Q2 Huong Dan AP Dung CNXL Nuoc Thai Y Te

7/25/2019 Q2 Huong Dan AP Dung CNXL Nuoc Thai Y Te

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NH XUT BN Y HCH NI, 2015

HNG DN P DNG CNG NGH

X L NC THI Y T(Ban hnh km theo Quyt nh s 105/Q-MT ngy 03/7/2014

ca Cc trng Cc Qun l mi trng y t)

B Y TCC QUN L MI TRNG Y T

D N H TR X L CHT THI BNH VIN


2/96


3/96

B Y TCC QUN L MI TRNG Y T

D N H TR X L CHT THI BNH VIN

HNG DN P DNGCNG NGH X L NC THI Y T

(Ban hnh km theo Quyt nh s 105/Q-MT ngy 03/7/2014

ca Cc trng Cc Qun l mi trng y t)

NH XUT BN Y HCH Ni, 2015


4/96

CH BIN

TS. Nguyn Thanh H

NG CH BIN

PGS.TS. Nguyn Huy Nga

NHM BIN SON

TS. Nguyn Thanh H

TS. Nguyn Th Lin Hng

TS. Lng Mai Anh

ThS. Phan Th L

ThS. L Vn ChnhTS. T Hi Bng

ThS. Cao V Hng

KS. Nguyn Tr Thm

CN. Thanh Huyn

KS. V Th Mai L

CN. Phm Th Qunh Trang

TH K BIN SON

ThS. L Mnh Hng


5/96

B Y TCC QUN L

MI TRNG Y T

S: 105/ Q - MT

CNG HA X HI CH NGHA VIT NAMc lp T do Hnh phc

H Ni, ngy 03 thng 07 nm 2014

QUYT NHV vic ban hnh ti liu hng dn qun l cht thi y t

CC TRNG CC QUN L MI TRNG Y T

Cn c Quyt nh s 1534/Q-BYT ngy 07/5/2013 ca B trng B Yt quy nh chc nng, nhim v, quyn hn v c cu t chc ca Cc Qun l

mi trng y t, B Y t;Cn c kt qu nh gi cc ti liu hng dn v qun l cht thi y t ca

cc thnh vin Hi ng Khoa hc v Cng ngh ca Cc Qun l mi trng yt (thnh lp ti Quyt nh s 25/Q-MT ngy 04/3/2014);

Theo ngh ca Trng phng Mi trng c s y t,

QUYT NH:

iu 1. Ban hnh km theo Quyt nh ny cc ti liu hng dn cc cs y t trin khai thc hin cng tc qun l cht thi y t gm:

1. S tay hng dn qun l cht thi y t trong bnh vin;

2. Hng dn p dng cng ngh x l nc thi y t;

3. Hng dn p dng cng ngh khng t x l cht thi rn y t.

iu 2. Quyt nh ny c hiu lc k t ngy k, ban hnh.

iu 3. Cc ng, b Chnh Vn phng Cc, Trng phng Mi trng cs y t, th trng cc c s y t v cc n v c lin quan chu trch nhim thihnh Quyt nh ny./.

Ni nhn:- BT. Nguyn Th Kim Tin ( bo co);

- TT. Nguyn Thanh Long ( bo co);

- TT. Nguyn Th Xuyn ( bo co);

- Website Cc Qun l mi trng y t;- Lu: VT, YT.

CC TRNG

Nguyn Huy Nga


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7/96

i

LI NI U

Nc thi pht sinh ti cc c s y t l loi nc thi nhim c tnh chtc th. Do , nu khng c thu gom, x l m bo cc quy chun hin hnhtrc khi thi ra mi trng c nguy c gy nhim, suy thoi cc ngun nctip nhn, nh hng n cht lng mi trng t v c th pht tn cc dch

bnh trong cng ng.

Hin nay, vic qun l nc thi y t ti Vit Nam cn mt s bt cp vcha p ng c cc quy nh hin hnh v bo v mi trng. Nhiu c s y

t cha la chn c loi hnh cng ngh ph hp vi iu kin thc t ca nv u t h thng x l nc thi. H thng x l nc thi ti mt s c sy t cha p ng c quy chun hin hnh. Bi vy, Cc Qun l mi trng yt, B Y t phi hp vi D n H tr x l cht thi bnh vin (vay vn ui ca Ngn hng Th gii) xy dng ti liu Hng dn p dng cng nghx l nc thi y t nhm gip cho cc bnh vin, cc c s y t trong vic lachn cng ngh x l nc thi ph hp trc khi quyt nh u t. Trong qutrnh bin son ti liu, chng ti nhn c nhiu kin ng gp b ch ca

cc cn b ti cc c s y t, cc chuyn gia trong nc v quc t hon thinti liu hng dn ny. ti liu c hon thin hn, gp phn gip cc c s yt trong cng tc u t v vn hnh hiu qu h thng x l nc thi, Ban binson rt mong nhn c thm cc kin ng gp t cc ng nghip v c gi.

Ban bin son xin trn trng cm n s tham gia, ng gp ca cc t chc,c nhn, cc chuyn gia t vn trong nc v quc t, c bit l s h tr ca Dn H tr x l cht thi bnh vin do Ngn hng Th gii ti tr trong qu trnhxy dng v ban hnh ti liu ny.


8/96

ii

DANH MC VIT TT

AAO

BOD

BYT

COD

CTYT

NTBV

QCVN

TCVN

TDSTS

TSS

XLNT

BV

NTYT

KTMT

HXD

KCN

XLMT

ATVSMT

BTNMT

N

CPSBR

Anaerobic - Anoxyc - Oxyc (Ym kh thiu kh hiu kh)

Nhu cu oxy ha sinh ha

B Y t

Nhu cu oxy ha ha hc

Cng trnh y t

Nc thi bnh vin

Quy chun Vit Nam

Tiu chun Vit Nam

Tng cht rn ha tanTng cht rn

Tng cht rn l lng

X l nc thi

Bnh vin

Nc thi y t

K thut mi trng

i hc Xy dng

Khu cng nghip

X l mi trng

An ton v sinh mi trng

B Ti nguyn v Mi trng

Ngh nh

Chnh phSequencing Batch Reactor (Hot ng gin on theo m)


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iii

MC LC

CHNG 1- NC THI Y T V CNG NGH X L NC THI

Y T TI VIT NAM .......................................................................................... 11.1. Nc thi y t ......................................................................................... 1

1.1.1. Lng nc thi y t pht sinh ........................................................... 1

1.1.2. c im ca nc thi y t ...............................................................2

1.2. Mt s quy nh v qun l nc thi y t ti Vit Nam .......................8

1.2.1. Mt s quy nh v thu gom, x l nc thi y t ..............................8

1.2.2. Quy nh v x thi, cp giy php x thi, quan trc mi trng .....8

1.2.3. Nguyn tc b tr cng trnh x l v im x nc thi ...................9

1.3. Cng ngh x l nc thi y t ti Vit Nam ......................................10

1.3.1. Cc giai on x l nc thi y t .................................................... 10

1.3.2. Mt s cng ngh x l nc thi y t hin ang p dng ti Vit Nam ... 29

1.3.3. nh gi u im - nhc im ca mt s m hnh cng ngh xl nc thi y t ..........................................................................................37

CHNG 2- HNG DN LA CHN CNG NGH X L NCTHI Y T ..........................................................................................................41

2.1. Mt s tiu ch nh gi cng ngh x l nc thi y t ph hp ....... 41

2.1.1. Cc tiu ch nh gi v k thut ...................................................... 41

2.1.2. Cc tiu ch nh gi v mt kinh t .................................................43

2.1.3. Cc tiu ch nh gi v mi trng .................................................44

2.1.4. Cc tiu ch nh gi v vn ha - x hi v qun l ....................... 45

2.2. Xc nh v lng ha i vi cc nhm tiu ch ............................... 46

2.3. Cc bc tin hnh la chn cng ngh x l nc thi y t ph hp ......48

CHNG 3 - MT S LU TRONG THIT K, LP T V VNHNH H THNG X L NC THI Y T ..............................................50

3.1. Mt s lu trong qu trnh thit k v lp t h thng x l nc

thi y t ........................................................................................................ 50


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iv

3.1.1. Mt s sai st cn trnh trong qu trnh thit k v lp t hthng x l nc thi y t ...........................................................................50

3.1.2. Mt s lu khi thit k v lp t h thng x l nc thi cho

mt s loi hnh c s y t c th ............................................................... 533.2. Mt s lu trong vn hnh v bo tr h thng x l nc thi y t .... 61

3.2.1. Nhng tn ti trong vn hnh v bo tr h thng x l nc thi y t ..61

3.2.2. Mt s lu trong vn hnh v bo tr cho mt s cng ngh x lnc thi y t c th ....................................................................................62

3.3. i vi cng tc gim st v quan trc ................................................67

TI LIU THAM KHO .................................................................................. 68


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v

DANH MC BNG

Bng 1-1:c tnh lng nc thi bnh vin............................................2

Bng 1-2:Khong cch ti thiu ca cng trnh x l nc thi bnhvin i vi khu dn c xung quanh .............................................................9

Bng 1-3: Lng bc x cn thit kh trng bng tia cc tm .............. 22

Bng 1-4: So snh mt s u, nhc im ca mt s m hnh cng nghx l nc thi bnh vin ........................................................................... 37

Bng 2-1:Cc tiu ch nh gi la chn cng ngh ph hp .............. 47

Bng 2-2:iu kin p dng nh gi s ph hp ca cng ngh x l ... 48Bng 3-1:Kh nng oxy ho hon ton ca zn vi cc hp cht hu c ....59


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vi

DANH MC HNH

Hnh 1-1: Song chn rc ............................................................................ 12

Hnh 1-2: S cu to b lng ng ....................................................... 13

Hnh 1-3: S cu to b lng hai v ...................................................... 13

Hnh 1-4: Gi th vi sinh vt ca b lc sinh hc ngp nc ....................15

Hnh 1-5: S cu to b lc sinh hc .................................................... 16

Hnh 1-6: Cu to hot ng a quay sinh hc ......................................... 17

Hnh 1-7: Bhiu kh truyn thng ...........................................................17

Hnh 1-8: S nguyn tc hot ng ca b SBR ...................................18

Hnh 1-9: B hiu kh thi kh ko di ....................................................... 19

Hnh 1-10: Mng oxy ha .......................................................................19

Hnh 1-11: Bi lc trng cy ......................................................................20

Hnh 1-12: Sn phi bn ............................................................................27

Hnh 1-13: S my quay ly tm ............................................................28

Hnh 1-14: S my p bn bng ti ......................................................28

Hnh 1-15: S x l nc thi bnh vin theo cng ngh lc sinh hcnh git ....................................................................................................... 29

Hnh 1-16: S x l nc thi bnh vin bng bn hot tnh trong b

hiu kh ....................................................................................................... 30

Hnh 1-17: S x l nc thi bnh vin theo nguyn l hp khi ......31

Hnh 1-18 : S x l nc thi bnh vin bng cng ngh AAO .........33

Hnh 1-19: S x l nc thi bnh vin bng h sinh hc n nh ....35

Hnh 1-20: S x l NTBV bng bi lc trng cy kt hp b lc

ym kh ....................................................................................................... 36

Hnh 3-1: S m hnh cng ngh x l nc thi cho c s khm

cha bnh ....................................................................................................54

Hnh 3-2: S m hnh cng ngh x l nc thi cho cc c s y t d

phng, cc c s nghin cu o to y dc, cc c s sn xut thuc ..... 57

Hnh 3-3:S m hnh B lc k kh kt hp kh trng bng ha chtx l nc thi ............................................................................................61


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1

CHNG 1NC THI Y T V CNG NGH

X L NC THI Y T TI VIT NAM

1.1. Nc thi y t

Nc thi y t l nc thi pht sinh t cc c s y t, bao gm: c s khm

bnh, cha bnh; c s y t d phng; c s nghin cu, o to y, dc; c s

sn xut thuc. Trong nc thi y t, ngoi nhng yu t nhim thng thng

nh cht hu c, du m ng, thc vt, cn c nhng cht bn khong v cht

hu c c th, cc vi khun gy bnh, ch phm thuc, cht kh trng, cc dung

mi ha hc, d lng thuc khng sinh v c th c cc ng v phng x c

s dng trong qu trnh chn on v iu tr bnh. Do nc thi y t cn c

thu gom v x l m bo theo cc qui nh hin hnh.

1.1.1. Lng nc thi y t pht sinh

Lng nc cp ca cc bnh vin trong mt ngy l c s tnh ton h

thng thu gom nc thi v la chn cng sut ca h thng x l nc thi mt

cch chnh xc nht. Tuy nhin, lng nc thi pht sinh cn c x l ti ccbnh vin thng c tnh ton da trn s lng bnh nhn hoc s ging bnh

(lng nc thi tnh trn bnh nhn trong ngy). T chc Y t Th gii (WHO)

a ra mt vi phng php c tnh lng nc thi pht sinh nh sau:

- Bnh vin quy m nh v trung bnh: 200 - 500 lt/ngi.ngy.

- Bnh vin quy m ln: 400 - 700 lt/ngi.ngy

- Bnh vin trng hc: 500 - 900 lt/ngi.ngyTuy nhin, lng nc thi thc t thu gom ph thuc rt nhiu vo cht

lng ca h thng thu gom trong cc c s y t. Trn thc t vi h thng thu

gom khng hiu qu, lng nc thi thc t thu c thng thp hn ng k

so vi cc gi tr c ch ra trong Bng 1-1.


