ti: Tnh ton thit k h thng x l nc thi nh my git m gia sc, cng sut 500m3/ngy mLI CAM N thc hin n ny thnh cng u tin nhm em xin chn thnh t lng bit n Thy V nh Khang gio vin trc tip hng dn nhm em trong sut qu trnh thc hin n. Bng kinh nghim bn thn, tch gp nhng thc tin cuc sng v ngi i trc Thy c kt nhng vn kin thc cho nhm em c c hi hc hi, trao i thm cho bn thn nhng thiu st. S tn tnh hng dn, gip v ng vin ca Thy gip nhm em rt nhiu trong vic hon thnh n ny.Nu khng c s quan tm tng bc ca Thy th n chc chn s khng c hon thnh nh mt ti khoa hc. Em xin chn thnh cm n qu thy c dy d chng em trong sut thi gian qua.Cui cng l li cm n chn thnh n gia nh, ngi thn cng ton th bn b nhng ngi lun ng vin tinh thn gip chng em hon thnh nhim v c giao.Vi thi gian c hn, khi lng cng vic kh ln nn khng th trnh khi thiu st trong n. Nhm em xin chn thnh cm n nhng nhn xt v kin ng gp b sung ca qu thy c v bn b n c hon thnh hon chnh hn.Tp.H Ch Minh, ngy 26 thng 2 nm 2014 Nhm sinh vin thc hin

PHIU NH GI CA GING VIN HNG DN

PHIU NH GI CA GING VIN PHN BIN

CHNG 1: TNG QUAN V NGNH GIT M GIA SC0. Tng quan v ngnh git mTheo thng k mi nht t S Cng Thng, mi ngy ton thnh ph (TP) tiu th hn 450 tn tht gia sc, gia cm, vi ngun cung ng t 17 im git m th cng tp trung, 5 c s git m cng nghip (CN) v khong 3.725 l m ti cc h gia nh. Tuy nhin, vn ng bn l sn phm t cc c s git m th cng tp trung v h gia nh thng hnh thnh t pht, khng theo quy nh v khng t tiu chun v sinh, mc d ang cung cp trn 80% nhu cu tiu th tht gia sc, gia cm cho ton TP. Cc cng on thng c tin hnh trn nn t, nn b tng khng m bo v sinh, v ngi dn rt thiu thc v v sinh git m. Hnh 1.1: Git m gia sc ngay trn sn, nn nhng Nguyn Hu Hip nh trc cng l git m An Nhn trn ng L c Th, phng 13 (qun G Vp, TPHCM) cho bit, gia nh ng phi sng chung vi mi hi thi t khi l m tp trung ny i vo hot ng. Theo ng Hip, mi hi thi t nc thi ca trung tm khin nhiu ngi khng n ng c. Sut ba nm nay, cc cuc hp ca t dn ph u nu tnh trng ny nhng khng thy chnh quyn gii quyt- ng Hip ni. Dn chng ti ra con mng en ngm sau khu vc git m. B V Th Tin, cnh khu git m cho bit: Nc thi chy v ti v ra mng bc mi, c ti n, xe ch gia sc chy qua mi hi thi li bc ln khin dn chng ti mt n mt ng. Tnh trng ny din ra lu nhng theo phn nh ca ngi dn sinh sng quanh cc khu vc ny khng nhn thy c quan chc nng kim tra x l. Trong cuc hp gn y nht, t son tho quy hoch u c chung nhn nh: Vn mt v sinh an ton thc phm, v sinh th y, mi trng vn cn kh nghim trng. Hin nay, c quan chc nng mi qun l c cc c s git m tp trung, cn cc h nh l nm ngoi kim sot.Mt s c s git m thng xuyn c hin din cn b th y, nhng tnh trng mt v sinh vn khng khc phc. in hnh l git m gia sc ti ch u mi Th c, cn b th y ch kim tra n gin v ng du yn lng ngi tiu dng.

Hnh 1.2: Nc thi x trn ti khu vc git m gia sc0. Ngun gc, tnh cht v thnh phn nc thi ca ngnh git m gia sc1. Ngun gc nhim ca ngnh git m gia sc Nc thi: Nc thi t qu trnh git m v lm sch gia sc Nc v sinh thit b trong c s v t chung tri Nc sinh hot cho cc cng nhn ca c s Khng kh:Vn ny sinh ch yu l cc mi kh chu t cc chung gia sc (phn, nc tiu, lng,..) v khu qun l thc phm ng lnh. Ting n:Ch yu gy ra do my mc, thit b, do vn chuyn v do gia sc b nht.1. Tnh cht nc thi ca ngnh git m gia scHuyt c thu li v s dng nh sn phm ph, cc thnh phn khc nh phn, nc tiu, long, nc ms a vo nc thi. V vy, nc thi ca ch bin tht cha cht bo, mng nhy, du m, lng, mu, bi bn vi ti lng nhim cao.Nc thi ca cc c s git m c nng cht rn cao, BOD v COD kh cao v lun lun cha mt lng ln cc cht hu c bao gm cc hp cht ca cacbon, nito, photpho. Cc hp cht hu c ny lm tng ph ca nc ng thi d phn hy bi cc vi sinh vt, gy mi hi thi v lm nhim ngun nc.Nc thi ca cng ngh ch bin tht gn ging nc thi sinh hot nhng c nhim cao hn nhiu. chng c nng du m, axit bo rt cao. Nc thi git m cn cha cht dinh dng nh Protein.Loi phn thi ra mi ngy ty thuc vo ging, loi gia sc, tui, khu phn thc n v trng lng ca gia sc.Bng 1.1: Lng phn v nc tiu thi ra hng ngy ca gia scLoi gia scLng phn v nc tiu (kg/ngy)

Tru b trng thnh10-15

Heo 2-3

(Ngun: Nguyn Kim Kiu- NNGNGHIP.VN, 22-5- 2013)1. Thnh phn nc thi ca ngnh git m gia scGn ging nc thi sinh hot nhng c nng nhim cao hn nhiu. chng c nng du m, acid bo cao. Nc thi cha nhiu protein. Khi diamin ha s to ra mt lng NH3 nn cn c nitrat h. Ngoi ra, trong nc thi cn c cha cht ty ra, long Do d phn hy sinh hc nn nc thi t hot ng git m d gy nhim ngun nc, c mi hi v cha vi khun gy bnh. Nc thi cn c nng cht dinh dng nh N, P cao nn d gy ph dng ha ngun nc.Bng 1.2: Thnh phn v tnh cht ca loi nc thi git mSTTThng sn vGi tr

1pH-5,3-8,9

2BOD5mg/L1500-7400

3CODmg/L2400-9600

4 dn inm3/cm2,8-6,1

5Cloritmg/L1,1-390

6Cht bomg/L115-300

7Axit hu cmg/L61-350

8H2Smg/L0-20

9Nito amonmg/L230-1120

10Photpho tngmg/L16-53

11 cngmg/L35,6-125

12 kimmg/L30-70

(Ngun: vin mi trng v ti nguyn)

CHNG 2: TNG QUAN V PHNG PHP X L2.1. Phng php c hcPhng php ny gi l phng php s bPhng php ny nhm mc ch: Tch cc cht khng ha tan, nhng cht l lng c kch thc ln ra khi nc thi. Loi b cc cn nng: mnh thy tinh, kim loi, nilon, iu ha lu lng, nng cc cht nhim trong nc thi To iu kin thun li cho cc cng trnh x l nc thi pha sau2.1.1.Song chn rcSong chn rc dng gi li cc cht thi rn c kch thc ln trong nc thi m bo cho cc thit b v cng trnh x l tip theo. Kch thc ti thiu ca rc c gi li ty thuc vo khong cch gia cc thanh kim loi ca song chn rc. trnh ng rc v gy tn tht p lc ta phi thng xuyn lm sch cc song chn rc bng th cng hoc c gii. Tc nc chy qua cc khe h nm trong khong 0,65m/s n 1m/s. Ty theo yu cu v kch thc ca rc chiu rng khe h ca cc song thay i.Da vo khong cch cc thanh, song chn c chia thnh 2 loi: Song chn th c khong cch gia cc thanh t 60 100mm. Song chn tinh c khong cch gia cc thanh t 10 25mm.

Hnh 2.1: Song chn rc th Hnh 2.2: Song chn rc tinh 2.1.2. Li lcLi lc dng kh cc cht l lng c kch thc nh, thu hi cc thnh phn qu khng tan hoc khi cn phi loi b rc c kch thc nh. Kch thc mt li t 0,51,0mm. Li lc thng c bao bc xung quanh khung rng hnh tr quay trn (hay cn gi l trng quay) hoc t trn cc khung hnh da..

Hnh 2.3: Li lc2.1.3. B lng ctB lng ct t sau song chn, li chn v t trc b iu ha, trc b lng t I. Nhim v ca b lng ct l loi b cn th nng nh ct, si, mnh v thy tinh, kim loi, tro tn, thanh vn, v trng bo v cc thit b c kh d b mi mn, gim cn nng cc cng on x l tip theo. Ct t b lng ct c a i phi kh sn phi v ct kh thng c s dng li cho nhng mc ch xy dng.

Hnh 2.4: B lng ct2.1.4 B lngB lng dng tch cc cht l lng c trng lng ring ln hn trng lng ring ca nc. Cht l lng nng hn s t t lng xung y, cn cht l lng nh hn s ni ln mt nc hoc tip tc theo dng nc n cng trnh x l tip theo. Dng nhng thit b thu gom v vn chuyn cc cht bn lng v ni ( ta gi l cn) ti cng trnh x l cn.Da vo chc nng, v tr c th chia b lng thnh cc loi: b lng t 1 trc cng trnh x l sinh hc v b lng t 2 sau cng trnh x l sinh hcDa vo nguyn tc hot ng, ngi ta c th chia ra cc loi b lng nh: b lng hot ng gin on hoc b lng hot ng lin tc.Da vo cu to c th chia b lng thnh cc loi nh sau: b lng ng, b lng ngang, b lng ly tm v mt s b lng khc.

