Thuyetminhdo an(Moi)

8/4/2019 Thuyetminhdo an(Moi)

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MC LC

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Phn I

TM HIU V

NC THI XI MI. Cng ngh x l b mt (xi m):

Cng ngh x l b mt (xi m) thng bao gm cc cng on sau:

- B mt ca vt liu cn m phi c lm sch lp m c bm dnh cao vkhng c khuyt tt. lm sch b mt trc ht phi ty ra lp m bo quntrn b mt bng cch ty ra vi dung mi hu c hoc vi dung dch kim

nng. Dung mi thng s dng l loi hydrocacbon c clo ho nhtricloetylen, percloetylen. Dung dch kim thng l hn hp ca xt, soda,trinatri photphat, popyphotphat, natri silicat v cht hot ng b mt (to nh).

- Hot ho b mt ca vt liu m bng cch nhng chng vo dung dch axitlong (H2SO4, HCl), nu m vi dung dch cha xianua (CN) th chng cnhng vo dung dch natri xianua.

- Giai on m c tin hnh sau , dung dch m ngoi mui kim loi cncha axit hoc kim i vi trng hp m c cha xianua.

Sau tng bc, vt liu m u c trng ra vi nc. Mt s dung dch m c

cc thnh phn ch yu sau:o Dung dch ch: axit + mui ch (II) dng borflorua hoc silicoflorua.o Dung dch ch- thic: axit, mui ch, thic (II) dng borflorua.o Dung dch ng hun: dung dch xianua trong ng nm trong phcxianua v thic trong phc hydroxo. Ngoi ra dung dch cn cha xianua tdo (NaCN).o Dung dch cadmi: axit + cadmi dng mui sunfat. Thng dng hn ldung dch cadmi dng phc xianua v xianua t do.o Dung dch crm: axit crmic v axit sunfuric.

o Dung dch vng: dung dch xianua, vng nm trong phc NaAu(CN)2 vxianua t do. C th s dng phc vng-sunfit.o Dung dch ng: axit + ng sunfat hoc ng borflorua.o Dung dch ng xianua (phc) v xianua t do, dung dch ng dng

polyphotphat v mui amoni.o Dung dch niken: mui niken sunfat, clorua v axit yu (axit boric) hocdung dch niken trn nn ca axit amonisulfonic.o Dung dch bc: dung dch bc xianua hoc dung dch bc thisunfat.o Dung dch km: phc km xianua v xianua t do hoc km sunfat,clorua vi axit boric hoc mui amoni lm cht m.

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Dy chuyn cng ngh chung ca cng ngh xi m:

AxitMui AuMui Ag

Mi nhn, nh bngc

Ty du, m

Lm sch bng hohcv in ho

Lm sch c hc

M crm M Niken M km M vngM ng

Cht lmbng

NiSO4

H3BO

3

Zn(CN)2

ZnCl2

ZnO

NaCNNaOHH

3BO

3

H2SO

4

NaCN

CuSO4

Cu(CN)2

Cr

6+

Ni

2+

, axit CN-, Zn2+ , axit Cu

2+

, axit CN

-

, axit

Vt cn m

Dung mi

NaOH, HCl, H2SO

4

Nc thi cha dumHi dung mi

Bi kim loi

Bi, g

Hi, axit

Axit, kim

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Mt v d v cng ngh xi m ph tng xe p v xe my thnh ph H ChMinh:

Nguyn liu ngm HCl thng quay NaOH mi ct nu NaOH (ty bmt) m Niken m Crm ly tm sy kh thnh phm.

Dy chuyn m

L m

B m

II. Lu lng v thnh phn, tnh cht nc thi:

Nc thi t xng xi m c thnh phn a dng v nng vpH bin i rng t rt axit 2-3, n rt kim 10-11. c trng chung ca ncthi ngnh m l cha hm lng cao cc mui v c v kim loi nng. Tu theokim loi ca lp m m ngun nhim c th l Cu, Zn, Cr, Ni, v cng tuthuc vo loi mui kim loi c s dng m nc thi c cha cc c t nhxianua, sunfat, amoni, crmat, Cc cht hu c t c trong nc thi xi m,

phn ch yu l cht to bng, cht hot ng bmt nn BOD, COD thngthp v khng thuc i tng x l. i tng x l chnh l cc ion v c mc bit l cc mui kim loi nng nh Cr, Ni, Cu, Fe,

Nc thi nn tch ring thnh 3 dng ring bit:

- Dung dch thi m c t cc b nhng, b ngm.- Nc ra thit b c hm lng cht bn trung bnh (mui kim loi, dum v x phng,- Nc ra long

4

H2SO4CrO3


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an ton v d dng x l, dng axit crmic v dng cyanidenn tch ring. Cht gy nhim nc thi xi m c th chia lm vi nhm sau:

o Cht nhim c nh cyanide CN-, Cr (VI), F-,o Cht nhim lm thay i pH nh dng axit v kim

o Cht nhim hnh thnh cn l lng nh hydroxit,cacbonat v photphato Cht nhim hu c nh du m, EDTA

Cc cuc kho st cho thy cc qu trnhtrong ngnh x l kim loi kh n gin v tng t nhau. Ngun cht thi nguyhi pht sinh t qu trnh lm mt, lau ra v t chy du. X l kim loi ihi mt s ho cht nh axit sunfuric, HCl, xt, lm sch b mt kim loitrc khi m. Th tch nc thi c hnh thnh t cng on ra b mt, lmmt hay lm trn cc b mt kim loi kh ln, gy nhim ngun nc v nh

hng n sc kho cng ng.Bng: Thnh phn nc thi c s xi m ph tng xe gn my (CEFINEA, 1996)

Ch tiu n v Nc thi Ni Nc thi mCr

Nc thingm NaOH

pH 5.47 3064 11.49TDS mg/l 502 82.3 2370Cl- mg/l 100 24 58SO4- mg/l 400 25 38Alk mgCaCO3/l 60 0 1513

Ni mg/l 286 4.3 -

Cr mg/l - 39.6 -Bng trn cho thy nc thi nhim ch yu do cc cht kim, axit v kim loinng Crm v niken.

