D4.1.4

Identification and description of hazards for water supply systems

A catalogue of today’s hazards and possible future hazards

Version August 2008

TECHNEAU, August 2008

© 2008 TECHNEAU TECHNEAU is an Integrated Project Funded by the European Commission under the Sixth Framework Programme, Sustainable Development, Global Change and Ecosystems Thematic Priority Area (contractnumber 018320). All rights reserved. No part of this book may be reproduced, stored in a database or retrieval system, or published, in any form or in any way, electronically, mechanically, by print, photoprint, microfilm or any other means without prior written permission from the publisher

TECHNEAU, August 2008


A catalogue of today’s hazards and possible future hazards Version August 2008

This report is: PU = Public

Colofon

Title Identification and description of hazards for water supply systems - A catalogue of today’s hazards and possible future hazards, updated version Authors � Ralph Beuken (Editor), María Reinoso – Kiwa

Water Research � Sebastian Sturm and Joachim Kiefer - TZW � Mia Bondelind, Johan Åström , Andreas Lindhe,

Lars Losén and Thomas Pettersson – Chalmers University of Technology

� Ingo Machenbach, Esa Melin, Thor Thorsen, Bjørnar Eikebrokk, Per Hokstad and Jon Røstum – SINTEF

� Claudia Niewersch, Daniela Kirchner – RWTH Aachen University

� Frantisek Kozisek and Daniel Weyessa Gari – SZU.

� Chris Swartz – WRC SA / SWUE � José Menaia - LNEC Quality Assurance Thomas Pettersson – Chalmers University of Technology Deliverable number D4.1.4 (This report is an updated version of Deliverable D4.1.1/2)


© TECHNEAU - 5 - August, 2008

Contents

Contents 5

1 Introduction 7

1.1 Background 7

1.2 Objectives 9

1.3 Methodology 9

1.4 Today’s hazards 9

1.5 Future hazards 10

2 Structure of TECHNEAU Hazard Database 11

2.1 Introduction 11

2.2 Structure of the Hazard Database 11

2.3 Review of TECHNEAU Hazard Database 15

3 Proposed methodology for hazard identification 19

4 References 21

Appendix 1 to 12: TECHNEAU Hazard Database 23

1. Surface water catchment 24

2. Groundwater catchment 27

3. Surface water intake and transport 30

4. Surface water infiltration 31

5. Groundwater and infiltration, water abstraction and transport 33

6. Treatment 35

7. Reservoirs and pumps 53

8. Transport and distribution 58

9. Internal piping 62

10. Consumer and taps 66

11. Organization 68

12. Future hazards (including the whole drinking water system) 70

Appendix 13: Methodology for hazard identification by using the THDB 76





1 Introduction

1.1 Background

The main objective of WA 4 (Risk assessment and risk management) is to integrate risk assessments of the separate parts of a water supply system into a comprehensive decision support framework for cost-efficient risk management in safe and sustainable drinking water supply. The steps in the risk management process are represented in Figure 1. For a further description of the risk management process see “Generic Framework and Methods for Integrated Risk Management in Water Safety Plans”, TECHNEAU, 2007 [5].

Figure 1: The risk management process and the position of hazard identification [5].

Risk Analysis

Define Scope Identify Hazards Estimate Risks

Qualitative Quantitative

Risk Evaluation

Define tolerability criteria

Water quality Water quantity

Analyse risk reduction options Ranking

Cost-efficiency Cost-benefit

Risk Reduction/ Control

Make decisions Treat risks Monitor

Get new

information

Update

Analyse sensitivity

Develop supporting programmes

Document and assure quality

Report and communicate

Review, approve and

audit



Another objective OF WA4 is to develop tools that the water utilities can apply when carrying out the risk assessment and risk management work. A conceptual structure model of the framework, which also includes the guides and tools that will be produced in WA 4, is presented in Figure 2. One of the first steps to be addressed in risk management is the identification and description of potential hazards, and therefore the TECHNEAU Hazard Database has been developed and presented in this report.

“Generic Framework for Integrated Risk Management in Water Safety Plans”

”Training

seminars

on RA

and RM”

”THDB”

TECHNEAU

Hazard

Database

”TRRDB”

TECHNEAU

Risk

Reduction

Option

Database

”WA 4

RA Case

Studies”

Good

examples!

TECHNEAU

Decision

support

tool

TECHNEAU Toolbox

”Guide on Integrated Risk Management”

”Guide on

Risk Evaluation”

TECHNEAU

Methods for

Integrated

Risk

Management

”Guide on Integrated

Risk Analysis”

”Guide on Integrated

Risk Analysis”

”Guide on Risk

Reduction/Control”

”Guide on Risk

Reduction/Control”

Two different approaches for hazard identification can be applied: a bottom-up approach and a top-down approach. The bottom-up approach has its origin in the recorded experience of the staff directly involved in operation and maintenance. In general, the information gathered is suitable for the assets of the water supply system. It has the disadvantage that focus can be given to well known incidents or that the subjective information can be used. The top-down approach is based on a description of a generic water supply process. As the supply process consists of a wide variety of potential elements, a generic list is extensive. The approach presented in this report is a top-down approach and can be used as a complement to the bottom-up approach.

Figure 2 Conceptual structure model of the TECHNEAU Generic framework, including guiding reports and toolbox with the applied risk management tools provided in WA 4



1.2 Objectives

The objective of this database is to help end-users working in water supply systems with the identification of relevant hazards by providing a catalogue with potential hazards of technical, environmental or human origin for the entire system. This report aims to guide end-users through the hazard identification process, providing a hazard database that could be used as a tool to identify hazards in a water supply system. In this report, the hazard database is also mentioned as THDB (TECHNEAU Hazard Data Base).

1.3 Methodology

One crucial aspect in setting-up a hazard identification database is the required level of detail. The database has to be generic for ease of use and at the same time be complete for providing sufficient information. The level of detail has been chosen so it can be regarded as a generic tool that can be applied in many different water supply systems. As the process of water supply is very complex, the database can never be a complete list but be used as a complement to the hazard identification process carried out by the local system experts. The authors opinion is that the most important aspects of the water supply process have been covered. Though, we realize that some parts are still missing, (e.g. the softening process) as this database mainly is intended to be used as a complement. The purpose of this document is a thorough review of the main existing hazards that may cause risks in the drinking water supply system. Existing national checklists and databases have been taken into consideration during the preparation of the hazard database [7] - [12]. Hazards derived from ‘possible futures’, described in WA 1, are also included into this report (Appendix 12). The description of the existing and future hazards will be used in the subsequent work packages in WA 4.

1.4 Today’s hazards

Traditionally, hazard identifications are performed for separate parts of the water supply system. Within the TECHNEAU project, the water supply system is regarded as a whole and the identification of hazards is done from the raw water source to the consumer’s tap. The consequences of hazards are related to all the stages of the water supply and the chain of cause and consequences is evaluated through the process. Applying this holistic view helps water companies in preventing sub-optimization of risk management when focusing on specific aspects of water supply. The hazards identified in this report are internal as well as external. Internal hazards are mostly related to failures or the absence of infrastructure. External hazards are for instance source water contamination, degradation of mains due to aggressive soils or terrorist actions.



The hazards identified in this report are general hazards of technical, geographical or human origin, having direct effect on the infrastructure for water supply. Other types of hazards, for example of political or economical origin are not assessed specifically in this report. To limit the scope, the database focuses on the primary process of water supply, while supporting activities like buildings, constructions, electrical installations are not addressed.

1.5 Future hazards

To manage risks effectively it is important to identify today’s hazards as well as future hazards. Based on a literature review, interviews, evaluation work carried out at Chalmers University of Technology, and contributions from WA 1 partners in the SEPTEDOR (Socio-cultural, Economical, Political, Technical, Ecological, Demographic, Organizatorial and Risk) analysis, major future trends have been identified. The implications of these trends for water supply have been studied and the following categories of hazards have been identified:

• Sabotage and terrorist attacks • Conflicts • New chemicals and changed chemical pathways • Emerging pathogens • Public concern • Climate changes • Aging distribution systems

The identified future hazards are presented in Appendix 12. For a more detailed description of the future hazards, see “Report on trends regarding future risks”, TECHNEAU, 2007 [4].



2 Structure of TECHNEAU Hazard Database

2.1 Introduction

For a proper identification of hazards the boundaries and structure of the system have to be defined. Within this project the water supply system is defined as all physical and organizational structures for the supply of drinking water, stretching out from the catchment area to the customer (from source to tap). Hazards related to the handling of water by consumers at home are covered as well, as these types of hazards can be of importance for the quality of the consumed drinking water, especially for consumers that do not have in-house service connections. As defined in Chapter 1, the hazards identified are related to the primary process of water supply.

2.2 Structure of the Hazard Database

The water supply system is subdivided into 12 sub-systems, of which 10 are physical sub-systems representing the installations, one is a non-physical sub-system representing organizational aspects, and one is representing future hazards. A flow-diagram presenting these sub-systems is given in Figure 3. All hazards identified in these 12 sub-systems are listed in the hazard database presented in Appendices 1 - 12. The breakdown, as given in this flow-diagram, is related to the ‘Generic system flow diagram’ as presented in the Water Safety Plans, which is described in the third edition of the Drinking Water Quality Guidelines of the WHO [2].



12. Future hazards12. Future hazards

Figure 3: Water supply system subdivided into 12 sub-systems.

(SW = surface water, GW = ground water, IW = Infiltration water)

The hazard database is presenting the identified hazards in a table at a sub-system level, as in Figure 2, but is also further sub-divided into component and element levels. At the component level the most important elements are given and at the element level the most relevant hazards are given in combination with a description of the cause of the hazard, the hazard type and the consequences. The format of the hazard database is derived from the Water Safety Plan approach [2]. The different components are presented in Table 1. A preview of the TECHNEAU hazard database is given in Figure 4. In the Guidelines for Drinking-water Quality [ 6] and Water Safety Plans [2] the following definitions are used: • A hazard is a biological, chemical, physical or radiological agent that has

the potential to cause harm. • A hazardous event is an incident or situation that can lead to the

presence of a hazard (what can happen and how). Within TECHNEAU a more broad definition of a hazard is given, as the project focuses on both water quality and water quantity. The hazard database makes use of the definitions given in Table 2.



