: 23


4.3.2 Ngn tip nhn nc thi: 4.3.2.1 Tnh ton kch thc h gom: Th tch h gom nc thi l: V = t.Q.k = 1,5 x 6,25 x 1,5 = 14 m3 Trong : t: Thi gian lu nc chn 1,5 gi Q: Lng nc thi trong mt gi (m3/h) k: H s khng iu ho (k = 1,5) Chn chiu su cng tc ca h gom: H = 2m Din tch b mt: F = V/H = 14/2 = 7m2 Chn kch thc lm vic h gom nc thi l: 3,5 x 2 x 2 = 14m3 Chiu cao bo v 1.5m. Vy chiu cao tng ca h gom nc thi l 3.5m 4.3.2.2 Tnh ton thit b trong h gom: Trong h gom b tr 2 bm, 1 bm nc thi sang b iu ho k kh, 1 bm d phng. Thit b i km vi 2 bm gm c 2 van cu, 2 van thau mt chiu, ng ng dn nc thi DN50. Cng sut bm c tnh theo cng thc: [24] Q.H ..g N= (kw) 1000 Trong : Q: Lu lng nc thi (m3/gi) H: cao ct nc ca bm (m) : Hiu sut ca bm ( = 0,60,9) chn = 0,8. : Khi lng ring ca nc thi, ly 1000 kg/m3 Vn tc nc chy trong ng: v = 1,2m/s H s Reynold: v.D. 1, 2.60.103 .1000 4 Re = = =7,1.10 3 1, 005.10 Trong : : Khi lng ring ca nc thi, = 1000kg/m3 D: ng knh ng, D = 60mm : nht nc thi, = 1,005Pa.s H s Reynol trn: D 60 Retron = 10 = 10 = 9230 0.065Nhm: III Trang: 24


Trong : : nhm tuyt i, = 2.5mm(24). i vi ng thp mi H s Reynol vng nhm:Re n = 560 D 60 = 560 = 51, 7.104 0.065

Qua tnh ton trn ta thy rng: Re tron BOD 5 = 225 mg/L 60% TSS => TSS = 48 mg/L Thng s u vo v u ra b Aerotank: u vo BOD5 = 225 mg/L COD = 245 mg/L TSS = 48 mg/L 4.3.4.1 Cc thng s thit k: Lu lng nc thi Q = 150m3/ngy.Nhm: III Trang: 27

u ra BOD5 30 mg/L COD 100mg/L TSS 50mg/L


Hm lng BOD 5 u vo = 225 mg/L Hm lng COD u vo = 245 mg/L Nhit duy tr trong b 250C Nc thi khi vo b Aerotank c hm lng cht rn l lng bay hi (nng vi sinh vt ban u) X 0 = 0 T s gia lng cht rn l lng bay hi (MLVSS) vi lng cht rn l lng (MLSS) c trong nc thi l 0,7MLVSS = 0, 7 ( tro ca bn hot tnh Z =0,3) MLSS

Nng bn hot tnh tun hon (MLSS = 10.000 mg/l). X r = 7.000 mg/l. Nng cht rn l lng bay hi hay bn hot tnh (MLVSS) c duy tr trong b Aerotank l: X = 3000 mg/l. Thi gian lu bn trong h thng, c = 10 ngy. H s chuyn i gia BOD 5 v BOD 20 (BOD han ton) l 0,68. H s phn hy ni bo, k d = 0,06 ngy -1. H s sn lng ti a ( t s gia t bo c to thnh vi lng cht nn c tiu th), Y =0,5 Kg VSS/Kg BOD 5. Loi v chc nng b: Aerotank khuy trn han chnh. u im: khng xy ra hin tng qu ti cc b bt c phn no ca b. 4.3.4.2 Tnh hiu qu x l: Xc nh nng BOD5 ha tan trong nc thi u raQ, So, Xo B Aerotank B lng Qe, S, Xe

Qr, S, Xr Qw, Xr

Trong :

Q , Qr, Qw, Qe: Lu lng nc u vo, lu lng bn tun hon, lu lng bn xa v lu lng nc au ra, m3/ngy S0 , S: Nng cht nn (tnh theo BOD 5) u voNhm: III Trang: 28


