bluuebunny/crossref_metadata_2025 huggingface dataset:
Recreational Use of Coastal Waters: Development of Health‐Related Standards
Authors: PIKE E. B.
Published: July 2007

Basic questions which must be answered before standards for protecting the health of recreational users of water can be developed are considered. These questions are then used to assess the ways in which such standards and guidelines have been developed in North America and Europe. Only the North American guidelines have used epidemiological investigations to define risks to health, and other standards are apparently arbitrary. All the standards considered are directed primarily at bathing, although other water sports may involve greater or lesser degrees of contact with water and hence different risks. The statistical difficulties in defining both the central levels of counts of faecal indicator bacteria and their variability are discussed, because these affect the way in which standards are drafted and implemented. The point is made that only longterm improvements in marine disposal schemes can improve microbiological conditions and reduce risks to health, and that the main benefit of standards is to point out where such improvements are needed.
Laboratory Investigation into the Performance of an In‐Sewer Vortex Flow Regulator
Authors: PARSIAN H. , BUTLER D.
Published: July 2007

Aspects of the hydraulic performance of an in‐sewer vortex regulator have been studied. These devices are increasingly used in stormwater management schemes, but their characteristics under a variety of prototypical situations have not been widely disseminated. The study used a full‐size laboratory mockup of a section of sewer and associated manhole with facilities for measuring discharges of up to 60 1/s. The performance of a typical vortex flow regulator was investigated under both steady and unsteady flow conditions. The steady head‐discharge relationship revealed the expected ‘kick back’region (during rising head); however, this was less pronounced during falling head. Under unsteady conditions, vortex initiation was affected and a hysteresis effect was noted. The influence of downstream surcharge was significant at lower upstream heads. Theoretical comparison showed that to obtain equivalent performance, an orifice of 62% of the diameter of the vortex regulator would be required, and 25% savings in storage could be made.
A Survey of Sheep‐Dipping Practices in the River Tweed Catchment
Authors: VIRTUE W. A. , CHURCH A. M.
Published: July 2007

Following an initial exploratory survey in 1989, a detailed survey was carried out in 1990–91, the results of which indicated that a significant number of sheep dippers in the River Tweed catchment were at risk of polluting adjacent watercourses. Those dippers identified as medium to high risk of causing pollution were re‐inspected in 1992 as a follow‐up to the previous survey and, although in many cases dipping practices had greatly improved, a number were still at risk – emphasizing the importance of continued monitoring.

To complement the survey, environmental samples were taken and, in most of the catchments, the dip‐active ingredients diazinon and propetamphos were found, confirming that the leaching of dip into a watercourse was occurring over a wide area throughout the Tweed catchment. The analysis of the environmental samples taken during the main dipping period each year of the survey showed that, in general, there was a significant decrease in diazinon and propetamphos in 1991 and 1992, compared to previous years.
Ozone and the Formation of Bromate in Water Treatment
Authors: BOURGINE F. P. , CHAPMAN J. I. , KERAI H. , GREEN J. G.
Published: July 2007

The ozonation of water is widely used within the drinking‐water industry. The improvement of the performance of the Barcombe water‐treatment works is envisaged. An ozonation stage and granular activated carbon filtration are being considered as an addition to the existing plant. As part of the investigation work, the influence of ozone on bromate formation was studied using a 3 m3/h pilot plant. The bromate production was found to depend upon (a) the applied ozone dose, (b) the contact period, and (c) the pH.

Using ozone in an appropriate way will be of benefit to the treatment process as well as meeting the new World Health Organization health guidelines for drinking water.
Streambed Sediment as a Barrier to Groundwater Pollution: Insights from Fieldwork and Modelling in the River Thames Basin
Authors: YOUNGER P. L. , MACKAY R. , CONNORTON B. J.
Published: July 2007

Integrated fieldwork and modelling has been undertaken to assess the vulnerability of riverside wells to pollution when river water is contaminated. Results highlight the importance of streambed sediments as a barrier to groundwater pollution by river water. The bed of the River Thames is lined with brown and grey organic‐rich silts of low hydraulic conductivity (about 0.002 m/d). A 3‐D model for solute transport in stream‐aquifer systems was developed and applied to two riverside sites in the middle Thames valley. Model results indicate that well‐water quality would only breach EC limits if the river was heavily polluted for a week or even a month (clearly an unlikely scenario). Sensitivity analyses showed the models to be far more sensitive to streambed parameters than to aquifer parameters. Thus it would be more sensible to focus fieldwork on the measurement of streambed properties than on the more usually measured aquifer parameters.
An Independent Perception of Regulation in Practice
Authors: WALKER D. L.
Published: July 2007

The paper reviews the regulation of water companies in England and Wales since 1989 by reference to the historical regulation of utilities in these countries. It considers how comparative competition, service standards and charging arrangements are developing. Particular mention is made of the debates over rates of return and household metering. The conclusion is that regulation, to be effective and appropriate, must be capable of evolution.
Reconstruction of British Nuclear Fuel's Drigg Marine Outfall
Authors: CLARK M. W.
Published: July 2007

In 1985 the House of Commons Environment Committee expressed reservations over some of the waste‐management procedures followed by British Nuclear Fuels Ltd at their Drigg low‐level radioactive waste disposal facility near Sellafield in Cumbria. These reservations prompted the company to implement a £20 million programme of improvements aimed at maximizing site usage, reducing trench leachate arisings and redirecting to the Irish Sea.