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2

Bng 1-1: c tnh lng nc thi bnh vin

TTQuy m bnh vin(s ging bnh)

Tiu chun nc cp(l/ging.ngy)

Lng nc thic tnh

(m3/ngy)

123456

700Bnh vin kt hp nghincu v o to > 700

700700600600600

1000

70100-200200-300300-400

>400>500

Ngun: Trung tm KTMT th v KCN Trng HXD, H Ni, 2002

S liu bng trn ch c tnh cht tham kho. Khi thit k h thng x lnc thi ti c s y t cn c hot ng kho st, nh gi chi tit lng ncthi thc t pht sinh. ng thi tham kho mc tiu th nc ca bnh vin hngthng theo ha n nc tiu th.

i vi cc c s y t d phng hoc cc trm y t x, tiu chun cp ncthng thp hn cc gi tr nu bng trn. Lu lng nc cp thng dao ng

t 10 m3

/ngy n 70 m3

/ngy i vi cc c s y t d phng v t 1 m3

/ngy - 3m3/ngy i vi cc trm y t x/phng. Theo kinh nghim thc t, thng ngita c tnh lng nc thi bng 80% ca lng nc cp.

1.1.2. c im ca nc thi y t

1.1.2.1. Thnh phn, thng s nhim chnh trong nc thi y t

a. Cc cht rn trong nc thi y t (TS, TSS v TDS)

Thnh phn vt l c bn trong nc thi y t gm c: tng cht rn (TS);tng cht rn l lng (TSS); tng cht rn ha tan (TDS). Cht rn ha tan c kchthc ht 10-8- 10-6mm, khng lng c. Cht rn l lng c kch thc ht t10-3- 1 mm v lng c. Ngoi ra trong nc thi cn c ht keo (kch thc htt 10-5- 10-4mm) kh lng.

Theo bo co ti nghin cu khoa hc B Xy dng Xy dng TCVN:Trm x l nc thi bnh vin - Cc yu cu k thut thit k v qun l vn

hnh. H Ni, 2008, trong nc thi bnh vin hoc cc c s y t khc, hmlng cn l lng dao ng t 75 mg/L n 250 mg/L. Hm lng ca cc cht


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3

rn l lng trong nc thi ph thuc vo s hot ng ca cc b t hoi trongc s y t.

b. Cc ch tiu hu c ca nc thi y t (BOD5, COD)

Cc ch tiu hu c ca nc thi y t gm c: nhu cu oxy sinh ha (BOD)v nhu cu oxy ha hc (COD).

BOD5gin tip ch ra mc nhim do cc cht c kh nng b oxy ho

sinh hc, m c bit l cc cht hu c.

BOD5thng c xc nh bng phng php phn hy sinh hc trong thi

gian 5 ngy nn c gi l ch s BOD5.

C th phn loi mc nhim ca nc thi thng qua ch s BOD5nh sau:- BOD

5< 200 mg/lt (mc nhim thp)

- 350 mg/l < BOD5 1500 mg/lt (mc nhim rt cao)

Trong nc thi bnh vin ti Vit Nam, COD thng c gi tr t 150mg/l

n 250 mg/lt.


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c. Cc cht dinh dng trong nc thi y t (cc ch tiu nit v phospho)

Trong nc thi y t cng cha cc nguyn t dinh dng gm Nit v Phtpho. Cc nguyn t dinh dng ny cn thit cho s pht trin ca vi sinh vt v

thc vt. Nc thi y t thng c hm lng N-NH4+

ph thuc vo loi hnh cs y t. Thng thng nc thi pht sinh t cc phng khm v cc Trung tm y tqun/ huyn thp (300 - 350 lt/ging. ngy) nhng ch s tng Nit cao khong t50 - 90 mg/l. Cc gi tr ny ch c tnh cht tham kho, khi thit k h thng x lcn phi kho st v nh gi chnh xc nng cc cht nhim trong nc thi cc thi im khc nhau. Trong nc, nit tn ti di dng nit hu c, nit amn,nit nitrit v nit nitrat. Nit gy ra hin tng ph dng v c hi i vi ngunnc s dng n ung. Pht pho trong nc thng tn ti di dng orthophotphat

(PO43-, HPO42-, H2PO4-, H3PO4) hay polyphotphat [Na3(PO3)6] v pht pht hu c.Pht pho l nguyn nhn chnh gy ra s bng n to mt s ngun nc mt, gyra hin tng ti nhim bn v nc c mu, mi kh chu.

Cc cht thi bnh vin (nc thi v rc thi) khi x ra mi trng khngqua x l c nguy c lm hm lng nit v photpho trong cc sng, h tng.Trong h thng thot nc v sng, h, cc cht hu c cha nit b amn ho. Stn ti ca NH

4+hoc NH

3chng t sng, h b nhim bn bi cc cht thi. Trong

iu kin c xy, nit amn trong nc s b cc loi vi khunNitrosomonasvNitrobacter chuyn ho thnh nitrit v nitrat.

Hm lng nitrat cao s cn tr kh nng s dng nc cho mc ch sinhhot, n ung.

d. Cht kh trng v mt s cht c hi khc

Do c th hot ng ca cc c s y t, c bit l cc bnh vin, cc hacht kh trng c s dng kh nhiu, cc cht ny ch yu l cc hp cht

ca clo (cloramin B, clorua vi,...) s i vo ngun nc thi v lm gim hiuqu x l ca cc cng trnh x l nc thi s dng phng php sinh hc.

Ngoi ra, mt s kim loi nng nh Pb (ch), Hg (Thy ngn), Cd (Cadimi)hay cc hp cht AOX pht sinh trong vic chp X- quang cng nh ti cc phngxt nghim ca bnh vin trong qu trnh thu gom, phn loi khng trit s ivo h thng nc thi c nguy c gy ra nhim ngun nc tip nhn.

e. Cc vi sinh vt gy bnh trong nc thi y t

Nc thi y t c th cha cc vi sinh vt gy bnh nh: Samonella typhigy


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bnh thng hn, Samonella paratyphigy bnh ph thng hn, Shigella sp.gybnh l, Vibrio choleraegy bnh t,...

Ngoi ra trong nc thi y t cn cha cc vi sinh vt gy nhim bn ngun

nc t phn nh sau:

- ColiformsvFecal coliforms: Coliforml cc vi khun hnh que gram mc kh nng ln men lactose sinh ga nhit 35 0.5 oC. Coliformckh nng sng ngoi ng rut ca ng vt (t nhin), c bit trong mitrng kh hu nng. Nhm vi khun coliformch yu bao gm cc loi nhCitrobacter,Enterobacter, Escherichia, Klebsiella v c Fecal coliforms(trong E. colil loi thng dng ch nh ngun nc b nhim bi

phn). Trong qu trnh xc nh s lngFecal coliformcn lu kt quc th b sai lch do c mt s vi sinh vt (khng c ngun gc t phn) phttrin c nhit 44oC.

- Fecal streptococci: nhm ny bao gm cc vi khun ch yu sng trongng rut ca ng vt nh Streptococcus bovisv S.equinus. Mt s loic phn b rng hn hin din c trong ng rut ca ngi v ng vtnh S.faecalisv S.faeciumhoc c 2 biotype. Cc loi biotype c kh nngxut hin c trong nc nhim v khng nhim. Vic nh gi s lng

Fecal streptococcitrong nc thi c tin hnh thng xuyn. Tuy nhin,n c cc gii hn nh c th ln ln vi cc biotype sng t nhin. Fecal

streptococcirt d cht i vi s thay i nhit . Cc th nghim v sauvn khuyn khch vic s dng ch tiu ny, nht l trong vic so snh vikh nng sng st ca Salmonella.

- Clostridium perfringens: y l loi vi khun ch th duy nht to bo ttrong mi trng ym kh. Do , n c s dng ch th cc nhim

theo chu k hoc cc nhim xy ra trc thi im kho st do kh nngsng st lu ca cc bo t. i vi cc c s ti s dng nc thi, ch tiuny l ch tiu quan trng nh gi do cc bo t ca n c kh nng sngst tng ng vi mt s loi virus v trng k sinh trng.

1.1.2.2. Ngun v tnh cht nc thi ca tng loi hnh c s y t

a. Ngun v tnh cht nc thi ca cc c s khm bnh, cha bnh

Nc thi t cc c s khm bnh, cha bnh pht sinh ch yu t: cckhoa lm sng; cc khoa cn lm sng; khu vc vn phng; nh bp, Tuy


18/96

6

nhin, lng pht thi ti cc khu vc ny l khc nhau. Thng thng lngnc thi pht sinh ln nht l ti khu vc iu tr ni tr bao gm nc thitm git, v sinh, tip n l khu vc phng khm, phng th nghim, phngm v khu vc vn phng.

Theo bo co ti nghin cu khoa hc B Xy dng Xy dng TCVN:Trm x l nc thi bnh vin - Cc yu cu k thut thit k v qun l vnhnh. H Ni, 2008 ch ra hm lng cht rn l lng ca nc thi bnhvin t 75 n 250 mg/l. ng thi theo s liu ti bo co kho st ca Vin Sckhe ngh nghip v mi trng ti nhim v Nghin cu xut gii php xl CTBV t tiu chun mi trng H Ni, nm 2004, ch s BOD

5t 120 n

200 mg/l, COD t 150 n 250 mg/l.

C th lit k cc yu t nguy hi c trong nc thi bnh vin t cc khoa,phng khc nhau nh sau:

- Cc ha cht lin quan n trng ra phim (cht hin hnh v cht n nh)c ngun gc t phng chiu chp X-quang. Cc ha cht c hi t phngny c th i vo nc thi qua qu trnh trng ra. Tuy nhin, hin nay khnng ha cht pht sinh ti phng ny rt hn ch do cc bnh vin pdng cng ngh k thut s trong vic chp X-quang hoc vic x l chtthi phng x c kim tra v gim st cht ch.

- Khu vc Nha khoa l ni c kh nng pht sinh thy ngn (Hg) vo nc thicao khi hn hng thy ngn c s dng trong hn rng khng c tch loi

bng thit b tch t pha di bn ra. Khoa chng nhim khun l ni sdng lng cht kh trng nhiu nht. Trong cht kh trng dng aldehydec s dng ph bin lm gia tng mc nhim trong nc thi. Nh bptrong bnh vin thng pht thi lng hu c cao, du m ng thc vt lin

quan n cc khu ch bin thc n vo trong nc thi. Khu vc git l lmcho nc thi c pH tng cao, tng hm lng pht pht v c bit l cchp cht cha clo c ngun gc t cht kh trng c s dng. khu vciu tr, lng khng sinh, cht kh trng (glutaraldehyde) lm cho nc thi nhim hn. ng thi, lng nhim hu c tng cao khi tip nhn dch rat c th ca ngi bnh. Phng th nghim l ngun pht sinh nc thi ccha ha cht, ha cht thng c s dng l cc cht halogen, dung mihu c, t bo (nhum Gram), formaldehyde,...

Ngoi cc thng s nhim trn, nc thi t cc c s khm bnh, cha


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bnh cn cha nhiu rc trong qu trnh hot ng ca cc khoa, phng, sinh hot

ca bnh nhn v ngi nh bnh nhn.

b. Ngun v tnh cht nc thi ca cc c s y t d phng, nghin cu

o to y - dc v cc c s sn xut thucCc ngun nc thi pht sinh t hot ng chuyn mn ca cc c s y

t thuc nhm ny ch yu l nc thi t qu trnh th nghim, sn xut thuc,tim phng, Do , ngoi nhng thng s nhim trong nc thi nh: COD,BOD

5, H

2S, tng pht pho, tng nit, SS, DO, vi sinh vt, nc thi ca cc c

s y t thuc nhm ny cn cha nhiu ha cht, d lng khng sinh c sdng trong sn xut thuc. Cc cht nhim ny thng theo con ng trng radng c v i vo nc thi, to nn tnh cht nhim c trng cho nc thi caloi hnh c s y t ny.

Nc thi thng c pH thp, thp nht l ti cc c s sn xut thucnu s dng cc hot cht c tnh khng sinh trong sn xut, lng d khng sinhthng lm cho gi tr pH gim xung. Tip n l cc c s nghin cu y-dcv cui cng l cc trung tm y t d phng. V cc ch tiu nhim nh: COD,BOD

5, H

2S, tng pht pho, tng nit, SS, DO, khng c s khc bit r rt trong

ba loi hnh c s y t ny (y t d phng; nghin cu y-dc; sn xut thuc) th

tch nc thi pht sinh ty theo chc nng, nhim v nhng thng khng nhiu.Lng rc c trong nc thi ca cc c s y t thuc nhm ny khng cao

do khng iu tr ni tr nn hn ch vic sinh hot n ung. ng thi, ch tiu nhim du m trong nc thi ca loi hnh c s y t thuc nhm ny cng thp.

Ringi vi c s o to y-dc c bnh vin hoc c s thc hnh cging bnh th nc thi c tnh cht, c im nhim tng t nh c s khm

bnh, cha bnh v cn c x l nh nc thi bnh vin.

c. Ngun v tnh cht nc thi cc trm y t x, phng, th trn

Trm y t x, phng, th trn (sau y gi l Trm y t x) v cc phngkhm t nhn thng khng c bnh nhn iu tr ni tr. Lng ngi ncc trm y t x khng nhiu tr thi gian tim chng. Nc thi pht sinh ivi loi hnh c s y t thuc nhm ny ch yu l loi nc thi sinh hot vmt lng nh nc thi pht sinh trong qu trnh lm th thut y t n gin.

Lng nc thi pht sinh trung bnh khong t 1-2 m3/ngy.m. Cc ch s

nhim nh BOD5, COD tng i thp, ch yu l NH4+

v mt s vi sinhvt gy bnh.


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1.2. Mt s quy nh v qun l nc thi y t ti Vit Nam

1.2.1. Mt s quy nh v thu gom, x l nc thi y t

Theo Quy ch qun l cht thi y t ban hnh km theo Quyt nh s43/2007/Q-BYT ngy 30 thng 11 nm 2007 ca B trng B Y t quy nh:

(1)Mi bnh vin phi c h thng thu gom v x l nc thi ng b. Ch thng thu gom ring nc ma b mt v nc thi t cc khoa, phng. Hthng cng thu gom nc thi phi l h thng ngm hoc c np y. H thngx l nc thi phi c b thu gom bn.

(2) Cc bnh vin khng c h thng x l nc thi phi b sung h thngx l nc thi hon chnh.