v nng cht nn sau khi qua b Aerotank v b lng , mg/l X ,Xr ,Xc: Nng cht rn bay hi trong b Aerotank, nng bn tun hon v nng bn sau khi qua b lng II, mg/l Phng trnh cn bng vt cht: BOD5 u ra = BOD 5 ha tan i ra t b Aerotank + BOD 5 cha trong lng cn l lng u ra Trong : BOD5 u ra: 20 mg/l BOD5 ha tan i ra t b Aerotank l S, mg/l Cn l lng u ra SS ra = 20 mg/l gm c 65% l cn c th phn huy sinh hc. BOD 5 cha trong cn l lng u ra c xc nh nh sau: Lng cn c th phn hy sinh hc c trong cn l lng u ra: 0,65 20 = 13 mg/l Lng oxy cn cung cp oxy ha ht lng cn c th phn hy sinh hc: 19.5 1.42 (mgO 2/mg t bo) = 18.5 mg/l Lng oxy cn cung cp ny chnh l gi tr BOD 20 ca phn ng. Qa trnh tnh ton da theo phng trnh phn ng: C 5 H 7O 2 N + 5O2 5CO 2 + 2H2O + NH3 + Nng lng 113 mg/L 160 mg/L 1 mg/L 1.42 mg/L => Oxy ha hon ton 1mg t bo cn 1.42mg oxy Chuyn i t gi tr BOD 20 sang BOD 5 BOD5 = 0,68BOD 20 = 0,68 18.5 = 13 mg/l Vy: 20 mg/l = S + 13 mg/l => S = 7 mg/l Tnh hiu qu x l tnh theo BOD 5 ha tan:E= So S 225 7 100 = 100 = 97% So 225 225 20 100 = 91% 225

Hiu qu x l BOD5 ca ton b s :Eo =

4.3.4.3 Tnh th tch ca b: Th tch b tnh theo cng thc:

Nhm: III

Trang: 29


V=Trong :

QY c (S o S ) X (1 + k d c )

V: Th tch b Aerotank , m3 Q: Lu lng nc u vo Q = 150 m3/ngy Y: H s sn lng cc i Y= 0,5 S0 S: Ti lng x l, S 0 S = 225 7 = 218 mg/l X: Nng cht rn bay hi c duy tr trong b Aerotank , X = 3000 mg/l kd: H s phn hy ni bo, k d = 0,06 ngy -1 c: Thi gian lu bn trong h thng, c = 10 ngyV= 150 0.5 10 218 = 34m3 3000 (1 + 0.06 10)

Chn chiu su mc nc trong b: H = 2.5m Din tch b: 34/2.5 = 13.6 m 2 Chiu di b : L = 5.5m Chiu rng b: B = 2.4m Chiu cao bo v: h = 0.3m Kch thc b: 5.5 x 2.4 x 3 (m 3) 4.3.4.4 Thi gian lu nc trong b: Th tch b tnh theo cng thc:=4.3.4.5 V 32 24 = = 5(h) Q 150

Lng bn phi x ra mi ngy: Tnh h s to bn t BOD5:Yobs = Y 0.5 = = 0.3125 1 + c K d 1 + 10 0.06

Trong :c = Thi gian lu bn; c = 10 ngy kd = H s phn hy ni bo; kd = 0.06 ngy-1 Y = H s sn lng, Y = 0.5 kg VSS/ kg BOD Lng bn hot tnh sinh ra do kh BOD5 (tnh theo MLVSS) Px (VSS) = Yobs x Q x (So S) Px (VSS) = 0,3125 x 150m3/ngy x (225 7)g/m3 x 10-3kg/g = 10.2 kg VSS/ngy

Nhm: III

Trang: 30


Tng lng cn l lng sinh ra mi ngy theo SS:MLVSS MLVSS = 0.7 MLSS = MLSS 0.7 P (VSS ) 10.2 Pxl ( SS ) = x = = 14.6 kg SS/ngy 0.7 0.7

Lng cn d hng ngy phi x i: Lng bn d cn x l = Tng lng bn Lng SS tri ra khi lng II P x= 14.6 (150 x 20 x 10-3) = 11.6 kg/ngy Tnh lng bn x ra hng ngy (Qw):c =VX Qw X + Qe X e VX Qe X ec 34 3000 150 14 10 = = 1.2m3 / ngay X r c 7000 10

Qw =

Trong :

V: Th tch b Aerotank , m3 Q: Lu lng nc u vo Q = 150 m3/ngy X: Nng cht rn bay hi c duy tr trong b Aerotank , X = 3000 mg/l c: Thi gian lu bn trong h thng, c = 10 ngy Xr: Nng cht rn bay hi c trong bn hot tnh tun hon Xr = 0.7 x 10.000 = 7000 Xe: Nng cht rn bay hi u ra ca h thng Xe = 0.7 x 19.5 = 14 Thi gian tch ly cn (tun hon ton b) khng x cn banT= VX 34 3000 = = 10 ngy thc t s di hn gp 3 n 4 ln v Px 10200

4.3.4.6 u:

khi nng bn cha trong b hiu qu x l thi gian u s thp v lng bn sinh ra t hn Px 4.3.4.7 Sau khi h thng n nh , lng bn h c x ra hng ngy: B = Qw x 10.000 g/m3=1.2 x 10000=12000 g/ngy =12 kg/ngy. Trong cn bay hi: B = 0,7 x 12 = 8.4 kg Cn bay hi trong nc x l i ra khi b QR x XRNhm: III Trang: 31