This paper provides information and test results associated with design considerations and initial dilution testing, respectively, of a computercontrolled long sea outfall system designed to discharge leachate to the Irish Sea. Information is also provided on difficulties experienced during construction of the outfall.
Construction and Operation of a Submerged Aerated Filter Sewage‐Treatment Works
Authors: ROBINSON A. B. , BRIGNAL W. J. , SMITH A. J.
Published: July 2007

The capacity of the sewage‐treatment works at Silchester in Hampshire has been enhanced and the effluent quality improved to a high standard by the installation of a new submerged biological aerated filter plant. Ten prefabricated steel submerged aerated filters reduce BOD and fully nitrify settled domestic sewage from a population equivalent of 20 000.

Comprehensive operating data are presented to demonstrate the ability of single‐stage submerged downflow aerated biological filters to produce a nitrified effluent. The final effluent quality remains consistently within consent limits at 4.8 mg/l BOD, 7.0 mg/l SS and 0.5 mg/l NH3‐N, all 95 percentiles. (Consent 7 mg/l BOD, 25 mg/l SS, and 5 mg/l NH3‐N, 95 percentiles.)

Data are presented on total coliform and E. Coli concentrations through the filter plant, showing better than 3 log reductions in the effluent.
Reconstruction of Windermere Sewage‐Treatment Works
Authors: STOCKS D. , HUNT R. , CONNOR H. , AGAR G. , CROSS R.
Published: July 2007

This sewage‐treatment works, which is located within the Lake District National Park, on the shores of England's largest lake, receives flows from the villages of Windermere, Bowness and Troutbeck and serves a population which can double from winter to summer.

The paper describes the logistical and other aspects of undertaking construction works within the confines of an existing site whilst maintaining treatment to incoming flows. The background and regulatory influences on the design of the scheme are covered, together with details of the new treatment units and the provision of facilities to strip phosphate from the effluent.
Treatment of Algal‐Laden Water: Pilot‐Plant Experiences
Authors: KAUR K. , BOTT T. R. , HEATHCOTE G. R. , KEAY G. , LEADBEATER B. S. C.
Published: July 2007

In recent years an increase in the eutrophication of reservoirs has added to the problems of lowland surface‐water treatment. A pilot plant was installed to test the effectiveness of various treatment regimes for a river source which was subject to occasional algal blooms, and a eutrophic reservoir source which was heavily contaminated with cyanobacteria (Oscillatoria sp.). The treatment processes adopted were dissolved‐air flotation for chemical coagulation, sand and anthracite filtration, comparative disinfection stages using ozone and chlorine followed by granular activated carbon filtration.

The dissolved‐air flotation plant was not particularly effective for the removal of algae, but the sand/anthracite filtration process was capable of removing 50% of the algae. The ozone disinfection stage was adequate for disinfection and also reduced algal numbers. Overall the chlorine/granular activated carbon method did not perform as effectively as the ozone/granular activated carbon process; the iatter process was +99% effective for algai control, with river and reservoir sources.
Use of Soil Maps to Predict the Incidence of Corrosion and the Need for Iron Mains Renewal
Authors: JARVIS M. G. , HEDGES M. R.
Published: July 2007

The requirement for revised asset management plans from water‐supply companies and the need to prioritize the renewal of buried water‐supply pipework has stimulated an interest in the spatial distribution of corrosion risk and intensity. This paper reports how the relationships between soil corrosion and the spatial distribution of soil types, as displayed on soil maps, can be combined to predict the likely incidence of aggressive soils and thereby identify those water mains which are most likely to need early replacement. The concept is illustrated by a project supported by Portsmouth Water plc.
UK Drinking Water: A European Comparison
Authors: FAWELL J. K. , MILLER D. G.
Published: July 2007

Introduction of the drinking‐water Directive has resulted in a much more quantified approach to drinking‐water quality. Increased attention from environmental groups and the media, together with occasional breaches of the limits, have resulted in a loss of confidence in the product. Infringements depend upon the stringency of the limits and the quality of available raw water. The UK is one of the few EC countries having to use a high proportion of surface water. The Directive has now been fully implemented in all member states, but information on compliance is poor. Only the UK and Ireland produce compliance reports. Published papers indicate that infringement problems exist throughout the Community, particularly for pesticides, nitrate, lead, coliforms and iron. Nevertheless, drinking water is of very high quality within the EC, and UK supplies compare very favourably with the rest.
Process Options for Phosphorus and Nitrogen Removal from Wastewater
Authors: COOPER P. , DAY M. , THOMAS V.
Published: July 2007