(3) Cc bnh vin c h thng x l nc thi t trc nhng b hngkhng hot ng hoc hot ng khng hiu qu, phi tu b v nng cp vnhnh t quy chun mi trng hin hnh.

(4) Cc bnh vin xy dng mi, bt buc phi c h thng x l nc thitrong hng mc xy dng v c c quan c thm quyn ph duyt.

(5) Cng ngh x l nc thi bnh vin phi p ng vi cc tiu chun,

quy chun mi trng, ng thi phi ph hp vi cc iu kin a hnh, kinh phu t, chi ph vn hnh v bo tr.

(6) nh k kim tra cht lng x l nc thi. C s qun l vn hnh vkt qu kim tra cht lng lin quan.

Cc yu cu ca h thng x l nc thi bnh vin:

(1) C quy trnh cng ngh ph hp, x l nc thi t quy chun k thutquc gia v mi trng i vi nc thi y t;

(2) Cng sut ph hp vi lng nc thi pht sinh ca bnh vin;

(3) Ca x nc thi phi thun li cho vic kim tra, gim st, ly mu;

(4) Bn thi t h thng x l nc thi phi c qun l nh cht thi rny t.

1.2.2. Quy nh v x thi, cp giy php x thi, quan trc mi trng

Cc c s khm cha bnh, cc c s y t thuc h d phng, o to, nghincu c pht sinh cht thi ly nhim, nc thi trc khi thi ra mi trng phi


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p ng cc yu cu gii hn cho php v cc thng s nhim theo QCVN28:2010/BTNMT - Quy chun k thut quc gia v nc thi y t. Cc c s snxut thuc, nc thi trc khi thi ra mi trng phi p ng cc yu cu giihn cho php v cc thng s nhim theo QCVN 40:2011/BTNMT: Quy chunk thut quc gia v nc thi cng nghip.

Trc khi thi nc thi ra mi trng, cc c s y t phi lm th tcxin cp php x thi theo quy nh ti Ngh nh s 201/2013/N-CP ngy 27/11/2013 ca Chnh ph quy nh chi tit mt s iu ca Lut Ti nguyn nc.

Quy trnh, th tc quan trc tc ng mi trng ti cc c s khm bnh, chabnh tun th theo quy nh ti Thng t s 31/2013/TT-BYT ngy 15/10/2013ca B Y t. i vi cc c s y t khng thuc khi khm bnh, cha bnh, quynh quan trc mi trng theo quyt nh ph duyt bo co nh gi tc ngmi trng (TM) hoc xc nhn cam kt bo v mi trng hoc quyt nh phduyt n bo v mi trng.

1.2.3. Nguyn tc b tr cng trnh x l v im x nc thi

H thng XLNT phi c b tr ph hp vi quy hoch pht trin ca ccc s y t v phi m bo khong cch ti thiu ca cng trnh i vi khu dn

c xung quanh.Bng 1.2: Khong cch ti thiu ca cng trnh x l nc thi

bnh vin i vi khu dn c xung quanh

STT Loi cng trnh

Khong cch ATVSMT ti thiu (m)ng vi cng sut (m3/ngy)

< 200 (m3/ngy) 200 - 5.000(m3/ngy)

1 Trm bm nc thi 15 20

2 Trm x l nc thi:

a X l c hc, c sn phi bn 100 200

b X l sinh hc nhn to, c snphi bn

100 150

c X l sinh hc khng c snphi bn, c my lm kh bn,c thit b x l mi hi, xydng kn

10 15

d Bi lc ngm trng cy 100 150


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STT Loi cng trnh

Khong cch ATVSMT ti thiu (m)ng vi cng sut (m3/ngy)

< 200 (m3/ngy) 200 - 5.000(m3/ngy)

e Khu t ti cy xanh, nngnghip

50 200

f H sinh hc 50 200

g Mng oxy ha 50 150

Ngun: QCVN 01:2008/BXD

Trong khong cch v sinh mi trng phi trng cy xanh vi chiu rng

10m. i vi loi trm bm nc thi s dng my bm th chm t trong gingga kn th khng cn khong cch an ton v sinh mi trng, nhng phi c ngthng hi x mi hi (x cao 3m). Khi khng din tch m bo khongcch ti thiu trn th phi c cc gii php cng ngh ph hp hoc xy dng, lpt hp khi cc cng trnh v thit b x l nc thi v phi c c quan qunl mi trng a phng chp thun.

Nc thi ca c s y t dn ra bn ngoi bng cng kn, vt liu khngthm nc. iu kin pha long vi ngun tip nhn c tt, nc thi phix ngp v c p lc.

1.3. Cng ngh x l nc thi y t ti Vit Nam

1.3.1. Cc giai on x l nc thi y t

Hin nay, c rt nhiu phng php x l nc thi. Ty thuc vo c imca mi loi nc thi p dng phng php x l cho ph hp. Vi cng trnhx l nc thi bnh vin, ngi ta thng phi b tr nhiu phng php trn

mt h thng x l vi nhiu thit b k thut khc nhau mi cho hiu qu v thiu sut x l cao. Ti Vit Nam nc thi y t do c th gn ging vi ncthi sinh hot nn vic thit k k thut v b tr thit b trong h thng x l ncthi y t kh tng ng vi h thng x l nc thi sinh hot thng thng. Cc

bc tin hnh x l cng bao gm cc bc nh: tin x l, x l cp mt, x lcp hai v sau x l.

1.3.1.1. Giai on tin x l

y l khu ht sc quan trng trong x l nc thi nhm m bo h thng


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x l nc thi hot ng hiu qu. Nu giai on ny thc hin khng tt s nhhng n s hot ng ca h thng x l nc thi. Bi vy, tt c cc c s yt c pht sinh dng nc thi c th (cht gy c t bo, cc ha cht t khoaxt nghim,) cn c thu gom x l s b ti ni pht sinh trc khi u nivo h thng thu gom nc thi chung ca c s y t v v khu x l tp trung.Do , trong giai on tin x l cn c thc hin nh sau:

- Cc c s y t c khoa y hc ht nhn phi tun th cc nguyn tc v anton phng x. Nc thi pht sinh t khu vc ny phi c lu gi ring thi gian lu hn 10 chu k bn hy ca cht phng x, sau mic thi vo h thng thu gom nc thi chung ca c s y t v v khux l nc thi tp trung;

- i vi cc bnh vin c khu vc cng tin, nh n vi s lng khch phcv nhiu thng c pht sinh lng du m ng thc vt cao, do cnc thit k h thng tch du m t cc dng thi khu vc ny trckhi u ni vo h thng thu gom nc thi chung ca c s y t;

- Ngoi hai dng thi c bit trn, trong cc bnh vin ln cn c cc bphn pht sinh ra cc dng thi c th cn phi c x l s b ngay tingun pht sinh trc khu u ni vo h thng thu gom nc thi v khu

x l tp trung. Chng hn nh nc thi pht sinh t phng xt nghim,khoa rng, khoa ha tr liu, khu vc git l,

Bi vy, vic thu gom ring cc dng thi c tnh c th trong ccbnh vin ln thc hin x l s b s gp phn nng cao v m bohiu qu x l nc thi ca c s y t.

1.3.1.2. Giai on x l cp 1

Giai on x l ny nhm loi b cc tp cht dng l lng nu nh thit k tiu chun. Qua cng on tin x l, hm lng COD, BOD trong nc thi yt gim ng k. Phng php p dng bao gm phng php vt l, lng lc,Thit b k thut phc v cho cng on ny thng thng nh: Song chn rc, blng cp mt, b iu ha.

Song chn rc

Song chn rc dng tch rc trong nc thi trc khi vo trm bm hoc

trm x l tp trung. bo v my bm khi b tc nghn th trong ngn thunc thi cn lp t song chn rc th cng hoc song chn rc c gii hoc song


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chn rc kt hp nghin rc. Khi khi lng rc ln trn 0,1 m3/ngy nn c giiho khu ly rc v nghin rc. Nu lng rc nh hn 0,1 m3/ngy th s dngsong chn rc th cng hoc gi chn rc. Song chn rc c loi song chn rc thv song chn rc tinh. Song chn rc th tch loi rc to ht sc quan trng.Song chn rc c tnh ton, la chn loi hnh v b tr sao cho ph hp nhtvi lu lng v tnh cht ca ngun thi.

Hnh 1-1: Song chn rc

B lng s cp

B lng s cp lm nhim v tch ct v cc hp cht v c. Vi vic x l

nc thi bnh vin, b lng s cp thng thng c s dng tp trung vo hailoi l b lng ng v b lng hai v, tuy nhin ty vo cc iu kin c th mtrong thit k c th m rng s dng cc loi b lng khc nhau (nh b lngngang) sao cho ph hp vi iu kin tng bnh vin v ph hp vi cng nghla chn. Thng thng gim thiu dung tch b trong cc h thng x l, blng v b iu ha c thit k lm mt.

- B lng ng:

B lng ng s cp c s dng tch cn, m bo cho hm lng cnl lng trong nc thi nh hn 150 mg/L trc khi a i x l sinh hc hockh trng.

Kt cu b lng s cp c b phn thu v tch cht ni. Mng trn thunc lng trong cc b lng c th lm theo dng phng hoc dng rng ca;ti trng thu lc ca mng khng qu 10 L/s.m.

Lng cn gi li trong b lng ng s cp ph thuc vo dng nc thi

qua b t hoi. Trong cn t b lng s cp cn nhiu trng giun sn v vi khungy bnh.


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- B lng hai v:

B lng hai v l cng trnh c cc mng lng din ra qu trnh lng trnglc tch cn lng theo dng chy ngang v ngn n nh ym kh bn cn lng.

B lng hai v c np y p dng thay th b t hoi khi lng nc thi lnhn 50m3/ngy v thay th b lng hai v (khng c np y) khi cn thit phit cng trnh x l gn nh khng m bo khong cch ly v sinh theo quy nh,nhng thng khng vt qu 500m3/ngy.

Hnh 1-2: S cu to b lng ng Hnh 1-3: S cu tob lng hai v

B c th c dng hnh trn hoc hnh ch nht. Thng khi cng sut t100m3/ngy th nn lm kiu trn, ng knh nh nht ca b l 3m. Khi cngsut n 500m3/ngy th nn lm kiu hnh ch nht, t l gia chiu rng v chiudi l 1: 2.

Thi gian x bn khi b l mt ngy/ln vi lng bn x bng lng bn

gi li trong b mi ngy. Khi iu kin x bn kh khn th nn xem xt n victng thi gian gia hai ln ht bn v tng th tch ngn cha bn. Tuy nhin, chuk x bn cng khng nn qu 5 ngy/ln.

1.3.1.3. Giai on x l cp 2

Nhim v ca giai on x l cp 2 l loi b carbon ha tan v cc dng hpcht nit, pht pho di tc dng ca h vi sinh vt trong nc thi. H vi sinh

vt tiu th cc cht hu c d phn hy trong nc thi di dng ha tan nh:ng, cht bo, cc phn t carbon mch ngn v hp thu cc dng vt cht


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kh tan hn trng thi l lng khc vo sinh khi. Trong qu trnh khong hacng nh qu trnh nitrate ha vi khun cn xy v dng cht tn ti. png hai iu kin thit yu ny, hai phng thc thng c s dng l h mnglc c nh bm dnh v bn hot tnh l lng.

H mng lc c nh bm dnh bao gm cc h nh: Lc sinh hc nh git,a quay sinh hc, mng lc ngp nc Ti cc h ny, vi sinh vt pht trintrn nn gi th v nc thi chy qua cc b mt ny. Cc my thi kh cng

bc hoc h thng c hc thng c s dng cung cp xy cho hot ngca h vi sinh vt. Trong h thng bn hot tnh l lng, bn hot tnh c trnvi nc thi v c cung cp oxy trong mt b c nh. Sau cng on lng,

bn hot tnh c tr li b hiu kh b p li lng sinh khi mt i qua

m bo kh nng x l ca h vi sinh vt.

loi b nit, cn c qu trnh oxy ha amoniac thnh nitrate di tc dngca cc vi sinh vtNitrospiravNitrosomonus. Tip theo l qu trnh kh nitratethnh kh nit. thc hin c cc qu trnh trn cn thc hin trong iu kinthiu oxy. Ngoi ra cng c th s dng cc k thut trong x l cp 3 nh lcct, bi lc sinh hc. Trong cc qu trnh Nitrate ha (Nitrication) v kh nitrate(Denitrication) cn c thc hin mt cch cn trng nhm to ra nhm (chng)

vi sinh vt thch nghi v n nh.Cc k thut x l cp 2 thng c s dng trong cc cng trnh x l

nc thi bnh vin ti Vit Nam bao gm:

a. B lc sinh hc

B lc sinh hc dng x l nc thi bng phng php sinh hc hiu khmc hon ton hoc khng hon ton. B hot ng theo nguyn tc vi sinh vtdnh bm trn vt liu lc rn v hnh thnh mng lc sinh hc. p dng ti Vit

Nam hin c hai dng b lc sinh hc bao gm:

- B lc sinh hc ngp nc

- B lc sinh hc nh git

B lc sinh hc ngp nc

B lc sinh hc ngp nc l loi cng trnh c gi th thay cho vt liu lc,t ngp trong nc vi sinh vt dnh bm. Vi sinh vt pht trin thnh cc lp

mng hp th cc cht hu c v cht dinh dng trong dng nc thi khi


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chuyn ng qua b mt lp m. B c th hot ng trong iu kin nc thikhng c xy (b k kh) hoc c sc kh bo ha xy (b hiu kh).

Gi th ca vi sinh vt k kh l cc tm nha hnh sng dnh kt vi nhau

thnh khi hoc cc loi cui, antraxit, gch v,... ng knh tng ng t40mm n 70 mm xp thnh ng trong b. Khi m c rng t 40% (gi thvt rn dng cc ng knh 40-50mm) n 98% (gi th l khi tm nha mnghnh sng). Nc thi dn vo trong b lc sinh hc k kh phi to c thnh

dng lan ta u trong khe h gia hai b mt gi th. Thi gian nc lu li trong

b khng nh hn 1,5 gi. Hiu sut x l nc thi t ti 50% theo BOD.

