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EAS 12:2012

ICS 13.060.20



© EAC 2012

SECOND Edition
2012


DRAFT EAST AFRICAN STANDARD

Potable Water


Specification

EAST AFRICAN COMMUNITY

EAS 12:2012

© EAC 2012



All rights reserved
















ii


Foreword

Development of the East African Standards has been necessitated by the need for harmonizing
requirements governing quality of products and services in the East African Community. It is
envisaged that through harmonized standardization, trade barriers that
are encountered when goods
and services are exchanged within the Community will be removed.

In order to achieve this objective, the Community established an East African Standards Committee
mandated to develop and issue East African Standards.


The
Committee is composed of representatives of the National Standards Bodies in Partner States,
together with the representatives from the private sectors and consumer organizations. Draft East
African Standards are circulated to stakeholders through the Nati
onal Standards Bodies in the Partner
States. The comments received are discussed and incorporated before finalization of standards, in
accordance with the procedures of the Community.

East African Standards are subject to review, to keep pace with technolo
gical advances. Users of the
East African Standards are therefore expected to ensure that they always have the latest versions of
the standards they are implementing
.

© East African Community 2012


All rights reserved
*

East African Community

P.O. Box 109
6

Arusha

Tanzania

Tel: 255 27 2504253/8

Fax: 255 27 2504255

E
-
mail:
eac@eachq.org

Web:
www.eachq.org





*

© 2012 EAC


All rights of exploitation of any form and by any means reserved worldwide for EAC Partner States’ NSBs

EAS 12:2012

© EAC 2012



All rights reserved
















iii


Introduction

The provision of

safe and quality drinking
-
water is high priority
for
human health
.

The appearance, taste and odour of drinking
-
water should be acceptable to the consumer. This will
build the confidence of

consumers, avoid complaints and, more

importantly,
prevent consumers f
r
o
m
the use of water from

sources that
may be

unsafe
.

Safety of water is affected by several factors including
environmental,
the nature of the sou
rce, the
human activities under
taken on or around the sources and the water harvesting, handling and
treatment that may be undertaken.
Thus,w
ater may be exposed to physical, chemical and
microbiological contamination that may make water unsafe for human consumption.

A few chemical contaminants have been shown to cause adverse health effects in humans

as a
consequence of prolonged exposure thro
ugh drinking
-
water

however; some
inorganic elements are
also
recognized to be essential elements in human nutrition.

Infectious diseases caused by pathogenic bacteria, viruses and parasites (e.g. protozoa and
helminths) are the most common and widespread h
ealth risk associated with drinking
-
water. The
greatest risk to public health from microbes in water is associated with consumption of drinking
-
water
that is contaminated with human and animal excreta, although other sources and routes of exposure
may also

be significant.

Consumers have no means of judging the safety of their drinking
-
water themselves.
Water Producers

have a challenge of ensuring the quality and safety of water they provide.
Regulators are required to
establish health
-
based targets that must

be met
by water operators.

This standard set
s

minimum requirements
for physical, chemicals and microbiological characteristics
that affect safety and quality drinking water. The use of this standard is expected to

ensure provision
of safe and quality wate
r for human consumption. The standard provides for the provision of safe
water through water safety plans, surveillance and monitoring of water sources. The standard is
based on
East Afric
an Partner S
tates standards and are science based.

EAS 12:2012

© EAC 2012



All rights reserved
















4


Potable
water


Specification


1

Scope

1.1

This East African Standard prescribes the quality requirements and Method of sampling and test
of
Potable water


1.2

Field of application

This standard applies to water of two categories:

a) potable water available from conventio
nal treatment p
rocesses such as
coagulation,flocculation,sedimentation, filtration, chlorination /ozonation; and used in food establishments
or distributed through the water distribution systems.

b) natural potable water available for water consumers from natural sourc
es such as boreholes,
protected springs, gravity flow schemes and harvested rain water which is commonly used for
consumption in the region .


This standard does not apply to natural mineral waters or packaged drinking water for which other
standards ap
ply.