The paper reviews the current capabilities of processes for phosphorus and nitrogen removal in relation to the EC urban waste water treatment Directive. The Directive is briefly described and the implications for the UK are discussed. This is followed by a review of biological and chemical processes for nutrient removal with special reference to their current state of application and performance. Particular attention is paid to processes for biological phosphorus removal which, in the past, was said to be less reliable than the chemical options but which is now being more widely applied in other parts of Europe as well as South Africa and North America. Processes for modifying both activated sludge and biological filter systems to meet the Directive are briefly described.
Integrated Catchment Management Planning
Authors: CHANDLER J.
Published: July 2007

Catchment management plans represent the National Rivers Authority's vision for the water environment. With the National Rivers Authority being organized by hydrological regions, the catchment is seen as the natural management unit, and catchment plans offer the means to integrate the Authority's work programme with those of other agencies. Catchment plans summarize relevant data and include an agreed action programme to optimize catchment uses, produced after wide consultation; they complement local authority statutory plans, are current for five to ten years, and will be reviewed regularly during this period. The catchment planning process is seen by the National Rivers Authority as a medium for promoting discussion, resolving conflict, assigning priorities, and setting targets by which progress on key issues can be monitored.
Urban Runoff: Nature, Characteristics and Control
Authors: ANDOH R. Y. G.
Published: July 2007

The paper describes the nature and characteristics of urban runoff and the effects of urbanization and industrialization on the hydrologic/hydraulic regime and on water quality. The need for control measures to alleviate and prevent problems caused by urban runoff is highlighted, and this is related to the adverse environmental impacts of urban runoff.

Measures and techniques currently available and under development for urban runoff control are described within the framework of regulators, service providers and the general public. The need for an integrated approach to urban runoff control is highlighted, and this is followed by a number of case studies demonstrating the cost‐effectiveness of an integrated approach.
Biological Processes at Saints Hill Water‐Treatment Plant, Kent
Authors: BOURGINE F. P. , GENNERY M. , CHAPMAN J. I. , KERAI H. , GREEN J. G. , RAP R. J. , ELLIS S. , GAUMARD C.
Published: July 2007

The new treatment plant at Saint's Hill has been operating since May 1992 and biologically treats ground‐water to remove iron, ammonium/ammonia and manganese. The paper describes the project, the processes involved, the significance of pilot‐plant studies, the different stages of commissioning and plant efficiency.

This method of treatment, although new to the UK, is well‐established in France, and reference to existing plants using the processes is made for purposes of indicating the range of applicability of biological treatment processes.

Specific conditions are required for biological processes. Not all raw waters can be economically treated to produce an environment which is appropriate for bacterial activity. Conditions for biological iron and manganese removal are different. The paper illustrates the importance of pilot studies to establish the feasibility of biological processes and to determine the design parameters for industrial‐scale works.
Experimental Work in Continuous Monitoring of Methane in Groundwater
Authors: BRADSHAW K.
Published: July 2007

This paper details a study to investigate the feasibility of continuously monitoring dissolved methane concentrations in groundwater. Diffusion cells have previously been used to measure methane in water but only at very shallow depths, due to the limitations of calibrations at pressures greater than atmospheric. The feasibility of using diffusion cells to determine dissolved methane at greater depths within a borehole has been established by conducting a series of laboratory experiments with a pressurized ‘bomb’. The diffusion cells have been calibrated for a range of pressures, equivalent to a depth of 90 m below water level, and dissolved methane concentrations (0–100%).

Further equipment is required and a suitable site has to be identified before field trials are performed. It should then be possible to determine the concentration of dissolved methane at depth within a borehole or reservoir, by (a) installing diffusion cells, (b) monitoring the carrier gas emissions, and (c) back‐calculating the data to determine in situ concentrations of dissolved methane.
The Consent Contract for Effluent Discharges
Authors: BAYES C. D.
Published: July 2007

The consent for the discharge of effluent is a contract between the discharger and the regulator. Its purpose is reviewed and compared with effluent performance characteristics. The evolvement of consent conditions and compliance assessment in Scotland is described, together with the challenge posed by the need to implement the urban waste water treatment Directive. A new framework for the consent contract is proposed for sewage and industrial discharges, which clearly prescribes the required effluent performance, authorizes non‐compliance, and embodies an explicit assessment of compliance.
Barrage Developments in the Welsh Region: The Role of the National Rivers Authority in Protecting the Aquatic Environment
Authors: Jones F. H.
Published: July 2007

During recent years, barrages and marina developments have increasingly been viewed as a means of improving the aesthetic and recreational qualities of degraded urban areas, thereby encouraging inward investment. However, barrage schemes can have major implications for the National Rivers Authority's statutory responsibility for flood defence, fisheries, recreation, water quality and conservation.

