1.
The Potential for Adapting the
UK Water Quality Regulatory
Model for ASEAN Cities
- Further development of a unique Singapore
model and a study of technical example of
metaldehyde-containing pesticides in UK as an
illustration of regulatory issues in the UK
By
Christopher CHUA Wee Hong
A dissertation submitted in partial fulfilment of the
requirements for the Degree of Masters of Science in Water
Regulations & Management
Centre for environmental Health Engineering (CEHE)
Faculty of Engineering & Physical Sciences
University of Surrey
September 2008
© Christopher CHUA 2008

2. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Declaration of Originality
“I hereby declare that the dissertation entitled ‘The Potential for
Adapting the UK Water Quality Regulatory Model for ASEAN Cities’
for the partial fulfilment of the degree of MSc in Water Regulations &
Management, has been composed by myself and has not been presented or
accepted in any previous application for a degree. The work, of which this is a
record, has been carried out by myself unless otherwise stated and where the
work is mine, it reflects personal views and values. All quotations have been
distinguished by quotation marks and all sources of information have been
acknowledged by means of references including those of the Internet.”
…………………………………….
Christopher Chua Wee Hong
Date: ……………………………...
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3. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Abstract
This dissertation considers the possibility of adapting the UK water
quality regulatory models for use in assisting ASEAN countries to develop
high levels of drinking water quality in their cities and surrounding rural
communities. The UK model could also potentially be modified by Singapore
in an innovative manner to further develop a unique water quality regulatory
model. Technology is available for ASEAN cities to provide safe drinking
water, but there is a concurrent need to develop the existing inadequate
regulatory framework to ensure a sustainable water supply.
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4. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Acknowledgement
This dissertation is in fulfilment of the 1st MSc in Water Regulations &
Management and would not have been possible had it not been for:
God almighty for His blessings and guidance.
Classmates, staff, lecturers and visiting professors of the Centre of
Environmental Health Engineering (CEHE) at the University of Surrey (UniS),
especially Prof Barry Lloyd and my supervisor, Mr Brian Clarke, who has
provided lots of support and made water policies & issues discussions so
interesting and so enlightening. Special thanks to Ms Collette Laurens, who
provided the best administrative support and advice throughout the course.
The Drinking Water Inspectorate (DWI) for their support and for the
many inspectors who has provided support and lectured during the modules &
industrial attachment and for sharing their experiences, in particularly Prof.
Jenni Colbourne, Dr Jim Foster, Ms Sharon Evans, Dr Steve Lambert and Mr
Andy Taylor. Special thanks to Dr Annabelle May and Ms Allen Jane for their
help and advice.
Ms Jill Dryer from Severn Trent Water Limited for providing valued
advice and comments.
Dr Lee Tung Jean & Mr Ridzuan Ismail from the Water Services
Division of the Ministry of Environment & Water Resources (MEWR),
Singapore, for providing advice and experience sharing on the regulatory
situation in Singapore.
Colleagues from PUB, especially Mr Harry Seah, Mr Chong Hou Chun,
Mr Haja Nazarudeen, Mr Woo Chee Hoe, for their help and patience in
answering my queries. Special thanks to my Director, Mr Ng Han Tong, for
his help and his support.
Georgia, my supportive wife and my 2 girls, Natalie and Rebecca, for
being patient with me in not being able to bring them on more European
sightseeing tours and not spending more time playing during this period.
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5. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Acronyms and Abbreviations
ADB Asian Development Bank
ASEAN Association of South East Asian Nation
AWGWRM ASEAN Working Group on Water Resources Management
AWGESC ASEAN Working Group on Environmentally Sustainable Cities
BOD Biochemical Oxygen Demand
CIA Central Intelligence Agency, US
CCTV Close Circuit Television
COD Chemical Oxygen Demand
DALY Disability-adjusted life year
DBOO Design, Build Own & Operate
DBPs Disinfection by-products
DEFRA Department of Environment, Food and Rural Affairs, UK
DoH Department of Health
DWD Drinking Water Directive
DWU Drinking Water Unit, NEA, Singapore
DWI Drinking Water Inspectorate of England & Wales
DT50 Half-life of 50% of chemical after application to degrade
EA Environment Agency, UK
EEC European Economic Community
EPHA Environmental Public Health Act 1987, Singapore
EOI Expression of Intent
EU European Union
FAO Food & Agricultural Organisation, United Nations
FSA Food Safety Authority
GAC Granulated Activated Carbon
GCMS Gas Chromatography-Mass Spectrometry
HACCP Hazard Analysis and Critical Control Points
HPA Health Protection Agency, UK
IuWRM Integrated urban Water Resources Management
Koc Adsorption coefficient
Kow Octonol-water partition coefficient
LOAEL Lowest Observed Adverse Effect Level
MDG Millennium Development Goals
MGD Million Gallons per day
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6. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
MEWR Ministry of Environment & Water Resources, Singapore
NOAEL No Observed Adverse Effect Level
NEA National Environment Agency, Singapore
NEWater Singapore’s third national tap
Ofwat Water Services Regulation Authority
OECD Organisation for Economic Co-operation and Development
PCV Parameter Concentration Value
PSD Pesticide Safety Directorate
PUB PUB, Singapore’s National Water Agency
QMRA Qualitative Microbial Risk Assessment
RESCP Regional Environmental Sustainable Cities Programme
RO Reverse Osmosis membrane filtration
SIWW Singapore International Water Week
TAC Treaty of Amity and Cooperation in Southeast Asia
TDI Total daily Intake
TEU Treaty of European Union 1992
TOC Total Organic Carbon
TQM Total Quality Management
UK United Kingdom
UKAS United Kingdom Accredited Service
UKWIR United Kingdom Water Industry Research
UN United Nations
UNDP United Nations Development Programme
WHO World Health Organisation
WHOPES WHO Pesticide Evaluation Programme
WHOROE WHO Regional Office for Europe
WSD Water Studies Division, MEWR, Singapore
WSP Water Safety Plans
YLD Years of healthy life lost in states of less than full health
YLL Years of life lost by premature mortality
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7. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Contents
Page
Abstract..................................................................................................................iii
Acknowledgement................................................................................................. iv
Acronyms and Abbreviations ................................................................................ v
Contents ................................................................................................................ vii
1. Introduction ................................................................................................- 1 -
2. Aims & Objectives ...................................................................................... - 2 -
3. Water Quality & Treatment ....................................................................... - 4 -
3.1. Water quality ........................................................................................ - 7 -
3.1.1. Microbiological water quality ................................................................ - 8 -
3.1.2. Chemical water quality ......................................................................... - 11 -
3.1.3. Acceptability water quality ...................................................................- 13 -
3.1.4. Radiological water quality ....................................................................- 14 -
3.2. Water treatment .................................................................................. - 15 -
4. Water Regulations ................................................................................... - 19 -
4.1. World Health Organisation................................................................- 19 -
4.1.1. Guidelines for safe drinking water ...................................................... - 20 -
4.1.2. Health- based targets ............................................................................- 21 -
4.1.3. Water Safety Plans ............................................................................... - 22 -
4.1.4. Surveillance .......................................................................................... - 27 -
4.1.5. Other Recommendations ..................................................................... - 29 -
4.2. European Union..................................................................................- 31 -
4.2.1. Drinking Water Directives ................................................................... - 33 -
4.3. United Kingdom................................................................................. - 35 -
4.3.1. England & Wales .................................................................................. - 35 -
4.3.2. The Water Supply (Water Quality) Regulations 2000 ...................... - 38 -
4.3.3. The Drinking Water Inspectorate (DWI) ........................................... - 39 -
5. Metaldehyde-containing pesticide in the UK ........................................ - 50 -