Gi th ca vi sinh vt hiu kh l cc tm nha hnh sng vt liu PVC, HIPS

hoc ABS, dy t 0,25 n 0,35 mm, gn vi nhau thnh khi hoc cc linh kinnha hnh dng kch thc khc nhau xp thnh khi trong b. Gi th vi sinh vt

hiu kh ngp nc cng c th l ct, antraxit, si cui v cc vt liu xp khc.

Cp khng kh cho b bng my thi kh, my sc kh dng jet hoc qut gi cng

bc hot ng lin tc. Oxy phn tn vo nc nh thit b khuch tn kh, aerolif

hoc eject. Trong b, nc thi c bo ha xy to thnh dng ng lin tc

qua cc lp m vi sinh. Thi gian nc lu li trong b trn 2 gi. Hiu sut x l

theo BOD5trong b t 70 n 90%.

Hnh 1-4: Gi th vi sinh vt ca b lc sinh hc ngp nc

kt hp x l nit trong nc thi, b x l k kh c b tr trc b

hiu kh. Trong b x l hiu kh, thi gian thi kh c tnh ton ko di trn 4

gi m bo cho qu trnh nitrat ha din ra. Sau mt phn hn hp nc

thi v bn th cp t b hiu kh c a v b k kh to iu kin cho qu

trnh kh nitrat din ra. Lng hn hp nc thi v bn tun hon t 0,15 n

0,25% lu lng nc thi vo b. Ti trng amoni tnh ton 0,3 - 2kg N-NH4+

/m3 vt liu m/ngy.


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B lc sinh hc nh git

Dng b lc sinh hc nh git c cp gi t nhin hoc cp gi nhn to.

Thng gi t nhin thc hin qua cc ca cp gi b tr u khp b mt thnh

b. Tng din tch l cp gi trong phm vi sn b v sn lc l 1-5% din tch blc. Thnh b kn thng gi nhn to. Dng qut gi thi khng kh vo khong

khng gian gia sn lc v sn y b vi p lc 100mm ct nc ( ch ca vo).

S n nguyn b lc khng di 2 v khng qu 8, tt c u hot ng. Tnh

ton mng phn phi v tho nc ca b lc sinh hc theo lu lng ln nht.

C thit b x cn v ra y b lc sinh hc khi cn thit.

Hm lng BOD5 ca nc thi a vo b lc sinh hc khng ln hn

200mg/L. Nu nc thi c BOD5ln hn 200 mg/L th phi tun hon nc.

Hnh 1-5: S cu to b lc sinh hc

Vt liu lc ca b lc sinh hc nh git ch yu l dng ht c th l

dm, cui, si, x keramzit, cht do (c kh nng chu c nhit 6 - 300C

m khng mt bn). Vt liu lc cn c chiu cao ging nhau, c ht ng u

theo chiu cao b.

Nc thi c phn phi trn b mt vt liu lc theo chu k bng nhiu

cch khc nhau. Khi phn phi nc bng cc loi vi phun vi p lc t do, p

lc ti vi phun cui cng khng di 0,5m ct p.

b. a quay sinh hc

a quay sinh hc c s dng x l nc thi trong cng on x l

sinh hc. H thng c thit k dng a vi vi sinh vt bm dnh trn a. H

chuyn ng c gn vo trc lm cho a chuyn ng quay trn. H thng ny


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gip cho oxy i vo su bn trong ca gi th sinh hc. ng knh a thng t

1-4 m, khong cch gia cc a l 10 - 20 mm. m bo s hot ng n nh

ca h thng, khong 40% a c t chm di nc thi v vn tc quay ca

a t t 1 - 1,6 vng/pht

Hnh 1-6:Cu to hot ng a quay sinh hc

c. B hiu kh truyn thng

B hiu kh trn l loi b hiu kh dng x l sinh hc hon ton hockhng hon ton cc loi nc thi bnh vin. Tc nhn x l nc thi l bnhot tnh. Trong qu trnh ny, cc loi vi khun hiu kh tch t thnh cc bng

bn (sinh trng l lng) s hp th cc cht hu c v s dng oxy c bo hatrong nc oxy ha cht hu c. Nng xy ho tan cn thit c duy trtrong hiu kh l 4 mg/L, ti thiu l 2 mg/L. Cp kh cho b hiu khc th bngmy thi kh hoc my khuy. Chiu su t thit b phn phi kh trong b hiukh ph thuc chiu su b, l 0,5 - 1m khi dng h thng cp kh p lc thp hoc3 - 6 m khi dng cc h cp kh khc.

Trong cc b hiu kh c h thng thit b x cn b v b phn x nc khi

thit b np kh. Trng hp cn thit, cn c thit b ph bt bng cch phun nchoc bng ho cht.

Hnh 1-7: B hiu kh truyn thng


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d. B hiu kh hot ng gin on theo m

B hiu kh hot ng gin on theo m (Sequencing Batch Reactor Sauy vit tt l SBR) kt hp c 3 qu trnh x l thiu kh, x l hiu kh v lng

bn hot tnh, c dng x l BOD v nit trong nc thi bnh vin. S bSBR ti thiu l 2.

Hnh 1-8: S nguyn tc hot ng ca b SBR

Trong b SBR, liu lng bn hot tnh dao ng t 0,5g/L n 6 g/L. Thigian cp nc thi v din ra qu trnh thiu kh t 1,0 gi n 1,5 gi; thi gian sckh tip theo t 1,5 gi n 5,0 gi; thi gian lng, x nc thi v bn t 1,5 gin 2,5 gi. Tng thi gian mt chu k trong b SBR t 4 gi n 9 gi. Lng bn

gi li sau mi chu k trong b SBR thng chim 20 n 30% th tch b.e. B hiu kh thi kh ko di

B Hiu kh thi kh ko di thng dng x l BOD, nit amoni v nnh hiu kh mt phn bn. Thi gian thi kh trong b hiu kh xy ha honton t (h) phi ln hn 4 gi. Cc cng trnh pha sau b hiu kh thi kh ko di oxy sinh ha hon ton cc cht hu c c thit k theo cc thng s sau:

- Thi gian nc lu li trong vng lng ca b lng t hai vi lu lng ln

nht khng di 1,5gi.


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- Lng bn hot tnh d chn bng 0,35 kg trn 1 kg BOD5. Vic x bn hot

tnh d cho php thc hin i vi b lng v b hiu kh khi liu lng bnt ti 5g/L - 6 g/L.

- m bn x t b lng l 98% v t hiu kh l 99,4%.

Hnh 1-9: B hiu kh thi kh ko di

f. Mng oxy ha

Mng xy ha hot ng theo nguyn l bn hot tnh, c dng x lnc thi bc hai hay bc ba. Lng bn hot tnh d l 0,4 kg/kg BOD

5- 0,5 kg/

kg BOD5, lng khng kh n v l 1,25 mg/mg BOD

5- 1,45 mg/mg BOD

5cn

x l. Mng xy ha c hnh van, chiu su khong 1,0m - 2,0m.

Mng xy ha lm thong trong bng thit b c kh nh my khuy trcng hoc trc ngang, gung quay,... t on knh thng. Hn hp nc thiv bn hot tnh t chy t knh oxy ha sang b lng th cp. Bn hot tnh t blng th cp c a lin tc vo mng. Thi gian nc lu li trong b lngth cp bng 1,5 gi theo lu lng ln nht. Bn tun hon t b lng 2 cdn lin tc v knh.

Hnh 1-10: Mng oxy ha


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g. Bi lc trng cy (bi lc sinh hc ngp nc)

Bi lc ngp nc x l nc thi gm hai dng: ngp nc b mt vngp nc pha di (bi lc ngm), thng p dng i vi vng t ct pha v

st nh x l sinh hc hon ton nc thi sau khi c lng s b. Cc bilc ngp nc thng c trng cy pha trn nn thng c gi tt l bi lctrng cy.

Bi lc c xy dng trn khu t bng phng c dc khng qu 2% vc mc nc ngm su trn 1,5 m. Bi lc ngp nc khng c xy dng trnnhng khu t c s dng nc ngm mch ngang cng nh khu vc c hang ngngm (vng cast).

Nc thi bnh vin trc khi chuyn n x l trong bi lc ngp nc phic x l s b trong b t hoi hoc trong cc loi b lng s cp khc.

Hnh 1-11: Bi lc trng cy

Trn khu t lm bi lc ngp nc trng cc loi cy thn lp hoc thn

rng v c r chm. Cc loi cy c hoa c khuyn co trng trn bi lc ngp

nc to cnh quan cho bnh vin.

Hiu qu x l BOD trong nc thi ca bi lc ngp nc c th ti 90%,

hiu qu x l theo Nit c th ti 60%. Vi thi gian lu thy lc ln (t 7 ngy

n hng thng).

h. S dng h thng thit b hp khi c sn

Do c im lu lng dng thi khng qu ln nn mt s c s y t s

dng cc h thng hp khi ch to sn d dng thao tc, lp t v vn hnh

h thng x l nc thi. Tuy nhin, ty vo tng n v sn xut m thit b hp

khi thng cha t 1-3 cng on x l. H thng hp khi s c gii thiu

c th cc chng tip theo d dng thao tc lp t v vn hnh h thng xl nc thi bnh vin.


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1.3.1.4. Sau x l

Sau x l l bc cui cng trong qu trnh x l nc thi trc khi

nc thi c thi ra mi trng tip nhn. Trong cng on sau x l c th

phi s dng n nhiu bin php kt hp. Trc khi kh trng nc thi, cnthit phi loi b trit cc cht hu c l lng cn tn ti. Kh trng nc

thi t c s y t phi c thc hin, c bit l khi nc thi x vo ngun

nc sng, h.

Ngoi ra trong qu trnh x l nc thi bng phng php sinh hc thng

pht sinh mt lng bn sinh khi, lng bn ny nhiu hay t ph thuc vo

thnh phn u vo v lu lng nc thi, bn sinh khi pht sinh cng cn c

bin php x l. Lng bn thi cha cc tc nhn nhim cng cn c xcnh v c bin php qun l thch hp.

a. Cc k thut kh trng nc thi y t

Nc thi t bnh vin hoc t cc c s hot ng y t sau khi x l cc

cht nhim hu c thng c kh trng trc khi x vo ngun nc. Ngoi

ra nu x l cp 2 bng bi lc hay h sinh hc n nh vi thi gian di (khong 1

thng) th c th khng cn phi kh trng. kh trng c th dng cc phng

php sau:

- Kh trng bng tia cc tm;

- Kh trng bng Clo hoc cc hp cht ca Clo (clorua vi, natri hypoclorid

iu ch bng in phn);

- Kh trng bng zn (sn xut ti ch).

Kh trng bng tia cc tm (Ultraviolet radiation UV)Kh trng bng tia cc tm ch p dng i vi nc thi sau khi lm sch

sinh hc hon ton v hiu qu hp th tia cc tm ca nc thi t ti thiu l

70%. Cng sut ca thit b c la chn da trn lu lng tnh ton gi pht

sinh nc thi ln nht v vi lu lng tnh ton gi pht sinh nc thi ln nht

ti thi im c ma trong trng hp h thng s dng thot nc chung. Lng

bc x c tnh ton nhm m bo nng coliformstrong nc sau kh trng

phi thp hn 3000 MPN/100 mL.


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Bng 1-3: Lng bc x cn thit kh trng bng tia cc tm

Loi nc thi Hiu qu kh trng (%) Lng bc x (J/m2)

Sau x l sinh hc honton

90,0 150 - 20099,0 200 - 300

99,9 300 - 500

Mng tip xc kh trng bng tia cc tm c thit k bng b tng ctthp, s n nguyn xc nh ty theo cng sut trm x l nhng ti thiu l 2n nguyn. Mi n nguyn cn c trang b ti thiu 2 module n tia cctm. n cc tm c kh nng pht x 90% sng UV c tn s 260 nm, cng sut

mi n khng thp hn 26,7 UV-W. Cc loi n thng c ch to dng ngc chiu di 0,75m - 1,5 m, ng knh 1,5cm - 2,0 cm. n c b tr c nhtheo module. Cc n trong tng module c lp t song song vi nhau, khongcch gia tm n 6,0 cm. Mi n c t trong ng lng bng thch anh c dy 1mm, c kh nng truyn qua ti thiu l 90% lng pht x tia cc tm ti

bc sng 260 nm.

Thit b pht tia cc tm bao gm:

- T in iu khin v phn phi in trung tm ti cc module n tia cctm v cc thit b bo ng;

- H thng n bo hiu v quan trc cng sng UV;

- H thng gt ra cc bng n tia cc tm;

- H thng qun l v iu khin mc nc;

- H thng cc tm knh chn an ton v thit b ngn nga nh hng sng UV.

Kh trng bng clo hoc cc hp cht ca clo

Clo v mt s hp cht clo l ha cht kh trng truyn thng c sdng trong kh trng nc thi y t. Hiu qu ca qu trnh kh trng bng clov cc hp cht clo b tc ng nhiu bi cht lng nc sau cc qu trnh xl. S dng cht kh trng vi liu lng thp, thi gian tip xc ngn trong khihm lng cht hu c trong nc thi cn cao s dn n hiu qu kh trngt thp.

Kh trng ch t hiu qu cao khi nc thi cha


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dng l lng. hm lng hu c cao hn c th s kt hp vi clo hnh thnhcc cht c tnh c hi hn i vi mi trng.

Thng thng, nc thi sau x l sinh hc c kh trng bng clo lng,

nc javel (NaOCl), hay Canxi hypoclorit (Ca(OCl)2). Clo lng c cung cp tcc nh my ha cht, vn chuyn ti khu x l nc thi bng bnh thp chu psut cao. Nc javel c th c sn xut ti ch bng cc thit b in phn muin. Liu lng clo hot tnh quy nh nh sau:

- Nc thi sau x l c hc l 10g/m3.