III. nh hng ca nc thi ngnh xi m n mitrng v con ngi:

1. nh hng n mi trng:

- L c cht i vi c v thc vt nc

- Tiu dit cc sinh vt ph du, gy bnh cho c v bin i cc tnh cht l hoca nc, to ra s tch t sinh hc ng lo ngi theo chiu di chui thc n.

Nhiu cng trnh nghin cu cho thy, vi nng ln, sinh vt c th bcht hoc thoi ha, vi nng nh c th gy ng c mn tnh hoc tch tsinh hc, nh hng n s sng ca sinh vt v lu v di.

- nh hng n ng ng dn nc, gy n mn, xm thc h thng cng rnh.

- nh hng n cht lng cy trng, vt nui canh tc nng nghip, lm thoiho t do s chy trn v thm ca nc thi.

- nh hng n h thng x l nc thi, cn tch ring nu khng s nh hngn hot ng ca vi sinh vt khi thc hin x l sinh hc.5


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2. nh hng n con ngi:

Xi m l ngnh c mt gy nhim mi trng cao bi hi ha cht, nc thic cha cc ion kim loi nng, kim loi c nh hng ti sc khe con ngi gynn nhiu cn bnh kh cha, nguy him ti tnh mng. Nc thi t cc qu trnhxi m kim loi, nu khng c x l, qua thi gian tch t v bng con ng trctip hay gin tip, chng s tn ng trong c th con ngi v gy cc bnhnghim trng, nh vim lot da, vim ng h hp, eczima, ung th,...Trong khun kh ca n ny ch ch trng vo tnh cht gy nhim mi trng

ca nc thi xi m do c tnh ca Crm.

3. c tnh ca Crm:

Mc d Crm tn ti nhiu trng thi khc nhau, ch c Cr(III) v Cr(VI) gy nhhng ln n sinh vt v con ngi.

a. ng xm nhp v o thi:

Crm xm nhp vo c th theo 3 ng: h hp, tiu ha v qua da. Cr(VI) cc th hp thu d dng hn Cr(III) nhng khi vo c th Cr(VI) s chuyn thnhdng Cr(III). D xm nhp vo c th theo bt c ng no, Crm cng c hatan trong mu nng 0.001mg/ml, sau c chuyn vo hng cu v s hatan hng cu nhanh hn 10-20 ln. T hng cu, Crm c chuyn vo cc tchc v ph tng. Crm gn vi Sidero filing albumin v c gi li phi,xng, thn, gan, phn cn li th qua phn v nc tiu. T cc c quan ph tng,Crm li c ha tan dn vo mu, ri c o thi qua nc tiu t vi thng

n vi nm. Do nng Crm trong mu v nc tiu bin i nhiu v kodi.

b. Tc ng n sc kho:

Qua ngin cu ngi ta thy Crm c vai tr sinh hc nh chuyn ha glucose,protein, cht bo ng vt hu nh. Du hiu ca thiu ht Crm ngi gm cgim cn, c th khng th loi ng ra khi mu, thn kinh khng n nh. Tuynhin vi hm lng cao Crm lm gim protein, axit nucleic v c ch h thngmen c bn.

Cr(VI) c hn Cr(III). IARC xp Cr(VI) vo nhm 1, Cr(III) vo nhm 3 ivi cc cht gy ung th. Ht th khng kh c nng Crm (v d axit crmic hayCr(III) trioxit) cao (>2g/m3) gy kch thch mi lm chy nc mi, hen suyn dng, ung th (khi tip xc vi Crm c nng cao hn 100-1000 ln nng trong mi trng t nhin). Ngoi ra Cr(VI) cn c tnh n mn, gy d ng, l lotkhi tip xc vi da.

c. Nng gii hn:

US. EPA gii hn nng ti a cho php ca Cr(VI) v Cr(III)trong nc ung l 100 g/l.

Quy nh ca SHA v nng ca Crm trong khng kh ti nilm vic l:6


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o Gii hn tip xc ngh nghip cho ngy lm vic 8 gi, tunlm vic 40 gi l 500 g/m3 i vi Crm tan trong nc v 1000 g/m3

i vi Crm kim loi v mui khng tan.o Nng ca Crm trioxit (axit crmic) v cc hp cht caCr(VI) trong khng kh ti ni lm vic khng cao hn 52 g Cr(VI)/m3

cho ngy lm vic 10 gi, tun 40 gi.

NIOSH xem tt c hp cht Cr(VI) c tim nng gy ung th ngh nghip va ra gii hn nng tip xc l 1 g Cr(VI)/m3 cho ngy lm vic 10 gi,tun 40 gi.

IV. Hin trng nhim mi trng do cng nghipxi m ti Vit Nam:

Kt qu cc nghin cu gn y v hin trng mi trng nc ta chothy, hu ht cc nh my, c s xi m kim loi c quy m va v nh, p dngcng ngh c v lc hu, li tp trung ch yu ti cc thnh ph ln, nh H Ni,Hi Phng, TP.HCM, Bin Ho (ng Nai) ... Trong qu trnh sn xut, ti ccc s ny (k c cc nh my quc doanh hoc lin doanh vi nc ngoi), vn x l nhim mi trng cn cha c xem xt y hoc vic x l cnmang tnh hnh thc, chiu l, bi vic u t cho x l nc thi kh tn kmv vic thc thi Lut Bo v mi trng cha c nghim minh.

