Drinking Water Quality & Health

Cost Benefit Analysis of Ubiquitous Data Collection in Water Distribution - CBA Scenarios

Ref: 13/DW/12/2            Price: £10

ISBN: 1 84057 692 8

The objective of this project was to determine whether, with the current and projected suites of sensors and data systems, it would be beneficial within AMP6 to promote real-time monitoring for key water quality and related metrics.
This report gives details of the cost of real time monitoring of water quality parameters. Benefits were defined using metrics that would maximise value to customer service and company operating efficiency. This information has informed a cost benefit analysis of a number of scenarios focused on addressing aesthetic water quality issues.

Cost Benefit Analysis of Ubiquitous Data Collection in Water Distribution - Technology Review and Market Assessment

Ref: 13/DW/12/1            Price: £10

ISBN: 1 84057 691 X

This report provides a detailed review of the current status of technology relating to water quality monitoring in distribution; including sensors, telemetry and data analysis and decision support systems. It also includes an assessment of the potential size of the UK markets for identified technologies as well as the likely timescales for development and it examines any emerging technology which may offer improvements for future monitoring.
The output of this study challenges suppliers and developers to deliver technology which meets the water industry's specific requirements for water quality monitoring in distribution.

WHO and EUREAU Support - Progress 2007-2009

Ref: 09/DW/11/3            Price: £10

ISBN: 1 84057 538 7

The UK Water Industry has helped to provide support for the World Health Organisation Guidelines for Drinking Water Quality for a number of years. The present contract began in April 2006 and has been extended to end in February 2010. A report was issued in December 2007. This report identifies progress from December 2007 to March 2009 and consolidates all of the information provided into one report. The format allows retention of the original background text to the substances to enable the reader to understand the context on the development of guidelines for chemicals.

Developing management strategies for increasingly frequent algal blooms in source waters

Ref: 20/DW/07/10            Price: £10

ISBN: 978-1-84057-888-1

This research aims to understand the potential for prediction, the implications of climate change, and potential for better management, through a process of literature review, data collation and analysis, and the investigation of predictive methods. A literature review provided the background for the development of an approach and tools. Data collected from the steering group were analysed. A predictive tool was developed, using the method of Support Vector Machine/Regression. The support vector regression model appears to be a reasonable method with which to analyse the multi-parameter interactions that are likely to govern algal blooms. There is an offset in predictions at present which limits the immediate usefulness of the model, which would make predictions ‘too late’ to be useful. This may be a reflection of the limited dataset, particularly if there are parameters (features) which we don’t have data for, but that may be significant to algal blooms.

Algal Toxins: Occurrence and treatability of anatoxin and microcystins.

Ref: 97/DW/07/5            Price: £10

ISBN: 1 84057 029 6

Laboratory cultures of a wide range of algal strains, primarily Anabaena species, failed to produce anatoxin a at high enough concentrations to allow investigation of treatability, despite the presence of very high concentrations of algal biomass. Sampling of reservoir with appropriate algal blooms also failed to identify high concentrations of anatoxin- a. Anatoxin- a may therefore present less of a risk to water supplies than previously thought. The treatability of microcystin variants other than LR was predicted through modelling techniques. The results of this exercise suggest that any strategies which are based on the known amenability of microcystin- LR to treatment should be suitable for removal of the other microcystin variants.

The Fate of Intracellular Microcystin- LR during Water Treatment

Ref: 96/DW/07/4            Price: £10

ISBN: 1 84057 098 9

Microcystin- LR is a toxin produced by blue- green algae. The presence of these algae in water supply reservoirs is a potential source of contamination of drinking water. Algal toxins can be stored within the algal cells until they die and lyse. Healthy algal cells could conceivably pass through treatment works intact and rech the customer's tap, or treatment processes may cause cell lysis and release of the toxins into the water. This study assessed the impact of water treatment processes on toxic algal cells containing microcystin- LR, and quantified the amount of toxin that could be released during cell lysis. The processes investigated were: physical mixing and pumping; pH adjustment; coagulation; chemical oxidation. The results show that some processes remove the cells altogether, whereas other cells cause cell lysis, and some are effective at destroying the toxin. Recommendations are made on which processes to use where algal toxins are consered a risk.

Synthesis of an Internal Standard for the Determination of Anatoxin- A in Water

Ref: 96/DW/07/3            Price: £10

ISBN: 1 84057 060 1

Anatoxin- A is a neurotoxin, produced by blue- green algae. These algae are sometimes present in reservoir waters, leading to concern over the potential presence of anatoxin- a in drinking waters. A method for the determination of anatoxin- a in reservoir water was developed in 1993, which involves high performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Its use has led to the detection of low levelsof the chemicals in some waters. It was considered that an internal standard would improve the performance of the method. Various potential internal standards were considered, and one (trideuterohomoanatoxin- a) was found to be suitable. This compound was synthesised by Cookson Chemicals, and sufficient material made available for an inter- laboratory performance testing exercise of the anatoxin- a method. Preliminary testing by WRc has shown an improvement in the performance of the method when using this internal standard.

The Toxicity and Significance of Toxins from Blue- Green Algae

Ref: 96/DW/07/2            Price: £10

ISBN: 1 84057 007 5

Blue- green algae are sometimes found in water supply reservoirs. Some algae produce toxins, and because of the possibility of these toxins reaching the customer's tap, it is appropriate to set limits for them in drinking water. In order to do this, it is necessary to know how toxic they are. This report reviews the data available on algal toxins, recommends limits for them in drinking water, and points to areas where more data is needed. The two main algal toxins of concern are microcystin- LR (a hepatoxin) and anatoxin- a (a neurotoxin). A limit of 1ug/ 1 for total microcystins, and 1ug/ 1 for anatoxin- a, were suggested as being appropriate to ensure that no adverse response occurs.

Pilot Scale GAC Tests to Evaluate Toxin Removal

Ref: 96/DW/07/1            Price: £10

ISBN: 1 84057 059 8

Blooms of blue- green algae on reservoirs can give rise to the production of toxins that may contaminate freshwaters. There is a potential risk of the toxins entering drinking water supplies and posing a health risk to consumers. There is, therefore, a clear need to identify treatment processes for removing and treating toxin contaminated water. This report describes work which investigated the removal of anatoxin- a by pilot scale GAC (granular activated carbon) adsorbers, and assessed the importance of biodegration. It also investigated microcystin- LR removal, using higher concentrations than in a previous study. The report concludes that GAC filters are highly effective in removal of both toxins, and recommends a suitable contact time for complete removal.

A Status Report on Algal Toxins & Water Treatment

Ref: 00/DW/07/6            Price: £10

ISBN: 1 84057 209 4

The objectives of the report are to provide an update of papers published on the removal of algal toxins by water treatment, and to review the significance of toxins to water supplies worldwide through surveys in the UK and overseas. In general, papers published since 1995 serve to support the findings from work funded by FWR and UKWIR. The occurrence of algal toxins in recent years would appear to be regional or localised. Generally, UK companies have appropriate measures in place for monitoring and control, and are keeping pace with relevant developments. Dominant algal species and toxins vary between countries. Some countries appear to have implemented extensive programmes of research, often collaboratively. However, many countries have yet to identify whether algal toxins pose a threat to their water sources, and this may in part be due to lack of funding.

Harnessing Pesticide Degrading Bacteria for Enhanced Drinking Water Treatment

Ref: 24/DW/13/11            Price: £10

ISBN: 978-1-84057-995-6

This research aimed to enhance biological pesticide degradation in the UK, focusing on ensuring drinking water safety through the use of molecular biology techniques for isolating and culturing pesticide-degrading organisms. The approach involved a literature search on bacterial biodegradation of micropollutants in UK drinking water, leading to the isolation and testing of nine bacterial strains against metaldehyde and glyphosate residues (AMPA). These strains underwent batch tests and microcosm trials in real water and sand from water treatment facilities, followed by bioaugmentation in pilot scale slow sand filtration systems. While efficient for metaldehyde, the biodegradation of AMPA proved more challenging. This research underscores the importance of optimizing conditions for effective bioremediation and translating laboratory findings to real-world scenarios. 

DWQ Big question - how can we achieve 100% compliance with drinking water standards at point of use by 2050?

Ref: 17/DW/13/2            Price: £10

ISBN: 1 84057 829 7

Drinking Water Quality Big Question:  How Can We Achieve 100% Compliance with Drinking Water Standards at Point of Use by 2050?

UKWIR has undertaken an ambitious programme to define longer term, strategic research needs in key areas via its Big Questions initiative.  To support the development of this drinking water quality (DWQ) Big Question, a community-owned list of prioritised research needs to achieve 100% compliance for drinking water quality was produced. 

The innovations needed in drinking water quality were evaluated from source to tap to capture the inter-dependencies within water systems and to identify the best intervention options to balance risk reduction and cost.  The approach for the prioritisation of DWQ research needs considered the degree of current knowledge, including uncertainty and gaps, and mapped that against the degree of risk associated with each contaminant.   Contaminants with lowest knowledge and highest risk were prioritised as the focus of future research at an interactive workshop.  The prioritised issues included those where little occurrence data exists, where there is a need to increase fundamental understanding, or where both occurrence data and understanding are lacking. 

You can download this report FOC via the UKWIR website. 

Chlorine Usage, Availability and Trends

Ref: 09/DW/13/1            Price: £10

ISBN: 1 84057 540 9

Questions over the availability and cost of chlorine, and its acceptability in relation to Health and Safety, environmental, customer, and by-product concerns, led to the need to consider alternatives for water treatment in the UK in the medium to long term. This work has quantified the dependency of the UK water industry on chlorine, and has assessed the likelihood of increased cost or reduced availability of chlorine in the near future. There is no indication that environmental, customer or by-product issues will reduce the acceptability of chlorine, nor is there a widespread policy among water companies for a move away from chlorine gas because of Health and Safety implications. Alternatives to chlorine for disinfection would increase the costs considerably, and in some cases the enegy use and greenhouse gas emissions would also be greatly increased.

Cryptosporidium: Enhancing the Water Industry’s Capability to Respond

Ref: 20/DW/06/22            Price: £10

ISBN: 978-1-84057-890-4

Cryptosporidium causes outbreaks of diarrhoeal disease and can be transmitted in drinking water. Not all species of Cryptosporidium infect people; by “genotyping”, we can identify which species are present. We have developed and validated a Polymerase Chain Reaction-based assay to characterise Cryptosporidium oocysts present, even in very low numbers (< 5), on microscope slides from water testing laboratories.

Improved typeability has been achieved for very low numbers of oocysts that will inform operational management activities (catchment characterisation) and investigations where water quality may be at risk.

We have produced written guidance for water testing laboratories, which includes improved communication, managing expectations, a new submission form and clarification of responsibilities of both the service users and the Cryptosporidium Reference Unit

The main benefit of this work will be improved industry response to Cryptosporidium detections and the management of events.

International Collaborative Cell Culture and UV Studies

Ref: 08/DW/06/21            Price: £10

ISBN: 1 84057 504 2

This report outlines the findings from a collaborative study into 'Cell culture sensitivity and assessment of ultraviolet light inactivation of cryptosporidium under realistic water treatment conditions' initiated by representatives of the Drinking Water Inspectorate (DWI), United Kingdom Water Industry Research (UKWIR), the American Water Works Association Research Foundation (AwwaRF), the United States Environmental Protection Agency (US EPA), Kiwa and the Water Services Association of Australia (WSAA). The research programme identified and assessed using 'blind trials' an optimum cell culture technique that is suitable for routine use in disinfection studies and general risk assessment.