The experiences gained by the National Rivers Authority's Welsh Region in its negotiations with promoters of the Tawe, Cardiff Bay and Usk barrages are presented. The paper describes the environmental safeguards secured for the Tawe barrage, together with some initial assessments of its impact on the aquatic environment following its completion in 1992. The experience gained with the Tawe barrage has contributed to a more rigorous approach being applied by the National Rivers Authority to the Cardiff Bay and Usk schemes.
The Specification of Filtering Materials for Rapid‐Gravity Filtration
Authors: STEVENSON D. G.
Published: July 2007

A UK standard for the specification, approval and testing of filtering materials has recently been published by British Water (formed by the merger of the British Effluent and Water Association and the British Water Industries Group) in response to an identified need. This paper reviews the considerations during the preparation of the standard and provides a technical background. The approach has been to base the standard on parameters which affect the behaviour of the material during filtration, rather than to specify material composition and appearance, which are unimportant. Standards and specifications are a basis for testing, and the inclusion of irrelevant parameters can lead to unnecessary work.
The Application of Risk Assessment to Contaminated Land: The British Gas Experience
Authors: WALKER P. L. , MUNRO S. , HAWKINGS C. L. , SHEPHERD F. E.
Published: July 2007

British Gas owns over 900 sites within the UK with a total land area in excess of 5500 ha. Many of the sites are former gasworks, chemical works or associated holder stations.

Although serious attempts were made to remove contamination during the last three decades, the operating and demolition standards previously considered to be adequate may no longer be acceptable and may have given rise to sites with the potential to contaminate adjacent land, surface waters and ground‐water. As a result, further actions may now be required on these sites to reach new environmental standards, thereby reducing any chance there may be of legal liability on the Company.

This paper describes the advantages and disadvantages of several qualitative and quantitative risk‐assessment methods which can be used to prioritize potentially contaminated sites for further investigation. The use of site investigation data to accurately target risk reduction in site remediation proposals is also discussed.
Integrated Catchment Modelling as a Water Resources Management Tool
Authors: RIPPON P. W. , WYNESS A. J.
Published: July 2007

Groundwater models are becoming increasingly important in water resources management. Most aquifers in the UK are closely linked with river systems, to which they contribute baseflow from seepages and springs. As a result, major groundwater abstractions almost inevitably affect river flows. To assess with confidence the effect of utilizing ground‐water resources, an aquifer and river system has to be linked within an integrated model which can simulate varying hydrogeological conditions throughout the catchment.

The main features of an integrated catchment management model, which links aquifer and river systems, are described in this paper. The model has been applied to a number of catchments in southern England including the River Darent in Kent, which is probably the most well‐known and worst‐affected of all rivers identified nationally as suffering from over‐abstraction.

The process of model preparation and calibration is illustrated with reference to the River Darent. Twenty years of river flow and groundwater hydrograph records were used in producing a close simulation of modelled and actual hydrological conditions. The model was then operated to assess a large number of possible options for restoring flows to the river. Examples of various management strategy simulations are given, leading to formulation of a water resources management plan for the Darent. This involved (a) reductions in selected abstractions, (b) flow augmentation using river support boreholes, and (c) meeting peak groundwater supply demands in drought periods.
Cost Implications of Dealing with Environmental Issues in River and Coastal Engineering Schemes
Authors: BROOKE J.
Published: July 2007

This paper identifies those stages of river and coastal engineering projects where expenditure on environmental issues might be necessary. It reviews the types of measures which may be appropriate and, using case studies, provides an order‐of‐magnitude indication of the costs (and benefits) of accommodating environmental needs.
Real‐Time Water Allocation for Irrigation
Authors: HANNAN T. C. , COALS V. A.
Published: July 2007

Throughout the world the importance of water management is becoming more important as the demand for water increases. As one of the major uses of water, irrigation could benefit from improved management practices. The establishment of a Water Operations Centre in Indonesia has seen the development of a real‐time water‐allocation model for a complex irrigation system covering 60 000 ha. The model uses linear programming (an optimization technique) to determine the best way in which to allocate limited water supplies while keeping crop yield losses to a minimum.
North Tyneside Bathing Waters’ Scheme
Authors: FRITH S. J. , STAPLES K. D.
Published: July 2007

The North Tyneside bathing waters’ scheme reduces the frequency and quality of storm sewage which is discharged inshore from existing interceptor sewers along the coast.

Flow‐simulation modelling is applied to the existing system to determine the frequency and volume of interceptor sewer overflow against a range of storm intensity and return periods. The models are extended to an evaluation of new systems of storm‐sewage management.