Sub-system Components 1. Surface water catchment 1.1. Catchment area

1.2. Monitoring system 2. Groundwater catchment

(including protection zones) 2.1. Catchment area 2.2. Monitoring system

3. Surface water intake and transport

3.1. Surface water intake 3.2. Surface water transport 3.3. Monitoring system

4. Surface water infiltration 4.1. Infiltration borehole(s) or pounds and surroundings

4.2. Catchment area 4.3. Monitoring system

5. Groundwater and infiltration, water abstraction and transport

5.1. Water abstraction facility 5.2. Ground water transport 5.3. Monitoring system

6. Treatment 6.1. Treatment, generic hazards 6.2. Chemicals used for treatment and

disinfection 6.3. Solids removal / screens 6.4. Coagulation / flocculation 6.5. Rapid sand filtration 6.6. Disinfection

A. Chlorination B. UV disinfection C. Ozone disinfection

6.7. Membrane filtration 6.8. Slow sand filtration 6.9. Activated carbon filtration

7. Reservoirs and pumps (either directly after treatment or in the distribution system)

7.1. Clear water reservoir 7.2. Pumping station 7.3. Valves (both in reservoirs as in pumping

stations) 8. Transport and distribution

(from trunk main to the water meter)

8.1. Network 8.2. Water meter and non return valves

9. Internal piping 9.1. Drinking water installation 10. Consumer and taps

(including communal taps) 10.1. Water collection 10.2. Water storage and transportation

11. Organization 11.1. Organization 12. Future hazards (related to the

entire drinking water system) 12.1. Source water 12.2. Treatment 12.3. Distribution 12.4. Consumers

Table 1: Subdivision of sub-systems into components.



Figure 4: Preview of the TECHNEAU hazard database.

Sub-system

Sub-system

Element

Component



Element: Lowest level of the system at which hazards are described.

Hazard: A source of potential harm or a situation with a potential of harm (e.g. a biological, chemical, physical or radiological agent or circumstances that has the potential to have a negative effect on the supply of safe and sufficient water).

Reference: Reference number of the hazard. Hazardous event: An event which can cause harm (e.g. an incident or

situation that can lead to the presence of a hazard, what can happen and how).

Type of hazardous event: Indication of the origin of the hazardous event. D: design-related O: operation-related E: external-related OS: consequence of a hazard in other sub-

system OS ref: reference of other sub-system

Type of hazard: Indication of the type of hazard. Biolog.: biological Chemic.: chemical Rad./ phys.: radiological or physical

(including turbidity) Unavail.: insufficient availability of

water supplied to customers Safety: safety to personnel External damage: external damage to third

parties, including liability Consequence description: Description of potential consequences of the hazard

to other sub-systems at firstly and the consumer secondly.

Consequence to sub-system: Reference of the sub-system affected by the hazard. Rel. hazard Column to be used by the end-user for marking the

identified hazards.

2.3 Review of TECHNEAU Hazard Database

The identification of possible hazards has been carried out by reviewing literature, interviewing experts, from previous experiences from the WA 4 partners and from the case study work in WA 4. For an overview of the used literature, see Chapter 4. The sub-systems have been set up by the TECHNEAU partners, for the contribution of each partner see Table 3.

Table 2: Definitions applied in the hazard database.



Sub-system TECHNEAU partner

1. SW catchment Chalmers University of Technology

2. GW catchment TZW, SZU and Chalmers University of Technology

3. SW intake and transport Chalmers University of Technology

4. SW Infiltration TZW and SZU

5. GW/IW abstraction and transport TZW and SZU

6. Treatment SINTEF, RWTH and Chalmers University of Technology

7. Reservoirs and pumps Kiwa Water Research

8. Transport and distribution Kiwa Water Research

9. Internal piping Kiwa Water Research

10. Consumer and taps WRC SA /SWUE

11. Organization SINTEF

12. Future hazards Chalmers University of Technology

In February 2007 the preliminary report version of this report has been made, see “Identification and description of hazards for water supply systems” [1]. This report has been updated with the information from six case studies carried out by the TECHNEAU partners in WA 4 and committed end-users. Through these case studies the database have been tested and improved (to this updated version). The contribution from each WA 4 partner for updating the database is given in Table 4. Testing of the database has also been done by the Riga Water Company.

Table 3: Contribution of the TECHNEAU partners



Responsible Case study town Parts checked

Chalmers Göteborg – Sweden Total THDB SZU Březnice – Czech

Republic Total THDB

TZW Freiburg-Ebnet – Germany

Total THDB

End-user Riga – Latvia Total THDB (except treatment)

SINTEF/ RWTH Bergen – Norway Subsystem 6 Kiwa Amsterdam – The

Netherlands Total THDB

Table 4: Updates and improvements by case-studies





3 Proposed methodology for hazard identification

This methodology gives a guide to end-users on the process to identify relevant hazards in the system for water supply. Several experiences on hazard identification by using the THDB have been gathered from testing in different water supply systems. The lessons learned are collected in order to facilitate the hazard identification process for the end-users. In Appendix 13 a detailed description of the hazard identification process is presented. To help also inexperienced users to get started with risk identification, the information in this appendix is relatively detailed. The hazard identification process can be carried out by following the steps in Appendix 13, which are summarized in Figure 5. Apart from using the hazard database, following the proposed method in this document, it can also be regarded as a straightforward check-list.



3. ASSEMBLE A TEAM

4. INTERVIEWS WITH EXPERTS

5. CONTACT WITH PARTICIPANTS AND ORGANIZATION OF MEETINGS

6. PREPARATION OF MEETINGS

7. SESSIONS 7a. Introduction 7b. THDB 7c. Definition of results.

8. REPORTING AND FEED-BACK

1. OBJECTIVES

2. SPLIT UP THE SYSTEM AND SYSTEM DESCRIPTION

Figure 5: Guidelines for the hazard identification process.



4 References

[1] Beuken, R., et. al. (2007) Identification and description of hazards for water supply systems, TECHNEAU (D4.1.1/2).

[2] Davison A, G. Howard, M. Stevens, P. Callan, L. Fewtrell, D. Deere, and J. Bartram (2005) Water Safety Plans, Managing drinking-water quality from catchment to consumer. World Health Organization, WHO/SDE/WSH/05.06.

[3] IEC (1996) IEC60300-3-9, Risk Management - Part 3: guide to risk analysis of technological systems, International Electrotechnical Commission.

[4] Rosèn, L., and A. Lindhe (2007) Trend report – Report on trends regarding future risks, TECHNEAU.

[5] Rosén, L., P. Hokstad, A. Lindhe, S. Sklet, and J. Røstum (2007) Generic Framework and Methods for Integrated Risk Management in Water Safety Plans, TECHNEAU.

[ 6] WHO (2006), Guidelines for drinking-water quality, First addendum to third edition. World Health Organization, Geneva.

Literature used as a reference for the TECHNEAU Hazard Database:

[7] DVGW (2006) Richtlinien für Trinkwasserschutzgebiete; I. Teil: Schutzgebiete für Grundwasser. Technische Regel, Arbeitsblatt W 101, June 2006.

[8] Glucina, K., A. Alvarez, and J.M. Laîné (2000) Assessment of an integrated membrane system for surface water treatment, Desalination 132, 73-82.

[9] Lipp, P. and G. Baldauf (2002) Application of out-in MF/UF-systems for drinking water treatment with air supported backwash – three case studies, Desalination 147, 63-68.

[10] Lozier, J., M. Kitis, C. Colvin, J.H. Kim, B. Mi, and B. Marinas (2004) Microbial removal and integrity monitoring of high-pressure membranes, Awwa Research Foundation.

[11] Nadebaum, P., M. Chapman, R. Morden, and S. Rizak (2004) A Guide To Hazard Identification & Risk Assessment For Drinking Water Supplies, Cooperative Research Centre for Water Quality and Treatment, Research Report Number 11.



[12] Public Health Risk Management Plan Guides, Ministry of Health, New Zealand, available on the Ministry of Health’s Web site: www.moh.govt.nz.

[13] Sturm, S. (2005) Schutz von Wassergewinnungsgebieten - Das neue DVGW-Arbeitsblatt W 101. Veröffentlichungen aus dem Technologiezentrum Wasser, 28 (ISSN: 1434-5765), 75–92, Karlsruhe.

[14] Technische Regeln der Deutschen Vereinigung des Gas- und Wasserfaches e.V.: W 213-3, W 213-1, W 213-4, 213-5, W 217, W 218, W 219, W 220, W 223-1, W 225, W 290, W 294, W 1000.

[15] Vrouwenvelder, J.S., J.W.N.M. Kappelhof, S.G.J. Heijmann, J.C. Schippers, and D. van der Kooij (2003) Tools for fouling diagnosis of NF and RO membranes and assessment of the fouling potential of feed water, Desalination 157, 361-365.



Appendix 1 to 12: TECHNEAU Hazard Database

In the following appendices the hazard database for the sub-systems are presented. 1 Surface water catchment

2 Groundwater catchment

3 Surface water intake and transport

4 Surface water infiltration

5 Groundwater and infiltration water abstraction and transport

6 Treatment

7 Reservoirs and pumps

8 Transport and distribution

9 Internal piping

10 Consumer and taps

11 Organization

12 Future hazards



1. Surface water catchment

Type of hazardous event Type of hazard Potential consequences Element Hazard Ref. Hazardous event

D O E OS

Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage

Description To sub system

Rel. hazard

1.1 Catchment area

Catchment zone

Contamination of catchment zone

1.1.1 Industrial discharge of chemicals

X

X Contaminated water (chemicals)

3 and 4

Catchment zone


1.1.2 Industrial discharge of biological matter

X X Contaminated water (pathogens)

3 and 4

Catchment zone


1.1.3 Emissions during accidents (fire or explosions) e.g. industrial accidents or forest fire

X X Contaminated water (chemicals)

3 and 4

Catchment zone


1.1.4 Traffic accidents with ships, trains, vehicles and planes

X X X X X X Contaminated water (chemicals)

3 and 4

Catchment zone


1.1.5 Toxic chemicals from air deposits or air pollution

X X X X Contaminated water (chemicals)

3 and 4

Catchment zone

Contamination of catchment zone (directly through the water, or indirectly through the air)

1.1.6 Nuclear power accident X X X X Contaminated water (radionucleids)

3 and 4

Catchment zone


1.1.7 Emissions and leakage, oil spills (MTBE) by shipping or traffic

X X X Contaminated water (chemicals, pathogens)

3 and 4

Catchment zone


1.1.8 Harbour activities X X X X Contaminated water (chemicals, pathogens)

3 and 4

Catchment zone


1.1.9 Latrines deposits from boats, etc.

X X X Contaminated water (chemicals, pathogens). Nutrient load in water.

3 and 4

Catchment zone


1.1.10 Intensive fishery, fish farming, massive fish death


3 and 4




D O E OS

Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Catchment zone


1.1.11 Disrupted inflow such as failure of dams and extreme runoff

X X X Contaminated water (chemicals). Insufficient raw water.