Nc thi m thng gy nhim bi cc kim loi nng, nh crm, niken... v pH thp. Phn ln nc thi t cc nh my, cc c s xi m c trc tip vo cng thot nc chung ca thnh ph m khng qua x l trit , gy nhim cc b trm trng ngun nc.

Kt qu kho st ti mt s nh my c kh H Ni cho thy, nng cht c c hm lng cc ion kim loi nng, nh crm, niken, ng ... u caohn nhiu so vi tiu chun cho php; mt s c s m in tuy c h thng xl nc thi nhng cha ch trng y n cc thng s cng ngh ca qutrnh x l iu chnh cho ph hp khi c tnh ca nc thi thay i. TiTP.HCM, Bnh Dng v ng Nai, kt qu phn tch cht lng nc thi cacc nh my, c s xi m in hnh c 3 a phng ny cho thy, hu ht cc

c s u khng t tiu chun nc thi cho php: hm lng cht hu c cao,ch tiu v kim loi nng vt nhiu ln tiu chun cho php, COD dao ngtrong khong 320 - 885mg/lt do thnh phn nc thi c cha cn sn, du nht....

Hn 80% nc thi ca cc nh my, c s xi m khng c x l.Chnh ngun thi ny v ang gy nhim nghim trng n mi trngnc mt, nh hng ng k cht lng nc sng Si Gn v sng ng Nai.c tnh, lng cht thi cc loi pht sinh trong ngnh cng nghip xi m trongnhng nm ti s ln n hng ngn tn mi nm. iu ny cho thy cc khuvc nhim v suy thoi mi trng nc ta s cn gia tng nu khng kpthi a ra cc bin php hu hiu.

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Phn 2

LA CHN V XUT

PHNG PHP V CNG NGHX L

I. Gii thiu cc phng php v cngngh x l nc thi xi m:

Phng php x l nc thi xi m ph bin nht l dng phng php ho hc ri

n trao i ion, phng php chng ct, phng php in thm tch. Chnphng php no l tu ch tiu kinh t - k thut cho php, iu kin mi trng aphng, yu cu, mc ch dng li hoc thi thng ra mi trng Chn phngphp no cng phi bo m cht lng mi trng theo TCVN 5945- 1995.

1. Phng php kt ta:

Qu trnh kt ta thng c ng dng cho x l nc thi cha kim loi nng.Kim loi nng thng kt ta dng hydroxit khi cho cht kim ha (vi, NaOH,

Na2CO3,) vo t n gi tr pH tng ng vi ho tan nh nht. Gi tr pHny thay i tu theo kim loi. ho tan nh nht ca Crm pH 7.5 v km l

10.2. ngoi gi tr , hm lng ho tan tng ln.Khi x l kim loi, cn thit x l s b kh i cc cht cn tr qu trnh kt ta.Th d nh cyanide v ammonia hnh thnh cc phc vi nhiu kim loi lm gimhiu qu qu trnh kt ta. Cyanide c th x l bng chlorine ho-kim, ammoniac th kh bng phng php chlorine ho im un (breakthrough point), tch kh(air stripping) hoc cc phng php khc trc giai on kh kim loi.

Trong x l nc thi cng nghip, kim loi nng c th loi b bng qu trnh ktta hydroxit vi cht kim ha, hoc dng sulfide hay carbonat.

Mt s kim loi nh arsenic hoc cadmium nng thp c th x l hiu qu khi

cng kt ta vi phn nhm hoc st. Khi cht lng u ra i hi cao, c th pdng qu trnh lc loi b cc cn l lng kh lng trong qu trnh kt ta.

i vi Crm VI (Cr6+), cn thit tin hnh kh Cr6+ thnh Cr3+ v sau kt ta vivi hoc xt. Ho cht kh thng thng cho x l nc thi cha Crm l ferroussulphate (FeSO4), sodium-meta-bisulfit, hoc sulfur dioxit. Ferrous sulphate(FeSO4), sodium-meta-bisulfit c th dng rn hoc dung dch. SO2 dng khnn trong cc bnh chu p. Qu trnh kh hiu qu trong mi trng pH thp. Vvy cc ho cht kh s dng thng l cc cht mang tnh axit mnh. Trong qutrnh kh, Fe2+ s chuyn thnh Fe3+. Nu s dng meta-bisulfit hoc sulfur dioxit,ion SO32- chuyn thnh SO42-.

Phn ng tng qut nh sau: 8


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Cr6+ + Fe2+ + H+ Cr3+ + Fe3+

Cr6+ + Na2S2O3 (hoc SO2) + H+ Cr3+ + SO42-

Cr3+ + 3OH- Cr(OH)3

Trong phn ng oxy ho kh, ion Fe2+ phn ng vi Cr6+, kh Cr6+ thnh Cr3+ v

oxy ho Fe2+ thnh Fe3+. Phn ng xy ra nhanh hn pH nh hn 3. Axit c thc thm vo t pH thch hp. S dng FeSO 4 l tc nhn kh c im bt likhi lng bn sinh ra kh ln do cn Fe(OH)3 to thnh khi cho cht kim ho vo. thu c phn ng hon ton, cn thit phi thm lng FeSO4 d, khong 2.5ln so vi hm lng tnh ton trn l thuyt.

Lng axit cn thit cho qu trnh kh Cr6+ph thuc vo axit ca nc thinguyn thu, pH ca phn ng kh v loi ho cht s dng.

X l tng m (batch treatment) ng dng c hiu qu kinh t, khi nh my xi mc lu lng nc thi mi ngy 100m3/ngy. Trong x l tng m cn dng hai

loi b c dung tch tng ng lng nc thi trong mt ngy Qngy. Mt bdng x l, mt b lm y.