UV Inactivation of Cryptosporidium

Ref: 08/DW/06/20            Price: £10

ISBN: 1 84057 474 7

Potential changes to the UK Drinking Water Quality Regulations could make Cryptosporidium inactivation using UV the most cost-effective treatment option in many situations. UV disinfection is well established in water tratment in the UK and elsewhere. There is now a substantial body of evidence to indicate that UV can provide high levels of inactivation of Cryptosporidium at doses typically used for water treatment disinfection. Turbidity below the regulatory limit of 1 NTU should not impair the disinfection performance of UV. Other water quality factors that could impair UV performance by affecting absorbance of UV or fouling of lamps can be dealt with effectively through operational control systems.
The report provides information and guidance on implementation of UV disinfaction to inactivate Cryptosporidium, based on a review of regulations and standards from other countries, particularly the USA.

Establishing the Relationship between Farm Re-stocking and Cryptosporidia: The Caldew Catchment Study

Ref: 05/DW/06/19            Price: £10

ISBN: 1-84057-374-0

This report details an investigation into the relationship between farm re-stocking and cryptosporidia. The study took place following the foot and mouth disease (FMD) related cull within the River Caldew catchment, Cumbria. The effects of restocking on the species and subtypes of Cryptosporidium in farmed livestock, wild animals and surface waters, were compared with isolates from farms that had been continually stocked.
Field studies took place in two phases with the aim of taking samples before and after re-stocking. Whilst differences were observed between the phases, the prevalence of Cryptosporidium oocysts in the catchment was similar. This may be related to the rapid restocking of the catchment following the FMD cull and the relative resistance of Cryptosporidium in the environment during the de-stocked period.
This report can also be accessed on the FWR website.

Reassessing Cryptosporidium Risk: Treatment Security, Regulatory Monitoring and Epidemiology

Ref: 03/DW/06/16            Price: £10

ISBN: 1-84057-299-X

Companies can re-assess sites designated as "at significant risk" to have them removed from the Regulatory monitoring category. The report reviews the Regulatory monitoring data for Cryptosporidium, examines approaches some companies have taken to reclassify or reduce risk, and evaluates the feasibility of identifying association between oocyst concentrations in water supplies and incidence of human cryptosporidiosis. The primary objective was to provide alternative or complementary approaches relating to water treatment plant operation, to allow companies to select those appropriate to specific sites.

Cryptosporidium: Implications for Variable Declining-rate Filtration

Ref: 00/DW/06/14            Price: £10

ISBN: 184057 201 9

The objectives of the work were to review the principles of variable declining rate (VDR) filtration and the implication for Cryptosporidium risk, in comparison with constant rate rfiltration, particularly in a UK context. Results are provided for a survey f UK water companies, which suggested that up to 50% of filters may operate with declining rate characteristics. Consideration of the mode of operation and review of the literature suggested that flow surges may be of lesser concern than for constant rate filters, and average turbidity should be no higher for VDR. However, the higher flowrate at the beginning of the run could increase the impact of the ripening period. This could be dealt with in the same way as for constant rate filters, for example by slow start or run to waste.

Cryptosporidium and Water Treatment: Particle and Spore Counting, GAC and ManganeseFiltration and Backwash Settlement

Ref: 98/DW/06/7            Price: £10

ISBN: 1 84057 148 9

These studies fill a number of gaps in knowledge of removal processes and monitoring of Cryptosporidium during water treatment. The main findings are as follows. (i) Evidence of the potential benefits of spore measurement for further optimisation of plant performance is provided, although aggregation of spores needs to be considerd when interpreting the results. (ii) Floc shear can impair the performance of settlement of backwash water with respect to oocyst removal, but the effect can be reversed use of polyelectrolyte. (iii) Ozonation greatly enhanced particle removal by GAC filters. (iv) Suspensions of latex microspheres provide a practical technique for on- site checks of particle counter calibration.

Theory and Guidance on Assessing and Managing Cryptosporidium Risk in Groundwaters

Ref: 98/DW/06/6            Price: £10

ISBN: 1 84057 146 2

The report reviews and categorises factors which influence the risk of contamination of groundwaters with Cryptosporidium oocysts, in order to provide the basis for risk ranking of sources. Treatment processes for physical removal of oocysts from groundwaters are reviewed, particularly membrane systems and proprietary depth filtration devices. Novel high intensity UV units may also offer promise for inactivation of oocysts. Technical and indicative cost information on these treatments are provided to help in the selection of suitable techniques for particular groundwater applications.

Particle Counting and Bacterial Spore Analysis for Water Treatment Works Monitoring

Ref: 97/DW/06/4            Price: £10

ISBN: 1 84057 028 8

The report describes the results of monitoring at five water treatment works using bacterial spores and particle counting, to assess their potential as indicators of the risk of Cryptosporidium oocyst breakthrough. Three alternative makes of particle counter showed very similar performance for monitoring filtered water. Particle counting was a more sensitive indicator than turbidity of the filtered water quality changes which occur at the beginning of a filter run. Bacterial spore measurement, particularly using aerobic Bacillus spores, showed potential as an indicator of treatment performance for particle removal from the raw water.

Cryptosporidium Removal during Water Treatment

Ref: 96/DW/06/3            Price: £10

ISBN: 1 84057 058 X

This report is a continuation of a 1994/ 95 UKWIR contract investigating aspects of water treatment plant operation which influence removal or inactivation of Cryptosporidium oocysts. The results have provided further evidence of the effectiveness of conventional water treatment processes for oocyst removal, and have highlighted the importance of the early part of the filter run with regard to the risk of oocyst breakthrough from rapid gravity filters. The objectives of this work were: To assess the use of particle counters as tools to assist in filter operation; To demonstrate the extent to which operational practices on rapid gravity filters can influence the risk of Cryptosporidium breakthrough; To evaluate the performance of slow sand filtration for oocyst removal; To assess the effect of environmental exposure of oocysts on their susceptibility to disinfection; To identify the potential for spores of aerobic bacteria to act as surrogates for oocysts during water treatment.

Removal of Cryptosporidium during Water Treatment

Ref: 95/DW/06/1            Price: £10

ISBN: 1 84057 015 6

This report describes in detail the work undertaken to identify Cryptosporidium risks associated with water treatment plant operation, and ways of overcoming these risks. Particular areas for investigation are: - Aspects of rapid gravity filter operation which can influence the risk of Cryptosporidium oocyst breakthrough into the filtered water; Use of particle size monitors as indicators of filtration performance, compared with turbidimeters; Effects of recycling of settled backwash water supernatants; Potential for penetration of oocysts into a slow sand filter bed; Potential of ozone and UV irradiation as disinfectants for Cryptosporidium; Potential for microfiltration for control of Cryptosporidium in water treatment; Use of bacterial spores as surrogates for Cryptosporidium during water treatment.

Statistical Process Control and Other Techniques for Managing Cryptosporidium Risk in Water Treatment

Ref: 99/DW/06/9            Price: £10

ISBN: 1 84057 177 2

The report provides statistical techniques to allow operators to identify abnormal variations in final water turbidity which could pose an increased risk of Cryptosporidium breakthrough, and to set alarms accordingly. Techniques are also provided to allow the performance of individual process units to be compared. Additionally, the application of risk assessment methodologies to water treatment are reviewed.

A Review of Chemical and Electrochemical Inactivation of Cryptosporidium

Ref: 99/DW/06/8            Price: £10

ISBN: 1 84057 166 7

Both ozone and medium pressure UV offer promise for oocyst inactivation. However, the inactivation option is not feasible for achieving the proposed Regulatory standard in the UK. This would not preclude it as part of an overall risk reduction strategy, however, particularly when the disinfectants may be installed for other purposes. At the present time there is disagreement over which of the techniques for assessing inactivation is the most valid, so that the benefits can be quantified. In the longer term, human cell culture techniques show promise in this respect. However, there is insufficient information currently available for confident design of systems for oocyst inactivation.

Application of Statistical Process Control in Water Treatment for Managing Cryptosporidium Risk

Ref: 00/DW/06/15            Price: £10

ISBN: 1 84057 214 0

The aims of the work were to demonstrate the use of SPC in water treatment, to enable companies to identify techniques of potential value to their operating regimes, and to assist in their implementation. With respect to management of Cryptosporidium risk at surface water treatment works, techniques have been reviewed to provide: · sensitive analysis of turbidity trends in final water to rapidly identify any deterioration in treatment performance, · comparison of the performance of individual filters, with the potential to allow individual filters to be managed based on clearly defined statistical targets, · a statistical basis for setting turbity alarms for final water. For groundwaters, data available from two sites indicated that short- term turbitity spikes associated with flowrate changes could be clearly distinguished from longer term trends associated with rainfall. The operational capacity to differentiate between these would help manage Cryptosporidium risks assocated with rapid surface water ing

Review of the Use of Tracers to Investigate Pathogen Transport and Attenuation in Groundwater

Ref: 00/DW/06/13            Price: £10

ISBN: 1 84057 197 7

The wide range of tracers and test methods available are extremely useful tools for investigating hydrogeological problems although they have not been widely employed in pathogen transport investigations. Tracers may be particularly valuable for proving a hydraulic connection between a contaminant source and an abstraction borehole and for understanding the mechanisms controlling pathogen movement.

Monitoring Tools for the Operational Detection of the Rapid Influence of Surface Recharge on theQuality of Groundwater

Ref: 00/DW/06/12            Price: £10

ISBN: 1 84057 196 9

This review evaluates the usefulness of existing monitoring tools in fast flow assessments in UK aquifers, identifies other potentially applicable parameters and key areas for research. Analysis of water utility monitoring data suggests that no single parameter is useful in all situations and that microbiological determinands, turbidity, temperature and chlorine demand may all have a role. New parameters which should be assessed for operational use are particle counting and size index.

Transport and Fate of Cryptosporidium and Other Pathogens in Groundwater Systems

Ref: 00/DW/06/11            Price: £10

ISBN: 1 84057 195 0

This review shows that there is little information on the fate and transport of pathogens in UK aquifers below the soil zone. Cryptosporidium migration into the unsaturated zone will be attenuated by the soil, but pathways which allow soil- zone bypass are common on UK aquifer outcrops. Once oocysts have entered the subsurface survival for long periods seems likely.

Second Edition of a Guidance Manual Supporting the Water Treatment Recommendations from the Group of Experts on Cryptosporidium

Ref: 00/DW/06/10            Price: £10

ISBN: 1 84057 189 6

The manual, which supersedes the previous edition 98/DW/06/5, provides guiding principles for water treatment works operation to minimise the risk from Cryptosporidium, together with supporting information to demonstrate their validity. Separate sections are provided for individual unit processes, each beginning with a list of operational recommendations. Supporting information is given in sub- sections and in appendices, cross- referenced asappropriate. The manual is intended for use by treatment works managers and operational support staff, such as process scientists, with a working knowledge of water treatment.

