pp tinh wqi

8/2/2019 PP Tinh WQI

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PHNG PH P T NH TO N CH S

CHT LNG NC (WQI)

P DNG CHO C C LU VC S NG

VIT NAM

TNG CC M I TRNG

TRUNG TM QUAN TRC MI TRNG

H Ni, 6.2011


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Ni dung trnh by

1. Khi nim2. Kinh nghim xy dng, p dng WQI trn th giiv Vit Nam

3. Phng php tnh WQI do Tng cc Mi trng

ban hnh4. Tnh ton v p dng thnghim WQI


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Khi nim v WQI

Ch s cht lng nc (vit tt l WQI) l mt ch

s c tnh ton t cc thng s quan trc chtlng nc, dng m t nh lng v chtlng nc v kh nng s dng ca ngun nc; c biu din qua mt thang im.


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C s xy dng phng php tnh WQI

Cc nghin cu, p dng AQI trn thgii v Vit Nam

Trn th gii: Hoa K, Canada, Chu u, Malaysia, n Vit Nam: Cc nghin cu ca PGS TS L Trnh, TS Tn

Tht Lng, TS Phm Th Minh Hnh Cc quy chun quc gia v cht lng nc hin hnh

QCVN 08:2008/BTNMT Quy chun quc gia v cht l

ngnc mt lc a QCVN 14:2008/BTNMT Quy chun quc gia v nc thi

sinh hot TCVN 5945:2005 Nc thi cng nghip, tiu chun thi


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Kinh nghim v WQI trn thgii v Vit Nam

Hoa K: WQI c xy dng cho mi bang, a scc bang tip cn theo phng

php ca Qu V sinh Quc gia M (National Sanitation Foundation-NSF) sauy gi tt l WQI-NSF

Canada: Phng php do C quan Bo v mi trng Canada (The Canadian

Council of Ministers of the Environment- CCME, 2001) xy dng

Chu u: Cc quc gia chu u ch yu c xy dng pht trin tWQI

NSF (ca Hoa K), tuy nhin mi Quc gia a phng la chn cc thng svphng php tnh ch sph ring

Cc quc gia Malaysia, n pht trin tWQI NSF, nhng mi quc gia c

thxy dng nhiu loi WQI cho tng mc ch sdng

Vit Nam:

WQI cha c trin khai chnh thc. Nghin cu ca PGS TS L Trnh, TS Tn Tht Lng, TS Phm Th Minh Hnh, cch tip cn

ci tin tWQI NSF.

Phng php WQI a ra bi y ban sng M Kng: tnh ton tng hp


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Kinh nghim v WQI

Thng thng mt ch s mi trng c xy dng

qua qua cc bc sau:

Bc 1: La chn thng s

Bc 2: Chuyn cc thng s v cng mt thang o (tnh

ton ch s ph)

Bc 3: Xc nh trng s

Bc 4: Tnh ton ch s cui cng


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Kinh nghim v WQI

Cc bc xy dng ch s mi trng nc

Bc 1: L chn thng s

C rt nhiu thng s th hin cht lng nc, ch s cht lng nc

khng th bao gm tt c cc thng s . (qu nhiu thng s cng khng

tt)

Vic la chn thng s ph thuc vo mc ch xy dng ch s WQI. Tuynhin cc thng s c la chn nn thuc vo tt c cc nhm c trng.

Hm lng Oxy

Ph dng

Cc kha cnh v sc khec tnh vt l

Cht rn l lng.


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Mt sphng php tnh ton WQI

Cc bc xy dng ch s mi trng

c 1: L chn thng s


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Cc bc xy dng ch s mi trng

c 1: L chn thng s


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Bc 2: Tnh to n chsph

Mi thng s c mt thang o ring Cc ch s ph c cng mt thang o

C 2 phng php thng c s dng l phng php chun ha v phng php Rating

Curve. a s cc nghin cu v WQI s dng phng php ng cong t l (Rating Curve)

Cc thang o thng c s dng:

-100 to 100 (Stoner, 1978)

-50 to 100 (Bronet al, 1979)

0 to 1 (Swamee and Tyagi, 2000)

0 to 10 (Cooper et al, 1994)

0 to 14 (Prati et al, 1971)

0 to 16 (Sargaonkar and Deshpande, 2003)

0 to 25 (Gray, 1996)

0 to 100 (Brown et al, 1973; Shyue et al, 1996; Liou et al, 2004; Sedeo-Daz and Lpez-