5.1. Metaldehyde ....................................................................................... - 50 -
5.2. Role of Regulation ............................................................................. - 53 -
5.3. Case Study .......................................................................................... - 54 -
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8. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Page
6. Water Situation in Southeast Asia .......................................................... - 57 -
6.1. Association of Southeast Asian Nations........................................... - 57 -
6.2. Singapore ............................................................................................ - 62 -
6.2.1. Water Quality Regulations .................................................................. - 64 -
6.2.2. Integrated Water Resources Management ......................................... - 68 -
7. Discussion................................................................................................. - 74 -
7.1. International guidelines .................................................................... - 75 -
7.2. EU & ASEAN perspectives ................................................................ - 77 -
7.3. UK and Singapore water quality regulatory model ......................... - 78 -
7.4. Proposed ASEAN Water Quality Regulatory Model ....................... - 82 -
7.5. Metaldehyde-containing pesticides, a practical issue..................... - 86 -
8. Conclusion ................................................................................................ - 87 -
Appendix A - The UN Millennium Development Goals .............................. - 90 -
Appendix B – International Drinking Water Guidelines ............................ - 92 -
Appendix C – EU Drinking Water Regulations .......................................... - 104 -
Appendix D – Drinking Water Regulations in UK ...................................... - 114 -
Appendix E – The Environmental Public Health (Quality of Piped Drinking
Water) Regulations 2008 ............................................................................. - 122 -
References ..................................................................................................... - 125 -
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9. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
List of Figures
Page
FIGURE 1 OVERVIEW OF DISSERTATION .................................................................................... - 3 -
FIGURE 2. DISEASES CONTRIBUTING TO THE WATER-, SANITATION- & HYGIENE-RELATED DISEASE
BURDEN .................................................................................................................... - 5 -
FIGURE 3 ADVERSE HEALTH EFFECTS OF CHEMICAL AT CONCENTRATION .................................- 12 -
FIGURE 4 MEMBRANE PROCESS CHARACTERISTICS ................................................................. - 18 -
FIGURE 5 DEVELOPMENT OF THE WATER SAFETY PLANS ........................................................ - 25 -
FIGURE 6 PARTIES ACTIVE IN EU WATER POLICY PROCESS ...................................................... - 32 -
FIGURE 7 MAP OF UK ............................................................................................................. - 35 -
FIGURE 8 THE CURRENT UK WATER INDUSTRY ...................................................................... - 36 -
FIGURE 9 THE DRINKING WATER INDUSTRY IN ENGLAND & WALES ........................................ - 37 -
FIGURE 10 ORGANISATION OF THE DWI................................................................................... - 41 -
FIGURE 11 ASSESSMENT OF INCIDENTS FLOW DIAGRAM .......................................................... - 46 -
FIGURE 12 INFORMATION PROFILE OF METALDEHYDE. ............................................................ - 50 -
FIGURE 13 MAP OF ASEAN...................................................................................................... - 57 -
FIGURE 14 ASEAN ORGANISATION STRUCTURE ....................................................................... - 58 -
FIGURE 15 ASEAN ENVIRONMENTAL GOVERNANCE STRUCTURE .............................................. - 59 -
FIGURE 16 MAP OF SINGAPORE ................................................................................................ - 62 -
FIGURE 17 CURRENT SINGAPORE WATER QUALITY REGULATORY MODEL .................................. - 65 -
FIGURE 18 CLOSING THE WATER LOOP IN SINGAPORE ............................................................. - 68 -
FIGURE 19 SINGAPORE'S CATCHMENT AREAS ............................................................................ - 70 -
FIGURE 20 PROPOSED BASIC WATER INDUSTRY MODEL ............................................................. - 83 -
List of Tables
Page
TABLE 1 PARAMETERS USED IN ASSESSING WATER QUALITY IN DIFFERENT SITUATION .......... - 10 -
TABLE 2 CATEGORISATION OF SOURCE OF CHEMICAL CONSTITUENTS ..................................... - 11 -
TABLE 3 SUMMARY OF MAIN WATER TREATMENT PROCESSES ................................................ - 16 -
TABLE 4 EXAMPLES OF DEFINITION FOR LIKELIHOOD AND CONSEQUENCES OF A HAZARDOUS
EVENT ..................................................................................................................... - 24 -
TABLE 5 RISK MATRIX ........................................................................................................... - 24 -
TABLE 6 MINIMUM FAECAL INDICATOR TEST FREQUENCY IN DISTRIBUTION SYSTEMS ............ - 29 -
TABLE 7 MINIMUM SAMPLE FREQUENCY FOR PIPED SUPPLY .................................................. - 29 -
TABLE 8 TOXICITY STUDIES ON METALDEHYDE ......................................................................- 51 -
TABLE 9 METALDEHYDE PROPERTIES TABLE ......................................................................... - 52 -
TABLE 10 WATER STATISTICS FOR SOUTHEAST ASIAN COUNTRIES (1995 & 2004) .................. - 60 -
TABLE 11 WATER RESOURCES STATISTICS FOR SINGAPORE ..................................................... - 69 -
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10. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
1. Introduction
ASEAN cities are growing at a rapid pace, yet it seems that safe
drinking water is still a growing issue which needs to be addressed for the
protection of public health and for the country’s developments. While the
ASEAN member countries have access to available funding, technology and
skills necessary for the provision of water services, it seems that their
institutional arrangements and regulatory framework are inadequate to
support these developments.
Within ASEAN, Singapore has successfully implemented an integrated
water resources management strategy that allows its population to have access
to an uninterrupted supply of safe drinking water. However, Singapore has
just started to develop its water quality regulatory model to ensure sustainable
drinking water quality. The Ministry of Environment & Water Resources
(MEWR), together with its two operational statutory boards (National
Environment Agency (NEA) and PUB, Singapore’s national water agency), is
responsible for environment and water resources in Singapore. PUB is
responsible for water resources management, while NEA is responsible for
environmental and public health issues.
Most of the European Union (EU) member states are developed
countries with access to safe drinking water. The EU implements the Drinking
Water Directive (DWD) to ensure a common approach to the provision of
water services in the EU. In the UK, the water quality regulatory model is
unique with a privatised water industry in England & Wales. The Drinking
Water Inspectorate (DWI) is the independent water quality regulator which
has been successful in ensuring that England & Wales enjoy a high quality of
safe drinking water. It is highly likely that the effective UK water quality
regulatory model could be adapted to assist the ASEAN countries to develop
high levels of drinking water quality for its population. Singapore’s fledging
water quality regulatory model could also be refined by adopting some of the
experiences gained by the DWI in implementing the UK model.
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11. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
2. Aims & Objectives
The focus of this dissertation is on the water quality regulatory models.
While there are other issues relating to regulating any water industry, such as
financial and environmental issues, these are beyond the scope of this
dissertation. Nevertheless, these issues need to be studied further to develop
a comprehensive model for the water industry.
This dissertation aims to:
• Analyse international drinking water quality guidelines, EU & UK
drinking water quality regulatory model;
• Assess water quality regulatory issues in the ASEAN member countries;
• Assess the water quality regulatory model in Singapore; and
• Assess issues relating to the metaldehyde-containing pesticide in the
UK as an example of a current issue in the regulatory system
The objectives of this dissertation are:
• Compare and contrast the regulatory approach in the UK and in
Singapore;
• Propose measures to enable Singapore to develop a unique water
quality regulatory model;
• Complete a detailed literature review, including DWI, MEWR, PUB &
NEA source materials;
• Develop a water quality regulatory model for the potential
improvement to safe drinking water in ASEAN cities and
• Complete a detailed study of issues and information relating to
metaldehyde-containing pesticide in the UK
The overview of the dissertation is shown in Figure 1.
