BOOK
Best Practice Guide on the Management of Metals in Small Water Supplies
(2016)
Additional Information
Book Details
Abstract
The management of small water supplies presents a unique challenge globally, in countries at all stages of development. A combination of lack of resources, limited understanding of the risks and poor expertise means that individuals and communities may face serious health risks from these supplies. This is not only due to microbiological contamination, but also from contamination by metals, either due to natural or man-made contamination of the source water or through leaching from plumbing materials due to inadequate conditioning and corrosion inhibition and use of inappropriate materials.
This Best Practice Guide aims to share best practice and experience from around the world on a practical level. It looks at general issues relating to small supplies and ways of managing these, adopting a Water Safety Plan approach to deliver sound and lasting improvements to quality. Management techniques and treatment relating to specific metals will be covered, from a theoretical and practical perspective, to deliver a publication that will act as an authoritative guide for all those faced with the problem of ensuring the quality of a small water supply. Varied case-studies will help to illustrate issues and ways in which they have been resolved.
Table of contents
The Difficulties of Managing Water Quality in Small Water Supplies; What are Small Supplies?; The Management and Regulation of Small Water Supplies; The Vulnerability of Small Water Supplies to Contamination by Metals; Water Safety Plans for Small Water Supplies; Making WSPs Work for Small Supplies; Teamwork- The Value of a WSP Team; A Practical Guide to Developing a WSP for a Small Supply; Practical Guidance for Risk Assessments; Establishing the Metals Problem: Risk Assessment, Sampling and Analysis; The Range of Possible Problems; Metal Solubility and Influencing Factors; Risk Assessment of Small Water Supply Systems; Sampling and Analysis; Consumer Awareness; Sources of Metals in Small Water Supplies; Origin of Contaminants; Contamination of Surface Waters; Contamination of Ground Water; Contamination from Treatment Processes; Contamination in Distribution Pipework; Contamination from Plumbing Fittings; Water Treatment Processes Available for Use on Small Water Systems; Process Selection; Types of Treatment; Practical Considerations of Treatment for Metals in Small Water Supplies; Iron; Manganese; Conditioning of Water to Prevent Dissolution of Plumbing Materials or Post-treatment Contamination; Treatment is Only Part of the Story; Indications and Effects of Post-treatment Metal Contamination in Small Water Supplies; Establishing the Source of the Problem; Factors Controlling the Corrosion of Metals into Small Water Supplies; The Conditioning of Water to Minimise Corrosion; Manual of Individual Metals in Small Water Supplies, Aluminium, Antimony, Arsenic, Barium, Beryllium, Boron, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Mercury, Nickel, Selenium, Tin, Tungsten, Uranium, Vanadium, Zinc; Case Studies; Arsenic removal in Small Supplies in Italy; A New Borehole Supply with Iron Removal for a Single Property in England, UK; Metals in Small Water Supplies in Areas of Water Scarcity in African Regions; Unexplained Lead Contamination of a Small Water Supply in Northern Scotland
EDITORS
Matt Bower, Drinking Water Quality Regulator for Scotland, UK
Colin Hayes, Swansea University, UK
Table of Contents
Section Title | Page | Action | Price |
---|---|---|---|
Cover | Cover | ||
Contents | v | ||
Authors | ix | ||
Editors | ix | ||