B= 150 x 14 x 10-3 = 2.1 (kg/ngy) Tng cn hu c sinh ra: B + B = 8.4 + 2.1 = 10.5 kg Px . 4.3.4.8 Xc nh lng bn tun hon: Da vo s cn bng sinh khi quanh b aeroten, xc nh t l bn tun hon da trn phng trnh cn bng sinh khi: QX0 + QrXr = (Q + Qr)X Trong : X0 : Hm lng cn l lng u vo,mg/l; Q : Lu lng vo b,m3/ngy; Qr : Lu lng bn tun hon, m3/ngy; Xr: Hm lng SS ca lp bn lng hoc hn tun hon,mg/l; X : Hm lng bn hot tnh trong b aeroten, mgMLSS/l. Gi s X0 = 0 v Qr = Q, Chia hai v cho Q, biu thc trn c th trin kh nh sau:=X 3000 = = 0, 75 X r X 7000 3000

Trong : = H s tun hon, = Qr/Q. Vy lu lng tun hon: Qr = Q = 0,75 x 150m3/ngy = 112.5m3/ngy 4.7 m3/gi Kim tra t s F/M (t s khi lng cht nn trn khi lng bn hot tnh) v ti trng th tch ca b:4.3.4.9

Ti trng th tch:LBOD = QS0 150m3 / ngy 225 gBOD5 / m3 = = 1kgBOD5 / m3 .ngy 3 V 34m 1000 g / kg

Tr s ny nm trong khong cho php ( LBOD = 0,8 1,9) T s F/M:F/M = S0 225mg / L = = 0,36ngay 1 X (5h / 24h / ngay ) 3000mg / L

Tr s ny nm trong khong cho php: F/M = (0,2 0,6) ngy-1. Trong : V: Th tch b Aerotank , m3 Q: Lu lng vi b, m3/ngyNhm: III Trang: 32


4.3.4.10

So: Nng BOD 5 u vo, mg/l : Thi gian lu nc, ngy X: Nng bn hot tnh c trong b Aerotank, mg/l

Tnh lng oxy cn cung cp: Lng xy cn thit trong iu kin chun (khng cn x l Nit)OCo = Q ( So S ) 1.42 Px f

Trong :

f: Hng s chuyn i t BOD5 sang BOD20, f = 0.68 1.42- H s chuyn i t t bo sang COD Px: Lng bn hot tnh sinh ra trong 1 ngy: Px = 10.2 (kg/ng)OCo = 150 (225 7) 1.42 10.2 = 33.6( kgO2 / ngay ) 0.68 1000

Lng xy cn thit trong iu kin thc t: Cs 1 1 OCt = OCo . . T 20 Cs C 1.024

Trong :

CS: Nng xy bo ha trong nc 20oC, CS

9,08 (mg/l)

C: Nng xy cn duy tr trong b, C = 1,5 2 (mg/l) (Tnh ton thit k cc cng trnh x l nc thi- Trnh Xun Lai) Chn C = 2 (mg/l) T = 25oC, nhit nc thi : H s iu chnh lng xy ngm vo nc thi (do nh hng ca hm lng cn, cht hot ng b mt), = 0,6 0,94. Chn = 0,71 9.08 1 OCt = 33.6 . = 54.7(kg / ngay ) . 5 9.08 2 1.024 0.7

Lng khng kh cn thit:Qkhi = OCt fa OU

Trong : Nhm: III

fa: H s an ton, fa = 1,5 2, chn fa = 1,5 (TnhTrang: 33


ton thit k cc cng trnh x l nc thi- Trnh Xun Lai) OU: Cng sut ha tan xy vo nc thi ca thit b phn phi tnh theo gam xy cho 1m3 khng kh. OU = Ou * h Vi: Ou: Ph thuc h thng phn phi kh. Chn h thng phn phi bt kh nh v mn, (tra bng 7-1 sch Tnh ton thit k cc cng trnh x l nc thi- Trnh Xun Lai). Bng : Cng sut ha tan xy vo nc ca thit b phn phi bt kh nh v mn iu kin th nghim Nc sch T = 20oC Nc thi T = 20oC, = 0.7 iu kin ti u Ou = grO2/m3.m 12 8.5 iu kin trung bnh Ou = grO2/m3.m 10 7

Ou = 7 (gO2/m3.m) h: ngp nc ca thit b phn phi kh, chn h = 2.5 (m) OU = 7 x 2.5 = 17.5 (gO2/m3)Qkhi =3 54.7 1.5 = 4688.6(m3 / ngy) = 195m /h 3 17.5 10

4.3.4.11

Tnh p lc my nn: p lc cn thit cho h thng ng nn: H d = hd + hc + hf + H Trong : hd: Tn tht p lc do ma st dc theo chiu di trn ng ng dn, (m) hc: Tn tht cc b (m) Tng tn tht hd v hc thng khng vt qu 0,4 (m) hf: Tn tht qua thit b phn phi (m). Tn tht hf khng qu 0,5 (m) H: chiu su hu ch ca b, H = 2.7 (m) Do p lc cn thit s l: Hd = 0.4 + 0.5 + 2.7 = 3.6 (m) p lc khng kh l:

Nhm: III

Trang: 34

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m p= 10.33 + H d = 1.35( atm) 10.33

Cng sut my nn kh:N= 34400( p 0.29 1) Qk 34400(1.350.29 1) 0.055 = = 2(kW ) 102 n 102 0.8

Trong :