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12. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Water Quality
International Regional National
United Nations European Union United Kingdom
• Millennium • Organisation • Regulations
Development Goals • DWD framework • Regulators (DWI)
WHO • Directives & Regulations
• Guidelines
Association of Southeast Asian Nations Metaldehyde-
ASEAN containing pesticide
• Organisation
• Metaldehyde
• Approach to issues
• Role of regulations
• Water Quality guidelines and objectives
• Case study
Rural Communities Urban Cities
Singapore
• Integrated Water Resources Management
• Statutory Authorities & Water Suppliers
• Current Regulations
Discussion & Conclusion
• Review of the WHO guidelines
• Comparison of the regulatory approach in UK & Singapore
• Proposed ASEAN Water quality regulatory model
• Proposed development of the Singapore water quality regulatory model
Figure 1 Overview of dissertation
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3. Water Quality & Treatment
World leaders of the 189 United Nation (UN) member states, at the
United Nations Millennium Summit held in New York on 6 - 8 September
2000, agreed to a common goal of the United Nations Millennium Declaration
to work together on global social issues and to ensure that the benefits of
globalisation be inclusive and equitable to all people, especially for those in
the developing countries or economies (UN, 2000)1.
This declaration led to the development of the time bound and
measurable Millennium Development Goals (MDG) which provides a
framework for global action towards a common goal. The MDGs, comprising
of 8 goals and 18 targets, are listed in Appendix A. The relevant target and
goal related to water and sanitation are Goal 7 and target 10, which states,
“Goal 7: Ensure environmental sustainability
Target 10: Halve, by 2015, the proportion of people without
sustainable access to safe drinking water and basic sanitation.”
(Lenten R. et al, UNDP, 2005)2
At the opening of the water exhibition organized by the American
Museum of Natural History and the UN Department of Public Information in
Oct 07, UN Secretary-General Ban Ki-moon said that “Safe drinking water and
adequate sanitation are crucial for poverty reduction, crucial for sustainable
development, and crucial for achieving any and every one of the Millennium
Development Goals.” Mr Ban also noted that high population growth,
unsustainable consumption patterns, poor management practices, pollution,
inadequate investment in infrastructure, and low efficiency in water-use are
putting huge stresses on the earth’s water resources and estimates that the
current 700 million people in 43 countries affected by water scarcity could
swell to more than 3 billion by 2025 (UN News centre, 24 Oct 2007)3.
The World Health Organisation (WHO) (2008) 4 affirms that “the
combination of safe drinking water and hygienic sanitation facilities is a
precondition for success in the fight against poverty and hunger (Goal 1),
primary education (Goal 2), gender equality and women empowerment (Goal
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14. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
3), child mortality (Goal 4), maternal health (Goal 5), HIV/AIDS and Malaria
(Goal 6), ensure environmental sustainability (Goal 7) and develop global
partnerships (Goal 8).”
Prüss-Üstün A. et al (2008)5 wrote that at least 10% of the world’s
disease burden (in disability-adjusted life years or DALYs, a weighted measure
of deaths and disability) could be alleviated by improvement in drinking water,
sanitation, hygiene and water resources management and these only include
those diseases which are quantifiable or have adequate evidence. The
proportion of diseases contributing to this disease burden is shown in Figure
2. Drinking water quality and access improvements are mainly related to the
reduction of diarrhoeal diseases, malnutrition and Trachoma.
Figure 2 Diseases contributing to the water-, sanitation- & hygiene-
related disease burden
(Prüss-Üstün A. et al, pp 11, 2008)5
Prüss-Üstün A. et al (2008)5 further concluded from a systematic
review of diarrhoeal disease literature, that improvement in water supply and
water quality would reduce the frequency of diarrhoeal diseases by 25% and 31%
respectively.
The WHO (2006)7 uses Disability-Adjusted Life Years (DALY) as the
common measurement to objectively evaluate and compare the effects of the
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15. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
diverse hazards associated with very adverse health outcomes and is defined
as the weighted sum of years of life lost by premature mortality (YLL) and
years of life lived in disability (YLD) or DALY = YLL + YLD. Each health
effect is weighted for its severity from 0 (normal good health) to 1 (death) and
multiplied by time duration and the number of people affected. DALYs are
used to compare health effects of different agents in water. The Guidelines’
reference level of risk is 10-6 DALYs per person-year.
A major concern of water supply is the spread of the infectious water-
related diseases through the water supply. This refers to diseases caused by
living organisms (bacteria, viruses or parasites like protozoa or helminths)
which are usually spread from person to another, or to or from animal, and is
related to water. Cairncross S. & Feachem R. (1993)6 classified these diseases
by their distinct route of transmission through water:
a) Water-borne route – transmission occurs when pathogens in water
is drunk by a person or animal;
b) Water-washed route – transmission is reduced when there is
sufficient quantity of water for hygiene purposes;
c) Water-based route – transmission is due to infection by pathogens
which spend part of its life cycle in water; and
d) Insect-vector route – transmission is spread by insects which either
breed in water or bite near water.
Cairncross S. & Feachem R. (1993)6 further recommended that water-
borne and water-washed diseases could be prevented with an improvement in
quality and sufficiency of safe drinking water supply and using this supply
rather than an unsafe source.
This underlies the importance of water and sanitation for any
sustainable developments in a country. Evidence exists to support the need
for improvements in drinking water, but there are still questions in
determining what it actually means to have adequate access to water of a
suitable water quality. What would be a safe concentration of any parameter,
such that it is considered safe?
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3.1. Water quality
The WHO Guidelines for Drinking Water Quality (WHO, 2006) 7
defines safe drinking water as water of a certain microbiological, chemical,
physical and radiological quality that does not represent any significant health
risk over a lifetime of consumption. In the 3rd edition of the WHO Guidelines,
the WHO has moved away from setting an international standard for drinking
water quality to a risk-based approach for setting national or regional
standards and regulations. The WHO framework for safe drinking water is
covered in Chapter 4.1.1.
As the setting of water quality standards depends on the local context
and conditions, the WHO recommends a preventive rather than remedial
approach to the management of water supplies. There is still a need then to
monitor at sufficient frequency and ensure that the final water quality meets
certain water quality standards. Water quality standards should be scientific
& evidence based and must be determined by local authorities based on
international guidelines, regional recommendations and national
requirements.
The WHO (2006)7 advises that national regulatory agency and local
water authorities determine and respond to the constituents of public health
significance, as under any given circumstances, only a few constituents are of
concern.
The WHO (2006)7 guidelines assumes a per capita consumption of 1
litre of unboiled water for microbial hazards and for chemical hazards, the
daily per capita consumption of 2 litres by a person weighing 60kg.
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3.1.1. Microbiological water quality
The WHO (2006)7 considers the control of outbreaks of water borne
diseases as the foremost priority in drinking water quality control. This is
because such infectious outbreaks could affect a large number of people in a
short period of time. The public health burden of the diverse pathogen-
causing infectious diseases depends on the severity, infectivity and exposed
population size.
Cairncross S. & Feachem R. (1993)6 highlighted that all faecal-oral
diseases and most of the water based diseases are caused by pathogens
transmitted in human excreta, normally in faeces. Cairncross S. & Feachem R.
(1993)6 also explained that as many of the pathogens are present in very small
number in polluted water, it is therefore common practice to detect “indicator
bacteria” instead.