Hnh 2.5: B lng 2.1.4.1. B lng ngB lng ng c dng hnh trn hoc hnh ch nht trn mt bng. B lng ng thng dng cho cc trm x l c cng sut di 20.000 m3/ngy m. Nc thi c dn vo ng trung tm v chuyn ng t di ln theo phng thng ng. Vn tc dng nc chuyn ng ln phi nh hn vn tc ca cc ht lng. Nc trong c tp trung vo mng thu pha trn. Cn lng c cha phn hnh nn hoc chp ct pha di.Hnh 2.6: B lng ng2.1.4.2. B lng ngangB lng ngang c hnh dng ch nht trn mt bng, t l gia chiu rng v chiu di khng nh hn v chiu sy n 4m. B lng ngang dng cho cc trm x l c cng sut ln hn 15.000 m3 / ngy m. Trong b lng nc thi chuyn ng theo phng ngang t u b n cui b v c dn ti cc cng trnh x l tip theo, vn tc dng chy trong vng cng tc ca b khng c vt qu 40mm/s. B lng ngang c h thu cn u b v nc trong c thu vo mng cui b.

Hnh 2.7: B lng ngang2.1.4.3. B lng ly tmB lng ly tm c dng hnh trn trn mt bng. B lng ly tm c dng cho cc trm x l c cng sut ln hn 20.200 m3 / ngy m. Trong b lng nc chy t trung tm ra quanh thnh b. Cn lng c dn vo h thu cn c xy dng trung tm y b bng h thng co gom cn phn di dn quay hp vi trc 1 gc 450. y b thng c thit k vi dc I = 0.02 0.05. Dn quay vi tc 2-3 vng trong 1 gi. Nc trong c thu vo mng t dc theo thnh b pha trn.

Hnh 2.8: B lng ly tm2.1.5. B vt du mB vt du m thng c p dng khi x l nc thi c cha du m ( nc thi cng nghip), nhm tch cc tp cht nh. i vi thi sinh hot khi hm lng du m khng cao th vic vt du m thc hin ngay b lng nh thit b gt cht ni.

Hnh 2.8: B vt du m2.1.6. B lm thongKhi hm lng cht l lng trong b lng > 150mg/l chng ta cn lm thong s b : Tng cng hiu qu x l nc thi Tng hiu qu kh BOD To iu kin cho cc cht l lng v cc cht ni trong nc thi phn b ng u khi qua cc cng trnh pha sau.

2.1.7. B lcB lc nhm tch cc cht trng thi l lng kch thc nh bng cch cho nc thi i qua lp lc c bit hoc qua lp vt liu lc nh ct, thch anh, than cc, than bn, than g, si nghin nh. Qu trnh phn ring c thc hin nh vch ngn xp, n cho nc i qua v gi pha phn tn li. Qu trnh din ra di tc dng ca p sut ct nc. B ny c s dng ch yu cho mt s loi nc thi cng nghip. B lc thng lm vic vi hai ch lc v ra lc.

Hnh 2.9: B lc2.2. Phng hp ha lBn cht ca qu trnh x l nc thi bng phng php ha l l p dng cc qu trnh vt l v ha hc a vo nc thi cht phn ng no gy tc ng vi cc tp cht bn, bin i ha hc, to thnh cc cht khc di dng cn hoc cht ha tan nhng khng c hi hoc gy nhim mi trng. Giai on 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 trong cng ngh x l nc thi hon chnh.Nhng phng php ha l thng c p dng x l nc thi l: keo t, ng t , tuyn ni, hp ph, trao i ion, thm lc ngc v siu lc

2.2.1. Phng Php Keo T V ng TQu trnh lng ch c th tch c cc ht rn huyn ph nhng khng th tch c cc cht gy nhim bn dng keo v ha tan v chng l nhng ht rn c kch thc qu nh. tch cc ht rn mt cch c hiu qu bng phng php lng, cn tng kch thc ca chng nh s tc ng tng h gia cc ht phn tn lin kt thnh tp hp cc ht, nhm tng vn tc lng ca chng. Vic kh cc ht keo rn bng lng trng lng i hi trc ht cn trung ha din 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 (coagulation), cn qu trnh to thnh cc bng ln hn t cc ht nh gi l qu trnh keo t ( flocculation).2.2.1.1. Phng php keo tKeo 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.S keo t c tin hnh nhm thc y qu trnh to bng hydroxit nhm v st vi mc ch tng vn tc lng ca chng. Vic s dng cht keo t cho php gim cht ng t, gim thi gian ng t v tng vn tc lng.C ch lm vic ca cht keo t da trn cc hin tng sau: hp ph phn t cht keo trn b mt ht ko, to thnh mng li phn t cht keo. S dnh li cc ht keo do lc y Vanderwall. Di tc ng ca cht keo t gia cc ht keo to thnh cu trc 3 chiu, c kh nng tch nhanh v hon ton ra khi nc.Cht keo t thng dng c th l hp cht t nhin v tng hp cht keo t nhin l tinh bt, ete, xenlulozo, dectrin (C6H10O5) v dioxyt silic hot tnh (xSiO2.yH2O).

Hnh 2.10: Qu trnh keo t2.2.1.2. Phng php ng tQu trnh thy phn cc cht ng t v to thnh cc bng keo xy ra theo cc giai on sau:Me3+ + HOH Me(OH)2+ + H+Me(OH)2+ + HOH Me(OH)+ + H+Me(OH)+ + HOH Me(OH)3 + H+Me3+ + 3HOH Me(OH)3 + 3H+Cht ng t thng dng l mui nhm, st hon hn hp ca chng. Vic chn cht ng t ph thuc vo thnh phn, tnh cht ha l, gi thnh, nng tp cht trong nc, pH.Cc mui nhm dc dng lm cht ng t: Al2(SO4)#.18H2O, NaAl2, Al(OH)2Cl, KAl(OH)2.12H2O, NH4Al(SO4)212H2O. Thng nhm sunfat lm cht ng t v hot ng hiu qu pH = 5 7.5, tan tt trong nc, s dng dng kh hoc dng dung dch 50% v gi thnh tng i r.Cc mui st c dng lm cht ng t: Fe(SO3).2H2O, Fe(SO4)3.3H2O, FeSO4.7H2O v FeCl3. Hiu qu lng cao khi s dng dng kh dung dch 10-15%.

2.2.2. Tuyn ni Phng php tuyn ni thng c s dng tch cc tp cht ( dng rn hoc lng) phn tn khng tan, t lng km ra khi pha lng. Trong x l nc thi tuyn ni thng c s dng kh cc cht l lng u im c bn ca phng php ny so vi phng php lng l c th kh c hon ton cc ht nh hoc nh, lng chm, trong mt thi gian ngn. Khi cc ht ni ln b mt, chng c th thu gom bng b phn vt bt. 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 ca tp hp cc bng kh v ht ln s ko theo 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

Hnh 2.11: B tuyn ni2.2.3. Phng php trao i ion Trao i ion l mt qu trnh trong cc ion trn b mt ca cht rn trao i vi ion c cng in tch trong dung dch khi tip xc vi nhau. Cc cht ny gi l cc ionit (cht trao i ion), chng hon ton khng tan trong nc. Cc cht c kh nng ht cc ion dng t dung dch in ly gi l cationit, nhng cht ny mang tnh axit. Cc cht c kh nng ht cc ion m gi l anionit v chng mang tnh kim. Nu nh cc ionit no trao i c cation v anion gi l cc ionit lng tnh. Phng php trao i ion thng c ng dng loi ra khi nc cc kim loi nh : Zn, Cu, Cr, Ni, Pb, Hg, Mn, cc hp cht ca Asen, phospho, Cyanua v cc cht phng x.