Qk: Lu lng khng kh: Qk = 195 (m3/h) = 0.055 n: Hiu sut my nn kh, chn n = 0,8

(m3/s) 4.3.4.12

Tnh ton ng ng trong b:

Chn h thng cp kh cho b gm 1 ng chnh, 3 ng nhnh vi chiu di mi ng l 5.5 m, khong cch gia 2 ng nhnh 0.8 m, khong cch gia ng nhnh ngoi cng vi thnh b l 0.4m ng knh ng chnh dn kh:D= 4 Qk 4 0.055 = = 0.08m = 80mm v 3.14 10

ng knh ng DN80 Trong : v: Tc chuyn ng ca khng kh trong mng li trong ng phn phi, v =10 15 (m/s), chn v = 10 (m/s) (Tnh ton thit k cc cng trnh x l nc thi- Ts.Trnh Xun Lai) ng knh ng nhnh dn kh:Dn = 4 Qk 4 0.055 = = 0.05m = 50mm 3 v 3 3.14 10

ng knh ng nhnh DN50 Chn dng a xp, c mng phn phi dng mn, ng knh 170mm, din tch b mt F = 0.02m2. Cng thi kh 200 lt/pht.a = 3.3 (l/s) S a phn phi trong b l:N= Qk 0.055 = = 16.7 a 3.3 3.3 103

Chn s lng a l 18 a, chia lm 3 hng, mi hng 6 a phn phi cch sn b 0.2m v mi tm a cch nhau 0.9m. Tr t gia 2 a k nhau tng tr mt, kch thc tr l 0.2m x 0.2m x 0.2m ng knh ng dn bn tun hon:Nhm: III Trang: 35

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m Db = 4 Qr 4 4.7 = = 0.033m vb 3.14 1.5 3600

ng knh ng tun hon bn DN32 Trong : Qr: lng bn tun hon (m3/h) vb: Vn tc bn chy trong ng trong iu kin bm (vb = 1-2 m/s). Chn vb = 1.5 m/s ng ng dn bn d:D= 4Qw 4 0.000014 = = 0.008m v 1 3.14

Chn ng DN15 Trong : Qw: Lu lng bn d (Qw =1.2 m3/ngy = 0.000014 m3/s) v: Vn tc bn trong ng. Cho v = 1m/s ng knh ng dn nc thi:D= 4Q 4 0.0017 = = 0.055m v 0.7 3.14

Chn ng DN50 Trong : Q: Lu lng nc thi (Q =150 m3/ngy = 0.0017 m3/s) v: Vn tc nc trong ng. (v = 0.3 0.7 m/s, chn v = 0.7m/s)4.3.4.13

Tnh ton bm bn: Lu lng bm: Qb = Qr + Qw = 112.5 + 1.2 = 113.7 (m3/ngy) = 0.0013 (m3/s) Chn ct p my bm: 8m Cng sut bm: Q . .g .H 0.0013 1000 9.81 16 N= b f = 1.5 = 0.38( Kw) 1000 1000 0.8 Chn cng sut N = 0.5(Kw)

4.3.5

Tnh ton b lng 2: 4.3.5.1Din tch mt bng ca b lng

Nhm: III

Trang: 36

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m S= Q(1 + ) X X r vL

Trong :

Q: Lu lng nc thi bng 150 m3/ngy = 6.25 : H s tun hon ly 0.75. X: Nng bn hot tnh trong b aerotent.(X = 3000 Xr: Nng bn hot tnh tun han. X r = 7.000 vL: Vn tc lng ca b mt phn chia (m/h) ng vi

m3/h.

mg/l)

mg/l.

nng CL.

vL = vmax e KCL 10

6

Trong : + CL: Nng cn ti mt lng L ( b mt phn chia) CL = Xr/2 = 7000/2 = 3500 (mg/l) = 3500 (g/m3) + vmax = 7 m/h + K = 600 (cn c ch s th tch 50 < SVI < 150)

vL = 7 e600350010=> S =

6

= 0.86( m / h)

6.25 (1 + 0.75) 3000 = 5.5m 2 0.86 7000

4.3.5.2Din tch mt bng ca b lng Din tch tit din t ca ng trung tm:s Qmax (1 + )Qmax (1 + 0.75) 0.0017 s= = = = 0.15( m2 ) V V 0.02

Trong : V: Tc chuyn ng ca nc thi trong ng trung tm, ly khng ln hn 30 (mm/s) (iu 6.5.9 TCXD-51-84). Chn Vtt = 20 (mm/s) = 0,02 (m/s) Qmax: Lu lng tnh ton khi c tun hon (m3/s) Din tch b nu k c bung phn phi trung tm: S b = S + s = 5.5 + 0.15 = 5.65 ng knh ca b

Nhm: III

Trang: 37

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m D= 4 Sbe 4 5.6 = = 2.8(m) 3.14 4s 4 0.15 = = 0.44(m) . Chn d =0.5m 3.14 a= Q 150 = = 27.2(m3 / m 2 .ngd) S 5.5

ng knh ng trung tmd=

Ti trng thy lc:

Vn tc ca nc i ln trong b:v= a 27.2 = = 1.13(m / h ) 24 24

Mng thu nc t vng trn c ng knh bng 0.8 ng knh b. ng knh mng thu nc: Dmng = 0.8 x 2.8 = 2.24 (m) Chiu di mng thu nc: L = 3.14 x 2.24 = 7.03 (m) Ti trng thu nc trn 1 mt chiu di mng: Q 150 aL = = = 31.3( m3 / mdai.ngd ) = 0.36 (l/s) < 10 (l/s) L 7.03 Ti trng bn:(Q + Qr ) X (150 + 112) 3000 103 b= = = 5.8(kg / m 2 .h) 24Sbe 24 5.65

4.3.5.3Xc nh chiu cao b: Chiu cao tnh ton ca vng lng trong b lng ng: htt = V.t = 0.0005 x 1.5 x 3600 = 2.7 (m) Trong : t: Thi gian lng, t = 1,5 gi (iu 6.5.6 TCXD-5184). V: Tc chuyn ng ca nc thi trong b lng ng. V = 0,0005 (m/s) (iu 6.5.6 TCXD-51-84). Chiu cao phn hnh nn ca b lng ng c xc nh: D d hn = h2 + h3 = be .tg 2 Trong : h2: Chiu cao lp trung ha (m) h3: Chiu cao gi nh ca lp cn lng trong b

Nhm: III

Trang: 38


Db: ng knh trong ca b lng, Db = 2.8 (m) d: ng knh y nh ca hnh nn ct, ly d = 0.5

m

: Gc ngang ca y b lng so vi phng ngang, khng nh hn 500, chn = 50ohn = 2.8 0.5 .tg 50o = 1.4(m) 2

Chiu cao ca ng trung tm ly bng chiu cao tnh ton ca vng lng v bng 2,7 m. ng knh phn loe ca ng trung tm ly bng chiu cao ca phn ng loe v bng 1,35 ng ng knh ng trung tm: D1 = hl = 1,35Dtt= 1,35 x 0.5 = 0.7 (m) ng knh tm chn: ly bng 1,3 ng knh ming loe v bng: Dc = 1,3 D1 = 1,3 x 0.7 = 0.9 (m) Gc nghing gia b mt tm chn so vi mt phng ngang ly bng 17o Chiu cao tng cng ca b lng ng s l: H = htt + hn + hbv = htt + (h2 + h3) + hbv = 2.7 + 1.4 + 0.3 = 4.4 (m) Trong : hbv: Khong cch t mt nc n thnh b, hbv = 0,3 (m) 4.3.5.4Kim tra li thi gian lng nc Th tch phn lng: 2 2VL = 4 ( D d ).htt = 3.14 (2.82 0.52 ) 2.7 = 16( m3 ) 4

Thi gian lng:T= VL 16 = = 1.46(h) Q + Qr 6.25 + 4.7

Th tch phn bn: Vb = F x hn = 5.65 x 1.4 = 7.9 (m3) Thi gian lu bn:T2 = Vbun Qr + Qw

Trong : Vbn : Th tch phn cha bn (Vbn = 7.9 m3)Trang: 39

Nhm: III


Qr : Lu lng bn tun hon: Qr = Q = 0,75 x 150m3/ngy = 112.5m3/ngy 4.7 m3/gi Qw: Lng bn x ra (Qw = 1.2 m3/ngy = 0.05 m3/h)T2 = 7.9 = 1.7(h) 4.7 + 0.05

Vi Q = 1.7 (l/s), ng dn nc t b lng sang b tip xc DN1004.3.6

Tnh ton b tip xc: Kh trng nc thi bng Clo:

4.3.6.1

Lng Clo hot tnh cn thit kh trng nc thi c tnh theo cng thc: (X l nc thi th v cng nghip,Tnh ton thit k cng trnh- Lm Minh Trit)Ya = a Q 3 6.25 = = 0.019(kg / h) 1000 1000

Trong : Q: Lu lng tnh ton ca nc thi, Q = 6.25 (m3/h) a: Liu lng Clo hot tnh trong Clo nc ly theo iu 6.20.3-TCXD-51-84, nc thi sau khi x l sinh hc hon ton, a = 3 Vy lng Clo dng cho 1ngy l: m = 0,45 (kg/ng) = 13.5 (kg/thng) Dung tch bnh Clo:V= m 13.5 = = 9.2(l ) P 1.47

P: Trng lng ring ca Clo4.3.6.2

Tnh ton b tip xc: Th tch hu ch ca b tip xc c tnh theo cng thc:V = Q t = 6.25 0.5 = 3.125(m3 )

Trong :

Q: Lu lng tnh ton ca nc thi, Q = 6.25 t: Thi gian lu nc, chn t = 30 pht (TCVN 51-

(m3/h)

84) Chn chiu cao lp nc trong b: H = 1.5 (m) Chiu cao bo v: hbv= 0.5 (m) Din tch b mt:

Nhm: III

Trang: 40

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m F= V 3.125 = = 2.1(m 2 ) H 1.5