Lloyd (2007)8 noted that Thermotolerant coliform and Escherichia coli
met 7 (bold) out of the following 11 criteria for the ideal water industry
indicator of the presence of enteric-pathogens:
- Presence of indicator denote the presence of all relevant pathogens;
- Detectable whenever a waterborne pathogen is present
- Present in greater number than the pathogens
- Absent when the pathogens are absent
- Abundant in human and animal excreta and absent from
other sources
- Unable to grow in water
- Survive longer than pathogens in water
- More resistant than pathogens to disinfectants
- Rapidly and reliably isolated
- Easily identified.
- Precisely enumerated.
The WHO (2006)7 recognised that these 2 indicator bacteria are
important parameters for verification of microbial quality and recommends
that E. coli or Thermotolerant coliform must not be detectable in a 100-ml
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18. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
sample of treated potable water. The guidelines for microbiological quality for
drinking water are found in Appendix B-1.
While indicator bacteria tests provide a quick overview of the possible
health risk due to faecal contamination, it does not allow the detection of
some pathogenic viruses and protozoan like Cryptosporidium or Giardia.
OECD & WHO (2003) 9 explained that this is because the viruses and protozoa
have different environmental behaviour and survival characteristics compared
to faecal bacteria. There is no single indicator organism that can be
universally used for all purposes in surveillance, as each has its own
advantages and disadvantages. Therefore, there might be a need for direct
pathogen testing, which is still in a developmental stage and requires a highly
specialised laboratory, highly trained staff, appropriate safety measures and
time.
OECD & WHO (2003)9 discussed some of the possible microbiological
alternative and non-microbial parameters which could be used to assess
microbial water quality in different situations. This is summarised in Table 1.
It is noted that all the parameters, except for Pseudomonas and Aeromonas
spp. are suitable parameters in outbreak investigations. A more detailed
explanation of the parameters is found in Appendix B-2.
The WHO (2006)7 thus recommends a qualitative microbial risk
assessment (QMRA), epidemiological studies and case histories of outbreaks
to determine the necessary microbial water quality improvements needed.
This takes into account the following:
• Hazard identification – identifying all potential hazardous events such
as the source(s) and possible time of occurrence and the selection and
control of possible representative organism to ensure the control of all
pathogens of concern.
• Exposure assessment – subjective estimation of the concentration of
pathogenic microbes ingested and the volume of water consumed
(treated and/or unboiled) by exposed individuals;
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19. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
• Dose-response assessment – study of dose-response of healthy
volunteer to derive the probability of adverse health effect after
exposure to pathogenic organisms and to determine the infective dose;
• Risk characterisation - integration of all available information from
exposure, dose-response, severity and risk of infection to determine the
disease burden of each potential disease in DALYs.
Table 1 Parameters used in assessing water quality in different situation
Sanitary survey, Treatment Disinfection Treated water Ingress in Regrowth in
Source-water & removal efficiency Distribution distribution
groundwater efficiency system system
characterization
Enteric viruses Total coliforms Total coliforms Total coliforms Total coliforms
Thermotolerant Thermotolerant Thermotolerant Thermotolerant Thermotolerant Thermotolerant
coliforms coliforms coliforms coliforms coliforms coliforms
Escherichia coli Escherichia coli Escherichia coli Escherichia coli Escherichia coli
Faecal streptococci Total bacteria Total bacteria Total bacteria Total bacteria
(enterococci)* (microscopic) (microscopic) (microscopic) (microscopic)
Somatic coliphages Viable bacteria Viable bacteria Viable bacteria Viable bacteria
(microscopic) (microscopic) (microscopic) (microscopic)
F specific RNA Heterotrophic Heterotrophic Heterotrophic Heterotrophic
phages bacteria bacteria bacteria bacteria
Bacteroides phages Aerobic spore- Aerobic spore- Pseudomonas,
forming bacteria forming bacteria Aeromonas
Clostridium Clostridium Somatic
perfringens perfringens coliphages
Giardia cysts, Giardia cysts, F specific RNA
Cryptosporidium Cryptosporidiu phages
oocysts m oocysts
Rainfall events* Particle size Bacteroides
analysis phages
Flow * Turbidity Flow Flow Flow
Solids (Total and pH Colour
dissolved)
Conductivity Disinfectant Disinfectant Disinfectant
residual residual residual
Turbidity
Organic matter Organic matter
(TOC, BOD, COD) (TOC, BOD, COD)
Microscopic
particulate analysis
Ammonia
* faecal streptococci and flow parameter are for sanitary survey and surface water characterisation only, while rainfall is
only used for sanitary survey and microscopic particulate analysis is meant for groundwater characterisation.
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20. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
3.1.2. Chemical water quality
Natural occurring or pollution derived chemicals are found in varying
quantities in water and can be a significant contribution to public health
problems. The chemicals can be grouped according to their original source as
shown in Table 2. The adverse health effects of most chemical contaminants
are associated with long-term exposure. Thomson T. et al (2007) 10
recommended that it is more effective to identify and focus on priority
chemicals of concern, as assessing and developing strategies for every
chemical would be impractical and require plenty of resources.
Table 2 Categorisation of source of chemical constituents
Source of Chemical constituents Example of sources
Naturally occurring (including Rocks, soils, cyanobacteria in eutrophic
naturally occurring algal toxins) lakes
Agricultural activities Manures, fertilizers, pesticides, intensive
animal practices
Human settlements Sewerage & waste disposal, urban runoff,
fuel leakage,
Industrial activities Mining, manufacturing, processing,
Water treatment or materials in Water treatment chemicals, disinfection
contact with water by-products (DBPs), storage tank/pipes
material corrosion and leeching
(Thomson T. et al, 2007)10
The WHO guidelines for drinking water quality (2008) 11 provide
guideline values for “36 inorganic constituents, 27 industrial chemicals, 36
pesticides, 4 disinfectants and 23 disinfectant-by-products”, of which the 95
chemicals of health significance in drinking water are found in Appendix B-1.
These chemicals are chosen based on the following criteria:
• Credible evidence of chemicals occurring in drinking water together
with evidence of actual or potential toxicity;
• Significant international concern; or
• Considered for inclusion or is included in the WHO Pesticide
Evaluation Scheme (WHOPES) programme
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21. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
The derivation of these guideline values are scientifically based on
health effect studies on human populations or toxicity studies on laboratory
animals, supported by other appropriate studies. Health effects studies on
human population are preferred, but there is limited value on such studies
because of the lack of qualitative information on the concentration to which
people have been exposed to and due to simultaneous exposure to other
agents. There is uncertainty in the findings from the more frequently used
toxicity studies on laboratory animals because of the relatively small number
of animals used and relatively high dose administered. This requires
extrapolating the results from animals to humans as the human populations
are usually exposed to low doses (WHO, 2006)7. This means that most
guideline values are likely to be very conservative.
As illustrated in Figure 3, different approaches are taken for the
different groups of chemicals:
• Carcinogens – non-threshold chemicals, where there are adverse health
effects at any level of concentration and no safe dose;
• Toxic substances – threshold chemicals, where there are no adverse
health effects below a certain concentration;
• Essential elements – necessary for humans and animals for normal
functions, for which there is a safe concentration range, where adverse
health effects are observed from deficiency (below safe concentration
range) and over-exposure (above concentration range).