Impact of dynamic system changes on customer acceptability

Ref: 22/DW/03/24            Price: £10

ISBN: 978-1-84057-946-8

Companies must work to ensure that customers continue to be satisfied with their drinking water when the treated water source they normally receive is blended or substituted with another. 
A tool has been designed to assess the impact of dynamic system changes on customer acceptability, named the “Blend Assessment Model” and is referred to as “the tool” within this document.

This document collates the process of researching the tools requirements, creating the tool and producing the accompanying monitoring guidance document.

Preventing Discolouration

Ref: 04/DW/03/21            Price: £10

ISBN: 1-84057-344-9

This report gives guidance on identifying and mitigating discolouration risks. In particular it: Explains the mechanisms by which discolouration occurs and identifies the factors which influence the risk of discolouration Reviews 170 previous discolouration incidents to identify their causes Proposes a process for assessing the risk of discolouration Gives guidance on various short-term measures for reducing discolouration risks This research is based on a literature review, a review of DWI incident assessment letters, field investigations and a workshop. The report comes with a CD ROM containing training material in the form of PowerPoint slides.

Distributing Drinking Water with Low or Zero Disinfectant Residual

Ref: 02/DW/03/19            Price: £10

ISBN: 1-84057-268-X

This collaborative project between UKWIR and Kiwa NV assesses the role of maintaining a disinfectant residual in water distribution through evaluation of literature, data and practical experiences in the Netherlands and in the UK. The report describes the advantages and limitations of the use of a disinfectant in drinking water during distribution. Areas for further research to improve operational management of the quality of drinking water in the distribution system have been identified. International cooperation, enabling comparison of different approaches and practices, proved very useful in identifying the main aspects of maintaining high water quality standards.

Operational and Maintenance Strategies for Maintaining Water Quality in Distribution Systems

Ref: 00/DW/03/12            Price: £10

ISBN: 1 84057 192 6

Various operational and maintenance strategies (and the activities that comprise the strategy) are adopted by water suppliers in order to maintain water quality at acceptable levels. Conversely, acitivities applied to a network for reasons other than water quality maintenance can be detrimental to the quality. Activities applied to networks were reviewed and ranked according to their impact on water quality. Guidance on designing a strategy for maintaining water quality is given. The procedure for undertaking a risk assessment of failing to conduct activities to maintain water quality is also provided.

Hydraulic Characterisation of Deposits and Review of Sediment Modelling

Ref: 01/DW/03/18            Price: £10

ISBN: 1 84057 241 8

Project aim is to identify the hydraulic characteristics of loose iron deposits and assess capabilities of sediment modelling to manage discolouration. The report is based on a combination of theoretical desk studies and the results of two field trials. Recommendations are given for typical sediment characteristics and values including specific gravity, particle size and sediment concentrations. Sediment transport theory and sediment analysis modules linked to hydraulic analysis software have been reviewed. Guidance is provided on assessing the risk of a discoloration when undertaking a specific network operation.

Changes in the Quality of Treated Water During Storage

Ref: 97/DW/03/8            Price: £10

ISBN: 1 84057 008 3

Analyses and discusses the results of a survey of treated water from twelve works to quantify "shelf life" and changes over time in terms of disinfection by- products and biological growth with respect to temperature, water type and disinfectant residual. Also assesses interaction of chlorine and monochloramine with biofilms and determines the formation of taste and odour compounds.

Migration Studies on Cement and Bitumen Coated Pipes

Ref: 97/DW/03/7            Price: £10

ISBN: 1 84057 065 2

Extracts of cement and bitumen coated pipes were tested for total organic carbon, polycyclic aromatic hydrocarbons, aluminium and pH. A general gas chromatography mass spectrometry scan was performed. The results are discussed in the context of such linings having to have, from December 1999, full approval under Regulation 25 of the Water Supply (Water Quality) Regulations 1989.

Review of the Identification Systems for Heterotrophic Bacteria Isolated from Water Distribution Systems

Ref: 96/DW/03/4            Price: £10

ISBN: 1 84057 055 5

Reviews the literature of commercial available techniques for isolating and identifying bacteria from water distribution systems. Evaluates three methods: API, Biolog and Cherlock MIDI using thirty eight water hetrotrophs isolated from borehole, upland and surface/ lowland waters. Concludes that, due to the limited number of water isolates in the databases, none of the systems were suitable.

To Quantify the Effect of Different Source Waters on Bacterial Growth in Chemostat DistributionSystems

Ref: 96/DW/03/3            Price: £10

ISBN: 1 84057 054 7

Quantifies the extent of bacterial growth in distribution systems from a borehole, a surface/ lowland and an upland source using chemostat distribution simulators. Reports the results of two runs varying the feed rate of the three test waters.

Sulphite Reducing Clostridia in a Revised Drinking Water Directive

Ref: 96/DW/02/5            Price: £10

ISBN: 1 84057 053 9

The revised Drinking Water Directive requires monitoring for sulphite reducing clostridia (SRC) and a limit of zero in 20 ml. Examines SRC as indicator of cryptosporidium and other pathogens and as a measure of treatment effectiveness. Concludes that SRC is ill defined and should be removed from the list of routinely monitored parameters.

Aspects of Modelling Chlorine Decay In Water Distribution Systems

Ref: 00/DW/03/15            Price: £10

ISBN: 1 84057 204 3

This report investigates the prediction of chlorine by means of a field study. The prediction of water age was successful. Further research is needed on chlorine decay. The importance of pipe material, diameter, temperature, pH, flow rate and degree of tuberculation are highlighted.

Benefits of Modelling Water Quality

Ref: 00/DW/03/14            Price: £10

ISBN: 1 84057 203 5

This report reviews the benefits/ disbenefits of modelling/ GIS tools for maintaining and monitoring water quality. It concludes that there are potentially great benefits but software capability is limited. The software that is readily available in the UK is listed with a summary of the capabilities of each package.

Effect of District Meter Areas on Water Quality

Ref: 00/DW/03/13            Price: £10

ISBN: 1 84057 205 1

From the modelling work, case study and discussions with the industry, it is concluded that the net long term effect of creating DMAs does not appear to be detrimental to water quality on a day to day basis. The short term effect of creating DMAs depends on the extent with which the network has a potential to cause water quality problems, eg does it contain deposits and/ or corroding mains. Where these exist it is highly likely that work to install new valves and the set up of the DMA will cause short term discoloured water for some customers.

Toolboxes for Maintaining and Improving Drinking Water Quality

Ref: 00/DW/03/11            Price: £10

ISBN: 1 84057 190 X

Toolboxes (or guidance documents) have been developed to facilitate implementation of the key findings from research on maintaining and improving drinking water quality in distribution. Individual documents have been written on seven key factors: disinfectant decay, trihalomethane formation, iron discolouration and particulates, tastes and odours, biofilms, coliforms, pH. 'Rules of thumb' for maintaining water quality are given in each toolbox. Guidance is also given on combining the rules. The toolboxes will be of interest to staff directly working in network operations as well as staff one step removed from the 'front- line'.

Chlorine and Monochloramine Demand of Materials for Drinking Water Distribution Systems

Ref: 98/DW/03/9            Price: £10

ISBN: 1 84057 144 6

Classifies disinfection demand of new pipe materials (polyethylene, PVC, grey iron, cast iron, bitumen lined or exposed ductile iron, cement and epoxy lined iron) and for old cement pipes, taking into account both the pipe wall and water effects. Defines a protocol allowing independent quantification and determines kinetic constants for models of chlorine and monochloramine decay during transit in pipes.

Strategic Review on Factors Controlling Microbiological and Chemical Quality of Water inDistribution Systems: Parts i-iv available as a set

Ref: 95/DW/03/1            Price: £10

ISBN: 1 84057

Reviews the literature on the topic areas of: factors that affect disinfectant residuals in distribution systems, the use of simulation systems for distribution networks, the biological stbaility of water taste and odour, and water quality modelling. Lists current organisations involved in this research and sets out priorities for UKWIR research.

Comparison of AOC and BDOC with Surrogates for Determining Nutrients in UK Drinking Water

Ref: 95/DW/03/2            Price: £10

ISBN: 1 84057 043 1

Measurements of nutrients in drinking water is currently carried out by one of two approaches, Assimilable Organic Carbon (AOC) or Biodegrable Dissolved Organic Carbon (BDOC). These approaches have evolved different analytical techniques. There was concern that the use of different methods may account for the apparent differences between typical AOC concentrations quoted for treated waters in the UK and those in mainland Europe. This work compared the KIWA AOC method with methods used in the UK for AOC and BDOC. Potential surrogates for AOC and BDOC were investigated. Waters from treatment works were monitored for nutrient content over a 24 hour period to investigate variability due to variation in flowrate. A desk study of the feasibility of reducing nutrients in water using current UK drinking water treatment practices was assessed. Substantial differences were found between methods carried out at different laboratories and between methods carried out at each laboratory. No surrogates were found for BDOC bu

Understanding and Preventing Discoloured Water

Ref: 01/DW/03/17            Price: £10

ISBN: 1 84057 215 9

This study aims to advance understanding on discolouration in drinking water. Work products include: - A literature review of corrosion and iron discolouration. - Analysis of relationships between corrosion, tuberculation and pipeline environment factors using information from a national pipe condition database. - Analysis of discolouration particles from distribution systems. - Detailed analysis of spatial and temporal relationships between discolouration and pipe bursts/ repairs in a DMA.

Predictive Statistical Analysis of Coliform Occurrences

Ref: 97/DW/02/3            Price: £10

ISBN: 1 84057 061 X

Bacterial coliforms are indicators of microbiological water quality. 99.5% of samples met with the microbiological standard in 1994, but intermittent occurrences of coliforms are still of concern to water supply companies. The objective of this project was to shed light on the reasons why coliforms occur in distribution systems. More specifically, it aimed to: identify statistical associations, both at the sample and zonal level, between coliform occurrences and other routine determinands in statutory monitoring data provided by UK water companies; and to develop and validate simple models for predicting increased probability of coliform occurrences in the drinking water supply. The study identified a variety of factors which influence the probability of coliform occurrences and these were used to put together a coliform predictive model. It was found that this model works well from one period to another and from one group of zones to another within the same company, but not very well from one company to anot

Developing a testing standard for nickel plated water fittings

Ref: 23/DW/04/22            Price: £10

ISBN: 978-1-84057-991-8

The project was initiated to address the ongoing issues of improving drinking water quality compliance for nickel at the kitchen tap and public health issues concerning nickel in drinking water. Nickel concentrations in potable water can be elevated where there are fittings or components of fittings that have been plated with nickel and chromium coatings. The project developed a testing methodology and criteria to identify nickel plated fittings based on standards used in UK, EU, Australia and New Zealand. The resultant project highlighted suitable laboratory based methodology, although more development is needed by associated industries to develop an accurate low level nickel technique for an equivalent field testing protocol. It is recommended the project outputs be adopted and used by fittings manufacturers to develop a long-term strategy to prevent unsuitable fittings being sold and used, reducing the risk of health impacts, and avoid non-compliance.