Lpez, 2007; Simes et al, 2008)

1 to 10 (Melloul and Collins, 1998)

10 to 100 (Dunnette, 1979)


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Bc 3: Trng s

Trng s c a ra khi ta cho rng cc thng s c tm quan trng khc nhau

i vi cht lng nc. Trng s c th xc nh bng phng php delphi,

phng php nh gi tm quan trng da vo mc ch s dng, tm quan trng

ca cc thng s i vi i sng thy sinh, tnh ton trng s da trn cc tiu

chun hin hnh, da trn c im ca ngun thi vo lu vc, bng cc phng

php thng k

Mt s nghin cu cho rng trng s l khng cn thit. Mi lu vc khc nhau

c cc c im khc nhau v c cc trng s khc nhau, v vy WQI ca cc lu

vc khc nhau khng th so snh vi nhau.


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Bc 4: Tnh ton ch s WQI cui cng

CCc bc bc xy dc xy dng chng ch ssWQIWQI

Trung bnh cng khngtrng sr

Trung bnh cng ctrng sr

Trung bnh nhnkhng trng sr

Trung bnh nhn ctrng sr

Tng khng trng sdng Solway

Tng c trng sdngSolway

Trung bnh bnhphng iu hakhng trng s

MinMax


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Bc 4: Tnh to n chsWQI cui cng

Cc bt cp khi tnh ton ch s WQI cui cng Tnh che khut : Mt ch s ph th hin cht lng nc

xu nhng c th ch s cui cng li th hin cht lng tt Tnh m h : iu ny xy ra khi cht lng nc chp nhnc nhng ch s WQI li th hin ngc li

Tnh khng mm do : Khi mt thng s c th b xung vovic nh gi cht lng nc nhng li khng c tnhvo WQI do phng php c c nh.


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Khc phc cc bt cp khi tnh ton ch s cui cng

Liou et al. (2004)

Swamee and Tyagi

Kt hp gia TB cng v TB nhn


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V d 1. Phng php tnh WQI ca bang Origon

B

c 1: La chn thng sPhng php WQI p dng ti bang Origon Hoa

k sdng 8 thng s:

Nhit , pH

DO

BOD, Tng N (ammonia+nitrate nitrogen), Tng P

Tng rn (Total solids)

Fecal coliform

MMt st s phng phphng php tp tnh WQI cnh WQI c thth


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Bc 2: Tnh ton ch sph: Phng php Delphi v Rating

Curve, thang o ca cc ch sph: 0 - 100

Chsph DO:SIDODO 3.3 mg/l SIDO = 10

3.3 mg/l < DO 10.5 mg/l

SIDO=-80.29+31.88*DO-1.401*DO210.5 mg/l < DO SIDO = 100



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Bc 2: Tnh ton ch sph

Chs phBOD: SIBOD

BOD 8 mg/l: SIBOD = 100*exp(BOD*-0.1993)

8 mg/l < BOD SIBOD = 10




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Bc 3: Trng s

Origon WQI s dng phng php trng s cn bng (khng c

trng s).

Bc 4: Tnh ton ch scui cng

Sdng hm sbnh phng iu ha

n

i iSI

nWQI

12

1Cc mc AQI v ngha 10 59 rt xu 60 79 Xu 80 84 Trung bnh

85 89 Tt 90 100 Rt tt



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VVdd 22. W. WQI a ra bQI a ra bi TS Tn Thi TS Tn Tht Lng cho sng t Lng cho sng ng Naing Nai

Bc 1: La chn thng s: Phng php Delphi

Cc thng s c la chn tnh WQI cho sng ng Nai:

BOD, Tng N

DO

SS

pH

Coliform



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VVdd 22. W. WQI a ra bQI a ra bi TS Tn Thi TS Tn Tht Lngt Lng

Bc 2: Tnh ton ch s ph - Phng php delphi v

Rating Curve

Cc ch s ph c tnh ton nh sau: (thang o 0 10)

BOD5 y = - 0,0006x2 - 0,1491x + 9,8255

DO y = 0,0047x2 + 1,20276x - 0,0058

SS y = 0,0003x2 - 0,1304x + 11,459

pH y = 0,0862x4 - 2,4623x3 + 24,756x2 - 102,23x + 150,23

N: y = - 0,04x2 - 0,1752x + 9,0244

Coliform y = 179.39x - 0,4067



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Bc 3: Trng s- Phng php Delphi