- Nc thi sau khi x l sinh hc hon ton l 3 g/m3.

- Nc thi sau khi x l sinh hc khng hon ton l 5g/m3.

Vic ha trn clo vi nc thi c tnh ton trn c s lu lng nc thiln nht trong ngy. Thi gian tip xc ti thiu ca clo vi nc thi trong btip xc l 30 pht. Vic ha trn clo vi nc thi c tin hnh bng cc thit

b ha trn, mng trn v b tip xc. V tr chm clo c b tr ti gn ca vob tip xc. B tip xc c thit k Clo v nc thi c xo trn hon tonv khng lng cn.

Bn lu tr clo c ch to bi cc vt liu khng b n mn bi clo nhnha PE, composit, Bn lu tr clo c trang b cc thit b: ca thm, vankha cp nc k thut, cp ha cht, x trn, x cn, x kh, bo mc nc,khuy trn c hc bng cc vt liu chng n mn bi clo. Bn lu tr clo t ticc ni khng c nh sng mt tri, thong kh v c nh trn b. Mt trm tithiu c 2 bn lu tr clo.

Phng ha chtc kt cu chng ng t, chng chy. Khu vc bn chaha cht c xy b ngn nc nhm hn ch khu vc b nh hng bi ha cht

trong trng hp s c v bn. Cc phng kho v phng k thut c b tr hthng thng gi v thay i khng kh trong phng.

Clo v hp cht clo l cht kh trng c th nh hng n sc khe v cnguy c ri ro gy mt an ton trong s dng nn khi s dng cn cn nhc v uim v nhc im ca sn phm ny.

u im

- Kh trng bng clo l k thut d thc hin trong h thng x l.


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- Hin nay, kh trng bng clo c mc chi ph thp hn so vi s dng tiacc tm v ozone.

- D lng clo cn li trong nc thi c th duy tr hiu lc kh trng.

- S dng clo kh trng l ng tin cy v hiu qu i vi ph rng ca ccsinh vt gy bnh khc nhau.

- Clo c hiu qu trong vic oxy ha mt s hp cht hu c v v c trongnc thi.

- Kh trng bng clo d kim sot liu lng v thay i mt cch linh hot.

- Clo c th loi b hoc lm gim bt mi trong qu trnh kh trng.

Nhc im

- Clo d thm ch nng thp l c hi vi i sng thy sinh.

- Cc loi hnh clo dng kh trng u c tnh n mn cao v c hi. Viclu tr, vn chuyn, x l thng c nguy c gy ra ri ro cao.

- Clo oxy ha mt s loi cht hu c trong nc thi, to ra cc hp chtc hi hn (v d nh: trihalomethanes [THMs]).

- Clo lm cho gi tr tng cht rn ha tan tng ln trong nc thi sau x l.

- Hm lng clorua (Cl-)tng cao trong nc thi sau x l.

- Mt s loi k sinh cho thy sc khng vi liu thp clo, trong ckn hp t ca Cryptosporidium parvum v trng ca giun k sinh.

- Tc ng di hn ca cc hp cht c clo vo mi trng xut pht t qutrnh kh trng nc thi cng cha c lm r.

Kh trng bng zn

zn l cht kh trng c tnh oxy ha mnh hn clo. Tuy nhin, zn lcht c mi kh chu v c hi vi c th ngi nng cao. zn c tnh khtrng tt v n nh hn clo. Ngoi ra n cn c kh nng ph hy cc cht khngsinh cn d trong nc thi sau x l.

H thng kh trng bng zn bao gm thit b iu ch zn v thit b phnng (ha trn v tip xc zn vi nc thi). H thng iu ch zn bao gm:thit b cp kh, my cp in, thit b iu ch zn v cc thit b lm ngui. H


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thng phn ng bao gm: thit b phn phi v tip xc, thit b x l zn d trongkh thi. Ngun kh cp iu ch zn c th l khng kh hoc xy sch.

Thit b iu ch zn thng c la chn sao cho lng zn cn thit

kh trng nc thi bng 60 - 70% cng sut cc i ca thit b. Thit b tipxc thng c thit k theo dng b xy bng b tng ct thp hoc bng thp ccu trc kn m bo kh thi c cha zn khng r r ra bn ngoi, c chiu sumc nc 4 - 6m, thi gian tip xc gia nc v zn l 10 - 20 pht. Dung tch

b tip xc c tnh ton da trn thi gian tip xc v lu lng nc thi vogi thi nc ln nht hoc lu lng gi ln nht vo thi im c ma i vitrng hp h thng thot nc chung.

b. K thut x l bn cnHin nay, bn cn t cc h thng x l nc thi bnh vin ch yu c n

nh, thng ht v a ra x l bn ngoi bnh vin. X l bn cn c th dngphng php lm kh bng th cng hoc s dng thit b chuyn dng.

Cc cng trnh n nh bn cn

n nh bn cn nhm mc ch: gim khi lng cn, gim tc nhn gybnh, gim mi hi thi hoc ngn nga kh nng thi ra v lm cho bn cn

thnh dng d dng tch nc.

- n nh ym kh bn cn

n nh bn cn ym kh c trng bng s phn hu k kh cc cht hu ctrong b kn. Qu trnh ny din ra rt phc tp c th phn ra lm hai giai on:

+ Giai on th nht c trng cho s hnh thnh s lng ln axit, dm, chtbo, hydrocacbon ngoi ra cn c: axit cacbonic, ru, cn, axit amin, axit

sunfuahydric, amoniac. pH gim xung


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Vi cc trm x l nc thi cng sut va v nh thng p dng kt hpvi n nh cn ym kh trong mt cng trnh nh: b t hoi, b lng 2 v, blng trong kt hp ln men cn. Sau khi n nh bn gim v th tch v khilng c a i chn lp hoc tip tc x l bng cc bin php ph hp khc.

- n nh bn cn bng ha cht

Bn cn cng c th n nh bng Clo. Dng sn phm cha Clo nhHyoclorit canxi - Ca(OCl)

2hay Clo hi cho vo dung dch cn c c kh

mi, oxy ho cc cht hu c, ngn cn qu trnh thi gia v dit trng. Sau khitrn cn vi Clo, bt u din ra qu trnh oxy ho cc cht hu c v pH ca cngim xung 2,5 4,5 lm cho cc vi sinh vt khng sng c v ngn cn qu

trnh thi ra (phn hu) ca bn cn. Sau 2 gi, pH tng v lng Clo d trongcn gim i, pH tng ln 5,5 - 6.

n nh bng phng php ny khng lm gim khi lng cn v cn cmi Clo. Tn nhiu Clo v to ra nhiu sn phm ph ca Clo vi Hydrocacbonc th gy hi nn ch p dng trong nhng trm x l c cng sut nh (


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- Sn phi bn

Sn phi bn l mt khu t xp c mt bng hnh ch nht d thm nc,xung quanh xy b chn. Cn t b lng t 1, bn hot tnh d t b lng t

2 hay cn ln men t b lng 2 v, b t hoi,... a ti sn phi tng t rithnh lp khng dy lm.

Hnh 1-12: Sn phi bn

Bng cch phi t nhin cn kh c th t m 75-80%. Tuy nhin snphi bn chim din tch ln, kh kim sot c mi. Cc vi sinh vt gy bnhtrong bn cn c th khuch tn ra mi trng xung quanh. Nu sn khng c miche th hiu qu hot ng thp v ma ma.

Khi nc ngm su hn 1,5m v t c kh nng thm tt th c th xy trnnn t t nhin, nu khng phi lm nn nhn to v c h thng thu nc.

- Lm kh bn bng bi lc trng cy

Bi lc trng cy c th c p dng lm kh bn thi. Bi lc trng lausy c kh nng hp thu nc qua d cy v thot hi nc qua l. y l mt

phng php lm kh n gin, hiu qu, thi gian loi b bn khong c th lnn 10 nm.

- Lm kh bn bng cc thit b c kh

gim bt din tch t xy dng cng nh khc phc hn ch ca sn phibn, c th ng dng phng php lm kh c hc bng quay li tm hay p lcbng ti. Nguyn l hot ng ca thit b ly tm ltch nc bng lc ly tm.Thit b ly tm cvn u t khng cao, chi ph qun l thp. H thng kn khngc mi, chim t din tch xy dng. Tuy nhin nhc im chnh l cht lng

bn kh nh hng rt nhiu bi c tnh cn ban u, bin dao ng ca m cn ln (60-85%).


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Trong giai on ny nc c tch khi bn nh trng lc qua khe h bng ti xung ngn thu nc di. Tip bn cn chy trn bng ti qua cctrc p vi lc p tng dn, giai on ny nc c tch ch yu nh lc p cacc trc v chy xung ngn thu. Kt qu l bn cn p cui bng ti gim m xung 65-85%.

Tuy nhin trong khun kh nghin cu, cc k thut lm kh bn cn trongx l nc thi bnh vin quy m nh cp qun/ huyn, cc thit b c kh t cs dng.

Hnh 1-13: S my quay ly tm

Hnh 1-14: S my p bn bng ti


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1.3.2. Mt s cng ngh x l nc thi y t hin ang p dng ti Vit Nam

1.3.2.1. X l nc thi bnh vin theo cng ngh lc sinh hc nh git(Biophil)

Nguyn l x l nc thi ca h thng

Song chn rcB thu gomNc thi

Ra ao, h B kh trng B lng 2 B sinh hcnh git

B iu hav lng 1

B nn bn

Hnh 1-15: S x l nc thi bnh vintheo cng ngh lc sinh hc nh git

Nc thi bnh vin c thu gom t h thng cng thot, qua song chn rcth nhm cn nhng vt ln nh: qun o, bm tim, chai l, gc... c kh nng

lm tc nghn ng ng v hng bm. Nc t ngn thu c bm ti b iuha v x l s b, nhm iu ha cht bn v lu lng nc thi ng thi tiy thc hin x l s b, cc vi sinh vt c sn trong nc thi xy ha mt phnhp cht hu c thnh cht n nh bng cn d lng, ng thi kh mt phnCOD, BOD.

Tip nc thi c chy trn hoc bm ti b lc sinh hc nh git tythuc cch b tr h thng ngm hay ni. Ti y da vo kh nng ca vi sinh vts dng nhng cht hu c c trong nc thi lm ngun dinh dng sng v

bin i cht, gii phng cc cht v c v hi. Trong b lc sinh hc nc thic ti u xung lp vt liu lc l cc loi cc, cui c kch thc nh hn30 mm, vi chiu cao vt liu lc t 1,5 - 2m. Cc ht vt liu lc s c bao bcmt lp mng vi sinh vt.

Nc ra khi b lc sinh hc c bm ln b lng th cp, phn bn lngxung y c a n b nn bn, phn nc trong dn n b kh trng tiu dit vi sinh vt gy bnh. Nc sau khi x l thi ra h thng cng thnh ph

hoc ao h.


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1.3.2.2. X l nc thi bnh vin bng bn hot tnh trong b hiu kh(Aerotank).


Hnh 1-16: S x l nc thi bnh vinbng bn hot tnh trong b hiu kh

Nc thi t cc b pht, khu v sinh cc khoa, phng, bung bnh cthu gom qua h thng cng thu n b iu ho c lp thit b song chn rc nhmloi b cc vt c kch thc ln nh bm tim, mnh thu tinh v, bng gc, vi,... m bo cho my mc, thit b v cc cng trnh pha sau hot ng chiu qu.

B iu ho lm nhim v iu ho lu lng v nng cht bn trongnc thi. Ti y, nc thi c khuy trn v lm thong s b nh h thng

sc kh, sau c bm ln b lng t 1 (b lng s cp). Cc bng cn bn,cht rn c kh nng lng s lng xung y v c a n b thu bn.

Nc phn trn i n b hiu kh, ti b ny hm lng bn hot tnh cduy tr l lng oxy ho cc cht bn, hp cht hu c thnh nhng cht n nhto bng cn d lng. Mi trng hiu kh trong b t c nh s dng h thngsc kh nhm duy tr hn hp lng trong thit b lun ch khuy trn hon tonvi khng kh. Sau mt thi gian lu nht nh, hn hp sinh khi c a sang

b lng t 2 (lng th cp).

Ti b lng t 2, bn c lng xung tch ra khi nc x l v mt


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phn bn lng tun hon tr li b hiu kh duy tr nng bn hot tnh trongb. Phn nc sch sau khi c lng ti b lng t 2 qua b kh trng vi dungdch Clo c nh lng bm vo, hoc qua b sc zn. Nc thi sau khi x lc x ra mi trng.

Phn bn to ra t b lng t 1, b lng t 2 c x nh k nh p lcthu tnh, bn c tho xung b nn bn. Ti b nn, bn c gim th tchv t phn hu, dit tr cc vi sinh gy bnh. Bn c nn gim th tch cchuyn n b cha bn v nh k em chn ti bi chn lp.

1.3.2.3. X l nc thi bnh vin theo nguyn l hp khi


Hnh 1-17: S x l nc thi bnh vin theo nguyn l hp khi

Vic thu gom v vn chuyn nc thi t cc khoa, phng, bung bnh vcc b pht trong c s y t c thc hin thng qua mng li thu nc thi n

b hp khi gm cc cng on: ngn thu nc thi c lp t r chn rc, ngn

iu ha, ngn lm lng s b, b hiu kh v ngn thu bn.

B iu ho lm nhim v iu ho lu lng v nng cht bn trong ncthi, ng thi ti y nc thi c trn vi cc ch phm vi sinh nhm tngnhanh qu trnh phn hy s b cc cht hu c, x l mt phn COD, BOD. Tiy, nc thi c khuy trn v lm thong s b nh h thng sc kh.

Phn nc thi sau khi qua b iu ha c lng s b v phn nc gntrong t b nn bn c chy sang b hiu kh gm 2 ngn, ti y hm lng

bn hot tnh c duy tr l lng xy ha cc cht bn, hp cht hu c


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thnh nhng cht n nh to thnh bng cn d lng. Ti b ny thc hin qutrnh kh BOD, COD v nit. Mi trng hiu kh trong b t c do s dngh thng sc kh nhm duy tr hn hp lng trong thit b lun ch khuytrn hon ton.