Hnh 2.12: Qu trnh trao i ion2.2.4. Hp phPhng php hp ph c dng rng ri lm sch trit nc thi khi cc cht hu c ho tan sau khi x l sinh hc cng nh x l cc b khi nc thi c cha mt hm lng rt nh cc cht . Nhng cht ny khng phn hu bng con ng sinh hc v thng c c tnh cao. Nu cc cht cn kh b hp ph tt v chi ph ring cho lng cht hp ph khng ln th vic ng dng phng php ny l hp l hn c. Cc cht hp ph thng c s dng nh than hot tnh, cc cht tng hp v cht thi ca vi ngnh sn xut c dng lm cht hp ph (tro, r, mt ca). Cht hp ph v c nh t st, silicagen, keo nhm v cc cht hydroxit kim loi t c s dng v nng lng tng tc ca chng vi cc phn t nc ln.2.2.5. Cc qu trnh 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 ca cc hp cht qua mng. Ngi ta dng cc k thut nh in thm tch, thm thu ngc, siu lc v cc qu trnh tng t khc.2.2.6. Phng php in ha Mc ch ca phng php ny l x l cc tp cht tan v phn tn trong nc thi, c th p dng trong qu trnh oxy ho dng cc, kh m cc, ng t in v in thm tch. Tt c cc qu trnh ny u xy ra trn cc in cc khi cho dng in mt chiu i qua nc thi. Cc phng php in ho gip thu hi cc sn phm c gi tr t nc thi vi s cng ngh tng i n gin, d t ng ho v khng s dng tc cht ho hc. Nhc im ln ca phng php ny l tiu hao in nng ln. Vic lm sch nc thi bng phng php in ho c th tin hnh gin on hoc lin tc. Hiu sut ca phng php in ho 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 nng lng.2.2.7. Phng php trch ly Trch ly pha lng c ng dng lm sch nc thi cha phenol, du, axit hu c, cc ion kim loi Phng php ny c ng dng khi nng cht thi ln hn 3-4 g/l, v khi gi tr cht thu hi mi b p chi ph cho qu trnh trch ly. Lm sch nc thi bng phng php trch ly bao gm 3 giai on: Giai on th nht: Trn mnh nc thi vi cht trch ly (dung mi hu c) trong iu kin b mt tip xc pht trin gia cc cht lng hnh thnh 2 pha lng. Mt pha l cht trch vi cht c trch, cn pha khc l nc thi vi cht trch. Giai on th hai: Phn ring hai pha lng ni trn Giai on th ba: Ti sinh cht trch ly gim nng tp cht tan thp hn gii hn cho php cn phi chn ng cht trch v vn tc ca n khi cho vo nc thi.2.2.8. Phng php trung haNc thi cha cc axit v c hoc kim cn c trung ho a pH v khong 6,5 n 8,5 trc khi thi vo ngun nc hoc s dng cho cng ngh x l tip theo Trung ho nc thi c th thc hin bng nhiu cch khc nhau: - Trn ln nc thi axit vi nc thi kim - B sung cc tc nhn ho hc - Lc nc axit qua vt liu c tc dng trung ho - Hp th kh axit bng nc kim hoc hp th amoniac bng nc axit Vic la chn phng php trung ho l tu thuc vo th tch v nng nc thi, ch thi nc thi, kh nng sn c v gi thnh ca cc tc nhn ho hc. Trong qu trnh trung ho, mt lng bn cn c to thnh. Lng bn ny ph thuc vo nng v thnh phn ca nc thi cng nh loi v lng cc tc nhn s dng cho qu trnh.2.2.9. Kh trng nc thi Sau khi x l sinh hc, phn ln cc vi khun trong nc thi b tiu dit. Khi x l trong cc cng trnh sinh hc nhn to (b bn hot tnh) s lng vi khun gim xung cn 5%, trong h sinh vt hoc cnh ng lc cn 1-2%. Nhng tiu dit ton b vi khun gy bnh, nc thi cn phi kh trng Clo ho, Ozon ho, in phn, tia cc tm2.2.10. Phng php oxy ho kh Mc ch ca phng php ny l chuyn cc cht nhim c hi trong nc thi thnh cc cht t c hn v c loi ra khi nc thi. Qu trnh ny tiu tn mt lng ln cc tc nhn ho hc, do qu trnh oxy ho ho hc ch c dng trong nhng trng hp khi cc tp cht gy nhim bn trong nc thi khng th tch bng nhng phng php khc, thng s dng cc cht oxy ho nh Clo kh v lng, nc Javen (NaOCl), Kalipermanganat (KMnO4), Hypocloric Canxi (Ca(ClO)2), H2O2, Ozon2.3. Phng php sinh hc Phng php sinh hc l phng php s dng kh nng sng v hot ng ca cc vi sinh vt c ch phn hy cc cht hu c v thnh phn nhim trong nc thi. Cc quy trnh x l sinh hc ch yu c 4 nhm chnh: qu trnh hiu kh trung gian anoxic k kh cc qu trnh h. i vi vic x l nc thi sinh hot c yu cu u ra khng qua kht khe i vi ch tiu N v P, qu trnh x l hiu kh bng bn hot tnh l qu trnh x l sinh hc c ng dng nht. Do vy phng php ny thng c p dng sau khi loi b cc loi tp cht th ra khi nc thi c hm lng cht hu c cao.Qu trnh x l sinh hc gm cc bc: - Chuyn ho cc hp cht c ngun gc cacbon dng keo v dng ho tan thnh th kh v thnh cc v t bo vi sinh. - To ra cc bng cn sinh hc gm cc t bo vi sinh vt v cc cht keo v c trong nc thi- Loi cc bng cn ra khi nc thi bng qu trnh lng2.3.1. Phng php sinh hc trong iu kin t nhin tch cc cht bn hu c dng keo v ho tan trong iu kin t nhin ngi ta x l nc thi trong ao, h (h sinh vt) hay trn t (cnh ng ti, cnh ng lc). 2.3.1.1. H sinh hc H sinh hc l cc ao h c ngun gc t nhin hoc nhn to, cn gi l h oxy ho, h n nh nc thi. Trong h sinh vt din ra qu trnh oxy ho sinh ho cc cht hu c nh cc loi vi khun, to v cc loi thy sinh vt khc tng t nh qu trnh lm sch ngun nc mt. h hot ng bnh thng cn phi gi gi tr pH v nhit ti u, nhit khng c thp hn 60C. Theo bn cht qu trnh sinh ho, ngi ta chia h sinh hc ra cc loi h sinh hc hiu kh, h sinh hc tu tin v sinh hc ym kh. H sinh hc hiu kh Qu trnh x l nc thi xy ra trong iu kin y oxy, oxy c cung cp qua mt thong v nh quang hp ca to hoc h c lm thong cng bc nh cc h thng thit b cp kh. su ca h sinh hc hiu kh khng ln t 0,5-1,5m. H sinh hc tu nghi C su t 1,5 2,5m. Theo chiu su lp nc c th din ra hai qu trnh: Oxy ho hiu kh v ln men ym kh cc cht bn hu c. Trong h sinh hc tu nghi vi khun v to c quan h tng h ng vai tr c bn i vi s chuyn ho cc cht. H sinh hc ym kh C su trn 3m, vi s tham gia ca hng trm chng loi vi khun k kh bt buc v k kh khng bt buc. Cc vi sinh vt ny tin hnh hng chc phn ng ho sinh hc phn hu v bin i cc hp cht hu c phc tp thnh nhng cht n gin d x l. Hiu sut gim BOD trong h c th ln n 70%. Tuy nhin nc thi sau khi ra khi h vn c BOD cao nn loi h ny ch ch yu p dng cho x l nc thi cng nghip rt m c v dng lm h bc 1 trong t hp nhiu bc.Hnh 2.13: H sinh hc2.3.1.2. Cnh ng ti v bi lcVic x l nc thi c thc hin trn nhng cnh ng ti bi lc l da vo kh nng gi cn trong nc trn mt t, nc thm qua t i qua lc nh c oxi trong cc l hng v mao qun ca lp t mt, cc vsv hiu kh hot ng phn hy cc cht hu c nhim bn, cng xung su th lng oxi cng gim dn v qu trnh oxi ho cc cht hu c gim dn, cui cng n su m ch din ra qu trnh kh nitrat. V vy cnh ng ti v bi lc ch xy dng nhng ni c mc nc ngun thp hn 1,5m so vi mt t.Nc thi truc khi a vo cnh ng ti v bi lc cn c x l s b nh qua song chn rc loi b rc, cc vt th cng, qua b lng loi ct, si v cc tp cht rn, loi b du m nhm trnh bt kn cc l hng v mao qun lm gim s thong kh nh hng n kh nng oxi ho cc cht bn ca h VSV.2.3.2. Phng php sinh hc trong iu kin nhn to2.3.2.1. B lc sinh hc B lc sinh hc l cng trnh nhn to, trong nc thi c lc qua vt liu rn c bao bc mt lp mng vi sinh vt. B lc sinh hc gm cc phn chnh nh sau: Phn cha vt liu lc H thng phn phi nc m bo ti u ln ton b b mt b, h thng thu v dn nc sau khi lc H thng phn phi kh cho b lc Qu trnh oxy ho cht thi trong b lc sinh hc din ra ging nh trn cnh ng lc nhng vi cng ln hn nhiu. Mng vi sinh vt s dng v xc vi sinh vt cht theo nc tri khi b c tch khi nc thi b lng t 2. m bo qu trnh oxy ho sinh ho din ra n nh, oxy c cp cho b lc bng cc bin php thng gi t nhin hoc thng gi nhn to. Vt liu lc ca b lc sinh hc c th l nha Plastic, x vng gm, Granit B lc sinh hc nh git B c dng hnh vung, hnh ch nht hoc hnh trn trn mt bng, b lc sinh hc nh git lm vic theo nguyn tc sau: Nc thi sau b lng t 1 c a v thit b phn phi, theo chu k ti u nc trn ton b b mt b lc. Nc thi sau khi lc chy vo h thng thu nc v c dn ra khi b. Oxy cp cho b ch yu qua h thng l xung quanh thnh b.Vt liu lc ca b sinh hc nh git thng l cc ht cui, ng knh trung bnh 20 30 mm. Ti trng nc thi ca b thp. Chiu cao lp vt liu lc l 1,5 2 m. Hiu qu x l nc thi theo tiu chun BOD t 90%. Dng cho cc trm x l nc thi c cng sut di 1000 m3/ngy m.Hnh 2.14: B lc sinh hc nh git B lc sinh hc cao ti B lc sinh hc cao ti c cu to v qun l khc vi b lc sinh hc nh git, nc thi ti ln mt b nh h thng phn phi phn lc. B c ti trng 10 20 m3 nc thi/1m2 b mt b /ngy m. Nu trng hp BOD ca nc thi qu ln ngi ta tin hnh pha long chng bng nc thi lm sch. B c thit k cho cc trm x l di 5000 m3/ngy m.2.3.2.2. B AerotankTrong b Aerotank xy ra 2 qu trnh c bn: Qu trnh tng sinh khi ca vsv. Qu trnh hot ng ca enzim hay qu trnh phn gii vt cht hu c trong nc thi. Ngun vsv c trong nc thi: Ngun ging VSV vt c nui cy ring (bn hot tnh) trong cc c s to ging v a vo tng thm kh nng chuyn ho vt cht hu c trong nc thi. Khi vo b Aerotank, VSV tri qua mt s giai on pht trin vi tc khc nhau. trng thi tnh, mi trng nc thi cha nhng cht hu c tng i ng nht, d phn hu nh nhau, VSV s pht trin theo mt qui lut ring bit. Lc u, chng tri qua giai on thch nghi, sau l giai on tng sinh rt nhanh, sau mt thi gian nht nh chng s to c trng thi cn bng (n nh) v kt thc bng giai on suy vong, lng sinh khi to ra nhiu hay t, thi gian ca qu trnh tng sinh di hay ngn cn tu thuc vo cc qu trnh bn ngoi tc ng vo VSV.i vi nhng vsv c nui cy trong mi trng nhn to th giai on thch nghi thng ngn hn so vi nhng VSV c trong mi trng nc thi. Bi v trong mi trng nhn to bao gm nhng thnh phn dinh dng c kim sot v d tiu hy, cn trong mi trng nc thi cc cht dinh dng thng ln vi cc cht c hi, mun pht trin c th VSV khng ch phi tri qua giai on qu trnh thch nghi vi cht dinh dng mi phc tp m cn phi thch nghi mi vi cc cht c hi.VSV pht trin trong b Aerotank thng rt chm v sinh khi to ra thng khng bng sinh khi to ra trong mi trng nhn to. Nguyn nhn ch yu l docc VSV c xu th s dng cc thnh phn dinh dng d phn hu trc, sau mi phn hu cc thnh phn kh phn hu.Sau cng, nhu cu oxi ho li gim v cn phi kt thc qu trnh lm vic ca b Aerotank. Sau khi oxi ho 80% - 90% BOD trong nc thi nu khng khuy trn v thi kh th bn hot tnh s lng xung y. Cn phi ly bn cn ra khi nc, nu khng kp thi tch nc s b nhim th cp ngha l sinh khi ca VSVtrong bn s t phn hy. Ngoi ra cn c cc hp cht cha cht bo, hydratcacbon, cc cht khong,khi t phn hy s lm nhim ngun nc.Hnh 2.15: B Aerotank2.3.2.3. Mng oxy haL dng ci tin ca Aerotank khuy trn hon chnh lm vic trong iu kin hiu kh ko di vi bn hot tnh (sinh trng l lng ca VSVtrong nc thi) chuyn ng tun hon trong mng. Mng oxi ho c dng hnh ch nht, hnh trn hay hnh elip. y v b c th lm bng b tng ct thp hoc o t c gia c. Chiu su cng tc t 0.7 1m.