3 and 4

Catchment zone


1.1.12 Sewer overflows due to rainfalls or failures

X X X Contaminated water (pathogens, chemicals). Insufficient raw water

3 and 4

Catchment zone


1.1.13 Erosion of sediments by dredging or shipping

X X X Contaminated water (sediment, chemicals, pathogens)

3 and 4

Catchment zone


1.1.14 Erosion into catchment with release of soil, sand or contaminants

X X X Contaminated water (chemicals)

3 and 4

Catchment zone


1.1.15 Earthquake, landslides X X X X Contaminated water (pathogens, chemicals). Insufficient raw water.

3 and 4

Catchment zone

Contamination by leakage of sea water into the fresh water

1.1.16 Salt intrusions from the sea X X X Contaminated water (salinity in elevated levels)

3 and 4

Catchment zone

Shortage of water 1.1.17 Drought, blockage of water upstream or abstraction

X X Insufficient raw water

3 and 4

Catchment zone

Raw water temperature above 25° C

1.1.18 Climate or cooling water from power plants

X X Warm raw water to the treatment.

3 and 4

Catchment zone


1.1.19 Disposal of manure X X X Contaminated water (pathogens, nutrient load, pharmaceuticals)

3 and 4

Catchment zone


1.1.20 Runoff from agriculture and urban green areas containing fertilizers, sludge, herbicides, etc

X X X Contaminated water (pathogens, chemicals, nutrient load)

3 and 4




D O E OS

Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Catchment zone


1.1.21 Continuous leakage from landfills, contaminated soils or waste dumps


3 and 4

Catchment zone


1.1.22 Discharges of treated wastewater

X X X X Contaminated water (pathogens, chemicals, nutrient load)

3 and 4

Catchment zone


1.1.23 Contaminated storm water X X X Contaminated water (pathogens, chemicals, nutrient load)

3 and 4

Catchment zone


1.1.24 Deliberate contamination by sabotage or terrorist action

X X X X X X Contaminated water (pathogens, chemicals, radionucleids). Insufficient raw water.

3 and 4

Impoundment reservoir

Contamination of reservoir

1.1.25 Birds droppings or animals allowed to cross a protection zone


3 and 4

Impoundment reservoir

Contamination of reservoir

1.1.26 Algae blooms (mostly during summer month's)

X X X Contaminated water (algae, chemicals, nutrient load)

3 and 4

1.2 Monitoring system

Monitoring system

Failure of monitoring system

1.2.1 Accident, defect, power failure, operational failure, sabotage, damaged monitoring devices

X X X X X X X Contaminated water. Insufficient raw water.

3 and 4



2. Groundwater catchment


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

2.1 Catchment area

Catchment area

Contamination of aquifers

2.1.1 Contamination by industrial operations (including continuous discharge as well as installations, construction work and other)

X X X X Contaminated water (pathogens, chemicals, radionucleids)

5

Catchment area


2.1.2 Contamination by waste water (e.g. by WWTP, sewers, latrines, sewage collection pipes passed through catchment area, etc.)

X X X Contaminated water (pathogens, chemicals). Nutrient loan in water.

5

Catchment area


2.1.3 Leaching of contaminants by built constructions (e.g. landfills using waste or contaminated ground, dumpsites, traffic facilities, installations for handling, storage and deposition of waste materials or excavation residues, etc.)


5

Catchment area


2.1.4 Traffic, incl. accidents (railway tracks, airfields, roads, parking areas, petrol filling stations, air accidents) loss of oil by cars or boats


5

Catchment area


2.1.5 Construction activities with interference in subsoil (e.g. waterway construction, installations for handling or storage of hazardous substances, facilities for construction workers; etc.) (incl. accidents)

X X X Contaminated water (chemicals). Insufficient raw water.

5




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Catchment area


2.1.6 Increase of vulnerability due to mining activities, gravel pits, excavations uncovering the GW, construction of facilities for geothermal power purposes and /or small water supply systems

X X X X Contaminated water (chemicals, radionucleids)

5

Catchment area


2.1.7 Agricultural runoff and leach-out containing fertilizers, sludge, herbicides, etc.

X X X Contaminated water (pathogens, chemicals). Nutrient load in water.

5

Catchment area


2.1.8 Manure spread or cattle in the zone

X X X Contaminated water (pathogens). Nutrient load in water.

5

Catchment area


2.1.9 Geophysical incidents (e.g. extreme hydraulic events such as torrential rain, floods, erosion, landslides, karstic land surface with open dolines; etc.)

X X X X Contaminated water (pathogens, chemicals)

5

Catchment area


2.1.10 Accidents or spreading out of hazardous materials during recreational activities (e.g. mass rallies, fish ponds, shooting galleries, sports facilities incl. motor sports, horse-race grounds, zoo / animal reserves, camps, campsites; etc.), or military field exercises and training areas.

X X X Contaminated water (pathogens, chemicals)

5

Catchment area


2.1.11 Contamination by forestry activities, wild life activities, natural fowls, dead animals, bird pest (flu)…

X X X Contaminated water (pathogens, chemicals)

5




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Catchment area

Infiltration of GW by alien water (e.g.: salt water intrusion, leaching of contaminated surface water... )

2.1.12 Wetlands & flood plains not hydraulically separated from the aquifer

X X X X Contaminated water (pathogens, chemicals). Nutrient load in water.

5

Catchment area

Shortage of ground water resources

2.1.13 Ground water aquifer is not sufficiently fed or water is abstracted by others

X X Unavailability of raw water

5

Catchment area

Reduced biological activity in the treatment

2.1.14 Water temperature under 4³C

X X X X Reduced biological activity in the treatment

6

Catchment area


2.1.15 Radioactivity fall-out X X Contaminated water

5

Catchment area


2.1.16 Terrorist and vandalism actions

X X X X X Contaminated water (pathogens, chemicals, radionucleids). Insufficient raw water.

5


Monitoring system


2.2.1 Accident, defect, power failure, operational failure, sabotage, damaged groundwater observation wells

X X X X X X Contaminated water. Insufficient raw water

5



3. Surface water intake and transport


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage

Description To sub-system

Rel. hazard

3.1 Surface water intake

Intake construction

Shortage / unavailability of water

3.1.1 Physical obstacles for the intake of raw water, ice formation

X X X X 1 X Insufficient raw water

4 and 6

Intake construction


3.1.2 Failure of the raw water intake

X X X X Insufficient raw water

4 and 6

Intake construction

Pipe burst 3.1.3 Bad condition or external causes (e.g. landslides, heavy traffic)

X X X X X X Insufficient raw water

4 and 6

Intake basin Contamination and / or unavailability of water

3.1.4 Water shortage or contamination leading to (partly) closing of intake, insufficient alternative raw water source

X 1 X X X Contaminated water. Insufficient raw water.

4 and 6

Pumping systems


3.1.5 Failure in the pumping system

X X Insufficient raw water

4 and 6

3.2 Surface water transport

Pumps Power failure 3.2.1 Power interruption and no backup power supply

X X X X Unavailability of raw water

4 and 6

Raw water mains

Pipe burst 3.2.2 Failure in mains or transport tunnels

X X X X X X Insufficient raw water

4 and 6


Monitoring system


3.3.1 Accident, defect, power failure, operational failure, sabotage, damaged monitoring devices

X X X X X X Contaminated water. Insufficient raw water.

4 and 6



4. Surface water infiltration


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

4.1. Infiltration borehole(s) or pounds and surroundings

Water source area

Direct contamination of infiltration boreholes and surrounding ground (bank) by man made activities (landfills, industrial waste outlets etc.) or accidents (e.g. traffic accidents)

4.1.1 Leaching out of contaminants from accidents with trains, vehicles and planes, from landfills or wastewater discharge


2

Water source area

Contamination of groundwater system by polluted surface water infiltration

4.1.2 Intensive agricultural activities (farming, application of fertilizers and pesticides, wood preservatives etc.)

X X X Contaminated water (pathogens, heavy metals, badly degradable organic compounds, nitrogen, phosphorous)

2

Water source area

Direct contamination of water source area

4.1.3 Sabotage acts, terrorism or vandalism.


2

Water source area

Direct contamination of infiltration boreholes and surroundings (bank)

4.1.4 Discharges from wastewaters, landfills, runoff, accidents or natural disasters (e.g. earthquake, flooding, landslide, fire…).

X X X Contaminated water (pathogens, chemicals, salts). Mechanical damage of abstraction sites.

2

Catchment area

Direct contamination of water source area

4.1.5 Bloom of toxic blue algae X X X Contaminated water (chemicals)

2




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

4.2. Catchment area

Catchment area

Shortage of infiltrated water to the soil/aquifer of abstraction area

4.2.1 Human activity by building different structures alongside the river bank, poor land use management, irrigation in agriculture, poor soil conservation etc., preventing passage of water from surface water, clogging of the infiltration ponds/riverbank

X X Water shortage in the soil and then poor discharge (water quantity)

2

Catchment area

Contamination of ground water system (infiltration) because of polluted source surface water

4.2.2 see Section: 1. Surface water, catchment area, i.e. 1.1 up to 1.4. (Industrial discharges, accidents…)

X

X X Contaminated water (pathogens, chemicals)

2

Catchment area

Conflicts 4.2.3 Conflicting interests between ecological aspects and drinking water aspects

X X Political actions leading to water shortage

2

Catchment area

Contamination of ground water system

4.2.4 Settling of pollutants from air X X X X Contaminated water (pathogens, chemicals)

2

Catchment area

Flood water entering the ground water system

4.2.5 Flooding X X X Contaminated water (pathogens, chemicals)

2


Monitoring system


4.3.1 Accident, defect, power failure, management failure, human mistake, sabotage, damaged groundwater observation wells

X X X X X X Contaminated water (pathogens, chemicals). Environmental pollution.

2



5. Groundwater and infiltration, water abstraction and transport


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

5.1 Water abstraction facility

Generic situation

Ingress of shallow water

5.1.1 Trees, roots, cracks in concrete (e.g. in chamber walls) or collection gallery.

X X X X X

Contaminated water (pathogens, chemicals). Damages to infrastructure.

6

Generic situation

Contamination of ground water

5.1.2 Infiltration of run-off water X X X X X

Contaminated water (pathogens, chemicals)

6

Openings in system

Contamination through openings ( e.g. well-head, ventilation pipe, grit chamber, stilling basin, overflow pipe, doors...)

5.1.3 Contamination by flooding, sabotage, animals, etc.

X X X X X X X


6

Asset protection (fences, closure)

Security failure, causing contamination

5.1.4 Improper locking of the system, sabotage, etc.

X X X X X X X X


6

Bentonite layers

Soil setting and hydraulic bypass

5.1.5 Improper or missing bentonite layers.

X X X X


6

Well chamber

Soil setting, flooding, chamber buoyancy, corrosive soil materials

5.1.6 Improper maintenance concept, flood alarm and sump pump lacking

X X X X X


6

Well chamber

Clogging of wells and pumps

5.1.7 Chemical composition of the aquifer water

X X

Unsuitable composition of raw water.