Khi lu lng 100m3/ngy, x l theo m khng kh thi do dung tch b ln. Xl dng chy lin tc i hi b axit v kh, sau qua b trn cht kim ho v blng. Thi gian lu nc trong b kh ph thuc vo pH, thng ly ti thiu 4 lnso vi thi gian phn ng l thuyt. Thi gian to bng thng ly khong 20 phtv ti trng b lng khng nn ly 20m3/ngy.Trong trng hp nc ra c hm lng crm thay i ng k, cn thit c b

iu ho trc b kh gim thiu dao ng cho h thng chm ho cht.

2. Phng php trao i ion:Phng php ny thng c ng dng cho x l nc thi xi m thu hiCrm. thu hi axit crmic trong cc b xi m, cho dung dch thi axit crmic quact trao i ion resin cation (RHmnh) kh cc ion kim loi (Fe, Cr3+, Al,). Dungdch sau khi qua ct resin cation c th quay tr li b xi m hoc b d tr. Do hmlng Crm qua b xi m kh cao (105-120kg CrO3/m3), v vy c th trao ihiu qu, nn pha long nc thi axit crmic v sau b sung axit crmic chodung dch thu hi.

i vi nc thi ra, u tin cho qua ct resin cation axit mnh kh cc kim

loi. Dng ra tip tc qua ct resin anion kim mnh thu hi crmat v thu nckh khong. Ct trao i anion hon nguyn vi NaOH. Dung dch qua qu trnhhon nguyn l hn hp ca Na2CrO4 v NaOH. Hn hp ny cho chy qua ct traoi cation thu hi H2CrO4 v b xi m. Axit crmic thu hi t dung dch honnguyn c hm lng trung bnh t 4-6%. Lng dung dch thu c t giai onhon nguyn ct resin cation cn phi trung ho bng cc cht kim ho, cc kimloi trong dung dch kt ta v lng li b lng trc khi x ra cng.

3. Phng php in ha:

Da trn c s ca qu trnh oxy ho kh tch kim loi trn cc in cc nhng

trong nc thi cha kim loi nng khi cho dng in mt chiu chy qua. Phng9


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php ny cho php tch cc ion kim loi ra khi nc m khng cn cho thm hocht, tuy nhin thch hp cho nc thi c nng kim loi cao (> 1g/l)

4. Phng php sinh hc:

Da trn nguyn tc mt s loi thc vt, vi sinh vt trong nc s dng kim loinh cht vi lng trong qu trnh pht trin khi nh bo ty, bo t ong, to, Vi

phng php ny, nc thi phi c nng kim loi nng nh hn 60 mg/l v phic cht dinh dng (nit, phtpho,) v cc nguyn t vi lng cn thit khccho s pht trin ca cc loi thc vt nc nh rong to. Phng php ny cn cdin tch ln v nc thi c ln nhiu kim loi th hiu qu x l km.

II. xut cng ngh:

1. c im thnh phn nhim ca nc thi:

THNG S N V NC THI NC THI SAU X L

Lu lng m3/ngy 30 30pH 4 6-9Oil mg/l 34-65 VtCr3+ mg/l 55-73


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3. Thuyt minh cng ngh:

Nc thi t nh my xi m c thu gom li ti h thu gom. Nc thi tip tcc bm sang b iu ho lu lng, ti y nc thi s n nh v lu lng,ng thi c loi b lng du m do b tr kt hp thit b vt du m vi thigian lu nc l 5h. Sau nc thi c a sang b phn ng v lng kt hp.Ti y trc tin chm dung dch H2SO4 h pH xung cn 2.1-2.3 (l pH toiu kin cho qu trnh oxy ha Cr6+), sau chm FeSO4 nhm oxy ho lng Cr6+

thnh Cr3+, khuy trong 5-10 pht vi tc khong 8 vng/pht, ngng khuy v yn trong 5-10 pht cho phn ng xy ra. Sau chm dung dch NaOH tokt ta Cr(OH)3, khuy trong 5-10 pht, tc khuy nh khi chm FeSO4, sau gim tc khuy cn 20 vng/gi thc hin lng. Qu trnh lng xy ra trongvng 4 gi. Phn nc trong qua 3 van x xung b cha v c bm qua thit btrao i ion (ct trao i ion) nhm x l nt nhng ion cn st li sau b phn ngv lng. Nc ra t ct trao i ion l nc sch t tiu chun thi loi B, c an ngun tip nhn.

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Phn 3:

TNH TON THIT K

CC CNG TRNH N VCc thng s ca nc thi theo bi:

THNG S N V NC THI NC THI SAU X L

Lu lng m3/ngy 30 30pH 4 6-9Oil mg/l 34-65 VtCr3+ mg/l 55-73


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Thi gian lu nc trong h thu gom ti thiu l 15-20 pht. Chn thi gian lunc l t = 20 pht

Th tch h thu gom:

V = Q*t = 30* 246020

x = 0.417(m3

) Kch thc h c xy dng nh sau:

o Cao: H = 1.5mo Chiu cao bo v: Hbv = 0.3mo Tng chiu cao: 1.8mo Di: L = 0.56mo Rng: B = 0.5m

Th tch thc ca h:V = 1.8*0.56*0.5 = 0.5(m3)

2. B iu ho:

-1.00

+1.2

May thoi kh

+0.00

a. Nhim v:

Nc thi thng c lu lng v thnh phn cc cht bn khng n nh theo thigian trong mt ngy m. S dao ng ny nu khng c iu ho s nh hngn ch cng tc ca trm x l nc thi, ng thi gy tn km nhiu v xydng c bn v qun l. Do vy, lu lng nc thi a vo x l cn thit phiiu ho nhm to cho dng nc thi vo h thng x l gn nh khng i, khc

phc nhng kh khn cho ch cng tc do lu lng nc thi dao ng gy rav ng thi nng cao hiu sut x l cho ton b dy chuyn.

b. Hnh dng-kch thc:13


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B iu ho t sau h thu gom, nhn nc thi bm trc tip t h gom, t nachm na ni trn mt t. Do ch c nhim v chnh l iu ho lu lng nnkhng cn c thit b khuy trn nhng c b tr h thng thi kh tuyn ni dum. Din tch b mt b kh nh, do ta ch cn vt du bng phng php thcng.