Thng qua vic ly kin ca 40 nh khoa hc v mi trng, ta c

bng cc trng snh sau:



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Bc 4: Tnh ton ch s cui cng phng php trung

bnh cng c trng s


n

i i

i=1

WQIA= q Wqi : Trqi : Trng sng s

Wi: ChWi: Ch ssphph


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So sSo snh phng phnh phng php tp tnh chnh ch ssphph gigia 2a 2 phng phphng php trp tr

Bang Origon

0

4

8

12

16

0 1 2 3 4 5 6 7 8 9 10 11 12

Sng ngNai

0

30

60

90

120

150

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

DO

pH

CCc dc dng ng ng khng kh tng tng ng nhaung nhau


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V d 3. Phng php Floria WQI

Bc 1: La chn thng s

Cc nhm thng s tnh ton WQI

trong ca nc: c, tng rn l lng

DO

Nh cu oxy (ph dng): COD, BOD, TOC

Cc cht dinh dng: Tng N, nitrat, Tng P

Vi khn: Tng Coliform v Fecal Coliform



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V d 3. Phng php Floria WQIBc 2: Tnh ton ch sph: pp Rating curve



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V d 3. Phng php Floria WQI

Bc 3: Trng s- trng scn bng

Bc 4: Tnh ton ch s WQI cui cng Trung bnh cng

khng trng s


Thang im WQI:

Tt: 0 44 Trung bnh: 45 59

Km: 60 99

SISIii : Ch: Ch ssphph

nn : S: S llng thng sng thng s


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VVdd 44. W. WQI a ra bQI a ra bi TS Phi TS Phm Thm Th Minh HMinh Hnhnh

Bc 1: La chn thng s: phng php phn tch hin trng

cc thng shin c trong mng li quan trc mi trng

Cc thng s tnh ton WQI: 8 thng s

COD, BOD5

DO

c, TSS

N-NH4+, P-PO43-

Tng Coliform



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Bc 2: Tnh ton ch sph - phng php Rating Curve



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Bc 2: Tnh ton ch sph



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Bc 3: Trng s- Trng scn bng

Bc 4: Tnh ton ch scui cng phng php phn tch

EFA (Explorerly Factor Analysis)



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Bc 4: Tnh ton ch scui cng phng php phn tch

EFA (Explorerly Factor Analysis)

Ngoi WQI c bn, c thtnh thm WQI m rng nh sau:



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Phn loi cht lng nc thng qua ch sWQI


Mc WQI ngha

91 - 100 Sdng tt cho mc ch cp nc sinh hot

76 - 90 Sdng cho mc ch sinh hot nhng cn cc binphp x l ph hp

51 - 75 Sdng cho mc ch ti tiu v cc mc ch tngng khc

26 - 50 Sdng cho mc ch giao thng thy v cc mc chtng ng khc

1 - 25 Nc nhim, cn x l


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V d 5. WQI CCME (Canada)

Khc bit so vi cc thng s trn:

La chn thng s: Sdng tt c cc thng sc trong chng

trnh quan trc

C th tnh ton cho s liu nhiu im quan trc, nhiu t quan

trc

Khng tnh ch sph cho tng thng sm tnh cho 3 ch sphnh sau:

F1: Phm vi

F2: Tn sut

F3: Bin



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V d 5. WQI - CCME

Tnh ton F1

F1 l t s cc thng s khng p ng c so vi mc hng dn

trong khong thi gian tnh ch s.

F1 = (s thng s vt qu tiu chun/tng s thng s)*100

Tnh ton F2

F2 l phn trm s mu khng p ng c mc hng dn

F2 = (S mu khng p ng tiu chun/Tng s mu)*100



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V d 5. WQI - CCME

Gi tr F3 c tnh ton qua 3 bc sau:

Bc 1:

Vi cc gi tr khng p ng c tiu chun (cao hn gii

hn trn hoc thp hn gii hn di), ta tnh gi trsau:

lch: D = (gi tr thng s/mc hng dn) 1

khi gi tr thng s cao hn gii hn trn ca mchng dn

lch: D = (mc hng dn/gi tr thng s) 1

khi gi tr thng s thp hn gii hn di ca mc

hng dn.