2

Normative references

EAS 15
-
1:2000, Methods of test for drinking water


Part 1: Physical methods of test for the quality of
drinking water

EAS 15
-
2:2000, Methods of test for drinking water


Part 2: Biological and microbiological methods

EAS 15
-
3
:2000, Methods of test for drinking water


Part 3: Determination of metal contaminants

EAS 15
-
4:2000, Methods of test for drinking water


Part 4: Determination of salts, cations and anions

EAS 15
-
5:2000, Methods of test for drinking water


Part 5: Deter
mination of gases, organic compounds
and radioactivity

ISO 4832

Microbiology of food and animal feeding stuffs


Horizontal method for the enumeration of
coliforms


Most probable number technique

ISO 7887

Water quality
-
Determination of colour

ISO 8245

Water quality


Guidelines for the determination of total organic carbon (TOC) and dissolved
organic carbon (DOC)

ISO 10523

Water quality


Determination of pH

ISO 7027

Water quality
-
Determination of turbidity


ISO 12020

: Water quality


Determination of

aluminium


Atomic absorption spectrometric methods

ISO 7888

Water quality
-
Determination of electrical conductivity


ISO 9297

Water quality


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m整e 潤)

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䥓O 㤹64
-
1

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慢s潲灴o潮⁳p散瑲潭整ey

EAS 12:2012

© EAC 2012



All rights reserved
















5


ISO 4833

Microbiology of food and animal feeding stuffs


䡯Hiz潮t慬 m整e潤 f潲o瑨t 敮畭敲慴e潮 潦 micro潲条oisms


䍯l潮y
-
c潵湴n瑥th湩煵e⁡ ″〠0e杲敥g⁃

䥓O 9㌰8
-
1

W慴ar 煵ality


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䵥m扲慮攠fil瑲慴i潮整e潤⸠

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-
1
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䡯Hiz潮t慬 m整eo搠f潲o瑨t e湵m敲慴e潮 潦 c潡杵l慳s
-
灯sitiv攠s瑡thyl潣潣ci (S瑡灨yl潣潣c畳 慵re畳 慮搠潴o敲e s灥ci敳)

P慲琠ㄠ㨠T散桮i煵攠畳i湧 B慩rd
-
Park敲e 慧慲
m敤ium

䥓O‶ 㘱
-
2

W慴arⁱ 慬ity


䑥D散瑩o渠nn
搠d湵m敲慴e潮 ⁴ e⁳灯r敳 ⁳畬p桩te⁲敤畣ing

䥓O‶ 㘱
-
㈠㨠W慴arⁱ 慬ity


䑥D散瑩o渠nd⁥ 畭敲慴eo渠nf⁴ 攠ep潲敳 ⁳畬灨i瑥
-
r敤畣i湧⁡湡敲潢敳
cl潳瑲i摩愩a


䥓O 7㠹9
-
㈺2W慴ar 煵慬ity


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P慲琠ㄺ

䵩湩慴arize搠m整e潤
(䵯s琠tr潢慢l攠e畭扥r) f潲⁳畲u慣攠e湤 w慳瑥t睡瑥r

䥓O′ 㔶7›⁍icr潢i潬潧yf f潯搠dn搠d湩m慬⁦敥摩湧⁳瑵t晳


䡯Hiz潮t慬整e潤⁦潲⁴桥o摥瑥ttio渠nf⁓hi来ll愠s灰.

䥓O‷ 㤹
-
2

W慴arⁱ 慬ity


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䵥m扲慮攠fil瑲慴a潮整e潤




EAS 12:2012

© EAC 2012



All rights reserved
















6


3

Terms and Definitions

3.1

Potable water

water that is safe and suitable for
human consumption
.



3.2

drinking water

potable water intended for human consumption

3.3

Treated water

water that
has undergone through processes such as
coagulation, sedimentation, filtration and
disinfection
.

3.4

Natural potable
water


water that is
from natural sources that is fit for human consumption
without
undergoing
any
form of
proces
sing

e.g. from boreholes,

springs or R
ain
W
ater
H
arvesting

3.5

Conventional Treatment


collection, storage and distribution of drinking water involving deliberate coagulation, sedimentation,
filtration, and disinfection to improve the safety and quality of the finished drinking water to consumers

3.6

Water Quality

The chemical, physical an
d biological characteristics of water in respect to suitability for an intended
use/purpose, e.g. domestic, car washing, farming, mining, industrial purposes or healthy ecosystem,

3.7

Safe water

Water that is free of
chemical substances
and

micro
-
organism
s in concentrations which could cause
illness or body disorders in any form.