Carcinogenic substances Toxic substances
Adverse (Boron, Cyanide, Lead)
(Arsenic, Vinyl Chloride)
health
effects Essential elements
(fluoride, selenium, iodine,
manganese, copper)
Concentration
NOAEL Safe concentration range (mg/l)
Figure 3 Adverse health effects of chemical at concentration
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For threshold chemicals, there is a need to derive the Tolerable Daily
Intake (TDI), which is defined as amount of substances in food and drinking
water, expressed on a body weight basis (mg/kg of body weight), that can be
consumed over a lifetime without appreciable health risk. The guidelines
values are derived as follows:
Where
NOAEL = No Observed Adverse Effect Levels
LOAEL = Lowest Observed Adverse Effect Level*
UF = Uncertainty factor
bw = body weight
P = fraction of TDI allocated to drinking water
C = daily drinking-water consumption
* If LOAEL is used, an additional uncertainty factor has to be applied
(WHO, 2006) 7
3.1.3. Acceptability water quality
Drinking water must not only be safe, but it must be acceptable to
consumers. While most consumers are not able to determine the safety of
their drinking water due to lack of equipments, they could reject the water due
to its physical appearance, taste and odour and use an alternate unsafe source.
The physical appearance, taste and odour of drinking water are affected
by microbiological and chemical contaminants in water (attached as
Appendix B-3), but the acceptability of drinking water by consumers is also
subjective and influenced by individual and local factors. As most of these
contaminants have microbiological and chemical health-based guidelines, the
parameters that fall into this category would include colour, pH, turbidity,
hardness and total dissolved solids. (WHO, 2006)7
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3.1.4. Radiological water quality
The WHO (2006)7 stated that the long-term incidence of cancer in
humans and animals could increase as a result of low to moderate dose of
radiation exposure. Radiation arises from naturally-occurring and man-made
sources.
The guideline value is the recommended reference dose level equivalent
to a cumulative 0.1mSv in annual drinking water consumption, given as
activity concentration (Bq/l). The WHO (2006)7 states that “The SI unit for
radioactivity is the Becquerel (Bq), where 1Bq = 1 disintegration per
second...The SI unit for equivalent and effective dose is the sievert (Sv) where
1Sv = 1 J/kg”. (WHO, 2007)7
The guidance levels for radionuclide in drinking water are attached as
Appendix B-1 and is calculated by
.
Where
GL = guidance level of radionuclide in drinking water (Bq/litre)
IDC = individual dose criterion, equal to 0.1mSv/yr for this calculation
Hing = dose coefficient for ingestion by adults (mSv/Bq)
q= annual ingested volume of drinking water, assumed to be 730l/yr
As the concentration of radionuclide in drinking water is relatively low,
the WHO (2006)7 recommends that it might not be justified to identify
individual radioactive species using sophisticated and expensive analysis
without first carrying out a screening procedure for detection limits of 0.5
Bq/litre for gross alpha activity and 1 Bq/litre for gross beta activity.
(WHO, 2007)7
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3.2. Water treatment
It is common to treat raw water to produce safe drinking water for the
protection of public health, as most raw water quality does not meet safe
drinking water standards. Allan S.C. (1997)12 cited that there are eight specific
reasons for treatment water:
• To remove disease-causing pathogens;
• To remove potentially toxic natural or synthetic substances;
• To remove dissolved and gaseous radioactivity;
• To improve organoleptic quality of water to prevent consumer rejecting
water due to its physical appearance, taste or odour;
• To prevent bacterial after-growth in the distribution system;
• To prevent deposition and silting up of pipes;
• To prevent corrosion and dissolution of pipes and fittings; and
• To comply with local, national and international law on water quality.
Water treatment is based on a multi-barrier approach to removing
contaminants and depends, amongst other things, on the quality of the source
water and final water quality desired. The conventional approach is to choose
a combination of the appropriate processes at the treatment works. Some of
the main treatment processes can be found in Table 3. Typical water
treatment processes usually comprises of pre-treatment, main treatment and
disinfection.
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Table 3 Summary of main water treatment processes
Processes Functions
Screens Sets of coarse (100mm spacing) to fine screens used as a physical removal of
larger particles such as litters or branches and for protection of downstream
processes
Roughening Coarse media (rock or gravel with size 4 – 12mm) pre-filter used to reduce
filters turbidity (60-90% removal) and faecal coliform bacteria (93 – 99.5%
removal)
Micro-strainers Stainless steel or polyester wire fabric mesh of apertures 15 – 45mm pre-
treatment strainers for removing 40-70% algae cells and large protozoa and
5-20% turbidity removal.
Aeration The use of a cascade or fountain system to introduce air into the raw water to
increase dissolved oxygen in water to protect downstream processes, reduce
CO2, raise pH, remove iron and manganese from water and improve taste in
water by stripping out hydrogen sulphide and volatile organic compounds.
Off-stream/ bank Self-purification reservoir storage to improve water quality before treatment
side storage and to ensure adequate supplies at periods of peak demand. Storage also
eliminates variation in water quality due to floods and surface run-offs.
Exposure to sunlight (natural UV radiation) kills some pathogens and
removes colour. Long term storage allows suspended solids to settle and
reduces turbidity, while algae can remove hardness by converting
bicarbonates to precipitate carbonates.
Coagulation & Chemical coagulant like alum (aluminium sulphate) or other salts of
flocculation aluminium or iron are added and rapidly mixed to allow colloidal particles in
the water to coagulate and then agitated to flocculate so that the flocs can be
removed more easily later. The efficiency of the process depends on the raw
water quality, coagulant dose, coagulant aid, mixing conditions and pH. Jar
tests are usually carried out to determine the optimum dose required.
Optimal coagulation can carry out 1-2 log removal of bacteria, viruses and
protozoa, as well as removing turbidity, suspended solids, certain heavy
metals and low-solubility organochlorine pesticides.
Sedimentation Solid-liquid separation process to remove the solids from the raw water by
allowing the flocs to settle.
Dissolved Air- DAF functions like a sedimentation tank to remove flocs, except that air
flotation (DAF) bubbles are introduced from the bottom of the tank to allow the floc particles
to attach to the air bubbles and float to the surface, where it can be skimmed
off. DAF is found to be effective in the removal of algal cells,
Cryptosporidium oocysts or humic acids.
Lime softening The addition of lime or soda ash to increase the pH of water to reduce
hardness by precipitating calcium and magnesium from the raw water.
Lime softening can also aid in the removal of bacteria (2 log removal
maximum), viruses (up to 4 log removal) and protozoa (up to 2 log removal)
at high pH (>11) depending on temperature, time of exposure and pH.
Ion Exchange The adsorption processes where there is a reversible interchange of same
charge ions between a solid ion-exchange medium and the raw water. With
different resins used, ion exchange can be used for water softening and for
removal of radionuclide and heavy metals, nitrate, arsenic, cadmium,
selenium, uranium and dissolved organic carbon.
Rapid gravity The use of single, dual- or multi-media of granular material like sand or
filtration anthracite of different grades to allow water to pass rapidly through the
relatively large gaps in between the grains to remove the suspended solids
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Processes Functions
through straining, adsorption, adhesion and sedimentation. Filtration rates
are typically 5 – 10 m/h. rapid gravity filtration can also remove turbidity,
adsorbed chemicals, oxidised iron and manganese from raw water. Under
optimum coagulation conditions, up to 2 log removal of bacteria, viruses and
protozoa can be achieved.
Pressure filters The rapid gravity filter process is carried out in an enclosed in an enclosed
cylindrical shell to eliminate the need for a separate pumping stage.