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V d 5. WQI - CCME


Bc 2: tnh ton gi tr nse

n l tng s mu

Bc 3: tnh gi tr F3

n

D

nse

k

i

i 1

01.001.03

nse

nseF


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V d 5. WQI - CCME

Tnh ton ch s cui cng

372.1100

2

3

2

2

2

1 FFFWQI

WQI Ecological condition Gradepoint Grade

95-100 Excellent: water quality is protected with virtual absence ofthreat or impairment; conditions very close to natural orpristine levels

4 A

80-94 Good: water quality is protected with only minor degree ofthreat or impairment; conditions rarely depart from natural ordesirable levels

3 B

65-79 Fair: water quality is usually protected but occasionallythreatened or impaired; conditions sometimes depart fromnatural or desirable levels

2 C

45-64 Poor (marginal*): water quality is frequently threatened orimpaired; conditions often depart from natural or desirablelevels

1 D

0-44 Very poor (poor*): water quality is almost alwaysthreatened or impaired; conditions usually depart fromnatural or desirable levels

0 F


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VVdd 66. W. WQI a ra bQI a ra bi UB sng Mekongi UB sng Mekong

Cc thng sc chn: DO, amoni, COD, tng P

WQI c tnh ton cho mi im quan trc theo cng thc nh

sau:

p: im s ca ca mi mu, (nu DO, NH4, COD v tng P p ngc mc ng dn s c 2 im; nu ch c NH4 v tng P p ngc mc hng dn s c 1 im, cc trng hp cn li s c 0im.

n: s mu trong 1 nmM: S im ti a c th t c ca cc mu trong 1 nm.


10.)...( 21 ppp

WQIn


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VVdd 66. W. WQI a ra bQI a ra bi UB sng Mekongi UB sng Mekong


Thng s nv

Mchngn

DO mg/l 6

Amoni mg/l


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Phng php tnh ton WQI do

Tng cc Mi trng ban hnh


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Phng phPhng php tp tnh WQI do TCMT ban hnh WQI do TCMT ban hnhnh

Gii thch tng1. Chs cht lng nc (vit tt l WQI) l mt chs c tnh ton t cc thng s quan trc chtlng nc, dng m t nh lng v chtlng nc v kh nng s dng ca ngun nc; c biu din qua mt thang im.2. WQI thng s (vit tt l WQISI) l ch s chtlng nc tnh ton cho mi thng s


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Mc ch ca vic s dng WQI

nh gi cht lng nc mt lc a mt cch tngqut;C th c s dng nh mt ngun d liu xydng bn phn vng cht lng nc;Cung cp thng tin mi trng cho cng ng mtcch n gin, d hiu, trc quan;Nng cao nhn thc v mi trng.


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Cc yu cu i vi vic tnh ton WQI

WQI c tnh ton ring cho s liu ca tng im quantrc;WQI thng s c tnh ton cho tng thng s quan trc.Mi thng s s xc nh c mt gi tr WQI c th, t

tnh ton WQI

nh gi cht l

ng n

c ca

im quantrc;Thang o gi tr WQI c chia thnh cc khong nhtnh. Mi khong ng vi 1 mc nh gi cht lng ncnht nh.


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Quy trnh tnh ton v s dng WQI

Thu thp, tp hp s liu quan trc t trm quantrc mi trng nc mt lc a (s liu qua xl).Tnh ton cc gi tr WQI thng sTnh ton WQI.So snh WQI vi bng cc mc nh gi chtlng nc.


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Thu thp, tp hp s liu quan trc

S liu quan trc c thu thp phi m bo cc yu cusau:

S liu quan trc s dng tnh WQI l s liu ca quan trcnc mt lc a theo t i vi quan trc nh k hoc gi trtrung bnh ca thng s trong mt khong thi gian xc nh i viquan trc lin tc;Cc thng s c s dng tnh WQI thng bao gm ccthng s: DO, nhit , BOD5, COD, N-NH4, P-PO4, TSS, c,Tng Coliform, pH;S liu quan trc c a vo tnh ton qua x l, m bo loi b cc gi tr sai lch, t yu cu i vi quy trnh quy

phm v m bo v kim sot cht lng s liu.