3.8

EAS 12:2012

© EAC 2012



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7


Surveillance

An independent continuous, specific measurement, observation and reporting for the purpose of water
quality management and operational activities

3.9

Disinfection

Reduction by means of chemical agents and/or physical methods, of the number of micro
-
organism to a
level that does not compromise public health


4. Requirements for potable water

4.1 General requirements

4.1.1

Potable water shall be as pleas
ant to drink as circumstances permit. Coolness, absence of turbidity
and absence of colour and of any disagreeable taste or smell are of the utmost importance in public
supplies of potable water.

4.1.2

Potable water shall be free from visible organisms

as algae, zooplanktons, flagellates and from
concentrations of particulate matter

4.1.3

The location, construction, operation and supervision of water supply source, its reservoirs and its
distribution system shall be such that they exclude any possible p
ollution of the water in compliance with
relevant national regulations

4.2
Physical characteristics affecting the quality of water

Potable water shall conform to the physical characteristics in table 1.

Table 1


The Physical Requirements

Sl.
No.

Characteristic

Treated
Potable
water

Natural potable water

Test method


i)

Colour

(
TCU
a

max)

Apparent
colour

15


50

ISO 7887


ii)

Turbidity
(
NTU

max)

5

25

ISO 7027

iii)

pH

6.5


8.5

5.5
-
9.5

ISO 10523

EAS 12:2012

© EAC 2012



All rights reserved
















8












4.3

Chemical characteristics affecting only the quality of potable water

Potable water shall
conform to the chemical characteristics affecting quality indicated in table 2.

Table 2


Quality requirements fo
r potable water

Sl. No.

Substance or characteristic

Treated potable
water

(mg/L max.)

Natural potable water

(mg/L max.)

Test
method

i)

Suspended matter

Not detectable


EAS 15

ii)


Total dissolved solids

700

1500



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qo瑡l牧anica瑴er

M⸰MP


䥓f‸245

iv)

qo瑡l⁨a牤nessⰠas⁃ 䍏
3
,

300

600

ISO 6059

v)

Aluminium, as Al
+++
,

0.2

0.2

ISO 12020

vi)

Chloride, as Cl
-

250

800

ISO 9297

vi)

Total Iron as Fe

0.3


ISO 6332

vii)

Sodium, as Na
+

200


ISO 9964
-
1

viii)

Sulphate

300

600


ISO
22743

ix)

Zinc, as Zn
++

5


ISO 8288

x)

Magnesium, as Mg
++


100


ISO 7980

xi)

Calcium, as Ca
++


150

300

ISO 7980


iv)

Taste

Not
objectionable

Not objectionable

-

v)

Odour

Odourless

Odourless

EAS 15

vi)

Conductivity


S/cm
)

1500

1500

ISO 7888

a)

True colour units (TCU) mean 15 hazen units after filtration.

EAS 12:2012

© EAC 2012



All rights reserved
















9




4.4

Chem
ical characteristics affecting
the safety of potable water

4.4.1 Inorganic contaminants

Potable water shall conform to the limits of inorganic contaminants affecting safety indicated in table 3

Table 3


Limits for inorganic contaminants in
natural and tre
ated potable
water and

Sl. No.

Substance

Treated potable
waterLimit of
concentration

mg/L, max.

Natural
potable
water

Test method



i)

Arsenic, as As

0.01

0.01

EAS 15

ii)

Cadmium, as Cd

0.003

0.003



iii)

Lead, as Pb

0.01

0.01



iv)

Copper, as Cu

1.000

1.000



v)

Mercury (total as Hg)

0.001

0.001



vi)

Manganese, as Mn

0.1

0.1



vii)

Selenium, as Se

0.01

0.01



viii)

Ammonia (N)

0.5

0.5



ix)

Chromium Total, as
Cr

0.05

0.05



x)

Nickel, as Ni

0.02

0.02



xi)

Cyanide, as CN

0.01

0.01



xii)

Barium, as Ba

0.7

0.7



xiii)

Nitrate as NO
3

45

45



xiv)

Boron, as (boric
acid
)

0.3

0.3



xv)

Fluoride, as F

1.000
a)

4.000



EAS 12:2012

© EAC 2012



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10


xvi)

Bromate, as BrO
3

0.01

0.01



xvii)

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〮MMP

〮MMP



xiii)

m桯sp桡t敳Ⱐ 慳

4
3
-

2.2

2.2




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䍨C潲i湥

〮M
-
〮M

乩l





a)If the product contains more than 1.50 mg/L fluoride, this information shall be
communicated to the relevant authority

b)Under conditions of epidemic diseases, it may be necessary to increase the
residual chlorine temporarily
.