Hnh 2.16: Mng oxy ha2.3.2.4. B sinh hc theo m SBRQu trnh x l gm 4 giai on: Pha lm y (fill): thi gian bm nc vo ko di t 1-3 gi. Dng nc thi c a vo b trong sut thi gian din ra pha lm y. Trong b phn ng hot ng theo m ni tip nhau, tu theo mc tiu x l, hm lng BOD u vo, qu trnh lm y c th thay i linh hot: lm y tnh, lm y ha trn, lm y sc kh. Pha phn ng, thi kh (React): To phn ng sinh ha gia nc thi v bn hot tnh bng sc kh hay lm thong b mt cp xy vo nc v khuy trn u hn hp. Thi gian lm thong ph thuc vo cht lng nc thi, thng khong 2 gi. Trong pha phn ng, qu trnh nitrat ha c th thc hin, chuyn Nit t dng N-NH3 sang N-NO2 v nhanh chng chuyn sang dng N-NO3. Pha lng (settle): Lng trong nc. Qu trnh din ra trong mi trng tnh, hiu qu thy lc ca b t 100%. Thi gian lng trong v c c bn thng kt thc sm hn 2 gi. Pha rt nc (draw): khong 0,5 gi. Pha ch : Ch i np m mi, thi gian ch i ph thuc vo thi gian vn hnh 4 quy trnh trn v vo s lng b, th t np nc ngun vo b. X bn d l mt giai on quan trng khng thuc 5 giai on c bn trn, nhng n cng nh hng ln n nng sut ca h. Lng v tn sut x bn c xc nh bi nng st yu cu, cng ging nh h hot ng lin tc thng thng. Trong h hot ng gin on, vic x bn thng c thc hin giai on lng hoc giai on tho nc trong. c im duy nht l b SBR khng cn tun hon bn hot ho. Hai qu trnh lm thong v lng u din ra ngay trong mtb, cho nn khng c s mt mt bn hot tnh giai on phn ng v khng phi tun hon bn hot tnh t b lng gi nng .2.3.2.4. Qu trnh x l sinh hc k kh B UASB Nc thi c a trc tip vo pha di y b v c phn phi ng u, sau chy ngc ln xuyn qua lp bn sinh hc dng ht nh (bng bn) v cc cht hu c b phn hy. Cc bt kh mtan v NH3, H2S ni ln trn v c thu bng cc chp thu kh dn ra khi b. Nc thi tip theo chuyn n vng lng ca b phn tch 2 pha lng v rn. Sau ra khi b, bn hot tnh th hon lu li vng lp bng bn. S to thnh bn ht v duy tr c n rt quan trng khi vn hnh UASB. Thng cho thm vo b 150 mg/l Ca2+ y mnh s to thnh ht bn v 5 - 10 mg/l Fe2+ gim bt s to thnh cc si bn nh. duy tr lp bng bn trng thi l lng, tc dng chy thng ly khong 0,6-0,9 m/h.

Hnh 2.16: B SBR Tip xc k khB ln men c thit b trn v b lng ring.Qu trnh ny cung cp phn ly v hon lu cc vi sinh vt ging, do cho php vn hnh qu trnh thi gian lu t 6 - 12 gi. Cn thit b kh kh (Degasifier) gim thiu ti trng cht rn bc phn ly. x l mc cao, thi gian lu cht rn c xc nh l 10 ngy nhit 32oC, nu nhit gim i 11oC, thi gian lu i hi phi tng gp i.

CHNG 3: QUY TRNH CNG NGH X L V THNG S THIT K H THNG X L NC THI NH MY GIT M GIA SC, CNG SUT 500M3/NGY M3.1. C s la chn phng n x l nc thi xc nh c dy chuyn cng ngh x l cn phi phn tch c cc ch tiu gy nhim, cng vic ny c tnh cht rt quan trng v n quyt nh dy chuyn cng ngh v hiu sut ca qu trnh x l nc thi.Lng nc thi chn nui ch yu l t cng on tm v ra chung, v vy m thnh phn ca nc thi ch yu l ca phn v nc tiu. l l do m hm lng BOD, Nit tng v photpho tng trong nc thi cao. Cng vic loi b Nit v photpho trong nc l rt kh, thng c x l bng phng php sinh hc.Bng 3.1: Thnh phn nc thai git m gia sc u vo, u raSTTc tnhGi trn vTiu chn thi ngun loi B (QCVN 24:2008/BTNMT)

1pH6.7-5,5-9

2BOD52500mg/L50

3COD3600mg/L100

4SS420mg/L100

5Ntng250mg/L50

6Ptng14mg/L6

7Coliform7*108mg/L5000

3.2. xut cng nghVic la chn cng ngh x l ph thuc vo cht lng c trng ca ngun nc. Cc vn cn cp n khi thit k qu trnh x l nc bao gm cht lng nc, yu cu v cht lng nc sau x l. Da vo cc s liu c sn so snh cht lng nc v nc sau x l quyt nh cn x l cht g ra khi nc, ri chn cc thng s chnh v cht lng nc v xut cng ngh x l nc m bo nc sau x l t tiu chun nc thai.

3.2.1. Phng an I3.2.1.1. S cng nghB lng 2B cha bnB lng 1B aerotankB kh trngNc thi B to bngB iu haB keo tNaOH hoc Axit phn nhmPolymer AnionSong chn rc v tch du m C quan chc nngNc thi ra t ct B, QCVN 24: 2008 THB

Bn d

Bn d

3.2.1.2. Thuyt minh Hnh 3.1 S qui trnh cng ngh theo phng n1

3.2.1.2. Thuyt minh quy trnh cng nghNc thi sn xut v nc thi sinh hot ca cc c s, nh my git m gia sc c dn v h thu v cho chy vo b tch du m v song chn rc. Du m c tch ra ni ln trn mt nc thi s c thi gt vo mng bng my gt v du ny c a i x l nh cht thi c hi, phn nc cn li s chy trn qua b iu ha.Trong b iu ha, nc thi c ha trn iu tit n nh v lu lng cng nh nng cht nhim trc khi c bm vo cc b x l. T b iu ha, dng thi c a vo h thng.Ti h thng XLNT, dng thi vi lu lng n nh (khong 21 m3/h) c bm vo b keo t v c ha trn u vi cc dung dch iu chnh pH, dung dch keo t, nc thi c dn sang b to bng v c b sung dung dch tr keo t (Polymer Anion) ng thi c khuy trn ch thy ng lc hc thch hp nhm tng kch c cho cc ht bng keo t. Hn hp bn v nc sau khi ra khi b to bng c dn sang b lng s cp thc hin qu trnh lng tch cn. Ti y, di tc dng ca trng lc v s chnh lch ca nc vi bn cn, phn bn ri xung y. Nc sau qu trnh x l ha l v tch cn m bo loi b phn ln cc kim loi nng v c a sang b Aerotank.Ti b Aerotank, nc thi c ha trn u vi khng kh sc t y b v cc chng VSV hiu kh (di dng bn hot tnh). Kt qu l cc cht nhim hu c c trong nc thi c oxy ha trit .Hn hp bn v nc sau khi ra khi b Aerotank c dn sang b lng th cp thc hin qu trnh lng tch cn. C ch lng tch cn ti b lng th cp din ra tng t nh qu trnh lng s cp.Nc sau khi x l t b lng th cp tip tc c dn sang b kh trng. Ti y nc c ha trn u vi dung dch Ca(OCl)2 ng thi lu vi thi gian thch hp thc hin qu trnh kh trng. Nc sch sau khi kh trng t tiu chun cho php (ct B, QCVN 24:2008) a v ngun tip nhn.Bn cn di y b lng s cp c bm bn bm v b cha bn. Bn lng di y b lng th cp c tun hon lin tc v b Aerotank b sung hm lng VSV cho b ny. nh k phn bn d (sinh khi c to ra t qu trnh x l) s c a v b cha bn. Ti b cha bn, bn d c bm v my p bn nhm lm gim th tch, thi ra bn thi v c cng ty c trch nhim thu gom, x l.