Sau khi qua x l ti b hiu kh, nc thi c bm ln thit b hp khidng thp, thit b x l c m vi sinh c ch to t vt liu nha (hoc vtliu hu c khc) c thng s: rng > 90%, b mt ring 250 - 300 m2/m3. Tiy thc hin cc qu trnh x l vi sinh nh sau:

- Trn kh cng bc c cng cao bng vic dng khng kh thi cngbc ht v y nc thi.

- Lc vi sinh dng xui c lp m vi sinh ngp nc.

Thi gian lu ca nc thi trong thit b hp khi l 2 - 2,5 gi. Khi ncthi ti qua lp vt liu lc bng cc phn t rn xp, cc vi khun s c hp

ph, sinh sng v pht trin trn b mt . Vi khun dnh bm vo vt rn nh chtgalatin do chng tit ra v c th di chuyn d dng trong lp cht nhy ny. utin vi khun pht trin tp trung mt khu vc sau chng pht trin lan dn v

ph kn b mt vt liu lc. Cc cht dinh dng nh mui khong, hp cht hu

c v oxy c trong nc thi khuych tn qua mng sinh vt v c th vo tn lpXenlulose tch ly pha trong cng. Sau mt thi gian, mng sinh vt c hnhthnh v chia thnh 2 lp: Lp ngoi cng l lp hiu kh, c oxy khuych tnxm nhp vo, lp trong l lp thiu oxy (anoxyc). Thnh phn sinh vt ch yuca mng sinh vt l vi khun, ngoi ra cn c cc ng vt nguyn sinh, nm, xkhun,... Sau mt thi gian hot ng, mng sinh vt dy ln, cc cht kh tch t

pha trong tng ln v mng b tch ra khi vt liu lc. Hm lng cn l lngtrong nc tng ln. S hnh thnh cc lp mng sinh vt mi li tip din.

Sau nc thi cng bn hot ha chuyn qua b lng t 2 (lng lamen) tch khi bn hot ha v cn hu c khc. Ti b lng lamen c xp m lmtng b mt tip xc, tng kh nng va chm. B ny c ng cp ha cht keot nhm to bng keo t nng cao hiu sut lng.

Phn nc trong c qua b phn kh trng bng dung dch NaOCl hocCa(OCl)

2nng 3 - 5 mg (tnh theo lng Clo hot tnh)/m3nc thi. Cui

cng nc thi c x ra ngoi cng thnh ph hoc ao, h, ng rung.

Phn bn, cn lng ngn lng v tng ngn x l sinh hc c my bm


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hi lu mt phn bn hot ha tr li thit b sinh hc m bo c nng x l cn phn bn d c bm v b nn bn.

1.3.2.4. X l nc thi bnh vin bng cng ngh AAO

Thi gian gn y khi u t xy dng mi h thng x l nc thi bnhvin ngi ta thng ch v la chn mt m hnh x l nc thi c ch tohp khi theo cng ngh AAO (Anaerobic/ym kh Anoxyc/thiu kh Oxyc/hiu kh).


Hnh 1-18 : S x l nc thi bnh vin bng cng ngh AAO

Nc thi t h thng cng thu gom chung ca bnh vin c dn vo biu ha c t song chn rc inox kch thc khe h 5-10 mm tch rc v ccvt th ln c trong nc thi. Thi gian nc lu trong b iu ha trung bnh t3 gi n 4 gi. Nc thi sau c x l cc cng on nh sau:

Ngn ym kh dng ngc vi vi sinh vt l lng c kt hp vi khi mgi th bng PVC chuyn dng to nn mng vi sinh vt k kh, lm tng mt vi sinh vt ln n khong 20.000 vi sinh vt/m3nc thi, m bo hiu qu xl theo COD v tng P ln n 75-80%.

Trong ngn thiu kh din ra qu trnh kh nitrat khi mt phn hn hp bnv nc thi cha nitrat c bm ngc t ngn hiu kh v. Trong ngn ny chyu din ra qu trnh h hp thiu kh v kt qu cui cng l gii phng N

2bay

ln v mt phn COD c x l.


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Trong ngn hiu kh, khng kh c cp bi my thi kh, to iu kin din ra qu trnh oxy ha sinh ha hiu kh cc cht hu c v qu trnh nitrat hadin ra. Kt qu l BOD trong nc thi gim r rt v amoni chuyn thnh nitrat.

Nh vy trong 3 ngn AAO s x l c cc cht nhim ch yu l huc (theo BOD v COD), tng nit v tng phospho.

Sau khi qua cc bc x l ni trn, hn hp nc thi v bn c qua ngnlng th cp tch phn ln lng bn hot tnh nhm hi lu v ngn anoxycv ngn oxyc. Phn bn d c a v b cha bn.

Nc thi sau ngn lng th cp c a vo ngn kh trng. Nc thi cth c kh trng bng hai cch:

- Kh trng bng b mng siu lc MBR (Membrane Biological Reactor) vikch thc l 0,3 - 0,5 m. Bng mng MBR c th loi c 98% vi khunc trong nc thi. Hu ht vi khunE.colic gi li trn mng lc. Ngoichc nng kh trng, trn b mt MBR cn tp trung bn hot tnh mt cao tip tc x l trit nc thi. Mng MBR c ra ngc bngthy lc theo chng trnh t ng lp sn.

- Kh trng bng NaOCl hoc Ca(OCl)2dng vin rn. Nc thi sau x l

i qua vi vn tc nht nh s lm ha tan ha cht kh trng vo nc.Phng php ny gim ng k thit b cng nh chi ph chun b v nhlng ha cht kh trng theo phng php truyn thng.

- Kh trng bng Cloramin B (C6H

5SO

2NClNa.3H

20) ang c mt s c s

y t s dng kh trng nc thi.

1.3.2.5. X l nc thi bnh vin bng h sinh hc n nh

Nguyn l x l ca h thngH thng x l NTBV p dng h sinh hc n nh khc vi h thng cng

ngh x l nc thi khc l ngi ta s dng nng lng t nhin, da vo skhuych tn khng kh v s quang hp l ngun oxy chnh. u im ca loicng ngh ny l khng tn nng lng vn hnh nn rt ph hp vi iu kinca cc nc ang pht trin. Phng php x l ny khng gy n, c th gymi kh chu nu vn hnh khng ng cch. Tuy nhin, i hi cc bnh vin

phi c t rng. H thng x l ny ng vai tr quan trng c bit trong x lnc thi cc nc c kh hu m.


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Hnh 1-19: S x l nc thi bnh vin bng h sinh hc n nh

1.3.2.6. X l nc thi bnh vin bng bi lc trng cy kt hp b lcym kh

Nguyn l x l ca h thng

Nguyn l hot ng ca bi lc sinh hc trng cy l da vo hot ngsinh trng ca mt s loi cy m ngi ta s dng chng nh mt gii phphu hiu cho vic x l nc thi vi ti lng nhim khng qu ln. Thngqua b r, cy s hp th cc tp cht v c v hu c trong nc thi, bin

chng thnh ngun dinh dng nui sng cy trong sut qu trnh sinh trngqua lm sch nc thi. Thng cc loi cy nh: lau sy, c nn, cy rng ckh nng x l kh tt nc thi. Trong cy lau sy c kh nng x l tt hnc. Kt qu th nghim cho thy, sy l loi c kh nng x l tt vi hiu sutcao trn 90% i vi tt c cc ch tiu nghin cu l BOD

5, COD, Coliform,

C nn c hiu sut loi b cc cht nhim thp hn sy. Trng cy rng trongnc thi, cy pht trin lin tc, l xanh, kh nng x l cht nhim kh tt,mt s ch s t 90%. Rng l loi thc vt ngp nc, c thn cng nn vn

c th sng v pht trin tt trong mi trng nc thi nhim. Ngoi ra, cvertiver c th x l t hiu sut 77%, tuy nhin cy pht trin khng tt, lvng nn khng ph hp lm.

Hin nay, c rt nhiu kiu bi lc c ng dng, tuy nhin c tnh hiuqu cao cn s dng bi lc sao cho ph hp vi iu kin ca tng khu vc pdng, cc ging cy trng cn ph hp vi iu kin mi trng sng ca tngkhu vc c h thng x l.


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Hnh 1-20: S x l NTBV bng bi lc trng cy kt hp b lc ym kh

c th x l c nc thi bnh vin khng ch s dng ring bi lctrng cy cho mt m hnh x l m cn phi kt hp c cc phng php tin xl m hnh c th hot ng hiu qu.

Nc thi t cc im thi trong bnh vin (khng bao gm cc ngun thinguy hi cn phn loi) c thu gom ti a v b thu gom, sau tip tc i qua

b lng. Ti b lng, nc thi cng c lm sch s b nh qu trnh sa lngcc tp cht v c v hu c c kch thc nh.

Tip tc nc thi c dn n b ym kh c vch ngn (ABR). Nh shot ng ca cc VSV ym kh m cc hp cht hu c b phn gii to ra cc

phn t nh hn v mt lng kh biogas nht nh sinh ra. Hn na, thi gian luti b ym kh c vch ngn l tng i di to iu kin phn hy ti a cc hp


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cht hu c trong nc thi. Sau khi qua b lc ym kh cc hp cht hu c bphn hy to thnh cc phn t nh nh NH

3, cc hp cht ca Nit v pht pho l

cc cht m h thc vt ca bi lc c th d dng s dng lm thc n. Nc thic lm sch nh bi lc trng cy sau tip tc c dn qua b kh trng

bng ha cht trc khi thi b ra mi trng.

1.3.3. nh gi u im - nhc im ca mt s m hnh cng ngh xl nc thi y t

Trong s 06 m hnh c gii thiu, mi mt m hnh u c mt su im v nhc im nht nh. Mt m hnh cng ngh ph hp phi ctnh ton, chn la sao cho ph hp nht vi iu kin thc t ca c s y t ang

hot ng, c tnh n s pht trin trong tng lai. Bi vy, trong khun kh cahng dn ny s a ra so snh v mt u, nhc im ca tng cng ngh, trnc s cc c s y t xem xt n v mnh ph hp vi phng php x l nonht la chn trc khi quyt nh u t.

Bng 1-4: So snh u nhc im ca mt s m hnhcng ngh x l nc thi bnh vin

TTM hnh

cng nghu im Nhc im

1 X lNTBVtheo cngngh lcsinh hcnh git

- X l tng i hiu qunc thi bnh vin cmc nhim va phi;

- Kt cu n gin, lp tn gin, thun tin, chi

ph u t khng cao;

- C th khng cn cpkh cng bc;

- Vn hnh v bo dngn gin, chi ph vn hnhkhng cao do tiu th tin nng, khng i hinhn vin vn hnh ctrnh cao;

- Chim t din tch hncng ngh bn hot tnh;

- Khng gy ting n.

- Chi ph u t cho h thngkhong 15 - 18 triu/m3 ncthi;

- Khng ph hp vi loi ncthi c mc nhim hu cv nit cao;

- Cn c b iu ha n nhnc thi v cn c b lng thcp h v cng knh;

- Khng vn hnh c nu mtin;

- Cn c trm bm nc thi saub lng 1;

- C th gy mi nu vn hnhkhng ng.


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TTM hnh

cng nghu im Nhc im

2 X l

NTBVbng bnhot tnhtrong bhiu kh

- X l hiu qu nc

thi c thnh phn hu c(BOD, COD) v amonicao;

- Kt cu thit b n ginnn chi ph u t thp;

- Chi ph u t cho h thng

khong t 15 - 18 triu ng/m3

nc thi;

- D xy ra hin tng bn khlng lm gim hiu qu x lnc thi. khc phc tnhtrng ny i hi nhn vin vnhnh c kin thc v trnh tt;

- Thit b hot ng t

ng khng tn nhiunhn cng vn hnh.

- Tiu hao nhiu in nng

cung cp khng kh cng bc,chi ph vn hnh cao; khng thvn hnh nu mt in;

- C th pht tn ting n, mihi v vi sinh vt gy bnh ra mitrng nu khng vn hnh ngcch;

- Cn thi gian kh lu h

bn hot tnh hot ng li bnhthng sau s c.

3 X lNTBVtheonguyn lhp khi

- X l hiu qu nc thic thnh phn hu c vnit cao. Hiu sut x ltng i n nh;

- K thut vn hnh ngin v n nh hn cngngh bn hot tnh;

- Chim t din tch hncng ngh bn hot tnh.

- Chi ph u t cao do phi sdng vt liu lc sinh hc (khong15-25 triu ng/m3nc thi);

- Chi ph vn hnh cao (1000 1200 ng/m3nc thi) do tiuhao nhiu in nng ( cung cpkhng kh cng bc) v hacht;

- Khng th vn hnh nu mtin;

- C th pht sinh ting n v mihi nu vn hnh khng ng;

- V bng thp khng ph hp

vi iu kin thi tit thay i.


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TTM hnh

cng nghu im Nhc im

4 X l

NTBVbngcngnghAAO

- X l hiu qu nc thi

c mc nhim cao;- Thi cng lp rp nhanh,kt cu gn, c ng, cth phi hp vi cc b xl sn c;

- Tiu th in nng tnn chi ph vn hnh thp(khong 400 550 ng/

m3nc thi);- Chim t din tch, cth lp t chm hoc ni,c th di chuyn;

- Khng pht tn mi hiv lp t chm v kn.

* i vi h thng s dng cng

ngh mng lc cho cng onkh trng:

i vi h thng cng ngh sdng mng lc, chi ph u t banu cao (khong 30 -50 triu ng/m3nc thi);

- Phi bo dng mng lc hngnm, i hi nhn vin vn hnh

c trnh , phi thay th mnglc sau khong thi gian hotng;

- Chi ph u t cao v chi ph bodng mng lc, thay th thit b

ph thuc vo nh cung cp ncngoi, y l ro cn chnh ivi cc c s y t khi p dng m

hnh ny.* i vi h thng khng sdng cng ngh mng lc chokh trng m kh trng bngha cht: chi ph u t ban u mc trung bnh (khong 15-25triu ng/m3nc thi);

5 X l

NTBVbng hsinh hcn nh

- X l hiu qu nc thi

c mc nhim thpv trung bnh;

- Chi ph u t thp;

- Chi ph vn hnh v botr rt thp;

- Vn hnh v bo tr ddng, khng i hi nhnvin vn hnh c trnh cao.