4.4.2 Organic contaminants


Potable water shall conform to the limits of organic contaminants affecting safety indicated in table 4


Table 4


Limits for organic con
taminants

in
treated and natural potable water

Sl. No.


Substance(Arrange alphabetical
order)

Limit µg/L max.

Test method


i)


Aromatics

Benzene

Toluene

Xylene

Polynuclear aromatic hydrocarbon


10

700

500

0.7


EAS 15











ii)

Chlorinated Alkanes and Alkenes


2






Carbon tetrachloride


1,2
-
Dichloroethane

30



EAS 12:2012

© EAC 2012



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11



1,1
-
Dichloroethylene

0.3




ㄬN
-
䑩chl潲o整ee湥






q整牡e桬潲潥瑨敮e






iii)


Phenolic substances





Phenols


2





㈬㐬2
-
qric桬潲o灨e湯l

㈰2




楶i


Trihalomethanes






Chloroform

30









Pesticides





Aldrin/Dieldrin


0.03





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〮M




㈬2
-

aic桬潲潰o敮潸y慣整ic⁡ id






䑄a
瑯t慬)

N




䡥灴慣hl潲o慮搠䡥灴慣桬潲ob灯xi摥

〮〳




䡥e慣桬潲潢enz敮e

N




䱩n摡n攠e䡃

2




䵥瑨潸ychl潲

20



癩v

Surfactants

(reacting with methylene
Blue)

200



vii)


Mineral
o
il

0.01



EAS 12:2012

© EAC 2012



All rights reserved
















12


viii)

Organic matter

3




4.5 Microbiological contaminants

Potable water shall conform to the limits of microbiological contaminants affecting safety in
dicated in ta
ble
5

Table 5



Microbiological limits for Potable water

Sl. No.

Type of
micro
-
organism

Potable
water

Test
method

i)

Total viable counts at

37 ºC, in

mL, max.

a)

100


ISO 4833


ii)

Total Coliforms

b
)

in 100
mL


Nil

ISO 4832


iii)

E.
c
oli

b)
in 100 mL



Nil


ISO 9308
-
1

iv)

Staphylococcus aureus
in
100 mL

Nil



ISO 6888
-
1

v)

Sulphite reducing
anaerobes in100 mL


Nil


ISO 6461
-
2


vi)

Pseudomonas aeruginos
a
fluorescence in 100 mL


Nil


-

vii)

Streptococcus faecalis

in
100mL

Nil

ISO 7899
-
2

viii)

Shigella

in 100 mL

Nil

ISO 21567

ix)

Salmonella

in 100 mL

Nil

ISO 6785


a)
This parameter is
for monitoring the system at source. Total time before analysis should be not
more than 6 h at 4 ºC
.

Determination of total viable counts shall start within 12 h after collection
of the
potable
water sample.

b) During the bacteriological
quality control for different types of water supply,refer to Annex A




EAS 12:2012

© EAC 2012



All rights reserved
















13


4.6 Radioactive characteristics

Potable water shall conform to the limits for radioactive materials stipulated in Table 6.

Table 6


Limits for radioactive materials in
treated and natural potable water

Radioactive material

Limit in pCi/L

Test method


i) Gross alpha activity


1

ISO 9696




ii) Gross beta activity


15

ISO 9697



5.Water safety plans

5.1
Drinking water systems operators shall develop, implement and maintain a water safety plan taking
into consideration the potential risks to the safety of the water from the supply catchment area to the
consumer.

5.2
A water safety plan shall consist of th
ree key components:

a) system assessment to determine whether the drinking
-
water supply chain (up to the point of
consumption) as a whole can deliver water of a quality that meets health
-
based targets;

b) identifying control measures in a drinking water
system that will collectively control identified risks
and ensure that the health
-
based targets are met; and

c) management plans describing actions to be taken during normal operation or incident conditions
and documenting the system assessment (including

upgrade and improvement), monitoring and
communication plans and supporting programmes.