3.2.2. Phng an II3.2.2.1 S cng nghBn d

B cha bnTHBLi chn rc

B lng ct + B vt du m+=+B iu ha

B UASBNc thiB lc p lcB lng li tmB AerotankB trung gianB kh trngNc thi u rat loi B (QCVN 24:2008)My thi khHa cht kh trng

Bn d

Hnh 3.2 Qui trnh s cng ngh theo phng n 2

3.2.2.2. Thuyt minh quy trinh cng ngh:Nc thi c a qua li chn rc nhm loi b mt phn rc, lng heo, lng b, cc cht l lng c kch thc ln trc khi vo b tch du kt hp b lng ct. Li ca thit b chn rc s gi li hu ht cc lng heo, cc cht l lng, trn b mt li. Thit b tch rc hot ng lin tc v rc c a vo cc thng cha rc.Rc t y c thu gom v em i chn lp ngoi h thng x l. Nc thi sau khi qua thit b li chn rc s t chy qua b tch du kt hp b lng ct. Ct, t, du m c xem l cc tc nhn gy nh hng cho h thng x l sinh hc, v cc cht ny hn ch kh nng s dng cht hu c ca vi sinh vt. Do , cng trnh sinh hc hot ng c hiu qu, b tch du kt hp b lng ct c s dng trong dy chuyn cng ngh ny. Phng php trng lc c p dng tch du m v ct ra khi nc thi. Du m c trng lng ring nh hn nc nn du m s ni ln trn b mt b v c h thng gt vng du thu gom vo bn cha du. Lng du ny cng s c thu gom nh k v em i x l thch hp.Ct c khi lng nng s t lng xung y. Lng ct ny s c a n b cha bn. Nc sau khi qua b tch du kt hp b lng ct s t chy vo b iu ha. Ti y, b iu hamy khuy trn chm s ha trn ng u nc thi trn ton din tch b, ngn nga hin tng lng cn b sinh ra mi kh chu. B iu ha c chc nng iu ha lu lng v nng nc thi u vo trm x l. Sau , nc thi tip tc qua b UASB. Ti b UASB, nc thi i t pha y b ln trn, i qua lp bn ht v ton b cc qu trnh sinh ha s din ra trong lp bn ny cc vi sinh vt k kh dng l lng s phn hy cc cht hu c c trong nc thi thnh cc cht v c dng n gin v kh CO2, CH4, H2S.Kh sinh ra trong iu kin k kh (ch yu l methane v CO2) s to nn dng tun hon cc b gip cho qu trnh hnh thnh v duy tr bn sinh hc dng ht trong b c n nh. Kh sinh ra t lp bn s dnh bm vo cc ht bn v cng vi kh t do ni ln pha mt b Trong b UASB c b phn tch 3 pha: kh , nc thi v bn. Nc thi sau khi c tch bn v kh c dn sang b Aerotank. B aerotank c la chn x l tng hp: kh BOD, nitrat ha, kh NH4+v kh NO3-thnh N2, kh Phospho. Ti y din ra qu trnh phn hy hiu kh cc hp cht hu c. B c thi kh lin tc nhm duy tr iu kin hiu kh cho vi sinh vt pht trin. Sau nc thi c dn sang b lng II, nc c phn phi vo ng trung tm ca b lng v c hng dng t trn xung. Cc bng cn vi sinh s va chm, tng kch thc v khi lng trong qu trnh chuyn ng trong ng tung tm. Bn lng xung y b. Mt phn c tun hon li b aerotank, mt phn c a n b cha bn. Nc trong chy trn qua mng rng ca ca b lng v t chy vo b trung gian. B trung gian lu gi nc trong khong thi gian nht nh. Sau , nc c bm vo b lc loi b trit cc cn cn st li trong nc trc khi i vo b kh trng. Ti b kh trng, nc thi c c kh trng trc khi x thi vo ngun tip nhn, x l trit cc vi trng gy bnh trong nc nh E.Coli, Coliform, Nc sau b kh trng t tiu chun x thi vo ngun tip nhn. Nc thi m bo t tiu chun x thi loi B theo QCVN 24:2008/BTNMT trc khi thot ra h thng thot nc ca khu vc.Trn c s u, nhc im cc ch tiu lin quan ca hai phng n ni trn, nhn thy phng n 2 ti u hn v cng l phng n c chn x l nc thi cho cs git m gia sc.Bng 3.2 Bng so snh phng n 1 v 2Phng n 1Phng n 2

Ging nhauX l nc thi u ra t tiu chun cao thi ra mi trng

Khc nhauTn chi ph ha cht cao cho b keo t, to bng.Sinh ra cht nhim th cp trong qu trnh x li hi trnh cao v mt trnh v k thut vn hnhChi ph vn hnh caoLng bn sinh ra nhiu hn phng n 2

Kh thi v mt kinh t trong vn u t ban u, kh nng ch c s chi tr.C th m rng khi hot ng sn xut tng ln.Chi ph vn hnh thp.Khng i hi cao v mt trnh v k thut vn hnh.Khng sinh ra cht nhim th cp.Din tch mt bng cn cho khu x l theo phng 2 ln hn phng 1

Trn c s so snh cc ch tiu lin quan ca hai phng n ni trn, nhn thy phng n 2 ti u hn v cng l phng n c chn x l nc thi cho c s git m gia sc.3.3 Tnh ton cc cng trnh theo phng n IILu lng nc thi ca nh my git m Qtb= 500 (m3/ ngy m)Chn h s khng iu ha l = 2,5 (Kh =1,5 -3,5)

Lu lng gi ln nht = 3.3.1 Li chn rac: Nhim vLi chn rc c nhim v tch cc vt th nh gi, rc, v hp, cc mu , g v cc vt khc trc khi a vo cc cng trnh x l pha sau. Li ca thit b lc rc tinh s gi hu ht cc lng heo, cc cht l lng, trn b mt li. Li chn rc c th t c nh hoc di ng, li chn rc gip trnh cc hin tng tc nghn ng ng, mng dn v gy tt nghn bm. Tn h tonChn li c nh dng lm c kch thc mt li d = 0,35mm tng ng vi ti trng LA = 700l/phut.m2, t hiu qu x l cn l lng E = 25%.Gi s li chn rc c chn theo thit k nh hnh c kch thc li B x L = 1 x 1 m. (Bang 10-5 X li nc thai thi va cng nghip Lm Minh Trit)Din tch b mt li:

S li chn rc:

(li)Ti trng lm vic thc t:

Ham lng cn l lng SS sau khi qua li chn rc:SS = 420.(100 -25)% = 315(mg/l)Gi s: Hm lng BOD5 ,COD ca nc thi qua qu trnh x l ti li chn rc gim 5% v cn li:BOD5 = 2500(100- 5)%= 2375(mg/l)COD = 3600(100-5)%= 3420(mg/l)Bng 3.3: Thng s li chn rcSTTThng s Gi trn v

1Din tch b mt li1,24m2

2Ti trng lm vic thc t434l/m2.ph

3S li chn rc2li

4Hm lng SS u ra315mg/l

5Hm lng BOD5 u ra2375mg/l

6Hm lng COD u ra3420mg/l

3.3.2. B lng cat: Nhim vu:Nhim v ca b lng ct l lng cc ht cn c kch thc ln nhm bo v cc thit b my mc khi b mi mn, gim s lng ng cc vt liu nng trong ng, knh, mng dnB lng ct dng tch cc hp phn khng tan v c ch yu l ct ra khi ngun nc.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 tip tuyn vi phn di hnh tr vo b. Ch dng chy kh phc tp, nc va chuyn ng vng, va xon theo trc, va tnh tin i ln, trong khi ct ht ct dn v trung tm v ri xung y.B lng ct tip tuyn: l loi b c thit din hnh trn, nc thi c dn vo b theo chiu t tm ra thnh b v c thu vo mng tp trung ri dn ra ngoi.B lng ct lm thong: trnh lng cht hu c ln trong ct v 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 ct v cc phn t nng c th lng. Tnh ton:

B lng ct ngang phi m bo vn tc chuyn ng ca nc l 0,15m/s v 0,3m/s v thi gian lu nc trong b l 30s t 60s (iu 6.3.20 TCXD 51 84).Chn thi gian lu ca b lng ct ngang: t = 60sCho vn tc nc trong b lng ngang: vm = 0,3 (m/s).Th tch tng cng ca b lng ct ngang

Din tch mt ct ngang ca b lng ct ngang:

Chiu rng ca b lng ct ngang:

h: chiu cao cng tc ca b lng ct ngang vi qmax: h = 0,25 1m (TCVN 7957-2008). Chn H = 0,3 m.Chia b lng ct thnh 2 ngn: n = 2.Chiu rng cua 1 ngn:

Chiu di ca b lng ngang:

Lng ct trung bnh sau mi ngy m:

Vi q0: lng ct trong 1000 mnc thi, q0 = 0,15 mct/ngmChiu cao lp ct trong b lng ct ngang trong 1 ngy m:

Vi tx = 1: chu k ly ct l 1 ngy mChiu cao xy dng ca b:HXD = h + hc + hbv = 0,3 + 0,026 + 0,3 = 0,626(m)Trong :h: chiu cao cng tc ca b lng ct h = 0,3m.hc: chiu cao lp ct trong b hc = 0,026m.hbv: chiu cao bo v hbv = 0,3m.Gi s: hiu qu x l hm lng BOD5, COD gim 5% v SS gim 35% ca nc thi sau qu trnh x l ti b lng ct ngang (Trang 122; Tnh ton thit k XLNT th v cng nghip, Lm Minh Trit ).Thng s u ra l:SS = 315(100- 35)% = 205 (mg/ l)BOD5= 2375(100-5)% = 2256(mg/l)COD = 3420(100- 5)% = 3249(mg/l)Bng 3.4 Tng hp thng s thit k b lng ctThng sn vGi tr

Chiu di, LM7,25

Chiu rng, BM0,2

Chiu cao cng tc, hM0,3

Chiu cao lp ct, hcM0,026

Chiu cao bo v, hbvM0,3

Chiu cao xy dng, HM0,626

S ngn trong b, nNgn2

Din tch mt ct ngang, Fnm20,05

Hm lng SS u ra ti b lng ct ngangmg/l205

Hm lng BOD u ra ti b lng ct ngang mg/l2256

Hm lng COD u ra ti b lng ct ngangmg/l3249

3.3.3 B vt du m Nhim vNc thi ca mt s nh my ch bin b, cc l m, x nghip p du thng c ln du m. Cc cht ny nh hn nc v ni ln trn mt nc. Nc thi sau x l khng c ln du m mi c php chy vo cc lu vc. Hn na, nc thi c ln du m khi vo x l sinh hc s lm bt c l hng vt liu lc v cn lm hng cu trc b hot tnh trong b aerotank Tnh tonThng s u vo:Hm lng SS = 205(mg/l)Hm lng BOD = 2256(mg/l)Hm lng COD = 3249(mg/l)Chn thi gian lu nc l T= 2h (quy phm 1,5-3h) Ti trng b mt U0 =40(m3/m2.ng) (nm trong gii hn cho php bng 4-3 sch tnh ton thit k cc cng trnh XLNT)Chn kiu thit k di:rng = 1:4Th tch b vt du:

Din tch b mt

Chiu rng b mt

Chiu di L=2B= 8(m)Din tch b F= 31,25(m2)Chiu cao b:

Thi gian lu nc trong b

Vn tc nc chy trong vng lng

Hiu qu kh BOD, COD

(theo chng 2:X l nc thi bng phng php c hc, sch K thut x l nc thi- Thc s Lm Vnh Sn, trng i hc Ti nguyn v Mi trng Tp.HCM) Hm lng BOD5, COD u ra ti b vt du mBOD5 =2256(100- 34,48)% = 1478(mg/l)COD = 3249(100- 34,48)% =2128(mg/l)Gi s: Hm lng SS sau qu trnh x l ti b vt du m l 5% (Chng 2, X l nc thi th v cng nghip, Lm Minh Trit)SS = 205(100 - 5)% = 195(mg/l)Bng3.5 Tng hp thng s thit k b vt du mThng sn vGi tr

Chiu di, LM8

Chiu rng, BM4

Chiu cao, HM3,33

Thi gian lu nc trong bH2

Din tch b mt b tch du m, Fm231,25

Hm lng SS u ra ti b tch du mmg/l195

Hm lng BOD5 u ra ti b tch du mmg/l1478

Hm lng COD u ra ti b tch du mmg/l2128

3.3.3. B iu hoa: Nhim vB iu ho c nhim v iu ho lu lng v nng nc thi dng vo, trnh lng cn v lm thong s b, qua oxy ho mt phn cht hu c trong nc thi. Nc thi c n nh v lu lng v nng thun li cho vic x l cc cng trnh x l sau, nht l s trnh c hin tng qu ti ca h thng x l. m bo iu ho nng , lu lng v trnh lng cn, b c b tr h thng thi kh lm vic lin tc. Tnh tonThng s u vo:Hm lng SS = 195 (mg/l)Hm lng BOD5 = 1478 (mg/l)Hm lng COD = 2128 (mg/l)Chn thi gian lu nc ca b iu ho t = 8h (quy phm 6 - 12h, theo chng 9, Tnh ton thit k XLNT th v cng nghip, Lm Minh Trit).Th tch cn thit ca b:

Chn chiu cao hu ch ca b iu hoa l H = 5,2m.Chiu cao bo v l Hbv = 0,3m. Chiu cao xy dng b iu ha l 5,5m.Din tch b:

Chn chiu rng b l 8m, chiu di b l 10m.Vy kch thc b iu ha l L x B x Hxd = 10x 8 x 5,5 (m).Tnh ton h thng sc kh:Chn khuy trn b iu ha bng h thng thi kh. Lng kh nn cn cho thit b khuy trn:

Trong :R: tc kh nn, R = 10 15 l/m3.pht. Chn R = 11 l/m3.pht = 0,011 m3/m3.phtVH: th tch ca b iu hoChon 2 may thi khi, lu lng mi may la Qk = 4,58 m3/ph, 1 lam vic va 1 d phongBng 3.6 Thng s tnh ton my thi kh b iu haLu lng khilit/phut.caiHiu sut chuyn hoa oxytiu chun su 4,6 m;%

ia s - li 11962540

Chup s li14712739

Ban s li571422633

ng platic xp cng b tri:

+ Dang li681132832

+ Hai phia theo chiu dai (dong chay xon hai bn)853111728

+ Mt phia theo chiu dai (dong chay xon mt bn)573401325

ng platic xp mm b tri:

+ Dang li281982636

+ Mt phia theo chiu dai571981937

ng khoan b tri vi tri:

+ Dang li281132229

+ Mt phia theo chiu dai571701519

Khuch tan khng xp:

+ Hai phia theo chiu dai932831223

+ Mt phia theo chiu dai283990912

Chn khuch tn kh bng a s b tr dng li. Vy s a khuch tn l:

(a)Trong : r: lu lng kh, chn r = 90 l/pht.a.Cc a c b tr dng li u khp y b. Phn phi a thnh 5 hng theo chiu di, mi hng 9 a.Chn ng ng dn kh:Vi lu lng kh qk = 4,58 m3/pht = 0,076 m3/s v chn vn tc kh trong ng vkk= 10 m/s (v = 10 15 m/s) c th chn ng knh ng chnh :

Chn ng chnh c ng knh 98mm.

i vi ng nhnh c lu lng v chn vn tc trong ng nhnh l 10 m/s ng knh ng nhnh l:

Chn ng chnh c ng knh 45mm.Tnh ton cc ng dn nc vo v ra khi b iu ho:Nc thi c a vo b iu ho, chn vn tc nc vo b l 0,7 m/s, lu lng nc thi 52,083m3/h, ng knh ng vo l:

Chn ng nha PVC c ng knh 170mmChn vn tc nc ra khi b l 1m/s, ng knh ng dn nc ra:

Chn ng nha PVC c ng knh 140mm.Gi s: Hiu qu x l hm lng BOD5, COD gim 5% v hm lng SS gim 4% ca nc thi ti b iu ha (theo X l nc thi cng nghip, Tnh Xun Lai)Thng s u ra:SS = 195 (100 - 5) % = 185 (mg/l)BOD5 = 1478 (100 - 5)% = 1404 (mg/l)COD = 2128 (100 - 5)% = 2021 (mg/l)Bng 3.7: Thng s b iu hoaSTTThng sGia trin v

1Chiu di, L10M

2Chiu rng, B8M

3Chiu cao, Hxd5,5M

4S a khuych tn kh, n45a

5ng knh ng dn kh chnh, D98mm

6ng knh ng nhnh dn kh, dn45mm

7ng knh ng dn nc vo b,Dv 170mm

8ng knh ng dn nc ra khi b, Dr 140mm

9Hm lng SS u ra ti b iu ha185mg/l

10Hm lng BOD5 u ra ti b iu ha1404mg/l

11Hm lng COD u ra ti b iu ha2021mg/l

3.3.5. B UASB Nhim vLm gim ng k hm lng COD, BOD trong nc thi bng cch s dng lp cn l lng (c cha rt nhiu vi sinh vt ym kh) trong dch ln men nh h thng nc thi chy t pha di ln. ng thi to thun li cho qu trnh x l hiu kh trong b aerotank. Tnh ton:Cc thng s u vo:Hm lng SS: 185( mg/l)Hm lng BOD5: 1404(mg/l)Hm lng COD: 2021(mg/l) Din tch b mt b UASB:

LA : Ti trng b mt phn lng, L = 12 m3/m2.ngy. (Bng 10 9, XLNT th v cng nghip , Lm Minh Trit).Th tich ngn phan ng b UASB:

Co: Hm lng COD u vo (mg/l).LCOD: Ti trng th tch hu c ca b UASB bn ht, LCOD = 8 kgCOD/m3.ngay. (Bng 10-10 - XLNT th v cng nghip - Lm Minh Trit).Chiu cao phn x l k kh:

Tng chiu cao ca b l:H = H1 + H2 + H3Trong : H1: chiu cao phn x l k kh, H1 = 3mH2: chiu cao phn lng, chn H2 = 1,5m.H3: chiu cao bo v, H3 = 0,3m. Chiu cao b: H = 3 + 1,5 + 0,3 = 4,8 (m)Chn H = 5m. B = 5m L = 6mLng bn nui cy ban u cho vo b (TS = 5%)

(tn)Trong :Css: Hm lng bn trong b. Css = 25 kg/m3 ( Bng 10-12 ,X l nc thi th v cng nghip, Lm Minh Trit).TS: Hm lng cht rn trong bn nui cy ban u.Hm lng COD ca nc thi sau x l k kh:CODra = (1 ECOD).CODvo = (1 0,65).2021 = 707 mg/lHm lng BOD5 ca nc thi sau x l k kh:BOD5 = (1 EBOD).BODvo = (1 0,75).1404 = 351 mg/lLng sinh khi hnh thnh mi ngy:

(kgVS/ng)Trong :Y: h s sn lng sinh t bo, Y = 0,04 g VSS/g CODkd: h s phn hy ni bo, chon kd = 0,015

: thi gian lu bn (35 100 ngy), chn = 90 ngyS0, S: lng COD u vo v u ra bLng bn d bm ra mi ngy:

(m3/ngy)CSS: hm lng bn trong b (kg/m3)Lng cht rn t bn d:MSS = Qw.CSS = 0,64 * 25 = 16(kgSS/ngy)Tnh cc ng phn phi nc vo b UASB:Vn tc nc chy trong ng chnh v = 0,8 - 2m/s, chn v = 1m/s.

D = == 0,086 (m)

Chn ng nha PVC c ng knh 90mm. T ng chnh chia lm 2 ng nhnh vo 2 n nguyn.Vn tc nc chy trong ng nhnh v = 0,8 - 2m/s, chn v = 1m/s.

Dn = = = 0,06 (m)

Chn ng nha PVC c ng knh 60mm.