6




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Infiltration dams

Contamination of ground water

5.1.8 Failures in operation of infiltration dams

X X X

Contaminated water (chemicals, pathogens)

6

5.2 Groundwater transport

Pumps Power failure 5.2.1 Power interruption and no backup power supply

X X X X Insufficient raw water.

6

Raw water mains

Pipe burst 5.2.2 Bad condition of mains or external causes (e.g. landslides, heavy traffic)

X X X X X X Insufficient raw water.

6


Monitoring system


5.3.1 Accident, power failure, operational failure, sabotage, damaged monitoring devices

X X X X X X Contaminated water. Insufficient raw water.

6



6. Treatment


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

6.1 Treatment, generic hazards

General Damage/destruction of treatment modules

6.1.1 Natural disasters (e.g. earthquakes, storms); fires; poor construction conditions of the buildings; etc.

X X X X X X X Contaminated water. No/insufficient water supply. Damages to infrastructure.

7

General Nuclear contamination (directly through the water, or indirectly through the air)

6.1.2 Nuclear accident X X X Contaminated water. Damages to infrastructure.

7

Raw water Insufficient quantity of raw water

6.1.3 Hazards in raw water abstraction or transport

X 02 X X X X Contaminated water. No/insufficient water supply.

7

Raw water Insufficient quality of raw water

6.1.4 Hazards in raw water abstraction or transport

X 02 X X X X Contaminated water. No/insufficient water supply.

7

Raw water Wrong sampling of the water

6.1.5 Contamination at sampling points (especially with negative pressures); sampling points no easily accessible.

X X X X X Reduced knowledge about real water quality

7

Design Inadequate design of the treatment process in relation to raw water quality (at all or due to peak pollution events) and to local conditions.

6.1.6 E.g. ineffective removal of contaminants and control of DBP (Disinfected By-Products), lack of specific knowledge due to outsourcing, etc..

X X X 01 X X X X X Contaminated water. No/insufficient water supply.

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Operation Non-optimal operation or maintenance of treatment process

6.1.7 E.g. not adequate coagulants or oxidants are used, improper pH value is maintained, no proper dose of coagulant or oxidants is used, lack of specific knowledge due to outsourcing, etc.

X X X X X X Contaminated water. No/insufficient water supply.

7

Flow control

Non-optimal flow

6.1.8 Flow meter is not calibrated X X X X X Contaminated water. No/insufficient water supply.

7

Use of materials

Contamination or wear due to the use of materials not suitable for contact with drinking water

6.1.9 E.g. coatings, ion-exchange resins, iron not protected against corrosion, etc.


7

Installations in basement

Submerging of pumps, etc and/or interruption of process

6.1.10 Main leak of pipe, burst of wall

X X X X X X X X Contaminated water. Damage to infrastructures. Safety and environmental impacts.

7

Electrical power

Power interruptions

6.1.11 No or unstable electrical power; no or failing back-up; automatic operation control switched off during storms and lightning; etc.

X X X X X X X X Contaminated water. No/insufficient water supply.

7

Maintenance of assets

Failure of the maintenance

6.1.12 Inappropriate maintenance scheme

X X X X X X X Contaminated water. No/insufficient water supply.

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

6.2 Chemicals used for treatment or disinfection

Quality of chemicals

Bad quality of chemicals

6.2.1 Problems at manufacturing and/or transport of chemicals; used of expired chemicals.

X X X X X X Insufficient treatment. Contaminated water (chemicals…). Blocking filters. Etc.

7

Dosing of chemicals

Improper dosing of chemicals

6.2.2 (a) failure of dosing unit incl. power supply; (b) no sufficient supply available; (c) personal (operational) failure; (d) incorrect measurement

X X X X X X Insufficient treatment. Contaminated water (chemicals). Blocking filters. Rapid corrosion of metals.

7

Use of chemicals

Staff getting into undesired contact with chemicals

6.2.3 Inadequate storage of chemicals

X X Health impact to the staff

No

6.3 Solids removal / screens

Screens Blockages in screening sleeves

6.3.1 Incorrect screen size or inadequate cleaning

X X X Contaminated water. No/insufficient water supply.

7

Screens Blockages in screening sleeves

6.3.2 Floods, algal bloom or vandalism

X X Contaminated water. No/insufficient water supply.

7

6.4 Coagulation / flocculation

Raking system

Excessive build-up of solids increase carryover and effect filter performance

6.4.1 Clarifier rake systems (scrapers) are not regularly maintained

X X X X Contaminated water (chemicals, pathogens, turbidity)

6.5 to 6.9 and

7

Dosing High coagulant residual or reduced capacity

6.4.2 Too low or too high coagulant dose

X X X X Contaminated water (chemicals, pathogens, turbidity..)

6.5 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Mixing flocculation, pH-control

Insufficient flocculation

6.4.3 Improper coagulant mixing and/or flocculation; inappropriate flocculant or flocculation agent; improper pH control.

X X

X X X Contaminants (e.g. flocculants) in the water after sedimentation or filtration

6.5 to 6.9 and

7

Coagulation / flocculation agents

Monomers in the water

6.4.4 Using polymers as flocculants containing non-flocculating-monomers

X X X Contaminated water (monomers)

6.5 to 6.9 and

7

Sedimentation basin

Inappropriate conditions during dispersion of flocculants or flocculation agents in the sedimentation basin.

6.4.5 Inappropriate pH, temperature and/or dispersing time of the dosing solution of flocculation agents, disturbing ingredients in the water the chemicals are dispersed with; precipitation due to stagnant regions in the water tank for flocculation agents build-up; etc.

X X X X X Contaminated water (chemicals, pathogens, turbidity)

6.5 to 6.9 and

7

Sedimentation basin

Adverse conditions after adding the water-flocculant/ flocculant agent mixture to the water

6.4.6 Insufficient turbulence for the initiation of aggregation; insufficient mixing of dosing mixture and water; influence of Ca, Mg, PO4, SO4, pH, acid capacity, dissolved organic matter; earth alkali (if polyacrylamid as flocculation agent); too short time between dosage of flocculant and flocculation agent; ozone in the water; existence of complex-binding organic substances or acid raw water when using aluminium as flocculation agent; etc.

X X X X X X Contaminated water (chemicals, pathogens, turbidity)

6.5 to 6.9 and

7


Incorrect dosing of the flocculants or flocculant agents

6.4.7 Failure of the dosing pump; power failure in an automatized controlled system

X X X X X Contaminated water

6.5 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Coagulation / flocculation process

Failure of the automatized, programmable control system

6.4.8 Power failure, programmable errors

X X X X X X X X Contaminated water (chemicals, pathogens,...)

6.5 to 6.9 and

7


Biological contamination during the flocculation

6.4.9 Microbiological activity when using flocculation agent contaminated by yeast

X X X X Contaminated water (pathogens)

6.5 to 6.9 and

7

Settling tank

Inadequate floc settling

6.4.10 Wind and/or low temperatures

X X X X Contaminated water (chemicals, pathogens)

6.5 to 6.9 and

7

Settling tank

Improper design of setting tank

6.4.11 Retention time too short; mechanical failure of the stirrer; up flow velocity too high; weir overflow rate too high; insufficient sludge draw-off; retention time too short; reaction zone and/or clarification zone not sized correctly; wrong media specifications; poor bubble formation; etc.


6.5 to 6.9 and

7

Flotation/settling tank

Improper operation or inadequate desludging programme

6.4.12 Air release nozzles not kept clean or blockages not cleared; floc carry-over takes place


6.5 to 6.9 and

7

Monitoring system

Failure of the monitoring of: physical (e.g. turbidity, flow, pH, Al/Fe-load), biological parameters (e.g. E. coli), pressure, chemical parameters

6.4.13 Insufficient sampling frequency at control point; inappropriate monitoring program; malfunction of measuring instruments due to construction, operation system or maintenance

X X X X X Delayed or no detection of contaminants in the water

6.5 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

6.5 Rapid sand filtration

Filter bed Filter damage 6.5.1 Deterioration; erratic hydraulic stress; filter blockage; air underneath the filter bed; reduced cleaning performance; pressure in closed filter layers related to hydro mechanical security devises or pressure-transducers; changing of the filter layers; intermixing of several layers in filters which are simultaneously cleaned with air and water; etc.

X X X X X X X Contaminated water (chemicals, pathogens, turbidity). Damage in the filter.

6.6 to 6.9 and

7

Filter bed Reduced filtration performance

6.5.2 Inappropriate filtration speed, filter material, running time, layer thickness; insufficient elimination of flocs and/or flocculants; high hydraulic load or variations in flow through the filters during the filter cycle; high particle load in incoming water; wrong choice or inadequate depth of the media; wrong media specifications; etc.

X X X X 8,1 or 2

X X X X Contaminated water (chemicals, pathogens, turbidity).

6.6 to 6.9 and

7

Filter bed Filter blockage 6.5.3 Undesired particles in the raw water; cleaning intervals too low or failure in the cleaning procedure; during installation insufficient flushing after the start up operation of the filter; insufficient pre-treatment; shift in the particle-size distribution; etc.

X X X X X X X Contaminated water (chemicals, pathogens, turbidity). No/insufficient water supply. Damage in the filter bed.

6.6 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Filter bed Filter blockage 6.5.4 Undesired particles in the filter due to failure of micro sieves or inadequate design

X X X X X X Contaminated water (chemicals, pathogens, turbidity). No/insufficient water supply.

6.6 to 6.9 and

7

Filter bed Filter damage 6.5.5 Cleaning air contaminated with e.g. flies, pollen

X X X X Contaminated water (chemicals, pathogens, turbidity). Damage in the filter.

6.6 to 6.9 and

7

Filter bed Shorter filter run-time

6.5.6 Changes in quality due to high turbidity in raw water or high dosage of Fe

X X X Inefficient operation and more breakthrough

6.6 to 6.9 and

7

Pump and flue damper

Incorrect flow 6.5.7 Failure of the flue damper or the dosing pump


6.6 to 6.9 and

7

Cleaning system

Contamination of the filter

6.5.8 Backpressure of the cleaning water; erratic distribution of the cleaning media due to changes in the support layer or other destruction in the filter layers; contaminants of the manufacturing process in the filter; etc.


6.6 to 6.9 and

7

Cleaning system

Contamination of the water downstream of the filter

6.5.9 Cleaning media contaminated; not discarding of the first filtrated water after the cleaning; microbiological activity due to insufficient cleaning; chemical contamination downstream of the filter.