Kch thc b: F = B x L = 1m x 2.1m Chn din tch 1 ngn theo mt bng: F1 = B x L1 = 1 x 0.8 = 0.8 (m2) S ngn trong b tip xc: n =F 2.1 = = 2.6(ngan) . Chn 3 ngn F1 0.8

Gia cc ngn c b tr vch ngn khng chi lc xy bng gch, dy = 100mm. Chiu di thc t ca b: Ltt = L + (n 1) = 2.1 + (3 1)0.1 = 2.3 (m)4.3.7

Tnh ton b cha bn: Sau khi mt lng bn tun hon v b Aerotank, do lng bn hot tnh cn li t b lng 2 nh (Qw = 1.2m3/ngy) v vy s dng b cha bn cha lng bn cn d. B cha bn b tr cc van x nc tch bn theo chiu cao b. Phn bn lng di y b c bm ht a ln thit b p tch bn (my p bn) B cha bn c dng hnh vung. y b c thit k vi dc 45% thun li cho qu trnh tho bn. Chn thi gian lu bn l: t = 2 ngy. Th tch b cha bn: V = t.Qw = 2 x 1.2 = 2.4 (m3) Chn kch thc b: L x B x H = 1.2m x 1.2m x 1.7m Chn kch thc y b: a x a = 0.5m x 0.5m Chiu cao bo v: hbv = 0.3m Chiu cao do dc y b gy ra: h = 1.2/2 x 0.45 = 0.27 (m) Chiu cao xy dng b cha bn: Hxd = H + hbv + h = 1.7 + 0.3 + 0.27 = 1.8 (m) T trng cn: 1.005 (tn/m3) (Trnh Xun Lai - 2000) Gi s nng bn sau khi p l: 2% Khi lng bn kh sinh ra mi ngy: M = 1.005 x 1.2 x 2% = 0.024 (tn/ngy) = 24 (kg/ngy) Khi lng bn sinh ra trong 2 ngy: 24 x 2 = 48 (kg) Lng polymer s dng: 5 kg/tn bn Khi lng polymer mi ln s dng : 48 x 5 x 10-3 = 0.24 (kg) Nng polymer s dng: 0.1% Lng nc sch s dng:

Nhm: III

Trang: 41

N X L NC THI TI: X L NC THI BNH VIN. Cng sut: 150m3/ngy m 0.24 (100 0.1) = 240(l ) = 0.24(m3 ) 0.1

Lu lng bn thi: Qw = 1.2m3/ngy Chn vn tc bn chy trong ng: v = 0.5 (m/s)D= 4Q 4 1.2 = = 0.006(m) = 7mm. v 3.14 0.5 24 3600

Chn D = 50 (mm)4.3.8

Tnh ton bn lc p lc: 4.3.8.1 Cc thng s thit k: (Qtb = 18,75 m3/h) h = 0,3 m de = 0,5 mm U = 1,6 h2 = 0,5 m de = 1,2 mm U = 1,5 v = 9 m/h n= 4 Chn thi gian hot ng ca nh my l 8h Chiu cao lp ct: ng knh ht ct: H s ng nht: Chiu cao lp than: ng knh ht ct: H s ng nht: Tc lc: S b lc4.3.8.2

Tnh ton b lc p lc: A= 2,083333 m2

Din tch b mt lc:

h Qtb 18, 75 A= = 2, 08( 2 ) = m ng knh b lc p lc v 9 D= 0,814544 (m)

D=

Chn ng knh D = 0.8 (m) h=Nhm: III

4 A n

4 2 8 .0 = 0 .8 ( ) 4 3 .1 4

m =

Khong cch t b mt vt liu lc cho n ming phu thu nc ra lc : 0,65Trang: 42


h=Trong :

vl

H 0 . 2 e5 ( 0 . 3 + 0 . 5 ) 0 . 5

0 . =2 5

0 . 6 5 ( )+

m

Hvl : Chiu cao lp vt liu lc( bao gm chiu cao lp than v lp ct) 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= 2

hbv: Chiu cao bo v t mng thu nc n np y pha trn (m), Tnh ton lu lng kh Tc ra nc vn= Tc ra kh vk= Ra ngc chia thnh 3 giai on: Ra kh trong vng 1-2 pht Ra kh kt hp vi ra nc trong vng 4-5 pht Ra ngc bng nc trong vng 4-5 pht Lng nc cn thit ra ngc cho 1 b lc: Wn= 1.82nuoc

H=

hv l H+ b v 0 . 6 t 5 u 0h . 8+ hh

0 .2 5

0 +. 3

2( )

=

m

hthu: Chiu cao phn thu nc( tnh t mt chp lc n y b), (m) 0,35 1 (m3/m2.pht) (m3/m2.pht)

Wn = A v

2 .0 8 t 4

=

0 .3 5 31 0

1 .8 2m(

) =

Lu lng bm ra ngc: Qn=Qn = A vnuoc

10.9(m3/h)2 .0 8 4 = 0 .3 5 3 6 0 1 0 .9 ( m h/ =)