Improved slug pellet formulations to reduce risks to water

Ref: 23/DW/14/16            Price: £10

ISBN: 978-1-84057-975-8

Slugs are important pests of farms and gardens and slug bait pellets are frequently used to manage pest populations. Metaldehyde, the active ingredient in some slug pellets, leaches into drinking water sources, causing significant issues for the water industry. This project aimed to investigate how slugs responded to different pellet formulations in order to minimise the loss of metaldehyde to soil water. Three Inorganic Controlled Release formulations tested failed to mask the presence of metaldehyde from the slug or reduce leaching. Slugs readily contacted bait pellets within a few hours of starting foraging, but the presence of metaldehyde or ferric phosphate discouraged feeding. Either metaldehyde or ferric phosphate based commercial slug bait pellets can be used for managing pest slug populations. The output and conclusion from this research should be utilised by water companies to help with their catchment management strategies.

GAC Quality and Operational Management including Regeneration, alternative adsorbents, ozone and alternative oxidation technologies

Ref: 17/DW/14/15            Price: £10

ISBN: 1 84057 828 9

The purpose of this project was to gather information to help optimise GAC system performance and to inform the selection of water treatment strategies to deal with the threats posed by emerging pesticides. This UKWIR project produced:

(i) A ‘Guidance Manual’ which presents a critical review of water companies’ use of GAC (and ozone) over the past 20 years to identify best practices, in tandem with a review of available alternative design, monitoring and management solutions; it included the key parameters of interest, as they were identified, regarding current and future challenges faced within drinking water treatment.

(ii) A report ‘Review of emerging adsorption media and advanced oxidation processes’, which identified 26 technologies and determined whether these technologies could provide a cost-effective solution to water quality issues; and to design an information framework for developers, manufacturers and suppliers. 

Pesticide Risk Mapping and Catchment Interventions - Phase 2

Ref: 16/DW/14/14            Price: £10

ISBN: 1 84057 822 X

Pesticide risk maps for mobile herbicides (applied to arable and grassland) and metaldehyde (applied to arable land only), covering much of the UK at a field level, have been produced.  These have been incorporated into new software tools for use of these risk maps in both a planning and operational sense.  The software solution development and roll out comprised various complementary components and catered for water companies with and without access to desktop ArcGIS ie: Desktop ArcGIS mapping tool for spatial and non-spatial data management or a standalone WinForms desktop tools for data management in companies without access to ArcGIS; Microsoft (MS) Excel based desktop tools for reporting, planning and costing; MS Excel based field risk calculator.  An accompanying survey of intervention effectiveness studies/trials within this AMP period allowed for the potential to improve default values built into the software as well as promote awareness of activities within the industry.

The QuickCalc Risk Calculator is available for free download to all by clicking here.

Maintaining Awareness of Microbiological Epidemiological Studies on Drinking Water

Ref: 99/DW/01/2            Price: £10

ISBN: 1 84057 178 0

no abstract available

Prevention and Control of Water Related Disease in Europe - an Economic Assessment

Ref: 00/DW/01/4            Price: £10

ISBN: 1 84057 202 7

The costs and benefits of the prevention of water related disease in the WHO pan- European region is examined, focusing on narrowing the gap between the Eastern and Western regions. It is estimated that 30 million water related disease incidents annually could be avoided in the Eastern region. To achieve this, an estimated annual expenditure of 30- 50 Euro per capita would be required, whilst the benefits of disease prevention were estimated at about 30 Euro per capita (or 13 bn Euro, total). However, the limitations of the study are discussed, and it is argued that the net benefits are likely to be substantial.

Maintaining Awareness of Microbiological Epidemiological Studies on Drinking Water

Ref: 95/DW/01/1            Price: £10

ISBN: 1 84057 097 0

Reviews the current status of epidemiological studies related to gastrointestinal illness in the community with a potential link to drinking water meeting current standards. Bases on literature search and discussions with experts. Includes a full critique of the two main international studies in canada and their relevance to the UK. Gives guidance for future studies.

Brass fittings as a source of lead and nickel in drinking water. Stage 3 Long term testing April 2015 to March 2016

Ref: 16/DW/04/19            Price: £10

ISBN: 1 84057 823 8

Metal leaching from pipes and fittings into drinking water has been an issue in the UK for several decades, particularly as standards have progressively tightened (the Prescribed Concentration Value (PCV) for lead reduced to 10 µg/l from 25 µg/l in December 2013). This study has examined the leaching of lead, nickel and other metals of interest from UK brass fittings and US low lead fittings in hard and soft water, with and without phosphate dosing. In Stage 1, laboratory and short term (up to 6 month) field experiments on lead leaching were undertaken on a range of brass fittings. In Stage two, longer-term (up to 2 years) lead and nickel leaching characteristics were examined together with experiments on the removal and addition of phosphate dosed water. Stage three, reported here, has continued the study of the long term leaching characteristics of lead and nickel from the brass fittings (up to 3 years including stages 1 and 2) and other metals of interest (Al, Cu, Zn, Fe & Mn), The overall findings show that metal leaching decreases with time in both hard and soft waters.  In non-phosphate dosed waters some individual brass fittings and combinations of fittings can potentially cause failures to Random Daytime Sample for lead and nickel, especially when new or following periods of stagnation. Phosphate dosing was shown to be an effective way of suppressing metal leaching (particularly lead, nickel, copper and zinc) from brass fittings.

Customer taps and their influence on water quality

Ref: 16/DW/04/18            Price: £10

ISBN: 1 84057 816 5

Water companies suspect that microbiological and metal water quality failures are increasingly attributable to the changing design and functionality of kitchen taps and their ancillary fittings. The past 10 year’s annual reports from the UK regulators, published literature and unpublished data from water companies on taps and their effects on water quality were reviewed. Links between tap design and water quality failures were established and a tap classification developed to enable water companies to better capture data whilst conducting sampling. The report sets out guidance on a range of measures to reduce the risk of contamination of drinking water and water sample failures from kitchen taps. Some are within the control of water companies and some require collaboration with other stakeholders.

Brass Fittings - Metallic composition of fittings

Ref: 15/DW/04/17            Price: £10

ISBN: 1 84057 799 1

This is one of two reports on Stage 2 of ongoing research to increase understanding of how brass fittings contribute to lead and nickel concentrations in drinking water. It examines the alloy composition of brass taps, connectors, stop taps, meters and ferrules, including some low lead models, using X-Ray Fluorescence (XRF) Spectroscopy and wet chemistry. XRF Spectroscopy is shown to compare favourably with wet chemistry analysis, offering a non-destructive means for screening brass fitting composition. The observed alloy compositions are compared with the composition of alloys currently included in the 4MS Composition List, but few matches were found. The relationship between lead and nickel yields after 16-hour stagnations and the alloy compositions of brass fittings is examined. The report also covers an exercise to examine leaching of other metals of interest, including copper, zinc and iron, from a range of brass fittings deployed on long term test rigs.

Brass fittings as a source of lead & nickel in drinking water - long term leaching studies

Ref: 15/DW/04/16            Price: £10

ISBN: 1 84057 798 3

This is one of two reports on Stage 2 of ongoing research to increase understanding of how brass fittings contribute to lead and nickel concentrations in drinking water. It examines yields of lead and nickel, and the effect of the addition and cessation of phosphate dosing on brass fittings deployed on long term test rigs. It also examines the effect of chlorine or chloramine dosed water on leaching from a laboratory trial. It identifies situations where individual brass fittings or combinations of fittings can routinely yield a few µg/l of lead or nickel and circumstances where their respective Prescribed Concentration or Value (PCV), of 10 µg/l and 20 µg/l respectively, could be exceeded following periods of stagnation. The dosing of phosphate is shown to quickly reduce leaching of lead and nickel, whilst the cessation of dosing is shown to increase leaching within a few days.

Customers' Lead Pipes - Understanding Reluctance to Change

Ref: 14/DW/04/15            Price: £10

ISBN: 1 84057 724 X

This study identifies successful ways of engaging with water customers who are at risk of exceeding the standard for lead in drinking water and encouraging them to replace their lead supply pipes. It also provides estimates of the number of customers likely to replace their lead pipes assuming different interventions, and hence determines the overall effectiveness of potential lead replacement programmes.
The research programme involved consulting with water companies about strategies they are adopting to encourage customers to replace their lead supply pipes, and how successful they have been. Secondly, it involved qualitative and quantitative surveys with water customers who have been advised to replace their lead supply pipes (following a failed lead test, or because they live in an area wide replacement programme location), and with customers who have chosen to replace their lead supply pipes without being encouraged to do so by their water company.

Brass Fittings - A Source of Lead in Drinking Water?

Ref: 14/DW/04/14            Price: £10

ISBN: 1 84057 715 0

This study investigated the contribution to lead in drinking water from typical brass fittings found between the water main and the kitchen tap. Fittings and circumstances that have the greatest potential to give rise to elevated concerntrations of lead in drinking water have been assessed through a combination of literature analysis, engagement with water companies and fittings manufacturers, laboratory stagnation tests and longer term field trials. The latter comprised deployment of test rigs containing a selection of high and low lead brass fittings at two water treatment works to compare leaching in hard and soft water, with and without phosphate dosing.
The practical studies showed that new brass fitiings leached lead at concentrations that could contribute significantly towards total lead in drinking water at the tap. However lead concentrations fell over a few weeks even in the non-phosphate dosed waters. It was also observed that there was often variation in the amount of lead that leached from the same type of fitting, lead leaching was higher in soft water, that low lead brasses leach less lead, and that phosphate dosing significantly reduces lead leaching.
The information will assist in developing strategies for the water industry and regulators to continue reducing lead levels in drinking water.

Lead Pipe Replacement - AMP6 and Beyond: The Perspectives of Customers and Landlords

Ref: 12/DW/04/13            Price: £10

ISBN: 1 84057 629 4

This qualitative research study explores potential ways of encouraging property owners to replace lead pipes; potential ways forward in terms of partnership working to resolve the issue; and provides insight into water customers' understanding of issues surrounding lead in drinking water and expectations and likely behaviour when made aware of the issues.
Topics such as awareness and attitudes to risk, key motivators/barriers to action, and views on portential interventions were explored with customers and landlords through a series of deliberative workshops across the UK and through depth interviews, respectively. Key stakeholders were consulted through interviews and a Knowledge Sharing Workshop.
The research findings suggest that a carefully designed and managed information campaign, targeting high risk groups in high risk areas, will be key to raising awareness on the issues of lead in drinking water and, ultimately, in encouraging customers to replace lead pipes. Other supporting recommendations are also provided.

Alternatives to Phosphate for Plumbosolvency Control

Ref: 12/DW/04/12            Price: £10

ISBN: 1 84057 622 7

This report and associated spreadsheet-based tool provide UKWIR and water companies with the opportunity to assess the long term economic costs and benefits of phosphorus dosing and possible alternatives to reducing lead levels in drinking water, such as lead pipe replacement or rehabilitation. It examines current water company approaches to meeting the new drinking water standard for lead of 10micrograms/litre, which is to be applied from December 2013. Existing industry data forms the basis of a spreadsheet-based tool for estimating financial and wider economic costs and benefits (eg impacts on health and phosphorus removal in wastewater treatment) of different approaches to managing lead levels in drinking water, prudently allowing assessment of potential future increases in phosphate prices. The report concludes that alternatives to phosphate dosing far outweigh its current cost; however, ensuring compliance is unlikely without remediation of customers' lead supply pipes as well as internal plumbing, lead solder and fittings containing lead. The report acknowledges uncertainties in impact estimation, particularly relating to health and the environment, but data within the tool can be easily updated as more accurate information becomes available.