An optimized solution is described in which new storm sewers are utilized for the storage of all storm‐sewage overflow discharges prior to screening and pumping of the storm sewage to sea via an outfall.
Pesticide Transport to Surface Waters within an Agricultural Catchment
Authors: WILLIAMS R. J. , BROOKE D. N. , MATTHIESSEN P. , MILLS M. , TURNBULL A. , HARRISON R. M.
Published: July 2007

This paper presents data on the distribution of seven pesticides in an agricultural catchment which is located within the Agricultural Development and Advisory Service farm at Rosemaund, 11 km north‐east of Hereford, UK. Data for aldicarb, atrazine, carbofuran, dimethoate, MCPA and isoproturon, are available for both the soil and surface waters (drain and stream water), with simazine data available only for the stream. Measurements were taken before and after pesticide application, which was made following normal agricultural practice. Soil residue data showed the degradation rates of the pesticides to be within the range of literature values. Pesticide levels in the stream and drains during runoff events following rainfall ranged from below detection limits (typically 0.02‐0.1 μg/1), to 264 μg/1 (for carbofuran). Over 90% of the events had detectable maximum concentrations. The percentage of pesticide applied, which was removed during individual rainfall events, was calculated. The maximum value estimated was 1.1%, again for carbofuran. Most of the events gave values several orders of magnitude below this value.

The data have been used to try to validate a range of models which could be used for screening new pesticides or for informing decisions on the use of existing pesticides. The results of the validations are summarized.
Upgrading the Activated‐Sludge Process for Total Nitrogen Removal in Hong Kong
Authors: WU D. K. C. , LAI H. C. , LAW K. W. , WONG W. C.
Published: July 2007

In order to protect the sensitive waters in Tolo harbour (Hong Kong), Sha Tin and Tai Po sewage‐treatment works were first designed to remove 70% of the nitrogen load from the sewage. Since then, due to continuing serious eutrophication problems in the harbour, both plants have been modified to increase the removal efficiency to 90%.

The modifications were based on the Bardenpho process. However, the designers of the two plants adopted different approaches to process intensity, complexity and control of bacterial foam. At Sha Tin, the average monthly results have shown an increase of total nitrogen removal from 60–70% to about 80% since its completion. The addition of methanol was found to be ineffective on further enhancement of the denitrification rate due to difficulties in the apportioning of the second anoxic zone. The overall monthly results for Tai Po have also shown an increase in the removal rate to about 80%, even though 90% was achieved for a short period of time. The major problem encountered at the latter plant was that the process design did not provide an effective control on bacterial foaming, which had affected the smooth operation of the process.
Prospects for New Techniques for Rapid Bacteriological Monitoring of Drinking Water
Authors: SIDOROWICZ S. V. , WHITMORE T. N.
Published: July 2007

The microbiological safety of water supplies is at present assured by monitoring for the absence of the faecal indicator organisms, total coliform bacteria and Escherichia coli. This monitoring work represents the bulk of the workload of microbiology laboratories in the water industry. The accuracy of current methods is not questioned, but the times taken to obtain a presumptive result (18 h) and a confirmed result (up to 72 h) impose delays, particularly with regard to the recommissioning of distribution systems. There is therefore a continued demand for more rapid techniques, which has not been satisfied, despite the advances in analytical methods which have been adopted in other industries. Alternatives to the traditional culture‐based methods are reviewed in this paper, and promising techniques for water applications are highlighted. Highly specific bacterial labelling methods and sensitive instrumentation for detection and enumeration already exist, so that rapid same‐day detection of coliforms is technically feasible. Suitable separation methods for rapid analysis of water samples have not yet been developed, but antibody‐mediated separations which are now employed in clinical and food microbiology may be applicable.
The Installation and Use of a Snow Pillow to Monitor Snow Water Equivalent
Authors: ARCHER D. , STEWART D.
Published: July 2007

In February 1993, a snow pillow was installed at Widdibank Fell near Cow Green reservoir (in Upper Teesdale) to monitor snow water equivalent.

This paper describes existing snow‐measurement techniques in the UK and the site‐selection process and installation details for the snow pillow. Following a winter of more than 100 days with snow cover at the site, the success of the pillow in representing site and catchment snow conditions and in providing operationally useful snowmelt information for flood warning has been assessed.
Preliminary Results of the Anaerobic Biotreatability of the Effluent from the Wet‐Air Oxidation of Sewage Sludge
Authors: CUTFORTH S. J
Published: July 2007

Wet air oxidation and other thermal processes can be used on all sludges, whether they are raw, mixed or digested. The process sterilizes the sludge and gives a considerable reduction in volume. However, apart from the high capital costs which are associated with this technique, one of its principal disadvantages is the high strength of the (effluent) liquor.