Slow Sand A non-pressurised, chemical-free biological filtration process where the raw
Filtration water is passed through 0.15-0.3mm diameter fine sand of 0.5m to 1.5m
depth and a flow rate of 0.1 to 0.3 m3/m2.h. There is a thin biological active
filter skin at the top called the Schmutzdecke. A matured slow sand filter can
remove biological particles such as bacteria, viruses, Cryptosporidium,
faecal coliform and other organic debris up to 4-log removal, iron and
manganese biologically and is effective for the removal of algae and organics,
including certain pesticides and ammonia.
Membrane – Physical pressure-driven filtration process to remove contaminants from
Microfiltration water using a semi-porous membrane media of pore size of 0.01-12µm at
(MF) operating pressure of 1 -2 bars. Microfiltration can remove algae, protozoa,
bacteria and microbes larger than 0.2 micron and is widely used to remove
chlorine resistant pathogens like Cryptosporidium oocysts and Giardia
cysts. Please see Figure 4.
Membrane Similar to MF except that pore size is in the range of 1nm – 100nm. UF
filtration – operates at less than 5bars and is capable of removing suspended solids
ultrafiltration (turbidity <0.1 NTU), organics (molecular cut-off weight of 800), bacteria
(UF) and viruses, including Cryptosporidium (at least 4 log removal). Please see
Figure 4.
Membrane Similar to UF, except pore size is in the range of 0.001mm to 0.01mm. NF
filtration – operates at about 5 bars and rejects divalent ions (magnesium and calcium),
nanofiltration organics (molecular cut-off weight above 200), suspended solids, bacteria
(NF) and viruses. Please see Figure 4.
Membrane Similar to NF, except pore size is less than 0.002mm. Operating at 15- 50
filtration - reverse bar, only water essentially passes through, while dissolved salts, suspended
osmosis (RO) monovalent ions and organics (molecular cut-off weight above 50).
Complete removal of bacteria, viruses and protozoa is possible with pre-
treatment and membrane integrity conserved. Please see Figure 4.
Activated carbon Normally in powdered (PAC) or granular (GAC) form using porous
adsorption carbonaceous material with large surface area (500-1500 m2/g) for the
removal of removal of pesticides and other organic chemicals, cyanobacterial
toxins, total organic carbon and for control of taste and odour.
Chlorine Chlorine is commonly used in destroying or inactivating most water-borne
disinfection disease-causing micro-organisms, and as a powerful oxidant to improve
water quality by removing reduced nitrogen, iron, manganese, sulphide and
certain organic species. Chlorine can combine with ammonia to form
chlorine residual (chloramines) to provide protection against
recontamination in the distribution network. Chlorine, chlorine dioxide or
chloramines can be used.
Ozone As a powerful oxidant, ozone is used as a primary disinfectant to effectively
disinfection inactivate harmful protozoan that form cysts and almost all other pathogens.
Ozone is also effective in removing some pesticides and organic materials.
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27. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
Processes Functions
Ultra-violet (UV) The adsorption of UV radiation with a frequency of 250 – 256 nm in their
disinfection DNA can inactivate microorganisms. A quick, chemical-free process, UV is
able to remove bacteria up to 8 log removal; viruses up to 6 log removal and
protozoa like Cryptosporidium oocysts by a 4 log removal depending on
dosing.
Plumb solvency Small quantities of phosphate can be added to reduce lead in pipe dissolving
reduction in treated water.
(Wikipedia, 2008)13 (WHO, 2006)7 (WHO & OECD, 2003)9
(Koch membrane, 2008)14 (Gray N.F., 2005)15
Figure 4 Membrane process characteristics
(Koch membrane, 2008)14
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4. Water Regulations
The purpose of drinking water regulations is to ensure that the
consumers have safe potable water through effective control. Legislation need
to:
• Define clearly the roles and responsibility of the stakeholders (water
supplier, policy and regulatory authorities, public health authorities,
consumers, chemical and material suppliers, analytical services
providers, etc) involved in drinking water supply;
• Have sufficient enforcement measures;
• Allows for changes and amendments needed for future conditions; and
• Be flexible enough to cater to different situations.
(WHO, 2006)7
The UNDP (2008)16 recognises that the lack of access to safe drinking
water results mainly from profound failure in water governance. Water
governance requires an integrated political, social, economic and
administrative system to manage water resources and provide water services
to the population.
To gain a better understanding of drinking water regulations, it is
useful to look at the international guidelines from the WHO, the regional
directives of the EU and the national regulations of the UK.
4.1. World Health Organisation
The WHO was established in 1948 with the aim of attaining the highest
possible levels of health for all people in all countries. Representatives of the
193 WHO member states and 2 associate members form the WHO Assembly,
which sets policies, approves budget and appoints the Director-General for a
5-year term. The WHO Assembly also elects the 34 member Executive Board.
Six regional committees focus on regional health matters. The WHO
constitution comprises of 82 articles which details the operations and
functions of the WHO. (WHO, 2006)17 (WHO, 2008)18
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The WHO published international drinking water standards in 1958,
1963 and 1971. These are superseded by the WHO guidelines for drinking
water quality, published in 3 volumes. The 1st edition and 2nd edition were
published in 1983-84 and 1993-97 respectively. (WHO, 2008)18
The 3rd edition of volume 1 of the Guidelines, a rolling edition, was
published in 2004 and the 1st addendum was added in 2006. Parts of the
previous Volume 2 are replaced by a series of publications providing
information on the assessment and management of risks associated with
microbial hazards and by internationally peer-reviewed risk assessments for
specific chemicals, while the previous volume 3 is still valid in providing
guidance on good practices in surveillance, monitoring and assessment of
drinking water quality in community supplies. (WHO, 2008)18
The 4th edition for Volume 1 of the Guidelines is currently in progress
(Davidson A. et al, 2005)19 (WHO, 2008)20. More than 20 WHO water quality
experts last met in Singapore to review the technical work for the 4th edition
on 24-27 Jun 08. This was held in conjunction with the Singapore
International Water Week (SIWW, 2008)21.
The WHO guidelines for safe drinking water are commonly used as the
reference source and form the basis of water quality standards for most
countries in the world. The guideline values for water quality parameters are
found in Appendix B-1.
4.1.1. Guidelines for safe drinking water
The Guidelines for drinking water quality (WHO, 2006)7 outline a
framework to ensure that safe drinking water could be provided as part of the
strategy for the protection of public health and the reduction of water-related
diseases. The idea is to critically analyse any drinking water system from
catchment to tap for hazards control and prevention.
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The framework comprises of the following:
• Health-based targets based on national and local conditions for the
purpose of protecting and improving public health;
• Water safety plans for a systematic multi-barrier approach to a
comprehensive risk analysis and management of water supply; and
• Surveillance to monitor and verify on the compliance with the water
safety plan and ensure the adequacy of supply for public health.
(WHO, 2006)7
4.1.2. Health- based targets
Health-based targets set the health and water quality goals for the
implementation of the safe drinking water framework to ensure realistic
targets for the effective protection of overall public health in the local context.
Every country and community will have different and unique levels of health-
based targets, as there is a need to take into account the status, trends,
contribution of drinking water to the transmission of infectious diseases and
to overall exposure to hazardous chemicals both in individual and overall
public health management, access to water, local situations (including
economic, environmental, social and cultural conditions) and local (financial,
technical and institutional) resources. (WHO, 2006)7
The 4 principal types of health-based targets include:
• Health outcome targets based on the reduction in the total disease
burden for a particular microbial or chemical hazards largely
attributable to water;
• Water quality targets for mainly chemical constituents, additives
or treatment by-products in water with stable concentrations that
represent health risks from long term exposure, typically expressed as
guideline values;
• Performance targets for control of constituents with fluctuations in
numbers or short periods that represent health risks in short term
exposure, typically expressed as required reductions; and
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• Specified technology targets for specific equipment or processes
or actions for smaller municipal, community and household drinking
water supplies, which typically include recommendations and guidance
for application and operation of such technology.