Investigation into the Emerging Issue of Fluorapatite Formation

Ref: 08/DW/04/11            Price: £10

ISBN: 1 84057 497 6

Fluorapatite is a crystalline compound of calcium phosphate incorporating fluoride ions in its structure. Crystals are hard and highly insoluble within the normal range of potable waters. Formation of the compound is accelerated by an increase in temperature and this study was commissioned as a result of problems experienced with fluorapatite scale in heating equipment, notably domestic boilers.
The study identifies water characteristics that influence fluorapatite formation and maps areas where fluorapatite has been observed in the UK to date and areas that are considered to be at risk should fluoride dosing be introduced in the future.
The report includes a simple Excel utility that allows water companies to review the risk of fluorapatite precipitation for the specific water quality prevailing in their supply areas. The report includes a number of methods of reducing the risk of fluorapatite formation.

Investigations into the Occurrence of Water Supply Zones that Demonstrate Resistance to Phosphate Dosing for the Control of Lead in Drinking Water

Ref: 08/DW/04/10            Price: £10

ISBN: 1 84057 471 2

Investigation of 13 UK water suppliers found three companies with a zone or zones that were resistant to phosphate use for plumbosolvency control: despite application of an appropriate dose and good control, lead concentrations had not decreased over several years. No common cause could be identified. Zones with greatest resistance had a history of exposure to significant background levels of phosphate in the source water; this requires further investigation. The majority of zones investigated had responded to phosphate; some demonstrated apparent resistance because the dose was insufficient, not applied for sufficient time or not well controlled. The investigation was hampered by a lack of robust data on lead pipe populations.

Concentration of Lead at Customer's Taps: Trends in Monitoring Data from 1990 - 1996

Ref: 98/DW/04/5            Price: £10

ISBN: 1 84057 147 0

Analyses concentrations of lead at customer taps for 24 water companies in the UK and determines trends in compliance from 1990 to 1996 using arithmetic mean, geometric mean and median values. Tabulates the effect of different limit of detection interpretation on compliance with the 10µg/ l limit. Assesses the effect of phosphate dosing on lead concentrations.

Metals Arising from Domestic Pipework and Fittings

Ref: 97/DW/04/1            Price: £10

ISBN: 1 84057 099 7

Examines fifteen metal contaminants in drinking water and their likely sources using reported prescribed concentration or values exceedences. Major source of contamination is from materials used in the distribution system with only lead being of significance from the domestic plumbing system. Discusses problems of non- approved fittings and use of corrosion inhibitors. Considers current methods of sampling the customer's tap and implications of new EC lead standard.

Approaches for Controlling Plumbsolvency

Ref: 97/DW/04/4            Price: £10

ISBN: 1 84057 100 4

Gives causes and extent of plumbosolvency in the UK in the context of the proposed EC Directives changes. provides a survey of current techniques and potential for application for a range of sample waters. Describes and compares pH control, alkalinity altering and orthophosphite dosing, as well as pipe replacement and relining techniques. Discusses situation in Europe, Japan and USA.

Concentration of Lead at Customers’ Taps: A Statistical Approach

Ref: 97/DW/04/2            Price: £10

ISBN: 1 84057 030 X

Uses real data from 1990 to 1995 from 24 water companies to test a wide range of possible statistical interpretations that are likely to emerge from the revised Drinking Water Directive. Shows the wide variation in compliance when using arithmetic and geometric mean, maximal values, percentiles etc. and when applying different sample sizes in water supply zones.

Maintaining and Improving Water Quality in Domestic Pipework and Fittings – Review ofDevelopments for Meeting Lead Compliance

Ref: 99/DW/04/9            Price: £10

ISBN: 1 84057 176 4

The statistical method used to interpret utility data is crucial in understanding the degree of compliance with the interim and final lead regulations. Analysis of data has indicated that control of particulate lead is important in reaching compliance. Relining or replacement is the only serious option to achieve compliance at 10* g/ l. The techniques available need further development before becoming feasible, cost effective options. Remote detection of lead pipes is currently not technically possible without direct access to the pipe.

Concentration of lead at customers taps': Trends in monitoring data 1990 to 1998

Ref: 99/DW/04/8            Price: £10

ISBN: 1 84057 175 6

Lead statutory monitoring data from UK water companies for 1997 and part of 1998 were collected and entered into an Industry database. Three methods of statistical analysis (arithmetic mean, geometric mean nad median) were used to assess whether water qualtiy zones would comply with the current and future maximum permissible lead concentrations in drinking water (i. e. 50, or 10 m g/ l). The results were incorporated with earlier data to show trends in lead compliance between 1990 and 1998. The effect of phosphate dosing was assessed for some companies.

Viruses in Groundwater

Ref: 18/DW/02/89            Price: £10

ISBN: 1 84057 861 0

Increasing attention is being given to the presence of viruses in groundwater. Whilst there have been a few well documented outbreaks, it has been suggested that viruses may also contribute to a low level of sporadic illness in communities served by groundwater supplies. This review assesses the evidence for the occurrence of viruses in groundwater and the associated health risk. It also considers the various routes of contamination and examines factors known to influence virus fate and behaviour in the underground environment. The adoption of a multiple barrier approach, which combines the benefits of source protection and effective disinfection, is seen as an effective strategy to minimise the risk posed by viruses in groundwater This approach can be strengthened by developing a sanitary survey that provides a rigorous and numeric site-specific risk assessment.

Cryptosporidium spp. in animal hosts with potential for impacting on sources of drinking water in the UK

Ref: 17/DW/02/85            Price: £10

ISBN: 1 84057 844 0

Over recent years, an increasing number of new species of Cryptosporidium have been discovered from a range of different animal hosts and molecular methods have greatly improved our knowledge of the public health significance posed by those species recognised. Research has shown that many species are not confined to a single host and that variation in pathogenicity exists within species known to infect humans. In light of these developments, this special topic review was undertaken to provide water companies with a current understanding of risks posed by this organism. It will permit more accurate sanitary surveys for identifying catchment control measures to reduce the risk from Cryptosporidium and the burden on water treatment.

Invasive and Non-Native Species (INNS) Implications on the Water Industry

Ref: 16/DW/02/82            Price: £10

ISBN: 1 84057 826 2

In light of new legislation, including the Infrastructure Act 2015, surrounding the control and management of Invasive Non-Native Species (INNS), this UKWIR project has assessed the potential obligations for the UK water industry and their role in meeting legal and social requirements.

Predictions of the likely INNS species threat for 10 INNS species over the period 2015-50 were compiled, together with a catalogue of management measures. Overall five key actions were identified, to support manage and aid compliance, these were: the development of INNS pathway management plans; the integration of companywide biosecurity policies into business as usual operations including supply chain management; the delivery of preventative surveillance monitoring programmes; the provision of appropriate wash down facilities; and continuous targeted stakeholder engagement.

This report is available to purchase in hard copy format at cost, or for free download by clicking here.

Review of health outcome targets adopted worldwide for assessing the microbiological safety of drinking water

Ref: 16/DW/02/80            Price: £10

ISBN: 1 84057 825 4

Around the world, countries are moving towards health-based targets for assuring the microbiological safety of drinking water. The status of these developments is reviewed in this report. It shows the adoption of the Disability Adjusted Life Year in several countries as a metric for assessing safety although the level of risk infection is preferred elsewhere. Implementation does, however, require knowledge of the pathogen burden in source waters and, for practical application during water treatment, quantitative microbial risk assessment has been used to convert these targets to required pathogen elimination credits. No standard framework was found to be available for conducting this exercise and different approaches have been used which vary in their complexity. If a suitable framework was adopted, UK water companies could benefit from such an approach as a means of demonstrating pathogen removal.

Effect of turbidity on the efficiency of disinfection of waterborne bacteria

Ref: 16/DW/02/79            Price: £10

ISBN: 1 84057 819 X

The overall objectives were to identify the major types of turbidity which pass into the final stage of disinfection and to carry out laboratory studies to identify differences in shielding, disinfectant demand, and disinfection rate caused by the major types of turbidity. With increasing turbidity there was an increase in particle concentration for all of the turbidity causing materials (TCMs) tested (clay, chalk, humic acid, iron, manganese dioxide). There were, however, differences in the number of particles that caused the same turbidity signal, due to differences in how the materials scatter and interact with the light used to measure turbidity. For the particles under investigation, iron and chalk might cause a significant shielding effect for bacteria during disinfection as a result of aggregation and they should be reduced in water as much as possible prior to disinfection.

Humic acid was the only TCM investigated that had a chlorine demand and this decreased the efficiency of disinfection. For UV treatment both humic acid and iron had a significant detrimental impact on disinfection due to decreasing UV transmission. 

UV Treatment of Pathogens Relevant to Dirnking Water - Recent Inactivation Data

Ref: 16/DW/02/77            Price: £10

ISBN: 1 84057 807 6

UV irradiation is known to be effective against a wide range of pathogen types. Recent UV inactivation data compiled for this report has confirmed its efficacy against Cryptosporidium and shown that it can provide effective treatment of many waterborne viruses and bacteria. Adenoviruses, however, have been shown to demonstrate a marked resistance to UV inactivation but also to be more sensitive to low (<220 nm) wavelengths than many other pathogens. Medium Pressure UV systems have been shown to be more effective than Low Pressure UV systems for adenovirus inactivation, although their performance is similar for bacteria and protozoa. Whilst organisms have mechanisms to repair damage caused by exposure to UV, these do not appear to be significant for drinking water.  The review has considered the impact of validation protocols on determination of UV efficacy.  Overall, UV treatment offers an additional barrier for pathogen elimination to compliment chlorination.

Inactivation of Microorganisms by Chlorine, Chlorine Dioxide and Monochloramine During the Final Stage of Disinfection in Water Treatment

Ref: 14/DW/02/73            Price: £10

ISBN: 1 84057 747 9

Chemical inactivation forms the final barrier in water treatment with free (available) chlorine being the predominant process. This study has compiled recently available data on its ability to inactivate a range of waterborne pathogens, especially viruses. For comparative purposes, chlorine dioxide and monochloramine were included within this review although not commonly used for this purpose in the UK.

Despite certain inconsistencies in the data, the findings support the view that a Ct of 15mg.min/l, widely adopted as a benchmark in the UK, is capable of achieving a minimum 4-log reduction in numbers of common waterborne viruses and bacteria under conditions normally experienced during treatment. This work will enable water companies to demonstrate the validity of their disinfection policies.

Sources and Occurrence of Enteric Pathogens in the Environment and Implications for Water Companies

Ref: 13/DW/02/69            Price: £10

ISBN: 1 84057 695 2

The recently introduced risk assessment strategy for managing water supplies requires companies to have knowledge of the specific pathogens likely to be found in each of their sources of drinking water. This review has compiled data on the occurrence and abundance of viruses, bacteria and protozoa reported for various types of source water. Information was limited, but where available it was used to assess its potential for estimating the numbers of pathogens in sources of drinking water to assist in producing effective disinfection policies.