This study investigated the feasibility of treating the liquor using an anaerobic digester, which resulted in a good reduction in BOD and a reasonable reduction in COD. The liquor was still strong, but could be returned to the inlet works of a sewage‐treatment plant without causing significant organic overloading.
Groundwater Management in France
Authors: RISLER J. J
Published: July 2007

Since 1935, France has experienced an evolution ‐ from legislation aimed at groundwater protection to regulations concerning water‐management incentives for increased use, in selected parts of acquifers, without causing over‐abstraction. During the 1960s, the protection of users became the main priority, and the water agencies have now become powerful bodies in the combat against water pollution and towards aquifer rehabilitation. The 1992 Water Act provided a balanced management of water resources (a) taking into account the water resource, surface‐water and groundwater, and (b) establishing a Water Directorate within the Ministry of the Environment. Reference is made to major achievements in the field of groundwater management and protection in terms of quantity and quality.
The Evolution of Water Resource Development in Northern Ireland
Authors: PLESTER H. R. F. , BINNIE C. J. A.
Published: July 2007

There is no shortage of a basic water resource in Northern Ireland because average rainfall across the province varies from 900 mm to 1100 mm per annum, east to west. However, as elsewhere, there is a constant need to ensure the provision of adequate water sourceworks.

In 1973, the Water Executive of the Department of the Environment for Northern Ireland took over responsibility for the water and sewerage services which were previously controlled by 76 local and district authorities. In some cases, source schemes which had been inherited reflected the parochial nature of the promoters rather than the wider regional approach. Upland impoundments were traditionally favoured and still account for 40% of all sources. Freshwater loughs were also used and Lough Neagh (the largest freshwater lough in the UK) accounts for 27% of all public supplies, with other loughs contributing a further 9%. River intakes at 13% and groundwater and springs at 11% make up the remaining sources.

This paper outlines how water resource developments have evolved in Northern Ireland and describes the approach and recommendations of the study.
Foaming in Activated‐Sludge Processes: An Operator's Overview
Authors: TIPPING P. J
Published: July 2007

The formation of stable surface foams, which is associated with characteristic filamentous microorganisms, is a worldwide phenomenon on activated‐sludge plants. In excess, it can create operating difficulties and may cause a violation of effluent consent conditions due to high concentrations of suspended solids and solids‐related biochemical oxygen demand. Despite its universal occurrence, the reasons for foaming are not clearly understood, and control measures tend to be non‐specific, hit‐or‐miss strategies.

This paper presents an operator's perspective on (a) the current knowledge of foam‐forming microorganisms, and (b) methods to control them.
Sewage Sludge Production, Treatment and Disposal in the European Union
Authors: HALL J. E
Published: July 2007

Sludge production and disposal are entering a period of dramatic change, driven mainly by EC legislation. The urban waste water treatment Directive will result in at least 50% more sludge being produced by the end of 2005 and, during the next decade, sludge disposal to all the established outlets could become increasingly difficult or, in the case of sea disposal, will become illegal. The challenge facing the members of the European Union is how to (a) maintain cost‐effective and secure methods of sludge disposal and (b) engender public confidence in all disposal and recycling options. What is required is not so much innovative technology, although this may be essential, but more innovative attitudes and approaches to promotion and defending existing outlets.

This paper describes the likely pattern of sludge production, treatment and disposal which will emerge during the implementation of recent EC directives and other national policies in Europe, and focuses on the areas and issues which require innovative approaches.
The Use of Bone Charcoal in the Treatment of Rural Water Supplies
Authors: LEWIS J.
Published: July 2007

As a result of the Water Act of 1989 on the quality of water intended for human consumption, a number of small spring sources in Yorkshire were the subject of legal undertakings for remedial action to reduce the concentration of trihalomethanes in the distribution system. The trihalomethanes are formed when the colour in these waters, which is made up of predominantly fulvic and humic acids, is chlorinated. Therefore, in order to solve the problem of trihalomethanes in treated water, colour removal was necessary.

The paper describes the use of bone charcoal in slow sand filters to remove colour from rural water supplies. It covers six months pilot‐plant work which was undertaken at Marsett water‐treatment works (near Richmond), and the implementation at other plants within Yorkshire. low‐rate filtration through bone charcoal ensured that the colour and trihalomethane concentrations in filtered water complied with EC standards, and the material coped well with rapid changes in raw water quality.
The Effectiveness of Buffer Zones in Conifer‐Afforested Catchments
Authors: WESTON D. G
Published: July 2007

This paper reports upon a study to determine whether buffer strips could improve the quality of soil‐water draining from conifer‐afforested slopes. Three sites in the Monachyle Glen catchment in the Trossachs (West Central Scotland) were sampled and several chemical indices were determined. Buffer strips engendered some variable and qualified improvements in soil‐water concentrations of some ions, although the improvement was accompanied by the anticipated loss of bases. Improvements in soil‐water quality were related to soil characteristics ‐ soils containing organic matter being more effective than mineral soils.
‘To Pump or Not to Pump’ Cost‐Benefit Analysis of Future Environmental Management Options for the Abandoned Durham Coalfield
Authors: YOUNGER P. L , HARBOURNE K. J
Published: July 2007