(WHO, 2006)7
The proportion of exposure to enteric pathogens or hazardous
chemicals attributed to drinking water needs to be considered, as there could
be other sources of exposure.
4.1.3. Water Safety Plans
The Water Safety Plan draws upon the multi-barrier approach and the
Hazard Analysis and Critical Control Point (HACCP) methodology used
extensively in the food industry, as well as approaches found in the quality
assurance standards management systems like ISO 9000 and total quality
management (TQM) (Godfrey S. & Howard G., 2004)22. Drury D. (2007)23
highlighted that the WSPs analyse quality assurance within the operations &
procedures and do not depend on end-point quality assessments.
The 3 components of the WSP are:
• System assessment of the entire drinking water supply chain from
catchment to tap, as a whole, can achieve the water quality as specified
in the health-based targets. The assessment identifies potential
hazards for each part of the supply chain, its individual level of risks
and the appropriate control measures;
• Operational monitoring of the rapid identification of deviation of
the required performances of each control measure for the hazards in
the systems; and
• Management plans to document the system assessment, normal
and incident operations, monitoring, validation, remedial actions,
reporting and communication procedures and supporting programmes.
(WHO, 2006)7
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DWI (2005)24 highlighted that the team responsible for developing the
water safety plans requires:
• Complete in-depth knowledge of each element of the specific water
supply chain and its capability to supply safe water which meets the
health-based standards and requirements;
• Identification of the hazards for each element of the water supply chain,
the consequences and frequency of occurrence of each hazard and the
level of risk each of these presents;
• Identification and validation of the short-term, medium-term and long-
term control measures to reduce each identified risk to an acceptable
level;
• Implementation of a routine monitoring system of those control
measures with action trigger criteria when the control measures are not
within the specified targets;
• Implementation of remedial action plans when a control measure is
outside of the specified target with checks to certify that the system is
brought back under control;
• Validation monitoring to determine whether the system is performing
as assumed in the system assessment; and
• Independent verification for the correct implementation of the WSP to
ensure that the water supplied is safe and meets health-based and other
regulatory targets.
The water safety plan team looks critically at the entire water system
and their individual components (from catchment, intake, each treatment
process, distribution, to the customer’s tap) to identify what the risk of every
possible hazard is, how to reduce and control the risk of the hazards and how
to show that the controls are working. Drury D. (2007)23 explains that the
development of a successful WSP requires the involvement and participation
by company staff members who have a deep understanding on how the
company operates each component of the water supply systems.
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A hazardous event is an incident or situation that can lead to the
presence of a hazard, which is anything that could cause harm. There is a
need to determine the risk of every hazardous event. Risk is defined as the
combination of the likelihood of a hazardous event occurring and the
consequences of the hazard. The definition of the likelihood and
consequences of an event, with examples in bracket, are shown in Table 4.
Table 4 Examples of definition for likelihood and consequences of a
hazardous event
Likelihood of a hazardous event Severity of the Consequences of a hazardous
occurring event if it occur
A Almost certain (Once a day) 1 Insignificant (No significant impact)
B Likely (Once a week) 2 Minor (minor impact to a small population)
C Moderate (Once a month) 3 Moderate (minor impact to a large population)
D Unlikely (Once a year) 4 Major (major impact to a small population)
E Rare (Once every 5 years) 5 Catastrophic (major impact to a large
population)
Risk prioritisation can then be carried out using a matrix as shown in
Table 5 to identify the significance of the hazard, the importance of each
hazard and the prioritisation of improvements needed. For example, an
insignificant hazard that is almost certain to occur will be ranked as a medium
risk event, while a catastrophic hazard which is unlikely to occur will be
ranked as a high risk event.
Table 5 Risk matrix
Consequences
Likelihood 1 2 3 4 5
A (Almost certain ) V High
B (Likely)
C (Moderate) Medium High
D(unlikely) Low
E (rare) Negligible
(WHO, 2005)25
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The steps taken to develop a WSP are illustrated clearly in Figure 5
(WHO, 2005)25.
Assemble the WSP Team Review
experience
and future
System assessment
Document and describe the system needs
Carry out a hazard assessment and
risk characterisation
Identify control measures
Supporting
Define operational limits and
Operational
monitoring
programmes
monitoring of control measures
Establish verification procedures
Review,
Establish management procedures
approval and
for corrective actions, normal
Communications
audit
Management &
operations and incident response
Establish record keeping
Validation and verification
Figure 5 Development of the Water Safety Plans
(WHO, 2005)25
A multi-disciplinary team of experts with a thorough understanding of
the individual elements of the water system needs to be assembled to develop
the WSP. The team should consist of specialists with knowledge of the
catchment and raw water sources, treatment processes, distribution networks,
drinking water quality, public health, domestic distribution system and
customer matters. Senior management support is crucial in the development
of the WSP. A team leader with sufficient authority, interpersonal and
organisation skill should be selected to drive the project and ensure focus.
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The role of each individual member should be defined properly.
Communication procedures with all stakeholders should also be established.
Next, the team should collect and evaluate information to document
and describe the entire water supply system. If information is missing, then
there is a need to determine how and where to collect the information. A
detailed flow diagram will be helpful in providing an overview. Stakeholders
and users are also identified.
For each element of the water supply system, the team should identify
potential failures, problems, their locations and implications in terms of
hazards and hazardous events. The team should also consider influencing
factors. This involves assessment of historic information and events as well as
predictive information based on expert knowledge. Next, the WSP team
should determine the consequence and likelihood of each hazardous event and
the need for action. This is usually done using the risk scoring matrix.
Concurrently with the identification of hazards and evaluation of risk,
the WSP team should document existing and potential control measures and
decide if these control measures are effective. There is also a need to
determine if the control measures could introduce or affect any other
hazard/risk and their subsequent control measures, if necessary. Risk of the
hazardous events should be reprioritised after the control measures are put in
place.
At the same time, if there are insufficient control measures or the risks
are not sufficiently reduced or mitigated, then the team should develop a
short-term, medium-term and long-term action and improvement plan to
mitigate or control each significant risk.
Following the identification of all hazardous events, their hazards,
associated risk and control measures, the WSP team will need to define
operational limits of all critical control points to monitor the control measures
and actions that need to be taken if there is a deviation. This ensures that the
control measures are effectively working within the operational limits, and
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quick notification and remedial actions taken when there is a deviation. The
documentation of the monitoring includes what to monitor, how to monitor,
where the monitoring is carried out, who will carry out the monitoring, who
will do the analysis and who receives the results for action.
A formal verification and auditing process needs to be established to
ensure that the WSP is working properly. Verification involves compliance
monitoring; internal & external auditing of operational activities; and
consumer satisfaction.
Management procedures can then be documented for standard and
incident operating conditions and the resultant corrective actions to be taken
when necessary. Emergency supplies, investigation plan, communication
procedures with stakeholders, reporting procedures and procedures for
regular review and management update are also included.
Supporting programmes should also be determined for each step of the
water safety plan, as the delivery of safe water through the WSP involves
managing people and processes. These programmes include training,
calibration, operation & maintenance, R&D, legal, hygiene and sanitation
aspects.
The entire WSP needs to be documented, presented and approved by
all stakeholders to allow “buy-in” and support. This is important if the WSP is
to be implemented effectively. There is also a need to include a provision for
the WSP to be reviewed and regularly updated.