Bng 3.8: Thng s b UASBSTTTn thng sGi trn v

1Chiu di b (L)6M

2Chiu rng b (B)5M

3Chiu cao b (H)5M

4ng kinh ng dn nc thai vao (D)90Mm

5ng kinh ng nhnh dn nc thai vao (Dn)60Mm

6Hm lng BOD5 u ra ti b UASB351mg/l

7Hm lng COD u ra ti b UASB707mg/l

8Hm lng SS u ra ti b UASB185mg/l

3.3.5. B AEROTANK: Nhim vu:B Aerotank c ng dng kh ph bin trong cc qu trnh x l hiu kh. Mc ch ch yu ca qu trnh ny l da vo hot ng sng v sinh sn ca vi sinh vt n nh cht hu c lm keo t cc ht cn l lng khng lng c. Ty thuc vo thnh phn nc thi c th, Nit v Photpho s c b sung gia tng kh nng phn hy ca vi sinh vt.Cc iu kin, yu cu v cc yu t mi trng nh hng n qu trnh x l:- iu kin u tin: cung cp oxi v lin tc cho b sao cho lng DO ra khi b lng II khng nh hn 2 mg/l.- Nng cho php cc cht bn hu c: nu c nhiu cht bn trong nc thi s ph hy ch hot ng sng bnh thng ca vi sinh vt trong nc thi, gy "qu ti" v nu c nhiu cht c hi s gy "sc" vi sinh vt. V vy, nu nc thi c nhiu cht bn th phi pha long trc khi x l.- Lng cc nguyn t dinh dng cn thit cho qu trnh sinh ha din ra bnh thng cn nm trong gii hn cho php: N, P, K, Ca, S, P,...C th chn theo t l sau:BODton phn : N : P = 100 : 5 : 1 hay COD : N : P = 150 : 5 : 1 Tinh toan:Cc thng s thit k nh sau:Lu lng nc thi : Q = 500 m3/ ngy m.Hm lng BOD5 trong nc thi dn vo aerotank l 351 mg/l.Hm lng COD trong nc thi dn vo aerotank l 707 mg/l.Hm lng SS trong nc thi dn vo aerotank l 185 mg/lBOD5, sau b lng II cn l 50 mg/lCOD sau khi ra khi b lng II: COD = 100 mg/lCn l lng SS ra khi b lng II= 100mg/lCc thng s vn hnhChn aerotank kiu xo trn hon ton tnh ton thit k.a. Thi gian lu bn: ngyb. T s F/M: 0,2 0,6 kg/kg.ngyc. Ti trng th tch : 0,8 1,92 kgBOD5/m3.ngyd. Nng MLVSS: 2500 4000 mg/le. T s tun hon bn hot tnh: Qth/Q = 0,25 1Gi s kt qu thc nghim tm c cc thng s ng hc nh sau:f. H s sn lng bn: Y = 0,6 mgVSS/mgBOD5.g. H s phn hu ni bo: kd = 0,06 ngy-1.p dng cc s liu sau dng tnh ton:h. T s MLVSS:MLSS = 0,8i. Nng bn hot tnh tun hon (tnh theo cht rn l lng) l 8000mg/l.j. Hm lng cht l lng d bay hi (MLVSS) trong hn hp bn hot tnh b aerotank X = 3500mg/lk. BOD5 : BOD20 = 0,68 Xc nh hiu qu x lHiu qu x l tnh theo BOD5

%Hiu qu kh COD

%Th tch b aerotank c tnh theo cng thc sau:

Thi gian lu bn, theo quy phm 5 15 ngy, chn = 10ngyQ : lu lng trung bnh ngy, Q = 500m3/ngyY : h s sn lng bn, Y = 0,6 mgVSS/mg BOD5S0: hm lng BOD5 dn vo aerotank, S0 = 351mg/lS: hm lng BOD5 ho tan ca nc thi dn ra khi aerotank, S = 50mg/l.X :hm lng t bo cht trong b aerotank, X = 3500 mg/l.kd: h s phn hu ni bo, chn kd = 0.06 ngy-1.Xc nh thi gian lu nc ca b aerotank:

Xc nh kch thc b aerotenk:

Bng 3.9: Cc kch thc in hnh ca aerotank xo trn hon tonSTTThng sGia tri

1Chiu cao hu ich, (m)3,0 - 4,6

2Chiu cao bao v, (m)0,3 - 0,6

3Khoang cach t ay n u khuch tan khi, (m)0,45 - 0,75

4Ty s rng: su (B:H)1:1 - 2.2:1

Chn chiu cao hu ch ca b l 4m, chiu cao bo v l 0,5m.Vy chiu cao tng cng ca b: H = 4,5m.Din tch mt bng b:

Chiu di ca aerotank l L = 8m.Chiu rng b aerotank l B = 5m.Kch thc b aerotank: L x B x H = 8 x 5 x 4,5Tnh ton lu lng bn thi b mi ngy:Gi s bn d c x b (dn n b nn bn) t ng ng dn bn tun hon v hm lng cht rn l lng d bay hi (MLVSS) trong bn u ra chim 80% hm lng cht rn l lng (MLSS). Khi lu lng bn d thi b c tnh da vo cng thc:

Trong :V : th tch aerotank, V = 161,25m3 X : hm lng bn hot tnh trong b aerotank, X = 3500mg/l.Qw: lu lng bn thi, m3.Xr: nng MLSS c trong bn hot tnh tun honXr= 0,8.8000 = 6400 mg/lQc: lu lng nc thi ra khi b lng II, Qc = Q = 500m3/ngy.Xc: nng SS sau b AerotenkT tnh c:

=8,2 (m3/ngy)Tnh h s tun hon :T phng trnh cn bng vt cht vit cho b lng II (xem nh lng cht hu c bay hi u ra ca h thng l khng ng k), ta c:

Lu lng bn tun hon:

Vy, ta c:

T s tun hon bn: Lng bun hoat tinh co trong b aerotenk:

Kim tra t s F/M v ti trng hu c:T s F/M xc nh theo cng thc sau:

(ngy-1)Ti trng th tch: ( kgBOD5/m3.ngy)C hai gi tr ny u nm trong gi tr cho php i vi aerotank xo trn hon ton:F/M = 0,2 0,6LBOD= 0,8 1,9(theo ti liu thot nc ca PGS. TS. Hong Vn Hu)Tnh lng oxy cn thit cn cung cp cho aerotank da trn BOD20H s to bn t vic kh BOD5

Yobs= (mg/mg)Lng sinh khi gia tng mi ngy tnh theo MLVSS:

= = 56 (kg VSS/ng)Lng oxy cn thit trong iu kin tiu chun:

OCo = = 142 (kgO2/ngy)Trong :Q : lu lng nc thi, Q = 500m3/ngy.So: BOD5 ca nc thi u voS : BOD5 ca nc thi u raf : h s chuyn i BOD5 sang BOD20, f = 0,681,42: h s chuyn i t bo sang BOD.Px: Lng sinh khi gia tng mi ngy tnh theo MLVSSLng oxy cn thit trong iu kin thc t: = (kgO2/ngy)Trong :CS : nng bo ha ca oxy trong nc nhit lm vic, CS = 9,08 mg/l.CL: lng oxy ha tan cn duy tr trong b, CL = 2mg/lTrong khng kh, oxy chim 23,2% th tch. Gi s rng trng lng ring ca khng kh l 1,2kg/m3. Vy lng khng kh l thuyt cho qu trnh l: (m3/ngy) Gi s hiu qu vn chuyn oxy ca thit b thi kh l E = 9%, h s an ton khi s dng trong thit k l f = 2.Vy lng kh theo yu cu l:

Tnh h thng phn phi kh: Chn a phn phi kh dng a xp ng knh 170mm, din tch b mt F = 0,02m2.

Lu lng ring phn phi kh ca a thi kh = 150 200 l/pht, chn = 200 l/pht.Lng a thi kh trong b aerotank:

(a) thun li cho vic b tr ta chn s a thi kh l 40 a.Phn phi a thnh hng 8 hng theo chiu di b, mi hng 5 a.Lu lng kh cp cho 1m3 nc thi:C = m3/m3)Lu lng khng kh cn kh 1kg BOD5:(m3kh/kgBOD5)Trong :Q : lu lng nc thi.Qkk : th tch khng kh.So : BOD5 trong nc thi u voS : BOD5 trong nc thi u raTnh ton my thi kh:p lc cn thit cho h thng ng nn kh c xc nh theo cng thc:Htc = hd + hc + hf + H = 0,4 + 0,5 + 4 = 4,9 (m)Trong :hd, hc: tn tht p lc dc theo chiu di ng v tn tht cc b ti cc im un , khc quanh (m), Tng tn tht hd v hc khng vt qu 0,4m.hf: tn tht qua cc a phn phi (m), gi tr ny khng vt qu 0.5m.H: chiu cao hu ch ca b aerotank, H = 4m.Chn ng ng dn kh:ng dn kh chnh:

Dc= = =0,13 (m) Trong :Qkhi: lu lng kh ng chnh.v : vn tc kh trong ng chnh, v = 10 15 m/s, chn v = 10m/s

Chn ng thp khng g ng knh 130mm.ng dn kh nhnh:

dn = = = 0,045(m)Trong :Qn: lu lng kh trn ng nhnhQn = Qkhi/n = 0,13/8 = 0,01625 (m3/s)n : s hng phn phi a sc khv : vn tc kh, chn v =10m/s

Chn ng thp khng g ng knh = 45mm.Tnh ng dn nc thi v ng dn bn tun hon:ng dn nc thi vo:Chn vn tc nc thi chy trong ng: v = 0,7m/sng knh ng dn l:

D1 =

Chn ng nha PVC ng knh ng = 103mm.ng dn nc thi ra:Chn vn tc nc thi chy trong ng v = 0,7m/sLu lng nc thi: Q + Qr = 500 + 428 = 928 (m3/ngy) Ttrong : Q: lu lng trung bnh (500m3/ngy)ng knh ng l:

D2 = ==0,14 (m) = 140 (mm)

Chn ng nha PVC c ng knh =140mm.ng dn bn tun hon:Chn vn tc bn chy trong ng: v = 1m/sLu lng tun hon : Qr = 428m3/ngng knh ng dn l:

D3 = == 0,09 (m) = 90 (mm)

Chn ng nha PVC ng knh ng = 90mm.

Bng 3.9: Thng s b AerotankSTTThng sGia trin v

1Th tich b: L x W x H8 x 5 x 4,5M

2Lu lng bun thai Qw 8,2m3/ngay

3Ty s tun hoan bun, 1,17-

4Lu lng bun tun hoan, Qr 17,8m3/h

5Thi gian lu nc, 8h

6Lng khng khi cn, Qkk 11333m3/ngay

7Lng khng khi cn kh 1kg BOD5, qkk 75,3m3/kgBOD5

8S ia s khuch tan khi, N 40a

9ng kinh ng dn khi chinh, Dc 130mm

10ng kinh ng dn khi nhanh, dn 45mm

11ng kinh dn nc thai vao, D1 103mm

12ng kinh dn nc thai ra va bun d, D2 140mm

13ng kinh dn bun tun hoan, D3 90mm

3.3.6. B lng II: Nhim v:Nc thi sau khi qua b Aerotank s c a n b lng II, b ny c nhim v lng cc bng bn hot tnh t b Aerotank a sang. Mt phn bn lng s c tun hon tr li b Aerotank, phn bn d c thi ra ngoi.