X X X X X Contaminated water (chemicals, pathogens, turbidity).

6.6 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Cleaning system

Disruption of the filtration

6.5.10 Disruption during cleaning process or maintenance or repair in combination with only one existing filtration-line

X X X No/insufficient water supply.

6.6 to 6.9 and

7

Cleaning system

Improper or infrequent backwashing or improper washing equipment

6.5.11 Poor construction or operation of backwashing concept; poor performance of air scourers; blocked nozzles; uneven distribution of water and air.

X X X X Contaminated water (pathogens, algal formations)

6.6 to 6.9 and

7

Cleaning system

Improper filter media

6.5.12 Sand not replaced when required


6.6 to 6.9 and

7

Cleaning system

Lower removal efficiency during the early stage of rapid filter operation (filter ripening)

6.5.13 Poor filter performance after washing.

X X X Contaminated water (pathogens).

6.6 to 6.9 and

7

Cleaning system

Refeeding cleaning water

6.5.14 Wrong management of the feeding water

X X X Contaminated water (pathogens).

6.6 to 6.9 and

7

Cleaning system

Contaminants in waste water

6.5.15 Inappropriate cleaning water treatment

X X X X X Environmental pollution, bad image

12

Cleaning system



X X X X X X X X Several possibilities depends on the kinds of failures

6.6 to 6.9 and

7

Monitoring Little local knowledge on operation and the condition of the installation

6.5.17 Monitoring on distance X X X X X Inefficient operation

6.6 to 6.9 and

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Monitoring Failure of monitoring

6.5.18 Absent or insufficient monitoring of the pressure difference and operational pressure; inappropriate monitoring and sampling concepts; malfunctioning measuring instrument; no manholes existing; etc.

X X X X X X X Delayed or no detection of contaminants in the filtered water, inappropriate operation

6.6 to 6.9 and

7

6.6 Disinfection

6.6.A Chlorination

Gas chlorination

Chlorine gas leakages

6.6.1 Chlorination facilities do not comply with safety regulations

X X X X Delayed or no detection of contaminants in the filtered water, inappropriate operation.

7

Gas chlorination

Unavailability of chlorine gas

6.6.2 Levels of gas bottles not checked; new bottles not ordered timeously; etc.


7

Dosing system

Malfunctioning dosing systems

6.6.3 Errors in chlorine solution concentration; blockages.

X X X Contaminated water (pathogens)

7

6.6.B UV disinfection

General Particles in the water during the disinfection process

6.6.4 Inappropriate pre-treatment X X X X X Contaminated water (pathogens)

7

General Pathogens are protected against the disinfection

6.6.5 Pathogens in aggregates with mucus


7

General Too short reaction time of disinfection agents in the water

6.6.6 Incorrect dosing location X X X Contaminated water (pathogens)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

UV lamps Too low UV dose 6.6.7 Decrease of lamp performance due to ageing or colour sediments on quartz tube. Electrical disruptions


7

UV lamps Improper installation

6.6.8 Incorrect specifications of lamps


7

Control system



X X X X X X X X Several possibilities depends on the kinds of failures

7

Power supply

Power fluctuations

6.6.10 No back-up power supply X X X X X Contaminated water (pathogens)

7

6.6.C Ozone disinfection

General Particles in the water during the disinfection process.

6.6.11 Inappropriate pre-treatment. X X X X X Contaminated water (pathogens)

7

General Formation of DBP (Disinfectant By Products)

6.6.12 Bromide content in the raw water

X X X 1,2 X Contaminated water (chemicals)

7

General Excessive ozone concentration

6.6.13 Insufficient contact time; insufficient reaction; too high dosage; etc.

X X X X Ozone release causing poisoning

No

Ozone contactor

Insufficient disinfection due to inadequate design

6.6.14 Insufficient contact time X X Contaminated water (pathogens)

7

Air compressor

No or inadequate air compression

6.6.15 Failing air compressor X X X Contaminated water (pathogens)

7

Oxygen supply

No or inadequate oxygen

6.6.16 Failing oxygen supply X X X Contaminated water (pathogens)

7

Ozone generator

No or inadequate ozone generation

6.6.17 Failing ozone generator X X X Contaminated water (pathogens)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Ozone generator

No or inadequate cooling system in the ozone generator

6.6.18 Failure in ozone generator cooling system

X X X X Contaminated water (pathogens). Damage in ozone generator.

7

Ozone gas meter

Ozone dose too low

6.6.19 Failure or wrong calibration of the gas meter.

X X X Contaminated water (pathogens). Damage in ozone generator.

7

Dissolved ozone meter

Ozone dose too low

6.6.20 Failure or wrong calibration of the dissolved ozone meter.

X X X Contaminated water (pathogens). Damage in ozone generator.

7

Ozone transfer lines

Leakage of ozone gas

6.6.21 Damage in ozone infrastructure

X X X X X X Contaminated water. Ozone pollution in environment and staff.

7

Side stream pump

Inadequate ozone dosing

6.6.22 Pump failure X X X X Contaminated water (pathogens)

7

Bubble diffuser

Decrease or irregular ozone transfer efficiency

6.6.23 Diffuser clogging or gasket leakage


7

Ozone contactor

Insufficient disinfection

6.6.24 Unusually high content of organic matter in raw water

X X 1,2 X Contaminated water (pathogens)

7

Ozone contactor


6.6.25 Water usage exceeding design flow

X X 5 X Contaminated water (pathogens)

7

Ozone contactor


6.6.26 Bromide content in the raw water

X 1,2 X X Contaminated water (bromate, pathogens)

7

Pumping system

Disruption of water to the disinfection

6.6.27 Pumps failure X X No/insufficient water supply

7

Power supply

Power fluctuations

6.6.28 No back-up power supply X X X X X Contaminated water (pathogens)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

6.7 Membrane filtration

General Reduced filtration performance

6.7.1 Operational fault with automatized process by unqualified staff

X X X X X X X Contaminated water. No/insufficient water supply.

7

Membrane module/ plant

Destruction of membrane modules

6.7.2 Structural damages, e.g. due to pressure shocks, cross flows, chemical damages or broken fibres, raw water bypass (due to failure of o-ring or glue line), etc.

X X X X X X X X Contaminated water. No/insufficient water supply. Damage to infrastructures.

7

Membrane Membrane fouling

6.7.3 Change in quality of raw water or incoming water; inadequate cleaning methods in combination with high concentration of contaminants

X X X X X X Contaminated water. No/insufficient water supply. Reduced capacity

7

Membrane Membrane damage

6.7.4 Erratic hydraulic stress, deterioration, inappropriate membrane material, exceeding the maximum pressure; chemicals in the incoming water being harmful for the membranes (accidental or deliberate pollution), incorrect dosage of chemicals for cleaning

X X X X X X Contaminated water (chemicals, pathogens…)

7

Membrane Membrane breakthrough, fibre breakage

6.7.5 Large particles due to inadequate pre-treatment; pressure of the back flush is too high (for capillaries)

X X X X X X X Contaminated water (chemicals, pathogens…)

7

Membrane Membrane imperfections

6.7.6 Manufacture deficiencies, e.g.: faulty barrier layer coating + polymerization, glue line discontinuities, inadequately sealing the edges of membrane leaves

X X X X X Contaminated water (chemicals, pathogens…)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Membrane Contamination of the water downstream of the filter

6.7.7 No discard of the first filtrated water after the cleaning; stored chemicals released into the water downstream of the filter

X X X X Contaminated water (chemicals, pathogens…). Health damage of the staff.

7

Outlet of membrane, pipe system, internal surfaces

Bacteria to treated water

6.7.8 Bacterial growth on permeate side or internal surfaces


7

Pipe system, pumps

Burst of pipes, pump failure

6.7.9 Plugging due to algal bloom, artefacts, accumulation; wear; wrong design

X X X X No/insufficient water supply.

7

Cleaning DBP (Disinfection By Products)

6.7.10 Disinfection of the membrane X X Contaminated water (chemicals)

7

Cleaning Wear at membrane components

6.7.11 Frequent backwashing X X X X X Contaminated water.

7

Pneumatic system/ electronic system

Failure of the compressor/the pneumatic system, or of the automatized, programmable control system.

6.7.12 Power failure; programmable errors; leakage in the air supply system

X X X X X X X Contaminated water. No/insufficient water supply. Several possibilities depends on the kinds of failures.

7

Monitoring Monitoring failure of the membrane

6.7.13 No particle counter or bubble test, pressure decay test

X X X X X Delayed or no detection of membrane failure

7

Monitoring Failure of the monitoring of: physical (e.g. turbidity, flow, TMP), biological parameters (e.g. parasites), pressure, chemical parameters

6.7.14 Inappropriate monitoring and/or sampling. Malfunction of measuring instruments. Power failure.

X X X X X X Delayed or no detection of contaminants in the filtered water

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

6.8 Slow sand filtration

Slow filter Disruption of the filtration

6.8.1 Disruption during cleaning process, maintenance or repair in combination with only one existing filtration-line

X X X No/insufficient water supply

7

Slow filter Filter blockage 6.8.2 Inappropriate quality of incoming water

X X X X X X X Contaminated water (pathogens, chemicals…). No/insufficient water supply.

7

Slow filter Reduced filtration performance

6.8.3 Inappropriate filtration speed, filter material, running time, cleaning, layer thickness, filter adjustment; insufficient removal of the top layer; inappropriate adjustments during start up phase; absent or insufficient monitoring of pressure differences and operational pressure; etc.

X X X X X X Contaminated water (pathogens, chemicals…). No/insufficient water supply.

7

Slow filter Filter breakage, damage of the filter

6.8.4 Blocking of the overflow pipe; extreme rainfalls; too low freeboard; etc.

X X X X X Damage caused by the overflowing water

No

Slow filter Filter breakage, damage of the filter

6.8.5 Deterioration, erratic hydraulic stress; rumpling of the filtration layer by small animals or insects; disturbance of microbial fauna in the filter or out washing of filter organisms; etc.

X X X X X X X Contaminated water (pathogens, chemicals…)

7

Out coming pipes

External water going into the pipes

6.8.6 Negative pressure in the pipes between the filters and the reservoirs because any valve is closed.

X X X X Contaminated water (pathogens, chemicals..)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard

Monitoring Bad quality of the sand

6.8.7 Wrong control of sand quality when renewing the material of the filter.

X X X X Contaminated water (pathogens, chemicals..)