4.1.4. Surveillance
Drinking water suppliers are legally and morally responsible for the
control of drinking water quality and the sufficiency of supply. The WHO
(2006)7 recommends the setting up of a separate surveillance agency
responsible for overseeing public health assessment in drinking water to
complement the water supplier in view of the conflict of interest between
public health and operational costs.
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Drinking water surveillance requires the long-term constant
assessment of the safety and suitability of drinking water supply for the
protection of public health. Surveillance provides information, which should
be effectively managed and used, as a collaborative mechanism and support
for the surveillance agency and water supplier, for the prioritisation of water
supply improvements. However, the surveillance agency would also require
legal instruments and authority to use enforcement, which should be used
only as a last resort.
The basic parameters for adequacy of supply that the surveillance
agency needs to assess public health are:
• Quality – validation and compliance audit of the approved WSPs;
• Quantity – proportion of population using different levels of drinking
water supply;
• Accessibility – percentage of population with reasonable access to
improved drinking water supply;
• Affordability – tariff paid by domestic customers; and
• Continuity – percentage of the time when drinking water is available.
(WHO, 2006)7
WHO (2006)7 recommended surveillance be carried out by audit-based
or direct assessment approaches.
The audit-based approach basically requires the water supplier to
undertake assessment activities, verification testing of water quality and to
furnish all relevant information to the surveillance agency, while the
surveillance agency is responsible for 3rd party auditing to verify compliance.
Accredited external laboratories commonly carry out analytical services, paid
for by the water supplier. The surveillance agency needs to have the expertise
and capability to:
• Review and approve water safety plans;
• Audit the water safety plans implementation periodically (at regular
intervals, following significant incidents or changes to the systems); and
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38. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
• Investigate and assess incident reports to ensure that the cause is
correctly determined and corrective actions taken and reported to
prevent reoccurrence of a similar situation.
The direct assessment approach will require the surveillance agency to
carry out independent testing of water supplies. The surveillance agency will
require its own or 3rd party analytical facilities and trained staff to carry out
sampling, analysis and sanitary inspection.
4.1.5. Other Recommendations
With a preventive approach, the WHO guidelines (2007)7 recommend
minimal dependence on end-point monitoring, as the sampling is meant only
as verification of water quality.
Simple and more frequent faecal indicator tests are recommended to
detect contamination in water supply. Faecal contamination is not distributed
evenly throughout the piped distribution system and can vary with local
conditions. The recommended minimum sampling frequencies for faecal
indicator tests are shown in Table 6.
Table 6 Minimum faecal indicator test frequency in distribution systems
Population Total no of samples per year
Point sources Progressive sampling of all sources over 3- to 5-year cycles
Piped supplies
5000 – 100 000 12 per 5000 population (rounded up)
>100 000 – 500 000 12 per 10 000 population plus additional 120 samples
>500 0000 12 per 100 000 population plus additional 180 samples
(WHO, 2006)7
Table 7 Minimum sample frequency for piped supply
Population Served No. of monthly samples
< 5000 1
5000 – 100 000 1 per 5000 population
> 100 000 1 per 10 000 population, plus 10 additional samples
(WHO, 1997)26
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39. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
The principal source of the chemicals found in water will determine the
location and frequency of sampling. However, the WHO (2006)7 recognises
that source water sampling once a year may be adequate for stable
groundwater source, while the variable surface water source might require
higher frequency. For piped supply, the recommended minimum sampling
frequencies are based on the population served, as shown in Table 7. The
sampling frequencies for other supplies in small communities are attached in
Appendix BAppendix B – International Drinking Water Guidelines.
Each location where the samples are taken should be individually
considered, but the samples must be representative of the water source,
treatment plant, storage facilities, distribution network, customer delivery
points and points of use. The general criteria of the selection of locations are
that:
- Samples need to be representative of the different sources as it is
obtained or enters the system;
- Yield samples, representative of the conditions at the most
unfavourable sources or places in the supply system and points of
possible sources of contamination, need to be included;
- Sampling locations should take into account the number of inhabitants
served by each source in multiple source systems;
- Locations need to be uniformly distributed throughout the distribution
system, taking into account population distribution and proportional to
the number of branches or links;
- Samples need to be representative of the system as a whole and of its
main components;
- There is a need to sample water in reserved tanks and reservoirs and
there should at least be one sampling point directly after the outlet at
each treatment works; and
- Sampling locations can be fixed or variable. Fixed sites are useful in
allowing results to be compared over time, while local problems are
more readily detected using random locations.
(WHO, 1997)26
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40. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
4.2. European Union
The European Economic Community (EEC) was originally set up to
create a common market between the constituent Member States, but has now
been extended to a large number of common policy goals which is directly or
indirectly related to attain conditions leading to a single market within the
combined territories of the member countries. The EEC was renamed as the
European Union (EU) in 1992 by virtue of the Treaty on European Union
(TEU). (Hedemann-Robinson M., 2007)27
The Single European Act amending the Treaties was enacted on 1 Jul
1987. The Act aims to create a single internal market and formulates a
European foreign policy. More importantly, it introduces explicit references
to the EU’s powers relating to environmental protection for the 1st time. This
includes:
‐ Article 100a which allows for environmental protection legislation
affecting the internal market to be adopted by the majority of member
states; and
‐ Article 130r, 130s & 130t, which specifies the objectives, means and
procedures for unanimous adoption of environmental legislation.
(European Community, 1996)28
The EU comprises of 27 member states, which are Belgium, France,
Germany, Italy, Luxembourg, Netherlands, Denmark, Ireland, United
Kingdom, Greece, Portugal, Spain, Austria, Finland, Sweden, Cyprus, Czech
Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia,
Slovenia, Bulgaria and Romania. (Europa, 2008)29
What is unique about the EU is that there are distinct, separate
legislative, executive and judicial organs of government, the power of which is
transferred from the member states to the community by virtue of treaties and
that the community law overrides the national laws.
(European Community, 1996)28
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41. The Potential for Adapting the UK Water Quality Regulatory Model for ASEAN Cities
The EU adopts the following type of legislation:
‐ Non-binding recommendations or resolutions
‐ Regulations which are binding and directly applicable to Member
States and overrides national laws
‐ Decisions which are directly binding to the persons (member states,
individual and legal persons) they are addressed to; and
‐ Directives which member states are required to transpose and
implement through their national law or regulations within a specified
time period (normally 18 months to 2 years).
(European Community, 1996)28
As illustrated in Figure 6, the EU water policy formation involves the
core European institution, Member States government and non-governmental
organisations with interest in water. The Council decides on the policy
objectives and directions, while the Commission develops and drafts the
directions into appropriate policy text and directives. The European
Parliament actively debates on the legislation and can amend the draft
legislation presented by the Council. The European Parliament shares the
responsibility of passing European laws with the European Council.
Representatives of sectors affected by water-related regulations and various
water-related organisations try to influence the process by lobbying. This
reflects the similar situation at the national level. The scientist and
technologist group is consulted on water-related technical issues and their
recommendations are critical to the nature of the policies.
EUROPEAN INSTITUTIONS
ORGANISED EUROPEAN
EUROPEAN
INTERESTS REPRESENTATIVES/
PARLIAMENT
ASSOCIATIONS
SCIENTISTS EUROPEAN
TECHNOLOGISTS COMMISSION
MEMBER STATES’ COUNCIL OF
GOVERNMENT MINISTERS
NATIONAL LEVEL EUROPEAN LEVEL
Figure 6 Parties active in EU water policy process
(Kallis G. & Nijkamp P., 1999) 30
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