Vt liu xy dng: b tng ct thp. Thnh b: 10cm

V khng c s dng nc ca nh my, chng ta ch tnh chn s b b iuho. Chn thi gian lu nc ca b iu ho l 5 gi.

Th tch b l:

V = Q*t = 30*24

5= 6.25(m3)

Hnh dng b iu ho l b dng vung, kch thc b:

o Cao: H = 1.9mo Chiu cao bo v: Hbv = 0.3mo T ng chi u cao 2.2mo Cnh y: B = 1.8m

Th tch thc:V = 2.2*1.8*1.8 = 8.7(m3)

c. Thit b vt du m:

Du m thng nh hn nc v ni ln trn mt nc. Nc thi sau x l khngc ln du m mi c php cho chy vo cc thu vc. Hn na, nu x l sinh

hc, nc thi ln du m khi vo x l sinh hc s lm bt cc l hng vt liulc, phin lc sinh hc v cn lm hng cu trc bn hot tnh trong aeroten. Dovy ngi ta cn n thit b vt du m.

y b iu ha ta b tr h thng thi kh tuyn ni du m, vt du bngdng c th cng.

3. B phn ng v lng kt hp:

a. Nhim v:

Do chn cch x l theo m nn kt hp hai chc nng phn ng v lng vo chungmt b. Chc nng ca b l oxy ho lng Cr6+ thnh Cr3+, nng pH, to kt taCr(OH)3, cui cng l thc hin qu trnh lng.

b. M t:

Do lu lng kh nh Q = 30m3/ngy nn ta chn cch x l theo m. Chia lm 4m, mi m c th tch 7.5m3, x l trong vng 5 gi.

Trc tin chm dung dch H2SO4 h pH xung thch hp t chm FeSO4 thchin oxy ho lng Cr6+ thnh Cr3+, khuy trong 5-10 pht vi tc khong 8vng/pht, ngng khuy v yn trong 5-10 pht cho phn ng xy ra. Sau chm dung dch NaOH to kt ta Cr(OH)3, khuy trong 5-10 pht, tc khuy

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nh khi chm FeSO4, sau gim tc khuy cn 20 vng/gi thc hin lng.Qu trnh lng xy ra trong vng 4 gi.B c thit k dng tr trn, y nghing v tm gc 600. Trong b b tr h thngcnh khuy thc hin qu trnh phn ng v lng. y b c ng x bn, trn thn

b thit k 3 van x nc. B c bng chn ng trn mt t.

Vt liu xy dng: thp khng r, thn b dy 5mm.

+3.450

+0.600

0.000

Thep khong g5

c. Tnh ton kch thc b:Dung tch cha nc ca b l 7.5m3. Chn chiu cao phn cha nc l Hn = 2m.

Din tch b mt cn thit l:

S =H

V= 75.3

2

5.7= (m2)

ng knh b:

D = ==

75.3*4*4 S2.185(m)

Ly ng knh b l D = 2.2my b nghing v tm 600 so vi phng thng ng.

Chiu cao ca phn chp nghing:

Hc = *2

Dcos600 =

2

1*

2

2.2= 0.55(m)

Chn chiu cao an ton trn mt thong l H = 0.3m

Tng chiu cao b l:

H = Hat + Hn + Hc = 0.3+2+0.55 = 2.85(m)d. B phn truyn ng: 15


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B phn truyn ng bao gm:

Mt khuy Trc khuy Cnh khuy

Chn cnh khuy loi turbin 6 cnh phng. Cnh khuy lm bng thp khng r.

ng knh cnh khuy:

Dk=

4

3

3

2D =

4

3

3

2*2.2 = 1.47 1.65 (m)

Ly ng knh cnh khuy Dk= 1.5m

Chiu rng cnh khuy:

q =5

5.1

5=

kD = 0.3(m)

Chiu di cnh khuy:

d = 45.1

4=k

D

= 0.375(m)

B dy cnh khuy:

s = 0.5cm pha u v nh dn n 0.2cm phn ui cnh.

Mt khuy t tm b, trn gin lm vic.

Trc khuy t trng vi trc tm ca b, cnh khuy cch y b mt on bngng knh cnh khuy (1.5m).

Vy chiu di trc khuy l

lk= 2.85-1.5 = 1.35(m)e. Sn cng tc: 16


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- Cu thang ln sn cng tc: t nghing 600 so vi mt t, di khong 4.2m.Tay vn cao 0.8m. C cc thanh chn dc.

- Sn cng tc: rng 0.6m, gm 2 thanh ging nhau t i xng qua tm mt b.Mt sn cu to t cc khung thp 20mm*20mm*5mm, chiu ngang khung hncc thanh thp 14a50. Hng ro trn sn cng tc: cao 0.8m, di xp x 2.3m,c cc thanh chn dc v mc ch an ton.

f. ng x bn:Lm bng thp khng r 140, c van iu chnh lu lng theo lng bn x ra.ng c hn ni vi phn ui chp nghing ca b, c hn dnh tm thp tngcng. ng b tr ngang chy thng ra sn phi bn. Cui ng ni vi on ng mm d phn phi bn ra b mt sn phi bn.