7

Monitoring Failure of the monitoring of: physical (e.g. turbidity, flow), biological parameters (e.g. parasites), pressure, chemical parameters

6.8.8 Inappropriate monitoring and sampling concepts, malfunction of measuring instruments. Power failure.

X X X X X X Delayed or no detection of contaminants in the filtered water

7

6.9 Activated Carbon Filtration

Activated carbon filter

Insufficient removal of target contaminants due to intrinsically insufficient adsorption capacity

6.9.1 Quality of virgin or reactivated GAC is unsuitable/inadequate (adsorptive capacity, pore size distribution, pore surface area, grain size distribution)

X X X X Contaminated water (chemicals)

7



6.9.2 Constant or periodically insufficient empty bed contact time (EBCT)


7



6.9.3 Loss of GAC during back wash (velocity of back wash too high)


7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard


Insufficient removal of target contaminants due to depletion and/or obstruction of adsorption capacity

6.9.4 Elevated concentration of adsorbing (target contaminants, NOM) and/or pore blocking (particles, turbidity) materials in water due to events in raw water source or upstream process steps


7


Insufficient removal and/or release of target contaminants due to depletion and/or obstruction of adsorption capacity

6.9.5 Overestimation of the filtration run time before reactivation is necessary


7


Insufficient removal and/or release of target contaminants due to depletion and/or obstruction of adsorption capacity

6.9.6 Velocity of backwash too high, so carbon with high load of adsorbed contaminants settles in deeper layers of the filter, where the concentrations of contaminants are much lower than in the top of the filter


7


Insufficient production capacity due increased head loss and/or to need for increased back wash frequency

6.9.7 Increased head loss build up rates due to elevated particles concentrations (raw water or carry over)

X X X X No/insufficient water supply

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard



6.9.8 Increased head loss build up rates due to unsuitable (too small) GAC grain size


7



6.9.9 Increased head loss build up rates due to ineffective back wash protocol


7


Stop the supply of water for the carbon filtration

6.9.10 Equipment failure (pumps, valves, nozzles, operating systems, etc)

X X X No water supply 7


Escape of activated carbon to the treated water

6.9.11 Failure / insufficient performance activated carbon retaining devices (sieves, supportive layer)

X X X Contaminated water (carbon particles)

7


Carbon dust in the air of the plant

6.9.12 Filling of activated carbon in dry state (not slurry)

X X X Reduced safety for the staff

No


Adverse and/or excessive biological activity in filter (causing oxygen depletion, biological contamination, etc.)

6.9.13 Too low filtration velocity or stagnant water in filters due to production halt.

X X X X X Contaminated water (chemicals, pathogens)

7




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail..

Sa-fety

External damage


Rel. hazard



6.9.14 Decrease in pH X X X X Contaminated water (chemicals, pathogens)

7



6.9.15 High water temperature X X X X X Contaminated water (chemicals, pathogens)

7



6.9.16 Prolonged wet storage of activated carbon before use


7



6.9.17 Increased biological growth in filters due to ineffective back wash protocol


7



7. Reservoirs and pumps


D O E OS Ref. OS.

Bio-log.

Chemic

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

7.1 Clear Water reservoir

General No water supply / Contamination of water

7.1.1 "Damage or destruction of reservoir due to natural disasters (earthquakes, hurricanes, floods, landslides, volcanic eruptions)"

X X X X X X X X No/insufficient water supply to customers and fire fighting. Contamination of water

8


7.1.2 Damage or destruction of reservoir due to human-caused accidents (car, truck or aircraft collision, landslides caused by reservoir leakage or nearby excavation)

X X X X X X X No/insufficient water supply to customers and fire fighting. Contamination of water

8


7.1.3 Intentional damage or destruction of reservoir (terrorism, sabotage, vandalism, arson)


8


7.1.4 Reservoir structure damage due to excessive internal pressure build-up

X X X X X X No/insufficient water supply to customers and fire fighting. Contamination of water

8

General No/deficient water supply

7.1.5 Wrong water level metering or data processing system malfunctioning

X X Improper pump control, inadequate pressure in network

8




D O E OS Ref. OS.

Bio-log.

Chemic

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

General Contamination of water

7.1.6 Intentional contamination of the network water (terrorism, sabotage, vandalism, arson)

X X X X X X Contamination of water with pathogens, toxins, toxic chemicals, or radioactive materials. Restriction on water use. Consumers' panic and loss of confidence

8

General Contamination of water

7.1.7 Introduction of contaminants by improper use of material or operational errors

X X X X X Water contaminated with chemicals and/or with taste and odour

8

Reservoir Contamination of water

7.1.8 Poor hygiene during reservoir construction, repair or cleaning

X X X X Water contaminated with pathogens and/or chemicals, and/or with taste and odour

8


7.1.9 Intrusion of contaminants (e.g., bird and animal faeces), dust or vermin through improperly sealed access openings or hatches and faulty or fouled screening of vents and overflow pipes

X X X X Water with pathogenic and/or chemical contaminants, dust and/or vermin

8


7.1.10 Intrusion of contaminants thought cracks in the reservoir roof

X X X X X Water with pathogenic and/or chemical contaminants, dust and/or vermin

8


7.1.11 Intrusion of contaminants thought cracks in the reservoir walls or floor

X X X X X Water with micro organisms and/or chemical contaminants

8

Reservoir Water quality deterioration

7.1.12 Aging of water due to low turnover rates or uneven hydraulic mixing

X X X X Water with poor microbiological quality and with taste and odour

8




D O E OS Ref. OS.

Bio-log.

Chemic

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard


7.1.13 Excessive accumulation of sediments on the reservoir floor

X X X 6 X X Water with poor microbiological quality and with taste, odour and colour

8


7.1.14 Excessive biofilm accumulation on tank walls

X X X 6 X X Water with poor microbiological quality and with taste and odour

8

7.2 Pumping station

General No/low pressure/flow in network water. Network water contamination

7.2.1 "Destruction of pumping station due to natural disasters (earthquakes, hurricanes, floods, landslides, volcanic eruptions.


8 X


7.2.2 Damage or destruction of pumping station due to human-caused accidents (car, truck or aircraft collision, landslides caused by leakage or nearby excavation)


8


7.2.3 Intentional damage or destruction of pumping station (terrorism, sabotage, vandalism, arson)


8

Pumps No/low pressure/flow in network water. Network water contamination

7.2.4 Damage or destruction of network pipes due to water hammer, caused by absent or malfunctioning surge tanks

X X X X X X No/deficient network-water pressure/flow. Contaminant intrusion into network water.

8




D O E OS Ref. OS.

Bio-log.

Chemic

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard


7.2.5 Pump malfunctioning/failure X X X X X X No/deficient network-water pressure/flow. Contaminant intrusion into network water.

8


7.2.6 Pump stoppage due to power failure/disruption and failing power back-up supply


8

Pumps Excessive pressure in network water

7.2.7 Excessively high pressure in the network due to wrong settings or deficient control of pumps operation

X X X Excessive pressure in the network. Increased pipe leakage/burst.

8


7.2.8 Low pressure in the network due to wrong settings, deficient metering or deficient control of pumps operation

X X X X X No/insufficient water supply to customers and fire fighting. Contamination of water

8

Pumps Water contamination

7.2.9 Contaminants pulled in at the suction side of a pump

X X X X Network water contamination (chemicals, micro organisms)

8


7.2.10 Introduction of pollutants by improper use of material or operational errors

X X X X Water contaminated with chemicals and/or with taste and odour

8


7.2.11 Poor hygiene during pump installation, maintenance or repair


8


7.2.12 Pump operation leading to rapid changes in water flow rate or direction

X X X X Network sediments re-suspension

8




D O E OS Ref. OS.

Bio-log.

Chemic

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

7.3 Valves (both in reservoirs as in pumping stations)

Isolation and control valves

No/low pressure/flow in network water. Network water contamination

7.3.1 Inadequate designed or operated valve, malfunctioning valve

X X X X X No/insufficient water supply to customers and fire fighting. Contamination of water

8

Control valves

No/low pressure/flow in network water. Network water contamination

7.3.2 Damage or destruction of network pipes due to water hammer


8

Control valves

Contamination of water

7.3.3 Introduction of contaminants by improper use of material or operational errors

X X X Water contaminated with chemicals and/or with taste and odour

8

Control valves

Contamination of water

7.3.4 Poor hygiene during installation, maintenance or repair of valves


8

Pressure reducing valves

Excessive pressure in network water

7.3.5 Inadequate settings or control, or malfunctioning/failure of pressure reducing valve


8



8. Transport and distribution


D O E OS Ref. OS.

Bio-log.

Chemic

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

8.1 Network

Pipes No/insufficient water supply

8.1.1 Pipe burst due to extreme external-stresses (e.g. storms, earthquakes, landslides, freezing and thawing, traffic incidents, etc)

X X X X X No/insufficient water supply to consumers and fire fighting

9


8.1.2 Pipe burst due to increased external-stresses on pipe (e.g. traffic, soil movement, etc) in combination with a reduced pipe condition


9


8.1.3 Pipe burst due to bad condition of pipe (e.g. internal /external corrosion)


9


8.1.4 Pipe burst/leakage due to increased internal-stress (e.g. pressure, transients)

X X X X 7 X X X X X X No/insufficient water supply to consumers and fire fighting

9


8.1.5 Loss of pipes' hydraulic capacity due to scaling/tubercle formation

X X 6 X No/insufficient water supply to consumers and fire fighting

9


8.1.6 Insufficient network capacity due to inadequate design

X X No/insufficient water supply to consumers and fire fighting

9

Pipes Network water contamination

8.1.7 Poor hygiene during pipes installation/repair

X X X X Contaminated water (turbidity, chemicals, pathogens)

9




D O E OS Ref. OS.

Bio-log.

Chemic

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard


8.1.8 Intrusion of contaminated water due to low (negative) pressure in the network, in combination with cracks or leaking joints


9


8.1.9 Migrating substances from polymer material (e.g. vinyl chloride leaching from PVC pipes)

X X Contaminated water (e.g. with vinyl chloride)

9


8.1.10 Leaching of contaminants from cement made or lined pipes

X X X 6 X Water contaminated with metals (e.g., aluminium, arsenic, barium, chromium, cadmium)

9


8.1.11 Leaching of organic compounds from bituminous sealants and linings

X X X X Water contaminated with PAHs and with taste and odour

9


8.1.12 Permeation of organic-pollutants in the soil through rubber joints or the (PE or PVC) pipe wall

X X X Water contaminated with chemicals (gasoline and diesel constituents, solvents, etc.)

9


8.1.13 Backflow or back-siphonage of non-potable water (e.g., wastewater) or fluids (e.g., industrial)

X X X X X Water contamination (pathogens, chemicals) due to backflow of non-potable water or fluids into network

9

Pipes Deterioration of water quality

8.1.14 Too long residence times of water in the network

X X X X X Water of poor microbiological quality and with taste and odour

9


8.1.15 Deficit in disinfectant residual, excess in water AOC/BOC

X X X 6 X Water of poor microbiological quality

9




D O E OS Ref. OS.