Implications of Microbial Colonisation of Water in Buildings

Ref: 13/DW/02/67            Price: £10

ISBN: 1 84057 663 4

The aim of this report is to provide water companies with an informed assessment of the current knowledge and understanding of the origin and behaviour of the organisms of potential health significance in plumbing systems. The review considers each organism separately and examines their ability to become established in plumbing systems, and suitable control measures. The risks presented by microbial colonisation of water systems in buildings predominantly concern Legionella, although a range of other organisms have also been implicated recently including Pseudomonas aeruginosa. These organisms are generally regarded as opportunistic pathogens, and have the shared ability to colonise plumbing systems. The study recognised that the water safety plan provides an ideal platform for managing the quality of water in buildings, and that all stakeholders have an important role in supporting their development.

Review of Quantitative Microbial Risk Assessment Applied to Drinking Water

Ref: 11/DW/02/64            Price: £10

ISBN: 1 84057 615 4

Quantitative microbial risk assessment (QMRA) has emerged as a tool for deriving estimates of the risk of exposure to pathogenic organisms through specific routes of transmission, that would otherwise be difficult to determine epidemiologically. It is being increasingly applied worldwide as a means of assessing treatment pactice and to judge whether drinking water is of an acceptable quality. This report reviews the developments in QMRA and considers its potential for use in determining the robustness of water company risk assessments, as a tool to support decision making, to evaluate the effectiveness of different control strategies and to assess the impact on water quality from extreme events or changing conditions.

Removal of Micro-organisms During Water Treatment

Ref: 10/DW/02/59            Price: £10

ISBN: 1 84057 553 0

Water companies are being encouraged to take an integrated approach to assessing and managing risks through the entire supply chain from catchment to tap. In this study, data have been extracted from the recent literature and used to derive indicative values for removal efficiencies of waterborne pathogens that can be achieved by the processes used in water treatment, including ozone and UV but not chlorine or chlorine-based disinfectants. This information could be used to validate the performance of these processes and may allow their contribution to be taken into account when setting an appropriate treatment policy for disinfection within the Drinking Water Safety Plan.

Validating the Cause of Coliforms in Drinking Water

Ref: 09/DW/02/58            Price: £10

ISBN: 1 84057 548 4

The response to the detection of coliforms in drinking water requires immediate action to investigate their origin and implement appropriate corrective action. This study, jointly supported by UKWIR and the Drinking Water Inspectorate (DWI), developed an approach for systematic investigation into the occurrence of coliforms and E.coli in water supplies. Water company procedures and reporting of incidents were reviewed for consistency of approach, and elements of good practice identified, This was developed into a procedure consisting of a sequence of steps, directed by a flow chart, with each step cross-referenced to a toolbox containing appropriate actions for each stage of the investigation. This allows water companies to respond in a timely and effective manner that is proportionate to the incident under investigation, whilst at the same time ensuring that public health is not compromised.

Integrating DOMS & Drinking Water Safety Plans

Ref: 08/DW/02/52            Price: £10

ISBN: 1 84057 515 8

This project considered the integration of water company Distribution Operation and Maintenance Strategies (DOMS), Drinking Water Safety Plans (DWSPs) and analysis within the context of the Capital Maintenance Planning Common Framework (CMPCF).
The project focused on providing guidance to companies on how they could address the integration of DOMS and DWSPs within their Draft and Final Business Plans by way of a Technical Note and a training and discussion workshop. In addition, the project team carried out interviews with six companies to explore the approaches to the three processes taken by the water industry.
The project also aimed to provide guidance to companies on longer term integration issues. Several recommendations were put forward for consideration by individual companies as potential steps towards integration. A principal output of this report was the proposal for an integrated process encompassing DOMS, DWSPs and CMPCF.

Real Time On-line Monitoring of Contaminants in Water - Developing a Research Strategy from Utility Experiences and Needs

Ref: 08/DW/02/51            Price: £10

ISBN: 1 84057 511 5

'Real Time On-line monitoring of Contaminants in Water' is a collaborative project between UKWIR, Awwa Research Foundation (AwwaRF) and Kiwa Water Research. The report describes current and emerging sensor technologies for real-time and on-line monitoring of contaminants in water, makes an inventory of water utility experiences and needs and presents a research agenda. Information was gathered from workshops with utility representatives in the UK, US and the Netherlands, from additional data provided by members of the Global Water Research Coalition, and from a technology review of current sensor systems.

Drinking Water Safety Plans - Stakeholder Communications

Ref: 08/DW/02/49            Price: £10

ISBN: 1 84057 500 X

This project investigated the communicaation of Drinking Water Safety Plans with four critical stakeholders: the Drinking Water Inspectorate (DWI), Counsumer Council for Water (CCWater), Health Protection Agency (HPA) and the Environment Agency.
The aim of the interviews with the stakeholders was to provide a consensus for communicataion on approaches to risk assessment between the industry, regulators and customer support groups. Of particular importance was to explore how the DWI can work with the water industry to provide a common and agreed approach to all stakeholders who may require information on water quality. The project porvided an arena for the exchange of information, clarification of particular requirements and exploration of future ways of working and relationships.

Drinking Water Safety Plans - Risk Based Approach

Ref: 08/DW/02/48            Price: £10

ISBN: 1 84057 499 2

This project has assessed the progress made with DWSPs by the UK water companies, the approaches taken to risk assessment and any strengths, weaknesses or issues with the DWSP process. An evaluation of how DWSPs integrate with and support the 2009 Periodic Review (PR09) process was carried out. The project has provided a clear view of progress made by the industry with the developemnt of DWSPs. The situation has been given additional urgency by the new regulatory requirements and the need for risk assessments for every water treatment works and water supply system to be completed by October 2008.
The evaluation of the DWSPs through the use of assessment criteria and categories has provided compamies with valuable feedback on their approaches to their DWSPs, particularly with regard to risk assessment where a wide range of approaches have been taken.

Scoping Study on the Implications of Bacterial Pathogen Associations with Protozoa in Drinking Water

Ref: 07/DW/02/46            Price: £10

ISBN: 1 84057 461 5

This review has briefly assessed the health risks associated with the relationship between bacterial pathogens and protozoa in water supplies. It appears that the protozoan host may protect these bacteria from disinfection during water treatment. The number of reported associations is increasing, with the most commonly reported being that between Legionella pneumophila, and several types of protozoa.

Biofilms appear to be the natural habitat for many of these protozoa. Evidence, so far only from laboratory studies, indicates that some bacterial pathogens are able to multiply within protozoa. This may give rise to elevated numbers of bacteria on lysis of the host. Faecal indicator bacteria do not appear to form such relationships, and so compliance monitoring should be unaffected.

This review indicates that these relationships are extremely unlikely to be the cause of water associated outbreaks of illness. However, their role in causing sporadic illness requires further investigation.

A Briefing on Microorganisms and Drinking Water Supplies - A Review of the Literature 2005-2006

Ref: 06/DW/02/42            Price: £10

ISBN: 1 84057 419 4

This review of the literature for 2005-2006, reveals, as in previous years, that there are no immediate or foreseeable threats to the safety of drinking water supplies in the UK.

The review recommends that the microbiological topics of most immediate, operation importance are:

• The efficacy of UV disinfection as an effective barrier to Cryptosporidium
• The potential microbiological challenges of using poorer quality source waters for drinking water supplies during droughts.

Some potential threats were identified, and in depth reviews of these should be considered, such as the growing evidence of associations between bacterial pathogens of concern and protozoa. These relationships could allow pathogens to survive water disinfection and enter supply.

Bacteriological Indicators of Water Quality

Ref: 05/DW/02/41            Price: £10

ISBN: 1 84057 394 5

This review and consultation has shown that analysis of the results of regulatory monitoring for total coliforms and heteroptrophic plate counts provides information on the condition and performance of the water supply system which can be usefully used as part of a risk management strategy. There is a consensus view that the detection of coliforms in a sample should initiate an investigation by the Operator but should not, on its own, be considered a failure to supply safe water.

A Briefing on Microorganisms and Drinking Water Supplies: A Review of the Literature 2004-2005

Ref: 05/DW/02/40            Price: £10

ISBN: 1 84057 392 9

This review focuses on the period of April 2004 to March 2005. Literature containing information relevant to the microbiological quality of water was appraised and the implications for the Industry assessed.
No immediate threats to the safety of drinking water supplies were identified. However, there were some topics that merit further consideration when prioritising future research needs. These are:
- Increasing evidence that UV irradiation .can provide an effective barrier against Cryptosporidium.
- Suggestions that drinking water could be responsible for sporadic cases of campylobacterosis.
- The public health significance of the release of Helicobacter and Mycobacteria from biofilms
- The role that chlorine residuals in distribution have in protecting public health

Catchment to Consumer: Water Safety Plans Part 2

Ref: 05/DW/02/39            Price: £10

ISBN: 1 84057 391 0

An Electronic Guidance Manual has been produced to guide water companies through developing and implementing Water Safety Plans (WSP). The manual is based on the framework developed during Part 1 of the UKWIR project report titled "Managing microbial and chemical risks from source to tap: report and toolbox", Ref. No. 03/DW/02/31, published in 2003).

It provides a practical interactive methodology, and incorporates the knowledge and flow paths compiled for Part 1 of the UKWIR project and the World Health Organisation (WHO) Guidelines for Drinking-Water Quality, 3rd Edition, 2004.

A Review of Ct in Water Disinfection

Ref: 05/DW/02/37            Price: £10

ISBN: 1-84057-377-5

The inactivation rate of microorganisms by disinfection is commonly expressed as the product of the concentration (C) and the contact time (t). In this report, methods for determining the optimum Ct value have been reviewed, as have influential factors such as temperature and pH. In the United Kingdom, water companies have developed their own strategies based essentially on chlorine residual measurement, contact time and compliance with statutory microbial standards. This has generally produced Ct values of around 15-30 mg.min/l that should be adequate to achieve compliance with the UK and European regulations and inactivate pathogenic bacteria.

This report provides a useful guide to the origins of the Ct concept, methods for its determination and factors influencing disinfection efficiency as well as a review of disinfection strategies used elsewhere in the world.

A Briefing on Microorganisms and Drinking Water Supplies: A Review of the Literature 2003-2004

Ref: 04/DW/02/35            Price: £10

ISBN: 1-84057-352-X

This series of annual reviews aims to provide the water industry with an "early warning" of potential threats to the safety of public drinking water supplies posed by emerging or novel pathogens.

The review has not highlighted any pathogens of immediate concern and there is no evidence to suggest that any emerging pathogens are posing a risk through public supplies in the UK. Overall, the microbiological quality of drinking water leaving treatment works in the UK is excellent and the adoption in the future of Water Safety Plans should provide added security to public health.

Current concerns about the microbiological safety of water derived from public supplies relate to the growth organisms, such as Legionella, Mycobacterium and Acanthamoeba, in distribution systems within buildings. Although Acanthameoba is a concern as a pathogen in its own right, it may play a role in the transmission of other pathogens.

The bacterial pathogens that continue to be of interest to public supplies are., Helicobacter spp. and Mycobacteria spp. Here further research work is currently in progress to ascertain the reality of the theoretical threat that these organisms could pose. Although viruses, such as norovirus, may be transmitted through drinking water, the use of disinfection in the UK ensures adequate protection. The risks posed by Cryptosporidium oocysts appears to have been addressed by the DEFRA Cryptosporidium regulations and the activity of the Water Companies.