Han dnh

Van xabun

Thep tang cng 5

g. Van x nc: 17


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Van x nc lm bng thp khng r, 49.

Gm 3 van b tr trn thn b, van c hn dnh vo thn, c ming thp m tngcng. Khi thc hin x nc, m van trn cng trc, khi mt nc h xung dn,m ln lt van th 2 v th 3.

o Van 1: cch mt nc 0.6mo Van 2: cch van 1 khong 0.7mo Van 3: cch van 2 khong 0.7m

3 van ny x nc ra b cha trung gian.

h. Tnh ton ha cht:

Gi s hiu sut ca ton qu trnh l H = 90%.

Khi chm FeSO4: phn ng xy ra theo t l nh sau:

Cr6+ + 3Fe2+ Cr3+ + 3Fe3+

S mol 0.001 0.003 0.001 0.003Xt trn 1 lit dung dch:

S mol FeSO4 l 0.003 mol

Trn l thuyt lng FeSO4 l:

0.003*152 = 0.456 g/l = 0.456 kg/m3

Xt trn c m: lng FeSO4 l

0.456*7.5 = 3.42 (kg/m)

Chm d 120% thc t lng FeSO4 chm vo l:

3.42*120% = 4.104 (kg/m)18


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Lng FeSO4 cn thit trong 1 ngy l:

4.104*4 = 16.416 (kg/ngy)

Hiu sut qu trnh l 90%

Sau phn ng:

o Cr6+ d: 0.0001 mol/l ng vi 0.0052 g/lo Cr3+ trong dung dch = lng sinh ra + lng c sn = 0.0009*52+0.073 =

0.1198 (g/l) ng vi 0.0023 mol/lo Fe3+ sinh ra: 0.0027 mol/l ng vi 0.1512g/l

Khi chm NaOH:

Cr3+ + 3OH- Cr(OH)30.0023 0.0069 0.0023

H=90% 0.00207 0.00622 0.00207

Lng NaOH chm vo c m l:

0.0069*40*7.5*120% = 2.488 (kg/m)

Lng NaOH cn thit trong 1 ngy l:

2.488*4 = 9.952 (kg/ngy)

Thc t khi phn ng xy ra khng hon ton, c hiu sut th lng NaOH cnthit ch l: 1.866 (kg/m)

Sau phn ng NaOH d 2.488-1.866 = 0.622 kg/m ng vi

0.00138 mol Lng Cr(OH)3 sinh ra:

0.00207*103*7.5 = 1.6 (kg/m)Ion Fe3+ tip tc phn ng vi OH- d trong dung dch to ra kt ta Fe(OH)3theohiu sut 90%:

Fe3+ + 3OH- Fe(OH)30.00046 0.00138 0.00046

H=90% 0.00414 0.001242 0.000414

Lng Fe(OH)3 sinh ra l:0.000414*107*7.5 = 0.33 (kg/m)

Do phn ng lun lun khng hon ton nn cc ion li tip tc xy ra, tuy nhinvi lng rt nh nn ta dng phn tnh ton ti y.

Vy sau 1 m, lng kt ta sinh ra l:

1.6+0.33 = 1.93 (kg/m)

Lng kt ta sinh ra trong 1 ngy l:

1.93*4 = 7.72 (kg/ngy)

Gi s m ca bn ti l 3%, khi lng ring = 1200 kg/m319


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khi lng bn l%3

72.7= 258 (kg/ngy)

Th tch bn sinh ra l:

1200

258= 0.215 (m3/ngy)

i. ng bm ha cht:

B tr 2 ng bm ha cht, mt ng chm dung dch FeSO 4, ng cn li chmNaOH. ng ng 49, xut pht t bm t di mt t, chy dc b st theothnh b. ui ng t ngang, song song vi mt nc trong b.

4. B cha trung gian:

a. Nhim v:

B cha nc trung gian t sau b phn ng, bn cnh b phn ng thu nc

sch t 3 van x.b. M t- Tnh ton kch thc:

B cha vung, t m xung di t, na chm na ni, ming b cao hn mt tkhong 1m.

B cha c thi gian lu nc l 5 gi. Th tch b c thit k ln cha thtch nc sch x ra t 1 m phn ng, tc l 7.5m3.

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+0.90

-1.40

Kch thc b:

o Cao: H = 2mo Chiu cao an ton trn mt thong: Hat = 0.3mo Tng chiu cao b l 2.3mo Cnh y vung: B = 1.94m

Th tch thc ca b:

V = 2.3*1.94*1.94 = 8.66(m3)

Vt liu xy dng: b tng ct thp.

5. Ct trao i ion:

a. Gii thiu:

Trao i ion l 1 qu trnh trong cc ion trn b mt ca cht rn trao i ion vi

ion c cng in tch trong dung dch khi tip xc vi nhau. Cc cht ny gi l ccionit (cht trao i ion), chng hon ton khng tan trong nc. Cc cht trao iion c th l cc cht v c hoc hu c c ngun gc t nhin hay tng hp nhnto.

Qu trnh trao i ion gm 4 giai on: trao i ion, ra ionit khi cc tp cht, tisinh ionit (dung dch axit/kim) v ra ionit khi dung dch ti sinh.

K thut trao i ion ng dng x l ngun nc thi cha ion vi mc ch:phc hi nc s dng, thu hi cc ion kim loi, ti s dng cc thnh phn quantm.

b. Tnh ton:21


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Hu ht qu trnh trao i ion xy ra trong ct trao i ion.

Ct trao i ion t ngay sau b cha nhm hon thin qu trnh x l nc.

+4.00

Tc th tch ca cht lng l:

Q =5

5.7= 1.5(m3/gi)

tR l thi gian tip xc theo tng rng (empty bed contact time), tR thng nm trong

khong 1.5-7.5 pht. Tc dng chy vF l gi tr nghch o ca tR.