Lu lng my thi kh ra ngc: Qk= 0.52 (m3/phut) = 31.2(m3/h)

Qn = ANhm: III

2 .0 8 v n u o c 4

3

=1

0 . 5m ( 2

p/h u3 t = )

3 1 .m ( h / ) 2Trang: 43

=


Tn tht p lc qua lp vt liu lc sch c xc nh theo Hazen:1 h = C 60 L V2 0 1.8 42 d t + 10

h

Trong :

C : H s nn p, C = 600 1200 ty thuc vo tnh ng nht v sch t0 : Nhit nc, 0C d10 : ng knh hiu qu,mm Vh : Tc lc,m/ngy L : Chiu dy lp vt liu lc, m i vi ct lc :

1 60 0 .3 9 24 / 1 0 0 1 .8 2 + 2 i vi than0Anthracite 5: 4 2 0 . 5 h=1 60 0 .5 h= 2 9 24 / 1 0 0 qua . 2 vt liu 1 . 2 Tng tn tht 0 1 28lp 5+ 4 2 lc:h= 0.18 + 0.052= 0.232m

y = 0 .1h m n g 8

y = 0 .0 5h 2 mn g

BOD5 cn l lng =(5mgSS/L) x 0.65x1.42x0.68=3mg/l BOD5 sau x l= BOD5 cn l lng + BOD5 cn ha tan = 3+4=7mg/l

PHN V. D TON KINH T5.1 Chi ph u t: Chi ph u t bao gm chi ph xy dng cng trnh v chi ph mua sm thit b.5.1.1

Tnh ton kinh ph xy dng cng trnh:

Nhm: III

Trang: 44


STT 1 2 3 4 5 6

Hng mc cng trnh H thu B iu ha B Aerotank B lng t 2 B tip xc B cha bn

c tnh 3.5 m x 2 m 5.5 m x 3.5 m 5.5 m x 2.4 m D = 2.5 m 1 m x 2.3 m 1.2 m x 1.2 m D = 1.3 m

Din tch 7.0 19.25 13.2 4.9 2.3 1.44 5.2 53.3

n gi 1.200.00 0 1.200.00 0 1.200.00 0 1.200.00 0 1.200.00 0 1.200.00 0 1.200.00 0

Thnh tin 8.400.000 23.100.000 15.840.000 5.880.000 2.760.000 1.728.000 6.240.000 63.948.000 6.394.800 70.342.800

7 Bn lc p lc Cng VAT (10%) Tng cng5.1.2

Tnh ton kinh ph mua sm thit b: c tnh Vt liu inox B x H = 0.5 m x 0.4 m N = 0.5 KW, H = 7 m N = 0.2 KW, H = 5m N = 2KW 0,5 KW SL 1 2 2 2 2 2 1 2 n gi 3.000.000 14.000.000 12.000.000. 16.000.000 10.000.000 3.000.000 247.000.000 16.300.000 Thnh tin 3.000.000 28.000.000 24.000.000 32.000.000 20.000.000 6.000.000 247.000.000 32.600.000

STT Thit b Li chn rc 1 2 3 4 6 7 8 9 Bm nhng chm t h thu sang b iu ha Bm nhng chm t b iu ha sang b Aerotank Bm thi kh cho b Aerotank Bm bn tun hon v b Aerotank v v b cha bn Bm bn t b cha bn v my p bn My p bn bng ti B nh lng ha cht Chlorin

Nhm: III

Trang: 45


10 11 12 13 14 15 16 17

18 Cng VAT (10%) Tng cng

Bm nh lng ha cht Polymer Bn trn ha cht a phn phi kh Thn a ABS + mng cao su Ct thch anh D = 1.2 mm Than Anthracite Mng rng ca thu nc b lng t 2 Bung phn phi trung tm b lng t 2 H thng van, ng ng, cc loi ph kin Dy dn in, Linh kin PVC bo v dy in

2 2 18 0.36 0.6 1 1 1 1

7.620.000 5.000.000 500.000 2.500 10.000 500.000 20.000.000 100.000.000 20.000.000

15.240.000 10.000.000 9.000.000 642.875 8.571.428 500.000 20.000.000 100.000.000 20.000.000 576.554.303 57.655.430 634.209.733

Tng chi ph u t = 634.209.733 + 70.342.800 = 704.552.533 (VN) 5.2 Chi ph vn hnh Chi ph vn hnh bao gm: chi ph s dng in, chi ph s dng ha cht, chi ph nhn cng v chi ph s dng nc sch. 5.2.1 Tnh ton chi ph s dng in SL Hot ng 1 1 1 1 1 Cng sut hot ng (kW) 0.5 0.2 0.5 2 0.5 S gi hot ng 24 24 24 24 4 in nng tiu th