Authors and Contributors | ix | ||
Acknowledgements | xi | ||
Review Panel | xi | ||
Abbreviations and Acronyms | xiii | ||
About this Best Practice Guide | xv | ||
Foreword | xvii | ||
Executive Summary | xix | ||
Chapter 1: The difficulties of managing water quality in small water supplies | 1 | ||
1.1 WHAT ARE SMALL WATER SUPPLIES? | 1 | ||
1.1.1 Definitions | 1 | ||
1.1.2 What does a small water supply look like? | 2 | ||
Individual responsibility supplies | 2 | ||
Community supplies | 3 | ||
1.2 THE MANAGEMENT AND REGULATION OF SMALL WATER SUPPLIES | 4 | ||
1.3 THE VULNERABILITY OF SMALL WATER SUPPLIES TO CONTAMINATION BY METALS | 4 | ||
Raw water sources | 6 | ||
Treatment | 7 | ||
Delivery to point of consumption | 7 | ||
REFERENCES | 7 | ||
Chapter 2: Water safety plans for small water supplies | 9 | ||
2.1 INTRODUCTION | 9 | ||
2.2 MAKING DWSPS WORK FOR SMALL WATER SUPPLIES | 10 | ||
2.3 TEAMWORK – THE VALUE OF A WSP TEAM | 11 | ||
2.4 A PRACTICAL GUIDE TO DEVELOPING A WSP FOR A SMALL SUPPLY | 11 | ||
2.4.1 Section 1 – Overview of the supply | 12 | ||
2.4.2 Section 2 – Risk assessment and identification of controls for risk | 12 | ||
2.4.3 Section 3 – Verification | 15 | ||
2.4.4 Section 4 – Action plan | 16 | ||
2.4.5 Section 5 – Review of the WSP | 17 | ||
2.5 PRACTICAL GUIDANCE FOR RISK ASSESSMENTS | 17 | ||
2.5.1 The catchment and the source | 17 | ||
2.5.2 Water treatment | 18 | ||
2.5.3 Networks and storage tanks | 19 | ||
2.5.4 Domestic distribution systems | 20 | ||
REFERENCES | 21 | ||
Chapter 3: Establishing the metals problem: Risk assessment, sampling and analysis | 23 | ||
3.1 INTRODUCTION | 23 | ||
3.2 THE RANGE OF POSSIBLE PROBLEMS | 23 | ||
Impact on human health | 23 | ||
Aesthetic effects and nuisance | 23 | ||
3.3 METAL SOLUBILITY AND INFLUENCING FACTORS | 24 | ||
Oxidative states of various metals | 24 | ||
pH, alkalinity and temperature | 24 | ||
Organic complexion | 25 | ||
Interaction between corrosion scales and water | 25 | ||
Corrosion inhibitors | 25 | ||
3.4 RISK ASSESSMENT OF SMALL WATER SUPPLY SYSTEMS | 25 | ||
Introduction | 25 | ||
Approaches to risk assessment | 26 | ||
Source water pollution by metals | 27 | ||
General water quality considerations | 27 | ||
Inventory of metal components and potential sources | 27 | ||
Visual evidence | 28 | ||
3.5 SAMPLING AND ANALYSIS | 28 | ||
Introduction | 28 | ||
Spot sampling | 28 | ||
Split-flow composite sampling | 28 | ||
Sequential profile sampling | 28 | ||
Differentiation between particulate and dissolved metals | 29 | ||
Analysing for metals and pH | 30 | ||
3.6 CONSUMER AWARENESS | 30 | ||
REFERENCES | 30 | ||
Chapter 4: Sources of metals in small water supplies | 33 | ||
4.1 ORIGIN OF CONTAMINANTS | 33 | ||
4.2 CONTAMINATION OF SURFACE WATERS | 34 | ||
4.3 CONTAMINATION OF GROUND WATER | 36 | ||
4.4 CONTAMINATION FROM TREATMENT PROCESSES | 41 | ||
4.4.1 Ion exchange processes | 41 | ||
4.4.2 Filter media | 41 | ||
4.4.3 Oxidation | 42 | ||
4.4.4 Coagulated treatment processes | 42 | ||
4.4.5 Corrosion of metals within the treatment process | 43 | ||
4.4.6 Metal contamination from treatment chemicals | 43 | ||
4.5 CONTAMINATION IN DISTRIBUTION PIPEWORK | 43 | ||
4.6 CONTAMINATION FROM PLUMBING FITTINGS | 45 | ||
REFERENCES | 45 | ||
Chapter 5: Water treatment processes available for use on small water supplies | 47 | ||
5.1 PROCESS SELECTION | 47 | ||
5.1.1 System installation and maintenance | 47 | ||
5.1.2 Point of use versus point of entry | 48 | ||
5.2 TYPES OF TREATMENT | 49 | ||
5.2.1 Physical filtration | 49 | ||
Loose media filters | 49 | ||
Cartridge filters | 51 | ||
5.2.2 Chemical or adsorptive filters | 53 | ||