Bio-log.

Chemic

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard


8.1.16 Too high dosage of disinfectant residual (e.g., malfunctioning dosing pump(s))

X X X 6 X X Water with taste and odour, increased formation of disinfection by-products

9


8.1.17 "Re-suspension of sediments or sloughing of tubercle/biofilm due to rapid changes in water

flow rate or direction"

X X X X X Water discoloration and increased microbial contents

9

Manholes, fire hydrants, meter boxes, connections, hatches (all access points to the water)

Network water contamination

8.1.18 Intentional contamination of the network water (terrorism, sabotage, vandalism, arson)

X X X X X X X Contamination of water with pathogens, toxins, toxic chemicals, or radioactive materials. Restriction on water use. Consumers' panic and loss of confidence

9

Valves and boosting pumps

No/insufficient water supply

8.1.19 Malfunctioning or failure of valves and/or (boosting) pumps

X X X 7 X No/insufficient water supply to consumers and fire fighting. Disruption of the system operational control.

9




D O E OS Ref. OS.

Bio-log.

Chemic

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Valves Network water contamination

8.1.20 Valve pit flood allowing contaminants intrusion thought defective valve sealing, in combination with low pressure in the network


9

Pressure reducing valves

Excessive pressure in network water

8.1.21 Inadequate settings or control, or malfunctioning/failure of pressure reducing valve


8

Fire hydrant No/insufficient water for fire fighting

8.1.22 Defective or clogged fire hydrant

X X X Fire fighting is hindered

No

8.2 Water meters and non return valves

Water meters

Over / under registration

8.2.1 Wear of water meter mechanical-parts

X X Improper billing 10

Water meters

No/insufficient water supply to consumers

8.2.2 Freezing of water within meters and/or external pipes exposed to extremely low temperatures

X X Water flow is obstructed

9-10

Water meters


8.2.3 Fouling of water meter due to sediments or biofilm

X X 6 X Water flow is obstructed

9-10

Non-return prevention devices


8.2.4 Fouling of non-return prevention devices due to sediments or biofilm

X X 6 X Water flow is obstructed

9-10

Non-return prevention devices


8.2.5 Absent, inadequate or defective non-return prevention devices allow backflow or siphonage of contaminated water from costumer premises or fire hydrants

X X X X X X Contaminants (microbial, chemical) enter into the network

9

Water meters


8.2.6 Meter pit flood allowing contaminants intrusion thought defective sealing, in combination with low pressure in the network


9-10



9. Internal piping


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

9.1 Drinking water installation

General No/Insufficient water supply

9.1.1 Bad design of the installation or low pressure in distribution network

X X 8 X Water pressure/flow is low or null in all or in some of the higher floors, backflow to distribution network

10, 8


9.1.2 Failure of booster pump in multi-storey buildings

X X X Water pressure/flow is low or null in all or in some of the higher floors, backflow to distribution network

10, 8


9.1.3 Pipe burst due to poor pipe material, excessive pressure, water hammer, building activities (e.g. drilling)

X X X No/insufficient water supply to consumers, damage due to leakage of water

10

General Excessive water pressure

9.1.4 Excessive pressure in the distribution system

X 8 X Costumer discomfort, internal piping leakage, appliance malfunctioning/failure

10

General Water contamination

9.1.5 Poor hygiene in plumbing systems installation/repair

X X X X Contaminated water (pathogens, chemicals, taste and odour)

10


9.1.6 Backflow or back-siphonage of contaminated water from other systems (e.g., waste, fire protection, garden watering and irrigation)

X X X X X X Contaminated water (pathogens, chemicals, taste and odour)

10




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

General Deterioration of water quality

9.1.7 Microbial regrowth enhancement by relatively high water-temperature or heating of water by warm objects at close distance

X X Water with poor microbiological quality, possibly with pathogens

10

Internal pipes

No/Insufficient water supply

9.1.8 Loss of pipes' hydraulic capacity due to incrustation build-up

X X 6 X Low pressure/flow in taps

10

Internal pipes

Water contamination

9.1.9 Corrosion of plumbing system materials, which is promoted by low pH, temperature, insufficient or excessive alkalinity in the water

X X 6 X Contaminated water (e.g., lead, copper or iron)

10

Internal pipes

Water contamination

9.1.10 Migrating substances from polymer material (e.g. vinyl chloride leaching from PVC pipes)

X X Contaminated water (e.g. with vinyl chloride)

10

Internal pipes

Water contamination

9.1.11 Plumbosolvency of lead pipes, which may be promoted by water low-pH and low alkalinity

X X 6 X Contaminated water (lead)

10

Internal pipes

Deterioration of water quality

9.1.12 Sediment accumulation and microbial growth in water stagnated at dead-end branches

X X X X Water contaminated with pathogens (e.g., Legionella) and with taste, odour and colour

10

Internal pipes


9.1.13 Iron corrosion from iron/steel pipes

X X 6 X X "Discoloured water (red-water) with metallic flavour causing reddish-brown stains on laundry"

10

Internal pipes

Annoying noise 9.1.14 Water hammer, high velocities and/or turbulence or cavitation

X X Nuisance to customers and neighbours

10




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard

Household storage tanks


9.1.15 Microbial growth due too long residence time of water, warm temperatures, sediment accumulation or exposition of the water to light

X X X X X Water contaminated with micro organisms, cyanotoxins, tank material leaching compounds and/or colour

10

9.2 Hot water plumbing system


9.2.1 Microbial growth in hot water system (heaters, storage tanks, pipes, taps and shower heads) with water bellow 65 ºC

X X X Contaminated water (Legionella, Mycobacterium avium, Pseudomonas aeruginosa)

10

Water heater

Reduced performance of the water heater

9.2.2 Scaling build-up leads to reductions in heater/tank heating efficiency, storage capacity and lifetime

X X 6 X X X Increases in energy consumption and operating temperatures, hot water shortages, premature equipment failure

10

Hot water shower or bath taps

Burns 9.2.3 Water from shower or bath taps supplied above 55ºC.

X X X X People (mostly young children and elderly) severely injured by too hot water

10

9.3 Point-of-Entry and Point-of-Use treatment devices


9.3.1 "Fouling of treatment devices by suspended solids, iron, manganese or copper"

X X X Water pressure/flow is low or null

10 X

General Contaminated water

9.3.2 Inadequacy of the treatment process for a targeted compound (e.g. (mis-)use of cation exchange to remove lead from hard water; (mis-)use of activated carbon to remove arsenic)

X X Water contaminated with inorganic or organic substances against consumers' believe

10




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Una-vail.

Sa-fety

External damage


Rel. hazard


9.3.3 Failure of the contaminant removal process (e.g., exhaustion of the resin or carbon adsorptive capacity; UV lamp bulb/housing opaqued by dirt)

X X X Water contaminated with inorganic or organic bustances or pathogens against consumers' believe

10


9.3.4 Enhanced corrosion of plumbing system and appliances materials (e.g., lead, copper) due to excessive water softening

X X X Water contaminated with chemicals (e.g., lead, copper)

10

General Chemical contamination

9.3.5 Backflow of liquid waste streams (e.g., reverse osmosis, ionic exchange resins) or backwash water (adsorptive media filters) to the treated water lines

X X X Water heavily contaminated with chemicals

10

General Deterioration of water quality

9.3.6 Growth/release of micro organisms from treatment devices (e.g. granular activated carbon filters)

X X X Water with poor microbial quality

10

General Chemical injuries 9.3.7 Unsafe handling or storage of strong caustics/acids used for adsorptive media regeneration

X X X Skin, eye or respiratory injuries upon exposition to strong acids/caustics

10



10. Consumer and taps


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Unavail.

Sa-fety

External damage


Rel. hazard

10.1 Water collection

Communal standpipes

Unavailability of water

10.1.1 Unavailability of water from distribution network

X

X 8 X No/insufficient water supply

Not relev.

Communal standpipes


10.1.2 Vandalism or improper use of standpipe or taps


Not relev.

Communal standpipes

Contamination of tap or surrounding parts

10.1.3 Unhygienic handling of tap e.g. by unwashed hands or presence of animals


Not relev.

Communal standpipes or ground tanks


10.1.4 No access or poor access to the standpipe or ground tank due to obstructions or other reasons

X X X X No/insufficient water supply

Not relev.

10.2 Water storage and transportation Water storage before consumption Open-top containers (buckets)

Water quality deteriorate during storage

10.2.1 Exposure to airborne substances, such as dust, dirt, flies or other contaminants

X X X X X Contaminated water (pathogens, chemicals…)

Not relev.

Open-top or closed-top containers

Water quality deteriorate during storage

10.2.2 Dissipation of chlorine residuals


Not relev.

Open-top or closed-top containers

Water quality deteriorate during storage or consumption

10.2.3 Poor sanitation conditions by consumers


Not relev.

Ground tanks

Contamination at collection area

10.2.4 Soiled nappies or soiled children washed directly at the ground tank


Not relev.

Ground tanks

Poor water quality from the containers

10.2.5 Poor condition and age of the containers, leaking containers

X X X X X Contaminated water (chemicals). No/insufficient water supply.

Not relev.




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad/ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Ground tanks


10.2.6 Top not fitted correctly over the tank allowing dirt and dust to enter the tank

X X X X X Contaminated water (pathogens, chemicals...)

Not relev.

Ground tanks


10.2.7 Biofilm formation from the inner walls of the ground tanks


Not relev.



11. Organization


D O E OS Ref. OS.

Biolog.

Chemic.

Rad/ phys

Unavail.

Sa-fety

External damage


Rel. hazard

11.1 Organization

Organization Disturbance of the process in general

11.1.1 Use of out-of-date guidelines X X X X X X X Contaminated water. No/insufficient water supply. Danger to the staff or environment

From 1 to 10


11.1.2 Inappropriate financial or technical conditions

X X X X X X X X Contaminated water. No/insufficient water supply. Danger to the staff or environment

From 1 to 10


11.1.3 Inappropriate personal organization (e.g. no assignment of responsibilities, no responsible person, inappropriate qualification)


From 1 to 10


11.1.4 Insufficient on-call-duty X X X X X X X X Contaminated water. No/insufficient water supply. Danger to the staff or environment

From 1 to 10


11.1.5 Insufficient and/or unqualified staff (e.g. certified, adequate labour)


From 1 to 10


11.1.6 Insufficient internal coordination and scheduling


From 1 to 10

Organization Disturbance of the process in

11.1.7 Operational fault in the automatized process due to

X X X X X X X Contaminated water. No/insufficient

From 1 to 10




D O E OS Ref. OS.

Biolog.

Chemic.

Rad/ phys

Unavail.