- Chi ph u t khong t 6 - 8

triu/m3

nc thi;- Khng ph hp vi nc thi

bnh vin c mc nhimcao;

- Chim nhiu din tch t sdng cho cng trnh.


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TTM hnh

cng nghu im Nhc im

6 X l

NTBVbng bilc trngcy kthp blc ymkh

- X l hiu qu nc

thi mc thp vtrung bnh;

- Chi ph u t khngqu cao;

- Hiu qu x l cc chtiu ha l tt nu tngcng dung tch b ymkh;

- Chi ph vn hnh v bodng thp;

- Khng i hi nhnvin vn hnh c trnh cao;

- To cnh quan thinnhin trong lnh, thnthin vi mi trng.

- Chi ph u t khong t 10 -

15 triu/m3

nc thi;- Phi u t b ym kh ln nunc thi c ti lng nhimcao;

- Chim nhiu din tch s dng;

- Hiu qu kh trng trn bi lckhng m bo nu thi gian lungn (di 07 ngy).


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CHNG 2HNG DN LA CHN CNG NGH X L NC THI Y T

2.1. Mt s tiu ch nh gi cng ngh x l nc thi y t ph hp

Do cc loi hnh c s y t l rt a dng v phong ph, nn gip cng tcla chn cng ngh XLNT ti u cho cc c s y t, rt cn xy dng mt b tiuch nh gi cng ngh XLNT y t hiu qu. V lu lng nc thi ca cc cs y t c th dao ng t mt mt khi i vi cc trm y t tuyn x/phng vn hng ngn mt khi i vi cc bnh vin tuyn trung ng. i vi cc loihnh c s y t khc nhau, s khc bit ca thnh phn nc thi cng khc nhau.

Bi vy, vic xc nh mt m hnh cng ngh ph hp x l nc thicho mi loi hnh c s y t cn cn c vo iu kin c th ca c s y t. Phi

bt u ngay t vic kho st thit k, ln phng n cng ngh, xy dng, lp tv vn hnh chy th. m bo hiu qu x l p ng cc yu cu t ra, hthng khi a vo s dng l hp l v hiu qu nht.

Trong phn nh gi cng ngh x l nc thi ti Chng 1 ca ti liu ny ch ra u, nhc im ca tng loi cng ngh x l ang p dng cho x l

nc thi y t hin nay Vit Nam. Thc t cho thy, ty theo iu kin c thca mi c s y t la chn p dng cng ngh ph hp nhm em li hiu qutrong x l. Vic xy dng b tiu ch nh gi gip cc c s y t la chn

phng n cng ngh thch hp nht cho n v mnh l rt cn thit.

Mt h thng x l nc thi c cho l bn vng da trn phng phpphn tch a tiu ch (Multi-criteria analysis) v c xem xt trn cc phngdin bao gm: cc tiu ch nh gi v k thut; cc tiu ch nh gi v kinh

t; cc tiu ch nh gi v mi trng; cc tiu ch nh gi v vn ha, x hi.Trong phn tip theo, s nu c th mi nhm tiu ch.

2.1.1. Cc tiu ch nh gi v k thut

Cc tiu ch nh gi v k thut ca h thng x l nc thi bao gm:

(1) Hiu qu XLNT (tun th theo QCVN)

i vi bt k h thng x l nc thi no, mc tiu quan trng nht l cht

lng nc thi sau x l phi t c cc yu cu ca quy chun mi trng hin


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hnh hay ni cch khc l cht lng nc thi sau x l c tun th QCVN linquan khng. y l tiu ch bt buc i vi m hnh cng ngh x l nc thi nichung v nc thi y t ni ring. Trong vic la chn m hnh cng ngh ph hp,vic nh gi v lng ha tiu ch ny da trn h s cng ngh ca m hnh v sliu nh gi hiu qu x l ca m hnh i vi cc cng trnh tng t.

(2) Hiu qu x l /chi ph u t

Hiu qu x l ca mi cng trnh n v cng phn nh s ph hp trongthit k, vn hnh cng trnh n v , ng thi nh hng n hiu qu x lca ton h thng. Xt hai h thng x l c chi ph xy dng v vn hnh tngng nhau, h thng c hiu qu loi b cht nhim cao hn th s an ton

trong vic tun th quy nh v mi trng hn. Vic nh gi v lng ha tiuch ny da trn h s cng ngh ca m hnh, kt qu x l i vi cc nhm chtiu theo quy chun Vit Nam hin hnh khi vn hnh h thng. T l ny cngln, hiu qu cng cao.

(3) Tui th hay bn ca cng trnh, thit b

bn ca cng trnh, thit b l tiu ch nh gi mc tin cy ca kt cucng trnh cng nh tui th ca thit b. i vi cc cng trnh x l nc thi,

cc thit b cng ngh lun phi lm vic vi cng cao trong mi trng khcnghit, vic dng h thng thay th v bo dng thit b l ht sc kh khn.V vy, tui th cng trnh hay bn ca cc trang thit b cng ngh cn cxem xt mt cch cn trng.

(4) T l ni a ha ca h thng hoc kh nng thay th linh kin,thit b

T l ni a ha ca thit b l tiu ch mang tnh khuyn khch cc nghincu trin khai i vi khoa hc trong nc. Vic s dng cc thit b cng ngh

c t trng ni a ha cao v c kim chng hot ng hiu qu trong cccng trnh tng t l c s gip nh u t xem xt u tin la chn. Tiu chny th hin s ch ng v d dng thay th linh kin trong bo tr, bo dngcng nh khc phc s c trong qu trnh vn hnh h thng.

(5) Kh nng thch ng khi tng nng hay lu lng u vo

y l mt tiu ch quan trng trong cc tiu ch k thut. Nc thi ticc c s y t ni chung thng c s dao ng khng nh v lu lng cngnh ti lng nhim, v vy cc m hnh cng ngh c kh nng thch ng i


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vi cc dao ng ca cc ch s nc thi u vo thng c nh gi vi sim cao hn.

(6) Thi gian xy dng h thng

Thi gian xy dng h thng l tiu ch m, mc quan trng ca tiu chny c th hin trong tng trng hp c th ca mi c s y t. Tuy nhin, mtm hnh cng ngh c nh gi cao hn khi c thi gian lp t v hon thinnhanh hn, thi gian vn hnh chy th v o to vn hnh ngn hn.

(7) Gii php thi cng d dng, thun tin

Gii php thi cng d dng, thun tin cng l mt tiu ch tnh n trong cc

tiu ch v k thut. i vi cc c s y t c v tr thi cng lp t phc tp nhgn khu dn c, din tnh nh hp, trong khi thi cng xy dng vn phi tip tchot ng th tiu ch ny cng cn c quan tm.

(8) Mc hin i v t ng ha ca cng ngh

Mc hin i v t ng ha ca cng ngh l mt tiu ch cn quan tm.i vi cng ngh x l nc thi y t, t trng cc thit b trong h thng chimkhng cao. Bi vy, vic thit lp mt h thng iu khin t ng ha l vic

khng qu kh. H thng iu khin t ng s gim ch ph nhn cng trong khuvn hnh, tng hiu qu x l ca h thng.

(9) Kh nng m rng ci tin module ca thit b

Kh nng m rng ci tin module ca thit b l mt tiu ch khi xem xtnh gi ph thuc nhiu vo iu kin ca tng c s y t. Khi nh gi tiu chny cn i chiu vi k hoch, quy hoch tng th chung a ra t trng imcho ph hp.

(10) Thi gian tp hun v chuyn giao cng ngh

Thi gian tp hun vn hnh h thng l mt tiu ch gin tip nh gi mc phc tp ca cng ngh. Tiu ch ny thng nh gi da trn xut ca ccnh cung cp.

2.1.2. Cc tiu ch nh gi v mt kinh t

Tng vn u t xy dng cng trnh, chi ph vn hnh v chi ph bo tr, bodng cng trnh l c s xc nh cc tiu ch nh gi v mt kinh t. Chi ph


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u t cng trnh c s dng so snh la chn phng n u t c li nhtv mt kinh t.

C th cc nhm tiu ch nh gi v mt kinh t nh sau:

(1) Chi ph xy dng v lp t thit b (tnh theo sut u t)

Chi ph xy dng bao gm chi ph nguyn vt liu xy dng, cng lao ng,vn chuyn v mt s chi ph ph tr khc. Chi ph ny c th c biu din quasut u txy dng trn mt n v nc thi.

(2) Chi ph vn hnh, bo tr, sa cha (tnh theo VN/m3nc thi)

Chi ph vn hnh bao gm: chi ph in, nc, ha cht, nhn cng. Chi ph

bo tr v sa cha cng trnh l chi ph dng cho vic bo tr, bo dng h thng(nh thay th ph tng, thit b trong bo tr, bo dng, thay th mng lc nu c).

2.1.3. Cc tiu ch nh gi v mi trng

Cc tiu ch nh gi v mi trng c c th nh sau:

(1) Din tch khng gian s dng ca h thng (tnh cho 1m3nc thi)

Din tch khng gian s dng ca h thng x l l mt tiu ch v mitrng cn nh gi trong cng tc la chn. i vi cc c s y t ti Vit Nam,din tch t s dng l hn ch do cc bnh vin ln thng nm trong khu vcng dn c. Vic la chn mt m hnh cng ngh c s dng t din tch tthng l tiu ch quan trng hng u i vi mt s c s. Mt m hnh chimt din tch t s dng, to cnh quan mi trng hi ha ti cc c s s chimu th trong vic la chn.

(2) T l s dng nguyn liu v nng lng (tnh cho 01 m3nc thi)

S dng t nng lng v nguyn liu ng ngha vi vic hn ch pht thith cp vo mi trng. V vy tiu ch ny c lit k vo nhm tiu ch v mitrng.

(3) Kh nng ti s dng cht thi th cp

Kh nng ti s dng sn phm th cp sau x l c lit k vo nhm tiuch v mi trng. Vic ti s dng nc thi sau x l cho vic ti tiu i vi

nc thi cc c s y t l vic c tnh kh thi. Vic ny rt c ngha i vi cc


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c s y t vng xa c iu kin khng thun li v nc cp. Hn na, vic ti sdng nc thi sau x l l vic lm tit kim ti nguyn, mang tnh bn vng vthn thin vi mi trng.

(4) Mc x l cht thi th cp

Trong x l nc thi y t, pht thi th cp ch yu l bn thi v kh thi.Mt m hnh cng ngh c nh gi cao khi quan tm n s pht thi th cptrong qu trnh x l. M hnh cng ngh hon thin khi cao cc gii php tngth trong x l trit c hai yu t nhim pht sinh ny.

(5) Mc ri ro mt an ton i vi ngi vn hnh, mi trng v giiphp phng nga, khc phc khi xy ra s c

y l tiu ch quan trng nm trong nhm tiu ch v mi trng. M hnhcng ngh t xy ra cc s c ri ro mt an ton i vi ngi vn hnh v mitrng cng nh vic d khc phc sau khi xy ra s c mi trng. i vi ccc s y t khng s dng cng ngh t ng ha trong x l hoc c v tr gnvi khu dn c, ngun nc sinh hot, cn phi nh gi ht sc thn trngtiu ch ny.

2.1.4. Cc tiu ch nh gi v vn ha - x hi v qun l

Nhm tiu ch x hi bao gm mc chp nhn ca cng ng i vinhng nh hng do h thng x l nc thi gy ra. C th nhm tiu ch ny

bao gm:

(1) Mc m hc ca h thng vi cnh quan khu vc

H thng x l ph hp vi quy hoch chung ca c s y t, thit k xydng p hi ha vi cnh quan chung l tiu ch c lit k vo nhm tiu ch

vn ha - x hi v qun l. i vi c s y t, c bit l i vi cc c s khmbnh, cha bnh vic to lp mt cnh quan thin nhin sinh ng, hi ha v thnthin vi mi trng l mt trong nhng yu t quan trng nng cao cht lngkhm bnh, cha bnh v iu tr.

(2) Kh nng thch ng vi iu kin mi trng ca vng, min

Kh nng thch ng vi iu kin mi trng vng min l mt tiu ch quantrng cn phi c xem xt mt cch k lng trong la chn cng ngh. Mtm hnh cng ngh c nh gi cao khi tnh ton ti cc nh hng trong


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iu kin kh hu ca cc vng, min. V iu kin t nhin cn phi ch ti ccyu t nh hng ca kh hu vng, min ln hiu qu x l ca h thng.

(3) Yu cu v ngun nhn lc qun l v vn hnh h thng x l

nc thi

Ngun nhn lc trong vn hnh h thng cng l mt tiu ch v mt qun l,tiu ch ny cng cn c xem xt k lng khi i chiu vi iu kin thc tca cc c s. Mt c s y t trong khu vc vng xa kh c th p dng m hnhcng ngh i hi i ng vn hnh v qun l c trnh chuyn su. Tiu chny cn c xem xt mt cch thn trng.

2.2. Xc nh v lng ha i vi cc nhm tiu ch

Trong bn nhm tiu ch c bn nu ti phn trn, thang im v cch choim i vi mi nhm tiu ch khi nh gi cng ngh x l nc thi c cth ho nh sau:

- Nhm cc tiu ch nh gi v k thut, y l nhm tiu tr quan trngnht v c lng ha vi s im l A/100 im;

- Nhm cc tiu ch nh gi v kinh t, c lng ha vi s im l

B/100 im;- Nhm cc tiu ch nh gi v mi trng, c lng ha vi s im l

C/100 im;

- Nhm cc tiu ch nh gi v vn ha, x hi, y l nhm tiu tr t quantrng nht, c lng ha vi s im l D/100 im.