Chn tR= 3 pht

Th tch tng nha l:

VR= Q*tR = 1.5*3 = 4.5(m3)

Chu k hot ng c tnh theo cng thc:

t =S

RR

aQ

va

*

*

aR: l dung lng hot ng ca nha (l/l), aR = 0.9-1.4 (cationit), chn aR= 1.2l/l

aS l dung lng trao i ca ion trong dung dch (l/l), aS = 1.8-2.0, chn aS = 1.8l/l

t = 2 (h)

Kch thc ct

Chiu cao ct thng bng 1.4 n 2 ln so vi chiu cao tng nha. Chn gi tr1,5

Chn chiu cao tng nha l 1.5m, vy chiu cao ct l22


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1.5*1.5 = 2.25 (m)

ng knh ct: d = 1.95m

6. Sn phi bn:

a. Nhim v:

Bn cn ca nh my x l c a sang thit b lm kh cn nhm mc ch:

- Gim khi lng vn chuyn ra bi thi- Cn kh d a i chon lp hay ci to t hn cn nc.- Gim lng nc bn c th ngm vo nc ngm bi thi- t gy mi kh chu v t c tnh

C nhiu loi thit b lm kh cn (sn phi bn, my lc cn chn khng, my lcp bng ti, my p cn ly tm,). Trong trng hp ny, ta s dng sn phi bnvi tiu ch tit kim chi ph, ph hp vi lng bn sinh ra trong 1 ngy khngnhiu.

b. M t-Tnh ton:

Sn phi bn chia thnh tng , kch thc mi ph thuc vo cch b tr ngxe vn chuyn bn ra khi sn phi v xa khi xc bn t phi ln xe. S lmvic ng thi ph thuc vo lu lng bn x ra hng ngy, dy bn cn lmkh, thi gian ca mt chu k phi.

y v thnh phi bn lm bng b tng ct thp m bo cch ly hon ton dungdch bn vi mi trng t xung quanh.

Th tch bn sinh ra 1 ngy l V = 0.215 m3.

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m u vo ca bn l 97%, m sau khi c lm kh l25%.

Khi lng ring bn t l 1200 kg/m3, khi lng ring bn khl 1600kg/m3.

Chn thi gian phi bn l 3 tun, tc 21 ngy. Gi s chiu cao bn 25% l 8cm sau 21 ngy. 1 m2 sn phi c lngcn l:

G = V* k*Ps

V: th tch ca phn sn c din tch l 1m2

V = 1*0.08 = 0.08(m3)

k: khi lng ring bn kh

k= 1400kg/m3

Ps: m ca bn sau khi phiPs = 0.25

G = 0.08*1600*0.25 = 32 kg/21 ngy

Lng bn cn phi trong 21 ngy:

7.72*21 = 162.12 kg

Din tch sn phi:

32

12.162= 5.07 m2

Tng din tch sn phi tnh c din tch ng bao quanh, h thu nc,trm bm a nc v khu x l:

5.07*150% = 7.6 m2

V din tch kh nh, lng bn sinh ra l khng ln nn ta ch thit k mt phibn. Kch thc phi bn l 3m x 2.5m.

Chiu su sn phi bn:

H = h1+h2+h3+h4

h1: dy y b tng = 200mmh2: b dy lp si = 200mmh3: b dy lp ct = 200mmh4: chiu cao cha bn + chiu cao an ton = 200mm

H = 800mm

24


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Phn 4:

TNH TON CHI PH

Do thi gian cng nh kinh nghim thc t c hn, bi n ny cha thc hin cvic tnh ton chi ph ca trm x l trn. Tuy nhin, qua tm hiu hin trn trang webca Ch cng ngh v thit b Vit Nam thuc B Khoa hc v Cng ngh c cho bnH thng x l nc thi nh my xi m kim loi vi c im v gi thnh nh sau:

M s: VN90 600

Tn CN/TB cho bn: H thng x l nc thi nh my xi m kim loi, nh my snxut mc vit theo m hnh hp khi t ng

Nc c CN/TB cho bn: VN Vit Nam

Ch s phn loi SPC:

90: Dich v v sinh, x l v rc thi

M t qui trnh CN/TB:

- Nc thi c iu chnh pH thch hp trc khi vo ngn trn v ngn phn ng.Ti ngn trn, ho cht thch hp c a vo phc v cho qu trnh phn ng tiptheo. Sau giai on phn ng, kim loi nng c trong nc thi xi m c tch dngkt ta ngn lng. Phn nc thi c tip tc i sang thit b tuyn ni p lc tch loi cc cht l lng c t trng nh, khng th lng. Nc thi trong c lng

ln 2, sang thit b hp th tch trit cc cht to mu trc khi thi ra h thngcng chung ca thnh ph.

- Cng sut: t 5 - 300 m3/ngy m.

- t tiu chun Vit Nam.

- Cc ch tiu kinh t - k thut khc: Gi thnh x l 1 m3 nc thi: 2.000 ng -2.500 ng.