Review of the Microbial Implications of Climate Change for the Water Industry

Ref: 04/DW/02/32            Price: £10

ISBN: 1-84057-318-X

This report assesses how the current predictions for climate change could impact on the microbiological quality of drinking water. On current evidence, changes in the worldwide geographical distribution of pathogens caused by climate change, including those borne by vectors such as mosquitoes, are unlikely to have a significant impact on infections from drinking water in the UK. At works using river abstraction, the predicted increased frequency of storm events will impact on raw water quality. Higher turbidity and associated increased microbial loadings will present a greater challenge to coagulation and disinfection processes It is concluded that the potential effects of climate change will not pose a threat to well managed water treatment plants. Problems could arise with private water supplies, and supplies derived from surface waters where filtration is not used. Groundwaters that can be influenced by surface water, but which are not filtered, may also be vulnerable.

Managing Microbial and Chemical Risks from Source to Tap: Report and Toolbox

Ref: 03/DW/02/31            Price: £10

ISBN: 1-84057-311-2

The traditional approach to assuring drinking water quality and safety by monitoring final water at the works and at the tap has been the foundation of regulation to date. Such an approach is resource intensive and, for many parameters, the quality of water is only known after it has been distributed; thus not providing sufficient re-assurance for consumers or suppliers. An alternative approach, being considered internationally, is to move to more proactive management of risks through greater process monitoring and control. The framework and toolbox outlined in this report provide a structure in which the proactive management approach can be adapted to the circumstances and requirements of individual water companies, building on existing company procedures.

A Briefing on Microorganisms and Drinking Water Supplies: A Review of the Literature 2002-2003

Ref: 03/DW/02/28            Price: £10

ISBN: 1-84057-297-3

This review is an expert independent assessment of the scientific literature on micro-organisms of concern in drinking water-related disease. It highlights those organisms of special concern and provides advice on their significance. The public water supplies in the UK are of good microbiological quality and are rarely the cause illness in the general population. Cryptosporidium remained the most important infectious disease threat to mains drinking water. Vigilance must be maintained to prevent potential problems and continue awareness of emerging pathogens. Recent research has shown that some private drinking water supplies with quality problems are associated with outbreaks of illness in communities.

A Briefing on Microorganisms and Drinking Water Supplies: A Review of Literature 2001-2002

Ref: 02/DW/02/26            Price: £10

ISBN: 1-84057-267-1

The report provides an expert independent assessment of the scientific literature on micro-organisms of concern in drinking water related disease. Relevant publications over the period of a year (April 2001 - March 2002) were examined to assess the risks to health of such organisms in UK drinking water supplies. The report examines the health significance of known and emerging human pathogens, including viruses, protozoa and bacteria and provides advice on their significance.

The Epidemiology of Cryptosporidiosis in England & Wales 1983 - 1997

Ref: 99/DW/02/18            Price: £10

ISBN: 1 84057 164 0

Review of the data from routine surveillance of laboratory confirmed infections and from investigations of outbreaks of cryptosporidiosis, held at CDSC, in order to assess the relative importance of host factors, such as age, and environmental factors, such as season and travel, on the epidemiology of the disease.  To assess the importance of waterborne infections, both drinking and recreational, in relation to other known routes of infection.

Impact of Service pipes on the Bacteriological Quality of Water Supplies

Ref: 98/DW/02/15            Price: £10

ISBN: 1 84057 141 1

Examines variables such as flow rates, materials, nutrients, temperature and residual disinfectant, to build up a picture of how bacteria can grow in service pipes. Shows that a number of factors affect the microbiological quality of water in customer pipework including higher temperatures, diurnal flow variations and pipe materials. Suggests several practices for limiting bacterial activity.

Prevalence Study of Specific Bacterial Infections - Geographical Distribution of Aeromonas and Yersinia in the United Kingdom

Ref: 97/DW/02/10            Price: £10

ISBN: 1 84507 027X

The Public Health Laboratory Service communicable disease database was used to identify 2,718 cases of gastro-enteritis where aeromonas were considered and 2,006 cases where yersinia were present between 1990 and 1994. Regional tables of incidents are produced. The analysis concludes that travel and food intake are implicated but not drinking water.

A Briefing on Emerging Pathogens and Drinking Water Supplies

Ref: 00/DW/01/3            Price: £10

ISBN: 1 84057 181 0

no abstract available

A Briefing on Microorganisms and Drinking Water Supplies - A review of Literature 2000 - 2001

Ref: 01/DW/02/24            Price: £10

ISBN: 1 84057 234 5

Over the last fifty years improvements in water treatment in developed countries has virtually eliminated outbreaks of bacterial and viral infection. However, parasites, treatment failure, re-emerging and novel pathogens still cause problems. Cryptosporidium, Eschcherichia coli O157, Giardia, Toxoplasma, Aeromonas and Norwalk-like viruses are highlighted in recent literature and Campylobacter infections have been linked to the consumption of untreated water. Cryptosporidium remains the principal cause of o

Health Significance of bacteria in distribution systems - Review of Mycobacterium SPP

Ref: 97/DW/02/9            Price: £10

ISBN: 1 84057 011 3

Reviews the literature on mycobacterium and discusses its detection and its relation to disease. Discusses the occurrence of mycobacterium in natural waters and in mains and domestic waters. There were few reports linking a disease process with mycobacterium. Describes methods for the treatment and control of mycobacterium.

Sulphite Reducing Clostridia in Drinking Water Supplies

Ref: 97/DW/02/8            Price: £10

ISBN: 1 84057 064 4

Sulphite reducing clostridia is an indicator for assessing microbiological quality of drinking water. Examines methods of analysis, frequency of occurrence, resistance to disinfection, and correlation with other indicators and pathogens. Summarises current routine monitoring in UK, together with costs of compliance with the proposed revised EC Directive.

Health Significance of Bacteria in Distribution Systems : Review of Yersinia

Ref: 96/DW/02/4            Price: £10

ISBN: 1 84057 133 0

Reviews the literature on the Yersinia genus of neterotrophic bacteria. Reports their effect on human health. Examines the effect of copper, chlorine, pH and temperature on their variability and virulence. Shows that there is no evidence of human yersiniosis infection in the UK by the presence of such organisms in drinking water.

The Significance of Fungi in Drinking Water Distribution Systems

Ref: 97/DW/02/12            Price: £10

ISBN: 1 84057 092 X

Collates the results of a literature survey and responses to questionnaires from the water companies throughout the UK. The survey indicates that improvements in water treatment methods were reducing the number of incidents. Concludes that no companies indicated human health problems had arisen in connection with animals in their distribution systems.

Influence of Phosphate on bacterial Growth in Water Systems

Ref: 97/DW/02/11            Price: £10

ISBN: 1 84057 091 1

Phosphate dosing is increasingly being used as a means of reducing plumbosolvancy in the UK. Reviews the literature of the impact of phosphate dosing, gives a theoretical assessment of whether there is a limiting factor on the growth of microorganisms and uses UK data to determine changes after addition of phosphorus. Estimates, from a desk study, the amount of additional phosphate discharged to the environment and its possible effects relative to other inputs.

A briefing on microorganisms and drinking water supplies – A review of literature 1999- 2000

Ref: 00/DW/02/22            Price: £10

ISBN: 1 84057 213 2

This report updates previous UKWIR publications assessing the risks of infection to consumers exposed to mains water in the UK, by analysing worldwide scientific literature on health related water microbiology. It highlights those organisms where concern has been expressed in the literature and provides advice on their significance. There were no major changes to the previous assessments of the risks of acquiring infection from mains water but several areas have been identified for further monitoring.

Association of Eschericia Cocli 0157 Infection With Drinking Water and Assessment of Risks

Ref: 98/DW/02/17            Price: £10

ISBN: 1 84057 145 4

Investigates the sources of E. coli 0157 , how it causes human disease and its survival in the environment. Gives microbiological evidence for an association between transmission of E. coli 0157 and water and describes the effects of water treatment and the isolation and detection methods available. Assesses the risks to the public and to water industry workers. Summarises known water- related outbreaks world- wide and the detection methods used.

Health Significance of Bacteria in Distribution Systems – Review of Literature for 1995- 1997

Ref: 98/DW/02/13            Price: £10

ISBN: 1 84057 130 6

Examines new evidence on the health significance of heterotrophic bacteria within distribution system published between 1995 and 1997. Discusses new pathogens, new waterborne diseases and summarises many recent outbreaks of waterborne infection in England and Wales, USA and world- wide. There is no new evidence of disease attributed to heterotrophic bacteria in water distribution systems.

Statistical Associations between Coliform occurrences in Water Samples and Fluctuations inChemical, Physical and Biological Factors

Ref: 95/DW/02/2            Price: £10

ISBN: 1 84057 042 3

This report identifies statistical associations both at the sample and zonal level, between coliform occurrences and other routine determinands in statutory monitoring data provided by water suppliers. It also develops and validates simple alogirthms for predicting increased probability of coliform failures. Plate count numbers were found to be a good predictor of local deterioration in water quality (with respect to coliforms) within a zone but not a very useful predictor of general differences between zones. The models developed appeared to predict quite well from one period to another, but not very well from one company to another.

Health Significance of Heterotrophic Bacteria Growing in Water Distribution Systems

Ref: 95/DW/02/1            Price: £10

ISBN: 1 84057 041 5

Reviews the literature on the relationship between water and human disease, identifying heterotrophic bacteria of concern. Discusses known pathogenic mechanisms and their application to heterotrophic bacteria capable of growing in distribution systems. Explores distinguishing between potentially pathogenic and non pathogenic strains. Where causative agents were identified none were caused by heterotrophic bacteria. Gives the implications for the immunocompromised and lists recommendations for future research.

Practicalities of Determining if there is a Level of Gastrointestinal Illness in the Community related to Potable Water

Ref: 97/DW/02/7            Price: £10

ISBN: 1 84057 063 6

A feasibility study to test statistical relationships between differences in rates of reported gastrointestinal illness between water supply zones. Using water company water quality data and public health illness data the study concludes that whilst there are possible relationships their significance is severely limited by the datasets available.

Health Significance of Bacteria in Distribution Systems : Review of Aeromonas

Ref: 97/DW/02/6            Price: £10

ISBN: 1 84057 062 8

Literature review on the aeromonas genus of heterotrophic bacteria. Discusses the types of infection associated with aeromonas in water, food and in the environment. Examines the effect of copper, chlorine, pH and temperature on their variability and virulence. Finds no evidence of human aeromonas infection in the UK by the presence of suchorganisms in drinking water.

Maintaining Awareness of Animals in Water Distribution Systems

Ref: 98/DW/02/14            Price: £10

ISBN: 1 84057 140 3

Collates the results of a literature survey and responses to questionnaires from the water companies throughout the UK. The survey indicates that improvements in water treatment methods were reducing the number of incidents. Concludes that no companies indicated human health problems had arisen in connection with animals in their distribution systems.