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Tnh ton WQI1. Bc 1. Tnh ton WQI thng s

1.1. WQI thng s (WQISI) c tnh ton cho cc thng s BOD5, COD,

N-NH4, P-PO4 , TSS, c, Tng Coliformtheo cng thc nh sau:

BPi: Nng gii hn di ca gi tr thng s quan trc c quy nh trongbng 1 tng ng vi mc iBPi+1: Nng gii hn trn ca gi tr thng s quan trc c quy nh trongbng 1 tng ng vi mc i+1qi: Gi tr WQI mc i cho trong bng tng ng vi gi tr BPiqi+1: Gi tr WQI mc i+1 cho trong bng tng ng vi gi tr BPi+1Cp: Gi tr ca thng s quan trc c a vo tnh ton.

1111

ipi

ii

iiSI qCBPBPBP

qqWQI (cng thc 1)


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Bng (1) quy nh cc gi tr qi, BPi

i qi

Gi tr BPi quy nh i vi tng thng s

BOD5(mg/l)

COD(mg/l)

N-NH4(mg/l)

P-PO4(mg/l)

c(NTU)

TSS(mg/l)

Coliform(MPN/100

ml)

1 100 4 10 0.1 0.1 5 20 2500

2 75 6 15 0.2 0.2 20 30 5000

3 50 15 30 0.5 0.3 30 50 7500

4 25 25 50 1 0.5 70 100 10.000

5 1 50 80 5 6 100 >100 >10.000


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Tnh ton WQI

1.2. Tnh gi tr WQI i vi thng s DO (WQIDO): c tnhton thng qua gi tr DO phn trm bo ha.

Tnh gi tr DO bo ha

Trong T: nhit mi trng nc ti thiim quan trc.

Tnh gi tr DO phn trm bo ha

Trong DOha tan: Gi trDO quan trcc (tnh theo mg/l)

32 000077774.00079910.041022.0652.14 TTTDObaohoa

DO%bo ha= DOha tan / DO bo ha*100


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Bng (2) quy nh cc gi tr BPi v qi i vi DO% bo ha

Nu gi tr DO% bo ha

nm trong khong t 112 - 200 thWQIDO c tnh theo cng thc 1 v s dng bng 2.

Nu gi tr DO% bo ha nm trong khong t 20 - 88 th WQIDOc tnh theo cng thc 2 v s dng bng 2.

i 1 2 3 4 5 6 7 8 9 10

BPi 20 20 50 75 88 112 125 150 200 200

qi 1 25 50 75 100 100 75 50 25 1

iipii

iiSI qBPC

BPBPqqWQI

1

1 (cng thc 2)


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Tnh ton WQI

1.3. Tnh gi tr WQI i vi thng s pHBng (3) uynh cc gi trBPi v qii vi thng s pH

Nu gi tr pH quan trc c nm trong khong t 8.5 - 9 thWQIpH c tnh theo cng thc 1 v s dng bng 3.

Nu gi tr pH quan trc

c nm trong khong t 5.5 - 6 thWQIpH c tnh theo cng thc 2 v s dng bng 3.

i 1 2 3 4 5 6

BPi 5.5 5.5 6 8.5 9 9

qi 1 50 100 100 50 1


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2. Bc 2. Tnh ton WQI

Sau khi tnh ton WQI i vi tng thng s nutrn, vic tnh ton WQI c p dng theo cngthc sau:

Trong

WQIa: Gi tr WQI tnh ton i vi 05 thng s: DO, BOD5,COD, N-NH4, P-PO4

WQIb: Gi tr WQI tnh ton i vi 02 thng s: TSS, c WQIc: Gi tr WQI tnh ton i vi thng s Tng Coliform WQIpH: Gi tr WQI tnh ton i vi thng s pH

3/12

1

5

1 2

1

5

1

100

c

bb

aa

pH

WQIWQIWQI

WQI

WQI


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3. Bc 3. So snh theo thangim

S dng bng xc nh gi tr WQI tng ng vi mc nhgi cht lng nc so snh, nh gi, c th nh sau:Mc WQI ngha

91 - 100 Sdng tt cho mc ch cp nc sinh hot

76 - 90 Sdng cho mc ch sinh hot nhng cn cc binphp x l ph hp, bo v i sng thy sinh

51 - 75 Sdng cho mc ch ti tiu v cc mc ch tngng khc

26 - 50 Sdng cho mc

ch giao thng thy v cc mcch tng ng khc

1 - 25 Nc nhim khng thsdng cho mc ch no


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Cng b WQI cho cng ng

Yu cui vi ni dung thng tin v WQIc cng b: Tn im v khu vc quan trc, tn trm quan trc; Thi gian quan trc; Gi tr WQI v mc nh gi cht lng nc

tng ng.