Tnh tonBng 3.10: Cc thng s thit k c trng cho b lng t IIvi bn hot tnh khuych tn bng khng kh nh sau:Thng sGia tri

Tai trong b mt, m3/m2.ngayTrung binh16,3 - 32,6

Ln nht40,7 - 48,8

Tai trong cht rn, kg/m2.hTrung binh3,9 - 5,9

Ln nht9,8

Chiu cao cng tac, m3,7 - 6,1

Chn ti trng b mt thch hp cho bn hot tnh ny l 20m3/m2.ngy v ti trng cht rn l 5,5kg/m2.hDin tch b mt b lng theo ti trng b mt:

AL = Trong :Q : lu lng trung bnh ngy, m3/ngyLA: ti trng b mt, m3/m2.ngyDin tch b mt b lng tnh theo ti trng cht rn:AS = Trong :Qr: lu lng bn tun hon, m3/ngyLS: ti trng cht rn, kgSS/m2.ngyDo AS > AL, vy din tch b mt lng tnh theo ti trng cht rn l din tch tnh ton.ng knh b lng:

D = = =5,8 (m)ng knh ng trung tm:d = 20%D = 20%.5,8 = 1,16 (m)Chn chiu cao hu ch ca b lng l hL= 3m, chiu cao lp bn lng hb= 1,5m v chiu cao bo v hbv= 0,3m. Vy chiu cao tng cng ca b lng II:Htc = hL + hb + hbv = 3 + 1,5 + 0,3 = 4,8 (m)Chiu cao ng trung tm:h = 60%hL = 60%.3 = 1,8 (m)Thi gian lu nc ca b lng:Th tch phn lng:

Thi gian lu nc:Th tch b cha bn:Vb = A.hb = 26,3.1,5 = 39,45 (m3)Thi gian lu gi bn trong b:tb =Ti trng b mt: (m3/m2.ngy)Gi tr ny nm trong khong cho php LS < 500 m3/m.ngyMng thu nc:Mng thu nc t vng trn, c ng knh bng 0,8m, ng knh b:Dm = 0,8.D = 0,8.5,8 = 4,64 (m)Chiu di mng thu nc:

Lm = Dm = .4,64 = 14,58 (m)Chiu cao mng hm = 0,5 mMng b tng ct thp dy 100mm, c lp thm mng rng ca thp tm khng g c dng ch V, gc 900C.Tnh ng dn nc thi v ng dn bn: ng dn nc thi vo:Chn vn tc nc thi chy trong ng: v = 0,7m/sLu lng nc thi vo b:Qv = Q+ Qr = 500 + 427 = 927 (m3/ngy) ng knh ng dn l:

= 0,14(m) = 140 (mm)

Chn ng nha PVC ng knh ng = 140mmng dn nc thi ra:Chn vn tc nc thi chy trong ng v = 0,7m/sLu lng nc thi : Q = 500m3/ngng knh ng l:

D = == 0,1(m) = 100 (mm)

Chn ng nha PVC c ng knh = 100mmng dn bn:Chn vn tc bn chy trong ng: v = 1m/sLu lng bn: Qb = Qr + Qw = 427 + 7,4 = 434,4 (m3/ngy)ng knh ng dn l:

D = == 0,08(m) = 80(mm)

Chn ng nha PVC ng knh ng = 80 mm.Bng 3.11: Thng s b lng t IISTTThng sGia trin v

1ng kinh b lng, D(m)5,8m

2Chiu cao b lng, H(m)4,8m

3ng kinh ng trung tm, d(m)1,16m

4Chiu cao ng trung tm, h(m)1,8m

5Thi gian lu nc, t(h)2h

6Thi gian lu bun, tb(h)2,19h

7ng kinh ng dn nc thai vao (mm)140mm

8ng kinh ng dn nc thai ra (mm)100mm

9ng kinh ng dn bun (mm)80mm

3.3.7. B trung gian Nhim vNc thi sau b lng ly tm c cho t chy sang b trung gian. B trung gian c s dng nh mt b cha, nhm mc ch n nh ngun cp nc cho thit b lc. Tnh tonQ = 500 m3/ngy = 20,83 m3/hTh tch b:V = t = 20,83 5,2 m3 Chiu cao hu ch l 2 mChiu cao bo v l 0,3 mChiu cao tng cng l HTC = 2 + 0,3 = 2,3 mKch thc b: L x B x H = 2 x 2 x 2,3 (m)Chn bm nhng chm hot ng lun phin t ti hm bm, mi bm c Q = =20,83 m3/h, ct p bm Hb = 10 mCng sut bm:N = = = 0,76 KW= N = 1,5 1,14 KWTrong : = 1,5 l h s d phng (t 1)Q = Nng sut bm, Q = = m3/sHb l ct p bm (Hb = 10m) l hiu sut bm, 75%Bng 3.12: Thng s b trung gianSTTThng sGi trn v

1Cng sut ca bm N 0,76KW

2Cng sut d phng 1,14KW

3Nng sut bm Q5,78.10-3m3/s

4Chiu cao ct p bm 10m

5Chiu di L 2m

6Chiu rng B 2m

7Chiu cao H2,3m

3.3.8. B lc p lc Nhim vB lc p lc loi b trit cc cn cn st li trong nc trc khi i vo b kh trng. Tnh tonThng s u vo: SS: Gi s chn b lc p lc hai lp: (1) Than Ancthracite v (2) Ct thch anh.Chn: Chiu cao lp ct h1 = 0,3m c ng knh hiu qu dc = 0,5mm, U=1,6Chiu cao lp than h2 = 0,5m v ng knh hiu qu 1,2mm, U= 1,5Tc lc v=10m/h va s b lc n= 2Tc lc tng cng vtc = 12m/h v thi gian ra lc ttc =6 pht(ngun: s 6.106 TCXDVN 33-2006) Din tch b mt mi b lc:

ng knh b lc p lc:

Khong cch t b mt vt liu lc n ming phu thu nc ra:

Trong : HVL= Chiu cao lp vt liu lc e = gin n lp vt liu lc khi ra ngc, e = 0,25 0,5Chiu cao tng cng b lc p lcH = h + HVL + hbv + hthu =0,65 + 0,8 + 0,25 + 0,3 = 2mLng nc ra lc (theo s 6.106 TCXDVN 33-2006). Chn: Tc ra nc vnc = 0,35(m3/m2.ph)Lng nc cn thit ra ngc cho 1 b lc

(m3/b)Lu lng bm ra ngc

Bng 3.13: Tng hp thng s tnh ton b lc p lcThng sn vGi tr

Din tch b mt lc Am21,22

S lng b lc nS lng2

ng knh mi b loc dm1,25

Chiu cao mi b lcm2

Lng nc cn thit ra ngc cho 1 b lc Wnm3/b4,27

Lu lng bm ra ngc Qng m3/h25,62

3.3.9. B kh trng Nhim vB kh trng nc thi sau khi x l bng phng php sinh hc cn cha khong 105 106 vi khun trong 100ml, hu ht cc loi vi khun ny tn ti trong nc thi khng phi l vi trng gy bnh, nhng cng khng loi tr mt s loi vi khun c kh nng gy bnh. Khi cho Chlorine vo nc, di tc dng chy ri do cu to vch ngn ca b v Chlorine l c tnh oxi ha mnh s khuch tn xuyn qua v t bo vi sinh vt v gy phn ng vi men bn trong ca t bo vi sinh vt lm ph hoi qu trnh trao i cht dn n vi sinh vt b tiu dit. Nc thi sau khi qua h thng x l t tiu chun ngun x thi: Loi B theo QCVN 24:2008/BTNMT. Tnh tonTh tch ca b

Trong : Thi gian lu nc trong b kh trng t = 30 phtVn tc dng chy trong b v = 2m/phtTit din ca b

Tong : Chiu su hu ch trong b H1 = 1,5mChiu su an ton H2 = 0,3mTng chiu su ca b H = H1 + H2 = 1,8mChn L = 5,5m B = 1,5m H = 1,8mLn ha cht dng kh trngLng Clo hot tnh cn thit cho mt n v th tch nc thi l: 3g/m3 (Theo gio trnh cp nc ca TrnHiu Nhu )Vy lng Clo cn thit kh trng trong mt ngy: mCl = 3.500 = 1500g = 1,5kg

Bng 3.14: Thng s b kh trngSTTTn thng sGi trn v

1Chiu di b (L)5,5m

2Chiu rng b (B)1,5m

3Chiu cao b (H)1,8m

CHNG 4: KIN NGH V KT LUN4.1. Kt lunTrong nhng nm gn y, ngnh git m gia sc nc ta c nhiu bc pht trin ng k p ng nhu cu ca ngi tiu dng. Nh c mt s chnh sch u t pht trin chn nui v git m ca nh nc nn hin nay trn c nc xy dng nhiu m hnh trang tri chn nui v nh my git m vi quy m ln. Tuy nhin cng vi s pht trin cao ca sn xut l nhng vn nhim mi trng ca ngnh git m ang ngy cng trm trng. Nc thi git m gia sc cha rt nhiu hp cht hu c, vi khun, giun sn nu khng c x l kp s gy nn nhiu hu qu xu cho mi trng. Mt s c s git m tuy c xy dng h thng x l nc thi nhng do cn nhiu hn ch v kinh ph v k thut nn cht lng nc sau x l vn cha t tiu chun cho php.V vy vic nghin cu tm ra mt quy trnh x l hiu qu v ph hp cho cc nh my git m l nhu cu tt yu v cp thit. Thnh phn nc thi git m ch yu l cc cht hu c v vy rt thun tin trong vic x l bng phng php sinh hc. Quy trnh x l nc thi git m vi phng n II m nhm xut l phng n tt nht tng i hiu qu cc thnh phn hu c trong nc thi p dng. V vy cc c s git m nu c iu kin nn p dng quy trnh ny hn ch cc tc ng xu n mi trng do hot ng sn xut ca mnh gy ra.4.2. Kin nghCng nhn cn c tp hun v kin thc, k thut vn hnh v k thut an ton nhm vn hnh h thng hot ng tt v hn ch s c.X l kp thi cc s c nhm trnh nhng tn tht cho c s, gim thiu nhim ti a, gp phn bo v mi trng ca nhn dn khu vc xung quanh.Trong qu trnh vn hnh cc b x l sinh hc, cn phi theo di v vn hnh hp l m bo iu kin ti u cho s pht trin ca VSV.

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