Granular Activated Carbon (GAC) | 53 | ||
Manganese dioxide | 53 | ||
Activated alumina | 54 | ||
Granular ferric oxide/hydroxide | 54 | ||
Other media | 55 | ||
Cartridge filters | 55 | ||
5.2.3 Ion exchange | 55 | ||
5.2.4 Reverse osmosis membrane | 56 | ||
Design of RO systems | 56 | ||
Monitoring and maintenance | 57 | ||
5.2.5 Distillation | 57 | ||
5.2.6 Treatment options and specifications | 58 | ||
REFERENCES | 60 | ||
Chapter 6: Practical considerations of treatment for iron and manganese in small water supplies | 61 | ||
6.1 IRON | 61 | ||
6.1.1 Principles of process design | 61 | ||
6.1.2 Iron removal – treatment methods | 62 | ||
Settlement | 62 | ||
Oxidation & filtration systems | 62 | ||
Filter washing | 64 | ||
Process refinements | 64 | ||
Problem waters | 65 | ||
Other oxidation regimes | 66 | ||
Regenerating filter systems | 67 | ||
Regenerating ion exchange systems | 67 | ||
6.2 MANGANESE | 68 | ||
REFERENCE | 70 | ||
Chapter 7: Conditioning water to prevent dissolution of plumbing materials or post-treatment contamination | 71 | ||
7.1 TREATMENT IS ONLY PART OF THE STORY | 71 | ||
7.2 INDICATIONS AND EFFECTS OF POST-TREATMENT METAL CONTAMINATION IN SMALL WATER SUPPLIES | 72 | ||
Lead | 72 | ||
Copper | 73 | ||
7.3 ESTABLISHING THE SOURCE OF THE PROBLEM | 74 | ||
7.3.1 Investigative sampling | 74 | ||
7.3.2 Indices | 75 | ||
7.4 FACTORS CONTROLLING THE CORROSION OF METALS INTO SMALL WATER SUPPLIES | 75 | ||
Contact time | 75 | ||
Temperature | 75 | ||
Galvanic effects | 76 | ||
Age of system | 76 | ||
pH and alkalinity | 76 | ||
Oxidising chemicals | 76 | ||
Natural organic matter (NOM) | 76 | ||
Chloride and sulphate | 77 | ||
7.5 THE CONDITIONING OF WATER TO MINIMISE CORROSION | 77 | ||
FURTHER READING | 78 | ||
Chapter 8: Manual of individual metals – occurrence, implications and management | 79 | ||
ABOUT THIS CHAPTER | 79 | ||
ALUMINIUM | 80 | ||
ANTIMONY | 81 | ||
ARSENIC | 82 | ||
BARIUM | 84 | ||
BERYLLIUM | 85 | ||
BORON | 86 | ||
CADMIUM | 87 | ||
CHROMIUM | 88 | ||
COBALT | 89 | ||
COPPER | 90 | ||
IRON | 92 | ||
LEAD | 94 | ||
MANGANESE | 95 | ||
MERCURY | 97 | ||
NICKEL | 98 | ||
SELENIUM | 99 | ||
TIN | 101 | ||
TUNGSTEN | 102 | ||
URANIUM | 103 | ||
VANADIUM | 104 | ||
ZINC | 105 | ||
REFERENCES | 106 | ||
Aluminium | 106 | ||
Arsenic | 106 | ||
Beryllium | 106 | ||
Cobalt | 106 | ||
Copper | 106 | ||
Lead | 106 | ||
Mercury | 106 | ||
Selenium | 107 | ||
Tungsten | 107 | ||
Uranium | 107 | ||
Zinc | 107 | ||
Chapter 9: Case studies | 109 | ||
9.1 ARSENIC REMOVAL IN SMALL WATER SUPPLIES IN ITALY | 109 | ||
9.1.1 Plant A: Adsorption with granular ferric hydroxide | 109 | ||
9.1.2 Plant B: Resins functionalized with ferric hydroxide | 111 | ||
9.1.3 Plant C: Chemical precipitation and adsorption with granular ferric hydroxide | 112 | ||
REFERENCES | 114 | ||
9.2 A NEW BOREHOLE SUPPLY WITH IRON REMOVAL FOR A SINGLE PROPERTY IN ENGLAND, UK | 114 | ||
9.2.1 Background | 114 | ||
9.2.2 Network requirements | 115 | ||
9.2.3 Drilling the borehole | 116 | ||
9.2.4 Time line | 117 | ||
9.2.5 Analysis | 118 | ||
9.2.6 Equipment data | 121 | ||
Borehole pump | 121 | ||
Iron reduction filter | 121 | ||
Tank | 122 | ||
Booster pump | 122 | ||
Sediment filter | 122 | ||
Ultra violet unit | 122 | ||
9.2.7 System flow tests | 122 | ||
9.2.8 Risk assessment | 122 | ||
9.2.9 Review | 122 | ||
ACKNOWLEDGEMENTS | 123 | ||
9.3 METALS IN SMALL WATER SUPPLIES IN AREAS OF WATER SCARCITY IN AFRICAN REGIONS | 124 | ||
REFERENCES | 125 | ||
9.4 UNEXPLAINED LEAD CONTAMINATION OF A SMALL WATER SUPPLY IN NORTHERN SCOTLAND | 126 | ||
9.4.1 Background | 126 | ||
9.4.2 Identifying the source of the problem | 126 |