5.3
A water safety plan shall include:

a) measures to protect the source of drinking water from risks of pollution.

b)measures to ensure all installations intended f
or the production of drinking water exclude any
possibility of contamination. For this purpose and in particular:

• the installation for collection, the pipes and the reservoirs shall be made from materials
suited to the water and in such a way as to prevent the introduction of foreign substances
in water;

• the equipment and its use for production shall meet hygieni
c requirements;

c) measures to ensure an appropriate treatment such as pretreatment processes, coagulation,
flocculation, sedimentation, filtration and disinfection are undertaken to assure the safety of water
for the consumers;

d) appropriate operationa
l monitoring system including monitoring parameters that can be measured
and for which limits have been set to define the operational effectiveness of the activity;
frequency of monitoring and procedures for corrective action that can be implemented in
res
ponse to deviation from limits. If, during production it is found that the water is polluted, the
producer shall stop all operations until the cause of pollution is eliminated; and

e) a verification plan to ensure that individual components of a drinking
-
water system, and system as
a whole is operating safely.



EAS 12:2012

© EAC 2012



All rights reserved
















14


6


Surveillance

6.1 General surveillance requirements

Drinking
-
water suppliers shall ensure, at all times, the quality and safety of the water that they produce.
Public health surveillance (that is, surveillance of health status and trends) contributes to verifying
drinking
-
water safety.

Adequate infrastruct
ure, proper monitoring and effective planning and management; and a system of
independent surveillance are basic and essential requirements to ensure the safety of drinking
-
water.

Surveillance shall cover the total supply network from the source of untrea
ted water to the consumer
delivery points.

A sampling programme that takes into consideration appropriate international recommendations shall be
established and implemented. The sampling shall be regular and its frequency shall mainly depend on the
follow
ing factors

a) quality of water harnessed including effects on the water from climatic, human and industrial
activities;

b) type of treatment for drinking worthiness;

c) volume of water processed;

d) risks of contamination;

e) background of public wat
er supply network;

f) population served; and

g) capabilities of the analytical facility (both in terms of capacity and in terms of analytical
performance)


6.2 Sampling requirements

A formal sampling programme shall be established and implemented.In the absence of a formally
established sampling programme, the minimum sampling frequency given in Table 7 shall be used as an
interim measure.


Table 7


Minimum frequency of sampling of
water for surveillance

Population served

Frequency
*
(minimum) of sampling

More than 100 000

10 samples every month per 100 000 of
population served

25 001


100 000

10 samples every month

10 001


25 000

3 samples every month

2 500


10 000

2 samples every month

Less than 2 500

1 sample every month

*
During the rainy season, sampling should be carried out more frequently



EAS 12:2012

© EAC 2012



All rights reserved
















15




6.3 Parameters required for minimum monitoring


It is recognized that, in many instances, the cost of performing

a full analysis against Table 1, Table 2,
Table 3, Table 4, Table 5, Table 6 and Table 7 can be prohibitive.


Analysis of the parameters in Table 8 may be deemed acceptable for the purpose of indicating on going
levels of operational efficiency in a water

treatment plant. However, a relevant authority may require
additional tests.


Property


Methods of test


Physicochemical
:

Conductivity, or dissolved solids

Colour

Turbidity;

Taste

Odour


See Table 1


Microbiological:


Faecal coliform bacteria or
E. coli
;

Clostridium perfringens

Heterotrophic plate count


See Table 5


Chemical:


Fluoride as F
-

Nitrate

Nitrite

pH value

Aluminum

Iron(total)

Ammonia

Residual chlorine

See Table 3


If abnormal results are encountered in any of these analyses, sampling
frequency shall be increased
and/or additional analyses carried out.


NOTE
:

A

consumer complaints register for the aesthetic qualities of the water should be maintained.



EAS 12:2012

© EAC 2012



All rights reserved
















16


ANNEX A(Informative)


Bacteriological quality for different
types of water supplies

Table A.1

Type of supply

Number per 100 ml

Test methods


Treated water entering the
distribution system

E. coli

Coliform organisms

Nil

ISO 4832

Nil

ISO 4832


Untreated water entering
the distribution system

E. coli

Nil

ISO
4832

3 coliform organisms in any one
sample

ISO 4832


Nil in any two consecutive
samples

ISO 4832


Nil in 98 percent of yearly
samples

ISO 4832

Water in distribution
system

E. coli


Nil

ISO 4832

3 coliform organisms in any one
sample

ISO 4832


Nil in any two consecutive
samples

ISO 4832

Nil in 95 percent of yearly
samples

ISO 4832

Unpiped supplies

E. coli

Coliform organisms


Nil

ISO 4832

10

ISO 4832

Emergency supplies of
water

E. coli

Coliform organisms


Nil

ISO 4832


Nil

ISO
4832