Deep mining activity has totally ceased in the Durham coalfield, and withdrawal of the regional dewatering scheme is being contemplated. Consequent groundwater rebound is expected to have severe and expensive environmental consequences, which could only be entirely avoided through indefinite pumping. However, continued pumping is expensive, at about $1 million/annum. The options of either abandoning or continuing pumping have differing time streams of future costs and, consequently, direct comparison of the expenditures involved is difficult. Both options are therefore analysed using economic evaluation criteria in order to determine the lowest cost alternative for the future. The overall outcome of the economic analysis, using both net present value and equivalent annual cost criteria, demonstrates that the option of continued pumping is less expensive than the option of abandoning pumping in all cases.
Memories, Reflections, and Dreams
Authors: BARRETT A. D
Published: July 2007

The author draws on his career by referring to (a) the type of knowledge which engineers acquire and lose over time, and (b) the importance of socio‐economic and environmental aspects of civil engineering projects.

In Memories, he recalls particular incidents in thirty countries and being confronted by unfamiliar cultures, and follows two vital threads which are woven into his experience, namely human nature and mother nature.

Reflections, based upon adult education, reveal aspects of the psychological understanding of human nature and the importance of biological diversity. The author finds some areas of apparently unresolved conflict between civil engineering and the environment.

Finally, in Dreams, the author quotes a United Nations set of priorities which provide a satisfying guide to the broad view of world developments and which can help to show the importance of biological and cultural diversity.
South West Water's ‘Clean Sweep’ Programme: Some Engineering and Environmental Aspects
Authors: BROKENSHIRE C. A
Published: July 2007

The requirements of environmental legislation demand a massive clean‐up of coastal discharges for Devon, Cornwall and West Dorset. South West Water Services Limited have developed a marine improvement programme which (a) is the largest of its type in Europe and (b) seeks to address the requirements of legislation incorporating town planning policies together with the increasing public awareness of environmental issues. The pressures around the region's coastline within the foregoing framework set the challenge of achieving the required understanding of coastal processes, together with the implementation of engineering solutions to meet with society's expectations. These have to be achieved at least cost and provide the most innovative and effective engineering solutions for the efficient implementation and management of such a programme.
Quality Control of Water‐Treatment Chemicals
Authors: KELLY C. , PORTER M. , GROOCOCK N. , BREACH R.
Published: July 2007

Quality control measures for regionally purchased treatment chemicals in Severn Trent Water Ltd apply from the point of manufacture through to their arrival and acceptance on a water‐treatment works. This approach involves a formalized examination of the control systems of treatment chemical suppliers and the introduction of standard documented acceptance procedures at each treatment works. These measures are intended to not only provide a high degree of reassurance to customers, but to ensure that staff of Severn Trent Water are purchasing and receiving cost‐effective materials which are of an acceptable quality in terms of active constituents and background contaminants, before use in the treatment of water
The Odour Potential: A New Tool for Odour Management
Authors: HOBSON J.
Published: July 2007

This paper outlines a recently developed test for assessing the level of odour associated with a liquid. Called the odour potential, the test involves measuring the threshold odour number of air blown through the liquid sample under conditions which are likely to establish equilibrium. The odour potential of liquids associated with wastewater treatment can vary from a few hundred for final effluents and fresh crude sewage, to over a million for septic sewage, and four million for some sludge liquors. Odour‐potential measurements may not be as useful as an odour map for ranking sources of odour at a sewage‐treatment plant, but they provide extra information for diagnosing the causes of odour.
Information from River‐Corridor Surveys
Authors: ANGOLD P. G. , GURNELL A. M. , EDWARDS P. J.
Published: July 2007

A river‐corridor survey (RCS), routinely undertaken on behalf of the National Rivers Authority (NRA), provides a consistent national approach to gathering and recording environmental information on 500‐m stretches of river corridor. The development of RCS is reviewed and the methodology which is currently applied within the NRA is described. A research programme, sponsored by the NRA, to develop scientifically‐valid methods for extracting quantitative information from RCS maps is outlined. The methodology allows for spatial distortions and operator variance in mapping the 500‐m stretches. It is based on an abundance scale and therefore provides data which can be quantitatively combined and analysed (a) to highlight different properties of the river corridor and (b) to summarize those properties over different corridor lengths. The results of an example application of these methods of information extraction to a 14.5‐km length of river corridor are presented.
A Unit Hydrograph Method for Storm Overflow Performance Simulation
Authors: BURROWS R. , MEHMOOD K.
Published: July 2007

The paper describes a unit hydrograph method, calibrated using the WALLRUS modelling suite, which was employed to simulate the long‐term behaviour of storm overflows in combined sewerage systems. It is shown that this procedure synthesizes overflow operation characteristics to acceptable engineering accuracy, measured relative to WALLRUS predictions. This is achieved at only a small fraction of the computer run‐time, and therefore makes practicable a wide range of overflow performance and river impact studies using local rainfall records of unlimited extent.
The Thames Water Ring Main: Mechanical and Electrical Installations
Authors: Went R. P. F. , Ricketts A. D. , McDonald H.
Published: July 2007

Along the route of the Thames Water ring main there are nine major unmanned pumping stations, in shafts, which lift the water from the tunnel and pump it into local distribution systems. Each shaft has the capacity to supply a town the size of Swindon with water, and has extensive mechanical and electrical installations ranging from large pumps to sensitive water‐quality and atmospheric monitoring systems.