STT

Thit b hot ng

n v

SL

H thu 1 Bm nc thi chm B iu ha 2 Bm nc thi chm B Aerotnak 3 Bm nc thi tun hon 4 My thi kh B lng t 2 5 Bm bn v b b cha bn B kh trng

ci ci ci ci ci

2 2 2 2 2

12 4 12 48 2

Nhm: III

Trang: 46


7 Bm nh lng Cl B cha bn 8 My p bn 9 Bm bn v my p bn 10 Bm polymer Hot ng khc 11 Chiu sng Tng n gi Gi in dng trong 1 ngy Gi in dng trong 1 thng (30 ngy) Gi in dng trong 1 nm (365 ngy) 5.2.2

ci ci ci ci ci kWh ng /ngy /ngy /nm

2 1 2 2 14

1 1 1 1 14

0.11 3.75 0.5 0.11 0.05

24 4 4 4 12

2.64 15 2 0.44 0.6 95 1000 95.000 2.850.000 34.200.000

Tnh ton chi ph s dng ha cht Mc ch s dng n v kg/ngy kg/ngy ng/ngy ng/thng ng/nm Liu lng s dng 0.45 0.24 n gi Thnh tin (ng/k (ng) g) 65.000 29.250 1.000 240 29.490 884.700 10.616.400

STT Tn ha cht 1

Dung dch Kh trng nc Clo thi 2 Polymer Keo t bn p bn Chi ph ha cht dng trong 1 ngy Chi ph ha cht dng trong 1 thng Chi ph ha cht dng trong 1 nm 5.2.3

Tnh ton chi ph nhn cng S ca lm vic 1 1 Lng thng (ng/thng) 3.000.000 3.000.000 6.000.000 Lng nm (ng/nm) 36.000.000 36.000.000 72.000.000

STT

Nhn cng

S lng 1 1

1 Cng nhn k thut 2 Cng nhn vn hnh Tng 5.2.4

Tnh ton chi ph s dng nc sch Lu lng (m3/ng) 0.24Trang: 47

STT Nhu cu nc sch 1 Pha ha chtNhm: III


2 Cp nc sinh hot + nhu cu khc Tng lng nc s dng n gi nc sch (ng/m3) Tng VAT (10%) Chi ph nc sch trong 1 ngy (ng/ngy) Chi ph nc sch trogn 1 thng (ng/thng) Chi ph nc sch trong 1 nm (ng/nm) 5.3 Chi ph x l nc thi Chi ph vn hnh trm x l nc thi STT Hng mc 1 Chi ph in nng 2 Chi ph ha cht 3 Chi ph nhn cng 4 Chi ph nc sch Chi ph vn hnh Lu lng ca trm x l: Q = 150 m3/ng. Chi ph x l 1 m3 nc thi:9.837.780 = 2.186 (ng/m3) 150 30

0.2 0.44 7.100 3.124 312 3.436 103.080 1.236.960

Thnh tin (ng/thng) 2.850.000 884.700 6.000.000 103.080 9.837.780

S tin bnh vin cn tr cho vic x l nc thi trong 1 ngy: 2.186 x 150 = 327.926 (/ngy)

TI LIU THAM KHO

Nhm: III

Trang: 48


[1]. B XY DNG, Tiu chun Xy Dng TCXD-51-84 Thot nc mng li bn ngoi v cng trnh, Nh bn i hc Quc Gia Tp.HCM, 2001. [2]. HONG HU, X l nc thi, Nh xut bn Xy dng, H Ni, 1996. [3]. LM MINH TRIT, NGUYN THANH HNG, NGUYN PHC DN, X l nc thi th v cng nghip, tnh ton thit k cng trnh, T sch Khoa hc, Cng ngh v Qun L Mi trng ca Vin Mi trng v Ti nguyn i hc Quc gia Tp.HCM, Thng 11-2001. [4]. LNG C PHM, Cng ngh x l nc thi bng phng php sinh hc, Nh xut bn Gio dc, H Ni, 2002. [5]. NGUYN NGC DUNG, X l nc cp, Nh xut bn xy dng, 1999. [6]. NGUYN VN PHC, Qu trnh v thit b trong trong cng ngh ha hc - Tp 13 - K thut x l cht thi cng nghip, Trng i hc k thut Tp.HCM. [7]. NGUYN TH THU THY, X l nc cp, sinh hot v cng nghip, Nh xut bn Khoa hc v k thut, H Ni, 2000. [8]. TRN VN NHN, NG TH NGA, Gio trnh cng ngh x l nc thi, Nh xut bn Khoa hc v k thut, H Ni, 2001. [9]. TRN HIU NHU, Thot nc v x l nc thi cng nghip, Nh xut bn Khoa hc v k thut, H Ni, 2001. [10]. TRNH XUN LAI, Cp nc, tp 2. Nh xut bn Khoa hc v k thut, HNi, 2002. [11]. TRNH XUN LAI, Tnh ton thit k cc cng trnh x l nc thi, Nh xut bn xy dng, 2000. [12]. TRUNG TM O TO NGNH NC V MI TRNG, S tay x l nc, Tp I, Tp II, Nh xut bn Xy Dng, H Ni, thng 5 1999. [13]. METCALF, EDDY, Wastewater Engineering treatment and reuse, Edition McGraw-Hill, 1991.

Nhm: III

Trang: 49

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