Sa-fety

External damage


Rel. hazard

general programming by unqualified staff

water supply. Danger to the staff or environment


11.1.8 Operational fault in the automatized process due to inappropriate IT policy

X X X X X X X Contaminated water. No/insufficient water supply. Danger to the staff or environment

From 1 to 10


11.1.9 Lack of feeling, unawareness of technical status of installations due to automatization


From 1 to 10


11.1.10 Low quality of data input to information systems, incomplete, errors, etc


From 1 to 10


11.1.11 Use of out-of-date or inappropriate software, that cannot be used by others


From 1 to 10



12. Future hazards (including the whole drinking water system)


D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

12.1 Source water

Source water Sabotage and terrorist attacks

12.1.1 Intentional chemical contamination

X X Contaminated water. No/insufficient water supply. Public concern, bad image.

1 to 5


12.1.2 Intentional microbial contamination


1 to 5


12.1.3 Non accessible information. To prevent sabotage and terrorist attacks information regarding source water, treatment and distribution are classified. Due to this all necessary information might not be available to the personal and people in general.

X X X X X X X If the personal operating the system does not have all necessary information, actions might be taken that introduce new risks to the system. Also people in general might, because of lack of information, act in a way that pose new risks to the system. Water shortage and health effects are possible.

1 to 5

Source water Conflicts 12.1.4 Military conflicts X X X X X X X Contaminated water. No/insufficient water. Technical damage.

1 to 5

Source water Conflicts 12.1.5 Political conflicts X X Political actions leading to water shortage

1 to 5

Source water Conflicts 12.1.6 Competing land use X X X X X Contaminated water. No/insufficient water.

1 to 5




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Source water New chemicals and changed chemical pathways

12.1.7 Discharge of new chemicals to source waters due to e.g. accidents or continuous leakage

X X Contaminated water. No/insufficient water supply. Remediation of supply system

1 to 5

Source water New chemicals and changed chemical pathways

12.1.8 Discharge of chemicals due to new applications

X X Because known chemicals are put into new pathways they may cause contaminated water, no/insufficient water supply, remediation of supply system

1 to 5

Source water Emerging pathogens

12.1.9 Presence of emerging pathogens able to overcome existing barriers

X X X Insufficient water quality. Increased number of waterborne infections. Remediation of supply system

1 to 5

Source water Climate changes 12.1.10 New precipitation and evaporation patterns

X X No/insufficient water supply

1 to 5

Source water Climate changes 12.1.11 The climate changes' effects on water quality (changed surface runoff and material transport effecting water quality)

X X X X No/insufficient water supply. Contaminated water (including higher temperature of supplied water)

1, 2 and 4

12.2 Treatment

Treatment Sabotage and terrorist attacks

12.2.1 Physical damage (e.g. bombing attack)

X X X X Water shortage and technical damage

6




6




6




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard


12.2.4 People entering into the plant, sabotaging the process

X X X X X Contaminated water. No/insufficient water supply.

6


12.2.5 Cyber attack (e.g. manipulation of operational steps)


6




6

Treatment Conflicts 12.2.7 Military conflicts X X X X X X X Contaminated water. No/insufficient water. Technical damage.

6

Treatment Conflicts 12.2.8 Political conflicts X X Political actions leading to water shortage

6

Treatment New chemicals and changed chemical pathways



6




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Treatment Emerging pathogens



6

12.3 Distribution

Distribution Sabotage and terrorist attacks

12.3.1 Physical damage (e.g. bombing attack)

X X X X Water shortage and technical damage

7 to 9




7 to 9




7 to 9


12.3.4 Cyber attack (e.g. manipulation of operational steps)


7 to 9




7 to 9

Distribution Conflicts 12.3.6 Military conflicts X X X X X X X Contaminated water. No/insufficient water. Technical damage.

7 to 9




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Distribution Conflicts 12.3.7 Political conflicts X X Political actions leading to water shortage

7 to 9

Distribution New chemicals and changed chemical pathways



7 to 9

Distribution Emerging pathogens



7 to 9

Distribution Aging distribution systems

12.3.10 Damaged distribution system and possible intrusion of contaminants

X X X X X X No/insufficient water. Contaminated water. Technical damage.

7 to 9

Distribution Aging distribution systems

12.3.11 Increased retention times due to oversized systems


7 to 9

12.4 Consumers

Consumers Sabotage and terrorist attacks

12.4.1 Changed human behaviour after terrorist attacks leading to avoidance of tap water

X X X X Indirect damage. Because of lack of trust in tap water people use water from other sources and if this water is of poor quality it might cause negative health effects

10

Consumers Emerging pathogens

12.4.2 Changed infection patterns (increased exposure to pathogens due to e.g. migration of citizens)

X X Increased number of waterborne infections

10




D O E OS Ref. OS.

Bio-log.

Chemic.

Rad./ phys

Unavail.

Sa-fety

External damage


Rel. hazard

Consumers Public concern 12.4.3 Reports on detection of chemicals or pathogens of very low tolerability

X X Anxiety and decreased trust in water supply

10



Appendix 13: Methodology for hazard identification by using the THDB

The hazard identification process can be carried out by following the steps below as guidelines. On purpose this methodology is detailed in order to help end-users in all steps of development to carry out the hazard identification process. In this methodology two approaches are mentioned. For a further explanation, see Chapter 1. STEP 1: Objectives

• Describe the overall objective of the risk management project and more specifically the objectives of the identification of risks in this specific activity.

• Define the scope: hazard identification of all the stages of the water supply chain or of separate parts of the system.

• Define the available costs, time frame, organization, who will this be reported to, the responsible person(s) and his/her role and responsibility.

STEP 2: Split up the system and make a system description

• Make a system description and, if necessary contact other stakeholders.

• Decide on the number of meetings needed and plan for these. The number of meetings needed depends on the complexity of the system, the parts of the systems that will be included and discussed and the available resources.

• Select the parts of the THDB that are useful for the specific location (some sub-systems or components may not be relevant for the system to be studied).

STEP 3: Assemble a team

• Select the participants for each meeting session: - Number of persons: responsible(s) + 2 to 4 experts - English speakers (THDB in English) - Different knowledge background:

o Specialists: technical experts with deep knowledge of the most relevant processes and parts of the system

o Generalists: people with overall knowledge and overall view of the system

o Also invite non-technicians for other info (financial, consumers, laws)

- Personality: cooperative, involved, open minded, not biased, etc.



STEP 4: Interviews with the experts (“bottom-up” method)

• Interview all the experts for their opinion on the most relevant hazards (“bottom-up” approach).

• Make a list of identified hazards structured according to the sub-systems and components of the THDB.

STEP 5: Contact with participants and organization of meetings

• Set the dates, places and duration for the meetings. As these meetings are rather intensive it is advised to plan maximum half a day per meeting.

• Send the participants the THDB, the system description and an introduction based on the items mentioned in step 1 and 2.

• For a more efficient meeting it is advised to ask the participants prepare themselves by going through the relevant parts of the THDB and by consulting others if needed.

STEP 6: Preparation of the meetings

• Prepare a short presentation (for content see Step 7a). • Prepare the material for the sessions, such as:

- Overhead projector, screen and computer (so the THDB can be shown on the screen and direct input is visible for everyone)

- Round-table setting - Flip-over and colour markers - Flow diagram of the system - Definitions of hazard, hazardous event, criteria for hazard

identification should be put up on a blackboard during the sessions to help structuring further discussions

STEP 7: Hazard identification session 7a: Introduction

The sessions with the participants could follow the following structure:

• Presentation of the participants. • Objective of the hazard identification and aim of the meeting. • Presentation of the definitions like: hazard, hazardous event, risk,

risk management, etc. • Presentation: THDB, system description, time-frame. • Description of how to work: how to use the THDB, what to look

for, how will the session be structured, set criteria for the hazard identification.

• Show the structure of the THDB, including different sub-systems.



7b: Hazard identification (“top-down”)

• For each component in the sub-systems: go through each row of the THDB asking participants if this hazard is expected to be relevant, if so indicate the result as a tick. A proposal for indicating relevant hazards is given in tip and ticks hereunder.

• Per component, make a list of the identified hazards and compare them with the “bottom-up” identified hazards.

7c: Definition of identified hazards

• Sum-up the list of identified hazards in each sub-system, ask the

participants if they agree with the results or if changes are to me made.

• Evaluate the hazard identification activity. STEP 8: Finalizing

• Make a draft report of the results. • Following items are advised to be mentioned in the report:

objective of the process, system description, short description of the THDB, identified hazards and an evaluation of the process.

• Ask for feed-back from the participants. • Make changes to the draft document. • Make a second draft report and discuss this with the management

officers. TIPS AND TRICKS FOR HAZARD IDENTIFICATION WITH THE THDB

1. The THDB contains a column called “Relevant hazard?” for marking identified hazards. Marks could be made in different ways, for example:

a. By adding a “tick” when the hazard is considered relevant for the company.

b. By ranking each relevant hazard, for instance: - X: hazard not relevant or not recognized as a problem

for the company. - 0: recognized hazard for the company, but control

measures have been taken. - 1: a minor risk that needs attention.1 - 2: a major risk for the company as a whole.

2. During the meetings, some definitions could be shown on the

blackboard: hazard, hazardous event, criteria for the evaluation.

1 It is not intended to start evaluating risks at this stage, however to indicate the magnitude of

the risk.



3. A flow chart of the system should be kept on a blackboard. 4. It is advised to start with an explanation of the overall system, the

parts that will be discussed during the session and then go through each sub-system.

5. It is better to start with future hazards (sub-system #12), in order to

avoid them being mentioned in other sub-systems. 6. When going through the sub-systems of the THDB, it is advised to

first show briefly all the component and elements of the sub-system to be discussed, so the participants would have an overview that can help them to identify the hazards.

7. After going through each sub-system, the participants could be asked

if they want to add something else that is not mentioned in the THDB. 8. Since the most important information for the hazard identification is

in the columns “hazard” and “hazardous event”, it could be useful to show only the first five columns of the THDB during the discussions and hide the last ones (hide “type of hazardous event”, “type of hazard” and “potential consequences”).

9. It is useful to use different colours in the cells of the “Relevant

hazard?” column. This can be done by using the conditional format option of MS Excel. (Path: Format/ Conditional formatting). For example, hazards ranked as 1 could be collared with orange, and hazards ranked as 2 could be collared with red.

10. As the distribution sub-system consists of a large number of pipes in

different circumstances, it could be helpful to define different typical situations for specific areas. Those situations would correspond to different pipe materials, diameters, regions, age and other characteristics.

D4.1.4

Documents

description of hazards

techneau techneau

water supply systems

water abstraction

hazard identification

drinking water system

surface water infiltration

surface water catchment