This paper outlines the principal features and scope of the mechanical and electrical installations in the shafts, including variable‐speed drives, pump control systems, gas‐monitoring and alarm systems, dehumidification plant, water‐quality monitoring systems, isolation and access arrangements.
The Impact of EU and UK Environmental Pressures on the Future of Sludge Treatment and Disposal
Authors: Davis R. D
Published: July 2007

Current and future production of sludge in the UK is estimated, and it is predicted that recycling to agricultural land and incineration (with energy recovery) will be the major disposal options for sludge in the future. Environmental pressures on sludge recycling to land may lead to restrictions on applications in terms of nitrogen content and more stringent limits for metals in soils. Attention to sludge quality and the development of quality management practices in utilization or disposal operations will help to minimize environmental concerns and facilitate sludge disposal to all outlets. Focal points for quality assurance in sludge recycling operations are listed, and environmental pressures on sludge use in agriculture are discussed in detail. Use in agriculture involves recycling a secondary resource, and calling the resource ‘biosolids’ is part of promoting this excellent example of good environmental management.
Thames Water Utilities’Emergency Response to the Bishopsgate Bomb in April 1993
Authors: Ford R. , Causley G.
Published: July 2007

ABSTRACT The paper describes Thames Water Utilities’response to the Bishopsgate bomb which exploded in the City of London in April 1993. Particular emphasis is placed on the procedures and control measures which were adopted to manage the activities associated with severe damage to water mains and sewers. The need for exceptional health and safety measures, whilst working in a potentially extremely dangerous environment, are highlighted.

Technical aspects of the repair work are discussed including the coordination with other utilities and the difficulties experienced in locating the position of underground apparatus which was subjected to bomb damage.
Recent Developments in Application of ‘Bursts and Background Estimates’Concepts for Leakage Management
Authors: Lambert A. , Morrison J. A. E.
Published: July 2007

ABSTRACT During the UK ‘national leakage control initiative’, which was carried out in 1991–94, Welsh Water formulated a conceptual model of leakage management which was intended for international application.

This paper explains how the concepts of ‘bursts and background estimates’(BABE) have been calibrated and extended to cover financial/economic analysis and pressure management, using specialist software for practical application and following the methodologies in the recent water industry ‘Managing Leakage’reports. Examples of applications of BABE software and concepts, in the UK and internationally, are also described.
Heavy Metals Entering Sewage‐Treatment Works from Domestic Sources
Authors: Comber S. D. W. , Gunn A. M.
Published: July 2007

ABSTRACTA programme was undertaken in order to quantify the heavy‐metal contribution from domestic sources with respect to total loads entering a chosen sewage‐treatment works. Input waters, household cleaning and body‐care products, and wastewater from household appliances, were sampled and analysed for heavy metals. The data were combined with literature values to predict the total load of heavy metals entering the sewage‐treatment works from the study catchment.

This paper identifies the major domestic sources of heavy metals and quantifies them based upon a catchment model.
Road Construction and River Pollution in South‐West Scotland
Authors: McNeill A.
Published: July 2007

During the period 1993–95, four engineering companies were involved in six separate projects entailing the construction of a motorway to replace the existing A74 Glasgow – Carlisle trunk road. The construction contracts were undertaken in a rural part of south‐west Scotland. This paper describes (i) the events which led to the serious pollution of rivers, (ii) the prosecution of offenders, and (iii) measures which have been taken to ensure that future road‐construction projects in Scotland do not impact upon the aquatic environment.
Peat Biofiltration as an Odour Control Technology for Sulphur‐Based Odours
Authors: Brennan B. M. , Donlon M. , Bolton E.
Published: July 2007

Due to their low odour thresholds and common occurrence in sewage‐treatment operations, volatile sulphur compounds are generally considered to be the most significant malodorants at sewage‐treatment works. Biofiltration is an odour‐control technology which has proven success in industrial and agricultural applications, and in more recent years has been applied in the water industry.

Experiments were carried out using a test rig to measure the removal efficiencies of hydrogen sulphide and methyl mercaptan, when passed through peat‐based materials, under a range of environmental conditions. Temperature, gas loading rate and inoculation with sulphur oxidizing bacteria were all found to significantly affect performance. Removal rates of over 99% of hydrogen sulphide, and 95% methyl mercaptan were achieved. Investigations of full‐scale installations at sewage‐treatment works supported the experimental results.