Tng gi tr: A + B + C + D = 100 im. Trong 04 nhm tiu ch, cc ch tiuc th i vi mi nhm tiu ch c gi tr l Ai; Bj; Cp; Dq. Ty thuc vo iu

kin thc t ca tng c s y t, vic nh gi v la chn cng ngh c th iuchnh cc gi tr Ai; Bj; Cp; Dq cho ph hp.

Vic nh gi (cho im) cng ngh x l nc thi theo mi nhm tiu chv cc tiu ch c th trong tng nhm (ti a hoc trong thang im dao ng)ty thuc vo cc c im, thng s ca h s thuyt minh cng ngh, kt qukho st hin trng ti c s y t v nh gi kt qu vn hnh thc t cng nghx l ti cc cng trnh tng t.

V d, i vi vic nh gi cng ngh x l nc thi ca cc c s y t


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trong ti liu ny, A c gi tr l 50 im; B c gi tr l 25 im; C c gi tr l 15im v D c gi tr l 10 im. Gi tr im s ca Ai; Bj; Cp; Dq v v d minhha c trnh by trong Bng 2-1. Tuy nhin, trong thc t, ty thuc vo yucu, iu kin c th ca tng c s y t, hi ng c th xem xt v thay i mcim ca cc nhm tiu ch nu trn.

Bng 2-1: Cc tiu ch nh gi la chn cng ngh hin c ph hp

TT Tiu ch nh gi im sti aV d

minh ha*Khong

dao ng*I Cc tiu ch nh gi v k thut: A 50

1 Hiu qu XLNT (tun th theo QCVN) A1 17 0-17

2 Hiu qu x l/ chi ph u t A2 3 0-3

3 Tui th hay bn ca cng trnh, thit b A3 5 0-5

4 T l ni a ha ca h thng hoc khnng thay th linh kin, thit b A4 10 0-10

6 Kh nng thch ng khi tng nng haylu lng u vo A5 3 0-3

7 Thi gian xy dng h thng A6 2 0-2

8 Gii php thi cng d dng thun tin A7 2 0-2

9Mc hin i v t ng ha ca cngngh A8 3 0-3

10Kh nng m rng ci tin modul ca thit

b A9 2 0-2

11 Thi gian tp hun v chuyn giao cngngh A10 3 0-2

II Cc tiu ch nh gi v kinh t: B 25

1 Chi ph xy dng v lp t thit b (tnhtheo sut u t) B1 9 2-9

2 Chi ph vn hnh, bo tr, sa cha (tnhtheo VN/m3nc thi) B2 16 2-16

III Cc tiu ch nh gi v mi trng C 15

1 Din tch khng gian s dng ca hthng C1 3 1-3

2 T l s dng nguyn liu v nng lng(tnh cho 1m3nc thi) C2 3 1-3

3 Kh nng ti s dng cht thi th cp C3 3 0-3

4 Mc x l cht thi th cp C4 3 0-3

5

Mc ri ro mt an ton i vi ngivn hnh, mi trng ( n, mi) v gii

php phng nga, khc phc khi xy ras c

C5 3 0-3

IV Cc tiu ch nh gi v vn ha - xhi v qun l: D 10


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TT Tiu ch nh gi im sti aV d

minh ha*Khong

dao ng*

1 Mc m hc ca h thng vi cnhquan khu vc D1 3 1-3

2 Kh nng thch ng vi iu kin mitrng ca vng, min D2 4 0-4

3 Yu cu v ngun nhn lc qun l vvn hnh h thng x l nc thi D3 3 0-3

Tng cng 100 100

(*): S im v khong dao ng ch c tnh tham kho

Mc ch nh gi s ph hp ca cng ngh x l nc thi l la chnmt m hnh cng ngh ph hp vi iu kin c th ca mt c s y t. V vy,khi cc cng ngh c a vo nh gi v la chn theo cc tiu ch choim ti Bng 2-1 phi m bo cht lng nc thi sau x l t yu cu caQCVN hin hnh khi x thi vo ngun nc tip nhn.

Bng 2-2: iu kin p dng nh gi s ph hp ca cng ngh x l

TT Ni dung Tiu chim nh giLa chn/

khng la chn

1 iu kin bt buc: Tiu ch I.1 10

2 Tng im: Tng im 50 Khng nn p dng50 < Tng im < 70 C th p dng

Tng im > 70 Khuyn khch p dng

2.3. Cc bc tin hnh la chn cng ngh x l nc thi y t ph hp

Bc 1: Kho st thc trng qun l nc thi v cc thng s u vo trongnc thi ca c s y t

- Xc nh cc iu kin v c s vt cht:iu kin c s vt cht cnxc nh bao gm hin trng h thng thu gom, hin trng h thng x lnc thi hin c, trn c s xc nh phng n xy mi hay ci toh thng.

- Xc nh v tr cng trnh, din tch t s dng cho cng trnh:y lnhng tiu ch quan trng trong vic xc nh loi hnh cng ngh x lnc thi cho mi c s y t.

- Xc nh lu lng nc thi thc t:Lu lng nc thi thc t cxc nh bng phng php o vo cc thi im x thi khc nhau trong


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ngy, sau ly gi tr trung bnh. T lu lng thc t kho st thu cs b xc nh tng mc u t thng qua cng sut ca h thng. Cntham kho qua s lng tiu th nc thc t ca c s y t hng thng.

- Xc nh thnh phn v nng nhim ca nc thi:Cc ch s COD,BOD

5, NH

4+, c phn tch t cc mu nc thi c ly vo cc

thi im khc nhau sau ly gi tr trung bnh.

- Xem xt ngun nhn lc vn hnh h thng cng nh ngun kinh ph cac s:Thng tin ny gip vic hoch nh qun l h thng x l ncthi sau qu trnh u t xy dng.

Bc 2:Xem xt trn c s yu cu u ra

Xc nh im x nc thi vo ngun nc tip nhn:Xc nh c imx nc thi sau x l vo ngun nc tip nhn l xc nh c yu cu ura i vi h thng x l nc thi. Trng hp im x thi l cng thot ncthnh ph yu cu u ra l mc B theo QCVN: 28/2010/BTNMT. Trong trnghp im x thi l sng, h vi ngun nc l nc mt s dng cho mc chcp nc sinh hot, th yu cu u ra bt buc phi l mc A. Tuy nhin, trongthc t cn tham kho quy nh ca a phng bit yu cu cht lng nc

thi khi x vo ngun tip nhn l mc A hay B. Thng tin ny l c s quan trngtrong vic nh hng cho im tiu ch v hiu qu x l ca h thng.

Bc 3:Phn tch cc thng tin thu thp la chn loi hnh cng ngh xl ph hp

Tin hnh lp hi ng hoc t chuyn gia c chuyn mn v kinh nghim xem xt, nh gi v la chn cng ngh x l nc thi y t ph hp vi iukin thc t ca n v. Thnh phn Hi ng hoc t chuyn gia ngoi i din

cc n v c lin quan bt buc phi c mt, nn c 01 chuyn gia v cng nghx l nc thi y t v 01 chuyn gia v xy dng cng trnh nc thi.


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CHNG 3MT S LU TRONG THIT K, LP T

V VN HNH H THNG X L NC THI Y T

Mt s vn trc trc pht sinh trong cc h thng x l nc thi ti cc cs y t ch yu xut pht t khu vn hnh v bo tr h thng. Phn ln h thngx l nc thi ti cc c s y t Vit Nam c thit k t chm nn thngkhng c quan tm bo dng thng xuyn. H thng thng hay phi ngngchy do vn kinh ph hot ng hn ch, nhn cng vn hnh khng c oto bi bn dn ti nhiu cng trnh u t rt tn km sau mt thi gian vnhnh b hng v khng cn hot ng. Bi vy, xin gii thiu mt s lu trong thit k, lp t v vn hnh h thng x l nc thi y t cc c s c th

tham kho nhm trnh nhng sai st mc phi trong qu trnh thit k, xy dngh thng x l nc thi ti c s, gp phn nng cao hiu qu ca cc cng trnhx l nc thi ti c s.

3.1. Mt s lu trong qu trnh thit k v lp t h thng x l ncthi y t

Trong hng thp k qua ti Vit Nam cng nh ti khu vc ng Nam , ccs c v sai lm trong k thut ti cc trm x l phi tp trung trong bao gm

cc trm x l nc thi y t ni chung c th tng hp vi 14 sai lm in hnh.Bi vy, trong qu trnh la chn cng ngh, thit k, xy dng, lp t cn xcnh mt cch c th cc thng s nhm trnh cc sai st ng tic.

Di y xin gii thiu mt s sai st cn trnh trong qu trnh thit k vlp t h thng x l nc thi y t.

3.1.1. Mt s sai st cn trnh trong qu trnh thit k v lp t h thng

x l nc thi y t(1) Xc nh sai cng sut thit k

Trong khu thit k, lng nc thi thc t ca cc c s y t thng khngc kho st mt cch chnh xc dn n cng sut thit k khng ph hp,c th b thp hn so vi thc t, gy kh khn trong x l hoc cao hn so vithc t gy lng ph trong qu trnh u t. Thng thng, cc h thng x l cthit k hot ng lin tc trong 24 gi. Tuy nhin, lng nc thi thng pht

sinh mnh trong thi im t 8 gi n 12 gi trong ngy, v vy cn thit k biu ha iu tit lu lng x l n nh.


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(2) Khng x l c ammonium (N-NH4)

Trong nc thi bnh vin thng ban u nit c thi ra di dng nithu c. Sau khong thi gian nht nh nit hu c chuyn thnh dng N-NH

4

trong nc thi. Tuy nhin, ti mt s h thng x l nc thi khng c thi gianlu ln cho qu trnh chuyn ha t nit hu c sang N-NH

4dn n cc qu

trnh nitrat ha v loi nit khng din ra trit lm cho hm lng N-NH4cn

cao trong nc thi u ra.

(3)Thiu cng on tin x l v iu ha lu lng

Trm x l dng phi tp trung thit lp cho cc c s y t c lp thngkhng quan tm n khu tin x l v b iu ha. Khi khng thit lp cng on

tin x l dn n khng tch loi c rc, ct v cc tc nhn gy hng my bmca h thng x l.

(4) Xc nh sai ti lng cht hu c v nit

Nc thi bnh vin thng c ti lng cht hu c khng cao nhng cnthit phi xc nh c th khi thit k h thng x l. y l im rt quan trng trnh hin tng cng sut cp kh trong giai on x l sinh hc hiu kh caohn nhiu so vi ti lng cht hu c trong nc, gy lng ph v lm tng chi

ph trong qu trnh x l.

(5) Khng tun hon bn b sung cho qu trnh loi nit (denitrifcation)

tng cng hiu qu vic loi b nit vi khun cn cung cp cht huc nh ngun thc n cho vi sinh hot ng. Nn khi hm lng cht hu c gimxung, lng bn tun hon s gip n nh v tng cng hiu qu qu trnh loinit. Tuy nhin, thc t cho thy cc h thng x l ang hot ng hin nay

Vit Nam thng t quan tm n chi tit ny dn n lm gim hiu qu x l.(6) Khng loi b c bn sau x l

Lng bn khng c loi b trit sau cng on lng lc s lm tngtng rn ha tan ca nc thi sau x l, do lm gim hiu qu trong khukh trng.

(7) Khng c b n nh bn v x l bn

Trong thc t cho thy, ti mt s c s y t bn thi c tch ra trong qu


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trnh x l nhng khng c bin php thch hp qun l v x l to ra mihi thi trong khu vc v gy ra nhim th cp.

(8) Thiu gii php loi b pht pho

Thng cc h thng x l nc thi y t t quan tm n loi b pht phodi dng P-PO

4(pht pht). Trong trng hp nc thi c hm lng pht pht

qu cao lm cho h thng khng ng bin kp loi b pht pht do cha thitlp cc k thut x l s dn n cht lng nc thi sau x l khng t ch tiuny theo quy nh.

(9) Thiu cc thit b o v gim st

Cc thit b o v gim st c bn cha c lp t nh (o lu lng, och s oxy ha tan), khi khng c cc thit b gim st cc ch s ny, s khngiu chnh c ch lm vic thch hp ca cc thit b lin quan trong hthng v do dn n mt s thit b thng phi lm vic qu ti gy lng phv tng chi ph x l.

(10) S dng khng ng liu lng cht kh trng v thi gian lu ncthi trong khu kh trng

Mi loi cht kh trng i hi mt liu lng v thi gian lu nht nhtng ng vi thnh phn nhim trong nc thi. Khi thit lp h kh trng ticc trm x l phi tp trung thng khng xc nh c liu lng, ng thi bkh trng thng qu nh nn khng thi gian lu trong khu kh trng.

(11) Cha tnh ton gii php khi phi ngng h thng sa cha, khcphc s c

Nhn chung nhiu h thng x l nc thi trong qu trnh thit k cha tnh

ton cho phng n phi ngng vn hnh h thng khc phc s c. Trongtrng hp ny phi c phng n lu gi nc thi hoc phi c h thng d

phng thay th cc thit b h hng m bo h thng hot ng bnh thngv bnh vin khng th ngng hot ng do s c ca h thng x l nc thi.

(12)Trong thit k thng t nng vn cng ngh x l nc thi cabnh vin

Thc t cho thy nhiu cng trnh u t t quan tm hoc xem nh vic thitk h thng in ng lc, iu khin v thit b bo v cc ng c cng nh ch


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vn hnh ca trm x l nc thi. Do khi h thng i vo vn hnh nysinh nhiu vn pht sinh phi u t b sung hoc khc phc.

(13) Cha quan tm n cc quy nh hin hnh khi u t cng trnh XLNT

Theo quy nh ti iu 6 ca Ngh nh 114/2010/N-CP ngy 06/12/2010ca Chnh ph, cc cng trnh u t xy dng trm XLNT phi lp quy trnh botr cng trnh v b phn cho trm x l

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