A Review of PPRA (Pre and Post Renovation Assessment)

Ref: 00/DW/02/20            Price: £10

ISBN: 1 84057 193 4

no abstract available

Investigating Water Mains Pre and Post Renovation Assessment Data

Ref: 98/DW/02/16            Price: £10

ISBN: 1 84057 142 X

In order to contribute to the understanding and evolution of the PPRA process, this research contract has the following objectives:
Based on PPRA data and other relevant data, derive a suite of criteria, statistical methods and sampling programmes that demonstrate water quality improvements most appropriate to given circumstances.
Develop existing methodology and/or new methods for agreeing schemes in AMP II and to support proposals for AMP III, including consideration of improvements in field data collection, non-steady-state flow simulations, serviceability, aesthetic water quality and other techniques to demonstrate improvements for customers.

Mains renovation pre and post renovation assessment improving understanding

Ref: 00/DW/02/21            Price: £10

ISBN: 1 84057 194 2

The study demonstrated that current methodologies are robust and provide reliable performance information. Alternative techniques are proposed; the most promising are continuous monitoring and use of hydraulic models to assist in site selection. The study has provided an increased awareness of many issues affecting the implementation of the PPRA process. Suggestions for optimisation of sample site selection are proposed. The use of hydraulic models has been appraised. Developments in in- line monitoring, particularly for turbidity, are taking place and are expected to result in apparatus which offer advantages for the PPRA process.

Guidelines for Pre and Post Rehabilitation Assessment

Ref: 99/DW/02/19            Price: £10

ISBN: 1 84057 172 1

Water companies undertake pre and post rehabilitation assessment (PPRA) to demonstrate the improvement to water quality following mains rehabilitation. This project was instigated to undertake an assessment of completed PPRA schemes and to develop guidelines to help companies to design their distribution system PPRA. Other objectives were to investigate the relationship between water quality and internal mains conditions (serviceability) and to identify trunk main PPRA requirements. The report contains the findings from the assessment of 51 schemes and step- by- step guidelines for all aspects of PPRA. Some issues need to be clarified with DWI. Conclusions for the other objectives are given

Can passive sampling devices provide more useful data than discrete samples?

Ref: 15/DW/14/13            Price: £10

ISBN: 1 84057 803 3

Passive Sampling Devices (PSDs) are devices that can be used to monitor both organic and inorganic compounds. They typically contain a receiving phase with a high affinity for the compound of interest, are usually deployed for a few weeks, retrieved and analysed for the compound of interest. The project has collated information from manufacturers, suppliers and users on available PSDs and their current use.

The conclusion was that there is a clear potential for the use of passive samplers of the integrating type for monitoring of both inorganic and organic compounds. PSDs are potentially most useful:

*for long-term trend monitoring;
*for investigative work tracing a source of pollution; and
*to be used instead of biota in environmental monitoring.

Pesticide Risk Mapping and Catchment Interventions - Phase 1

Ref: 15/DW/14/11            Price: £10

ISBN: 1 84057 788 6

Pesticides used in farming that are difficult to remove by existing potable water treatment processes can cause drinking water to fail EU water quality standards. This project developed a pesticide risk mapping methodology for mobile herbicides and metaldehyde, transparent to all stakeholders, for the identification of high risk sites where catchment intervention stands a good prospect of addressing potential risk and making significant improvements in raw water quality.  The risk mapping approach, which builds on existing risk mapping approaches, has been implemented at both a 1 km grid resolution covering the UK and field level scale for example catchments.  Accompanying assessments of interventions that might address losses of pesticide from high risk sites have been outlined along with their likely effectiveness, barriers to uptake and typical costs of implementation.  Use of these mapping resources will aid targeting of limited resources and catchment stakeholder engagement programmes.

Please click here to download a free report, produced to promote dissemination of the risk mapping approach within the stakeholder community. This downloadable report only covers the risk mapping tasks within the project.

Finding Alternatives and Less Shortage Risk Chemicals in Water Treatment

Ref: 15/DW/14/10            Price: £10

ISBN: 1 84057 781 9

Water treatment chemicals are critical to the provision of safe, wholesome drinking water; a shortage could present a substantial risk to water supply. This project identified chemical and non-chemical alternatives that could reduce dependence on a number of key water treatment chemicals, including phosphoric acid, polyelectrolytes and chlorine gas.

The effects of future chemical shortages could be mitigated by focused research and development on alternative chemicals and technologies, and appropriate forward planning by water companies.

Satellite Remote Sensing Data for Proactive Catchment Management Volume 1 - Summary Report

Ref: 15/DW/14/9            Price: £10

ISBN: 184057 572 5

This desk study focuses on how Earth Observation (EO) methods can support the targeting of catchment management activities, including targeted engagement with land managers to change management practices, and the provision of spatially-distributed land use inputs into catchment-scale hydrological and nutrient pollution models.

Volume 1 is a Summary Report, while Volume 2 explores land management issues and the extent to which optical and radar techniques can identify catchment features and changes over time in lowland and upland environments, including cereal and break crops, grassland, outdoor pigs, exposed peat and heather management.

Volume 3 provides a technical explanation of EO technologies including emerging methods, typical costs, practical constraints (incl. spatial and temporal resolution), and processing chains, supported by case study examples. Reviews conclude that at both field/farm and catchment scale, information of interest to the water industry can be successfully mapped from EO, both in terms of resolution and information content.

Remote Sensing for Catchment Management Phase 2

Ref: 15/DW/14/12            Price: £10

ISBN: 1 84057 791 6

The benefits of catchment management are widely recognised within the water industry. Understanding the delivery pathways of sediment, pesticides and nutrients, and the timing of diffuse pollution is a key challenge to achieving drinking water standards and improving the quality of watercourses.
 
The research has developed new approaches to catchment management, looking at land in a different way using a combination of remote sensing imagery and ground-based surveys. In circumstances where methods such as walkover surveys may not be appropriate, for example in upland and larger catchments, remote sensing tools offer an alternative way of identifying field scale solutions. The use of imagery is also very effective when engaging with landowners.
 
An approach has been developed which starts with readily available imagery from satellites and aerial platforms to identify potential risk in a catchment, and which then focuses in on sub-catchment and field scale solutions that require more detailed imagery.  

Evidence Review of Catchment Strategies for Managing Metaldehyde

Ref: 13/DW/14/7            Price: £10

ISBN: 1 84057 729 0

This report presents a detailed comparative evaluation of the effectiveness of current strategies for managing metaldehyde in drinking water and assesses the role that catchment-based approaches can play in managing the risk from metaldehyde.. Specifically, it summarises the current extent and severity of metaldehyde non-compliance in the UK and the water industry's response to it; collates data on the costs of implementing catchment management initiatives; reviews the effectiveness of catchment management and abstraction management in limiting metaldeyde concentrations in drinking water; and highlights key evidence gaps and examples of best practice. The results are interpreted to provide insight into the degree of control provided by current management strategies, and to identify what additional measures and mechanisms may be required to prevent future non-compliance with the 0.1μg/l drinking water standard.

Emerging Pesticides; What Next? Stage 2: Trials of Emerging Technologies

Ref: 14/DW/14/8            Price: £10

ISBN: 1 84057 709 6

Metaldehyde and emerging pesticides present a major problem to the water industry. In 2009, metaldehyde concentrations up to 1µg/L in raw waters resulted in 73 WTWs failing the drinking water pesticide standard. Catchment management and exisiting treatment have been unable to control metaldehyde concentrations completely, and metaldehyde accounted for the majority pf pesticide failures in 2012.

This project aimed to identify cost-effective metaldehyde treament solutions: in Stage 1, partial regeneration of granular activated carbon (GAC) and 25 emerging treatment technologies were reviewed in desk studies; in Stage 2, partial regeneration of GAC and the three most promising treatment technologies - LED-UV photocatalytic oxidation, ultrasonic-enhanced ozonation, and high-rate polymeric carbon adsorption - were evaluated in small-scale trials.

Whilst each approach approach showed some capacity for removal of metaldehyde from water, the technologies were unsuitable for larger scale implementation in the short-to-medium term because of costs, performance or their current state of development.

Emerging Pesticides; What Next?

Ref: 13/DW/14/6            Price: £10

ISBN: 1 84057 662 6

Metaldehyde and similar emerging pesticides present a major problem to the water industry. In 2009, metaldehyde concentrations up to 1μg/L were measured in raw waters and 73 WTWs failed the drinking water pesticide standard. Catchment control measures implemented in recent years have not solved the problem and raw water metaldehyde concentrations are again of concern. Previous UKWIR work highlighted the limitations of existing treatment and identified the need for effective and affordable alternatives.
This present work aimed to identify cost-effective solutions for pesticide removal. Desk studies were carried out to investigate the optimisation of existing treatment processes and to identify emerging treatment technologies and processes that show particular promise.
Recommendations were made to carry out laboratory and pilot-scale studies to investigate the enhancement of existing GAC capacity by in-situ or on-site regeneration, and to investigate the performance for pesticide removal of catalysed LED photo-oxidation and ultrasound-enhanced ozonation.

Turbidity in Groundwater - Understanding Cause, Effect and Mitigation Measures

Ref: 12/DW/14/5            Price: £10

ISBN: 1 84057 633 2

Water companies must ensure that the turbidity specification for potable water of 1NTU is met. There is currently little information regarding turbidity in groundwater and the cause is not fully understood. The common assumption is that turbidity in groundwater indicates a fast transport pathway connecting potentially contaminated surface water with the aquifer.
The principal objective of this research project was to provide the evidence base to ensure the most appropriate investment decisions are made by water companies to meet the turbidity specification.
The research found that there is no relationship between turbidity and microbiology, although Chalk sources appear more susceptible to E. coli than other aquifers. The occurrence of turbidity is site specific with a variety of causes. Mitigation measures could include use of variable speed pumps, automatic pumping to waste, blending or engineered solutions.

Treatment for New and Emerging Pesticides

Ref: 11/DW/14/4            Price: £10

ISBN: 1 84057 605 7

Metaldehayde is used to control slugs in agriculture and has been identified in many raw and some drinking waters in recent years. This project investigated the removal of metaldehyde and other emerging pesticides by conventional and alternative treatment processes, reviewed sensors and on-line analytical technologies, and also investigated the leaching of metaldehydes from slug pellets. The results demonstrated that conventional treatment could deal with only low concentrations of metaldehyde at substantial cost. Alternative treatments and detection techniques were identified, and it was demonstrated that changes in slug pellet manufacturing could reduce the amount of metaldehyde released to watercourse.

Membrane Treatment - Technical Guidance Document

Ref: 05/DW/14/1            Price: £10

ISBN: 1 84057 390 2

The report provides background information on the various proprietary membrane processes. It also gives case study information and general methodologies for fouling amelioration and integrity testing along with appropriate strategies provided for membrane plant maintenance and recommended ranges of values for key plant operational parameters, based on practical experiences.
Evidence provided across 17 UK membrane plants and 10 in the US, reveals that the US plants generally perform with fewer problems encountered concerning periodic fouling and loss of membrane integrity, despite generally poorer qualities of water being treated. The observed differences appear to be associated with more frequent backflushing, lower design operating fluxes and a rigorous cleaning protocol.
The report recommends that UK plant be operated under conditions that more closely resemble those of the US plant; benefits from optimal membrane operation are self-evident.  Any strategy which extends membrane life through adopting the most effective cleaning protocols and pre-treatment processes is likely to be favoured provided the amortised cost of these does not exceed that from recovered membrane expenditure.