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Cng b WQI cho cng ngHnh thc cng b:

Bo chTruyn thanh

Truyn hnhBng thng tin in tTrang thng tin in t


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V d tnh ton WQI

Vi s liu quan trc gi nh nh sau:

BOD5

(mg/l)

COD

(mg/l)

N-NH4

(mg/l)

P-PO4

(mg/l)

c

(NTU)

TSS

(mg/l)

Coliform

(MPN/100ml)

DO

(mg/l)

pH

T(oC)

5 17 0.7 7 4 45 3500 4.9 6.5 28


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V d tnh ton WQI

Tnh ton WQI thng s BOD, COD, NH4, PO4, c,

TSS, Coliform:

5.87755646

751005

BODWQI

7.715017301530

5075

CODWQI

40257.015.01

2550

4

NHNWQI1

4

POP

WQI

100doducWQI 6.4025457030702550

TSSWQI

90753500500025005000

75100

ColiformWQI


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V d tnh ton WQI

Tnh ton WQI thng s DO:

DO%bo ha=4.9/6.06876*100=80.7

Tnh ton WQI thng s pH:

06876.628000077774.0280079910.02841022.0652.14 32 baohoaDO

8675757.80758875100

DOWQI

100pHWQI


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V d tnh ton WQI

Tnh ton WQI

Kt lun: Vi gi tr WQI = 71 th ta c kt lun lngun nc s dng c cho mc ch titiu v cc mc ch tng ng khc, th hin lmu vng.

7190)16.40(2

1)100407.715.8786(

5

1

100

1003/1

WQI


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p dng th nghim WQI

p dng thnghim cho LVS Cu

Chng trnh quan trc LVS Cu 2008, 2009 Quan trc trn cc nhnh sng: Sng Cu, sng Cng,

sng Ng Huyn Kh, cc nhnh sng khc

Tn sut quan trc 6 t/nm

S im quan trc 34 im

S lng thng s: 28 thng s


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Tnh ton th nghim WQI

Tnh ton thnghim cho LVS Cu

Sng Cu

T l cc thng s so vi QCVN 08:2008/BTNMT T l WQI thuc cc mc phn loi cht lng nc

Vic nh gi cht lng nc thng qua WQI n gin hn so vi vic nh gi cng

lc nhiu thng s. V d nh nm 2008 ti sng Cu c nhiu thng s nh BOD, COD png c mc A1 vi t l rt cao, tuy nhin thng s N-NH4

+ li p ng c mc A1 vit l rt thp, trong khi vi kt qu tnh ton WQI ta c th thy ngay t l s mu quantrc t cht lng nc c th s dng tt cho mc ch cp nc sinh hot (gi tr WQInm trong khong 91 100) l 11,8%.


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p dng th nghim WQI

p dng thnghim cho LVS Cu

Gi rWQI trung bnh cc i m quan trc thuc LVS C u

Cht lng nc ca LVS Cu c s bin ng rt mnh gia cc nhnh sng v gia 2 nm2008 v 2009. Cht lng nc nm 2009 thp hn nm 2008 ti a s cc i m quan trc trncc nhnh sng.


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p dng th nghim WQI

p dng thnghim cho LVS Nhu y

Chng trnh quan trc LVS Nhu y 2008, 2009 Quan trc trn cc nhnh sng: Sng Nhu, sng y,

sng ni thnh H Ni, cc nhnh sng khc

Tn sut quan trc 6 t/nm

S im quan trc 40 im

S lng thng s: 28 thng s


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p dng th nghim WQI


Sng y

T l cc thng s so vi QCVN 08:2008/BTNMT T l WQI thuc cc mc phn loi cht lng nc

Theo nh kt qu tnh ton WQI nm 2008, t l cc mu c cht lng nc c th s dng cho

mc ch cp nc sinh hot (mc 76 90) t n 36%, tuy nhin nm 2009 t l ny gimxung di 5%. Nguyn nhn ca iu ny l do thng s N-NH4+ v T ng Coliform khng png vi t l B2 kh cao.


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p dng th nghim WQI


Gi trWQI trung bnh cci m quan trc thuc LVS Nhu y

Theo nh kt qu tnh ton WQI trung bnh cc t, tt c cc i m quan trc trn LVS Nhuy ch s WQI trung bnh nm 2009 thp hn nm 2008.


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XIN CH N TH NH C MN

pp tinh wqi

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