Yu cu k thut trong vn hnh lp t:

Lnh vc p dng:

61: Cng ngh ho cht. Cng nghip ho cht

7025: Nc thi, lm sch v s dng nc thi

87: Bo v mi trng

u im ca CN/TB: - Gi c ph hp. - Thit b theo m hnh hp khi, c th thorp tng cm. - Nc thi sau x l t yu cu v cht lng

Mc pht trin:

Thng mi ho

Hnh thc ng k:Nhn hiu thng mi 25


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Nm ng k: None

Phng thc chuyn giao:

Hnh thc cung cp:

Cho gi tham kho:Gi bn thit b:90 triu/h x l 5 m3/ngy m

Ph o to:5 triu

Ph t vn k thut:10 triu

Nh vy thit b c cho bn trn c cng ngh khng hon ton ging cng nghm chng ta thit k trn, nhng c kh nhiu iu tng t. Chng ta c th

da vo c on chi ph.Mt cng ngh khc cng c cho bn trn trang web Ch cng ngh v thit b VitNam thuc S Khoa hc v Cng ngh, tuy nhin cha cung cp gi thnh, chng tixin a ra nghin cu phn cng ngh:

CNG NGH MICRO-CELL X L NC THI M KIM LOI (CR6+, CU 2+, NI 2+

M s ca cng ngh thit b: VN03TMSH0099

Ngy gii thiu cng ngh thit b: 14/05/2004

Ngy cp nht cng ngh thit b: 14/05/2004

Xut x: Vietnam

Phn loi SPC: Dch v x l cht thi, rc thi

Lnh vc p dng: X l mi trng

M t tm tt cng ngh thit bNc thi --> chn rc --> iu ha --> iu chnh pH --> thit b kh micro-cell -->iu chnh pH --> lng/lc --> TCVN 5945 (B) Bn thi cha Fe2O3, CuO, NiO cx l bng: Sn phi bn hoc My lc bnCN/TB duoc ap dung:X l nc thi cng nghip c cha kim loi nng

u im ca CN/TB- Khng cn tch dng nc thi ( thng dng Cr 6+ phi x l ring) nn h x ln gin, gn hn - Gim chi ph c bn t nht 50% - Ch cn kim sot mt thng s

cng ngh l pH nn vn hnh rt n gin - Chi ph vn hnh thp26


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Mc pht trin ca thit b cng ngh

s dng sn xut th (quy m pilot).

s dng sn xut quy m cng nghip.

thng mi ha.

Yu cu k thut trong vn hnh, lp tNng lngin: 3 - 6kw (ph thuc vo phng php tip xc)

Nh xng, t ai: 120 m2Nguyn liu: Phoi st, H2SO4, vi, "xc tc" A,B

Phng thc chuyn giao CN/TB

Patent

B quyt

License

o To

T vn k thut

Cha kha trao tay

Theo tha thun ca khch hng

Hnh thc cung cp CN/TB

Bn trc tip theo hp ng

Theo n t hng

Qua tng i l

i l c quyn

i l bn l

Qua im tip th SP/DV KH-CN ti: 79 Trng nh Qun 1, TP.H ChMinh

Thi gian v hnh thc bo hnhThit b cng trnh: 1 nmCng ngh: vnh vin

27


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Phn 5:

KT LUN V KIN NGH

Ngy nay cht lng cuc sng con ngi ang c nng cao rt nhiu nh vo spht trin ca khoa hc k thut vi nhiu ngnh sn xut c y mnh. Kinh t phttrin cng lm ny sinh nhiu nhu cu vt cht ca con ngi, t cc ngnh cngnghip khng ngng c pht minh v a vo hot ng sn xut. Nhng cng t

pht sinh ra mt vn mi m con ngi cn gii quyt. l vn mi trng.Vn ngy cng ln hn v hin nay mc bo ng. Chnh v th vic cn

bng gia kinh t v mi trng l bi ton kh cn s hp tc tham gia ca tt c mingi trn th gii.Xi m l mt trong nhng ngnh sn xut thit yu nhng gy ra s nhim mi

trng. Hin nay, ngy cng nhiu phn xng xi m c m ra nhm p ng nhucu th trng. Th nhng hu nh cc nh qun l ch quan tm n vn li nhuntrong khi rt xem nh, hoc gn nh khng h lu tm n vn mi trng. Cc

phn xng xi m khng b tr cc cng trnh x l nc thi m thi thng ra ngoimi trng.Ti thnh ph H Ch Minh, hn 80% nc thi ca cc nh my, c s xi m khngc x l. Chnh ngun thi ny v ang gy nhim nghim trng n mitrng nc mt, nh hng ng k cht lng nc sng Si Gn v sng ng Nai.c tnh, lng cht thi cc loi pht sinh trong ngnh cng nghip xi m trong nhngnm ti s ln n hng ngn tn mi nm. iu ny cho thy cc khu vc nhim v

suy thoi mi trng nc ta s cn gia tng nu khng kp thi a ra cc bin phphu hiu.Trong ni b n ny cha c iu kin tnh ton c th chi ph xy dng v vnhnh trm x l trn. Tuy nhin cn nhn mnh rng, d chi ph ban u c th l ngk nhng li ch mi trong m n em li v lu di l rt ln v rt ng u t.Chnh v vy vic thuyt phc cc nh qun l thy c tm quan trng ca vic bov mi trng cng nh lm mi ngi dn ni chung hiu iu l mt cng vicm cc nh mi trng hc cn hng ti.

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TI LIU THAM KHO

1. Trnh Xun Lai Tnh ton thit k cc cng trnh trong hthng x l nc thi Nh xut bn Xy dng

2. Nguyn Phc Dn Tp bi ging K thut x l ncthi.

3. L Vn Ct Hp ph v trao i ion trong k thut x lnc v nc thi

4. B Xy dng Tuyn tp Tiu chun xy dng ca VitNam NXBXD

5. B Xy dng TCVN: Thot nc bn ngoi mng li vcng trnh

6. Hong Vn Hu - Thot nc - tp 2: X l nc thi -NXBKH&KT

7. Lng c Phm Cng ngh x l nc thi bng binphp sinh hc NXBGD

8. Syed R.Qasim, Edward M.Moley, Guang Zhu Water Works Engineering: Planning, Design & Operation.

9. Integrated Solid Waste

10. S tay x l nc 1 & 2

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