bluuebunny/crossref_metadata_2025 huggingface dataset:
Expert Systems for the Interpretation of River Quality Data
Authors: WISHART S. J. , LUMBERS J. P. , GRIFFITHS I. M.
Published: July 2007

Sample data on river quality are used for a variety of management purposes. The paper considers the role of expert systems in interpreting such data. An example is given of a prototype rule‐based system designed to aid in assessing compliance with European Community (EC) Directives. It is suggested that, although this type of formal characterization is a necessary part of management, it provides poor information for decision making. The development of an expert system to provide a more accurate and informative interpretation of episodic pollution events is then described. The paper concludes by discussing the practical application of these approaches.
Process Automation of The Hague Sewage‐Treatment Plant
Authors: OOSTERLEE G. J.
Published: July 2007

The process control of sewage‐treatment plants is normally carried out by conventional means. Special circumstances forced the application of a state‐of‐the‐art process automation system for The Netherlands’largest sewage‐treatment plant (Houtrust) at The Hague.

The plant incorporates the use of oxygen‐enriched air for use in the secondary treatment process, and the final settling tanks are constructed one above the other (in two tiers). The automation system is built up with locally‐placed process computers, and a central video operating system is included with a data‐processing computer; these are interconnected by a data transmission bus of redundant design. The central control system is also connected to the main sewage pumping stations of The Hague district, for collecting data and controlling these stations from the plant.

After the start‐up of the plant, it took several months of tuning the control system to gain proper process control, the main problem being the influence of pump switching in the intermediate pumping stations on the oxygen supply to the aeration tanks.
The Design, Construction and Performance Assessment of a Storm King Storm‐Sewage Overflow
Authors: JEFFERIES C. , DICKSON R. A.
Published: July 2007

A new storm‐sewage overflow was commissioned in the spring of 1989 at Lochgelly, Fife, incorporating two proprietary Storm King overflow devices. A programme of monitoring their performance was carried out throughout 1989 to determine whether the units behaved satisfactorily and whether the discharge was equivalent to that passing a 10‐mm screen.

The twin Storm King units each have a diameter of 7.2 m with a continuation flow of 110 1/s and a peak design inflow of 2530 1/s. The paper describes their design and construction, involving difficult access and site problems. Results are quoted from the sampling programme, which included flow measurement, automatic bottle sampling, and detailed visual evidence.
Agricultural Pollution: Control and Abatement in the Upper Thames Region
Authors: BARKER P.
Published: July 2007

The paper describes the approach and methods used during a three‐year programme to improve river‐water quality in an area seriously affected by agricultural pollution.

Low base‐flow river systems serving clay catchments exhibit flash characteristics which required long‐term permanent solutions to ensure improved river water quality under all weather conditions. The approach which was used needed to identify polluters and convince them (a) that effective remedies had to be found and implemented within a reasonable time scale, and (b) that there would be serious consequences of failure to undertake improvements. The initial contact with dischargers, the attitudes adopted and responses received are considered and discussed. Progress throughout each phase of the programme, the solutions used and the degree of improvement achieved are assessed. Legislative changes during the period of the programme, other factors influencing agricultural pollution of watercourses, and likely future implications of these, are discussed.

The success of the programme resulted in the elimination of all major sources of agricultural pollution.
Characterization and Treatment of Leachates from Hong Kong Landfill Sites
Authors: ROBINSON H. D. , LUO M. M. H.
Published: July 2007

Development of a large landfill site in the North‐Eastern New Territories of Hong Kong, which will receive 25 million m3 of wastes during a life of about 13 years, must include the provision of a scheme to manage leachates which will arise in the tropical climate of the region.

The paper presents detailed results from a study commissioned by the Environmental Protection Department of the Hong Kong Government, to characterize and treat leachates generated by landfills in Hong Kong, in order to design a suitable management scheme. Field and laboratory trials which were carried out during 1989 showed that, although leachates from Hong Kong landfills have some specific characteristics (e.g. concentrations of amm.N to 5000 mg/l), they can be treated to high standards by aerobic biological processes.

As a result of these studies, a scheme has been designed which will provide a high degree of environmental protection in respect of leachate, as the landfill is developed.
Hydraulic Feasibility Studies for the Design of the Leningrad Flood Barrier
Authors: MANEVICH Ya. Z. , MISHCHENKO S. M.
Published: July 2007

Flood events in Leningrad occur almost every year and are caused by the propagation of long waves forming as a result of serious depressions in the Baltic Sea and the Gulf of Finland. The flood‐defence works extend along the boundary between Neva Bay and the Gulf of Finland. One of the main requirements is to maximize the existing natural hydraulic conditions when there is no danger of flooding.

During the course of hydraulic studies, the currents and water levels in the enclosed water area were investigated during and after construction of a flood barrier. Model studies were carried out at the design stage and throughout the entire construction period.
Groundwater Abstraction and River Flows
Authors: OWEN M.
Published: July 2007

Considerable attention has been focused in the last few years on certain rivers which are perceived to be experiencing increasingly frequent low flows. A common feature of these is a high level of abstraction, predominantly of groundwater. The mechanics of the effect of groundwater abstraction on river flow are outlined in the paper and illustrated by reference to the River Colne in the Chilterns. The National Rivers Authority is actively investigating these low flow conditions both regionally and nationally. Approaches to the philosophy of alleviation schemes and two national research and development projects relevant to general principles are discussed. The issue of low flows is set in the context of achieving a balance between the uses of water resources for supply and to support the environment.
Water Quality of the North Sea: Concerns and Control Measures
Authors: ZABEL T. F. , MILLER D. G.
Published: July 2007

The quality of the North Sea has become a topic high on the political agenda. Various claims have been made about quality deterioration but hard evidence has been less available. The paper reviews these concerns, summarizes the scientific evidence and considers the specific contaminants involved, together with estimates of inputs and the available controls. The new initiatives stemming from the Ministerial conferences and the evolving legislation should go a long way towards producing reassurance on the one hand and solutions to real problems on the other.
Protection of the Mediterranean Marine Environment
Authors: SALIBA L. J.
Published: July 2007

The specific problems of the Mediterranean, leading to progressive deterioration of the marine environment as a result of an interplay of climatic, oceanographic and socio‐economic factors requiring cooperative in addition to individual intervention, are briefly described, and areas of concern are identified. Events leading to the adoption of the Mediterranean Action Plan in 1975 by governments of the region, to control the situation, are outlined.

The main components of the Action Plan (legal, environmental assessment and environmental management) and institutional and financial framework, together with its gradual evolution from a mainly marine pollution orientated programme into a comprehensive environmental one for the whole of the Mediterranean basin, are described.

The Plan's achievements in (i) the progressive reduction of marine pollution at source, (ii) the establishment and enhancement of national pollution monitoring programmes, (iii) the formulation and adoption of common environmental quality criteria and standards, (iv) the creation of alternative scenarios for Mediterranean development, and (v) orientation towards integrated coastal zone planning and management programmes, are discussed, together with technical and political problems in implementation.

The role of the Mediterranean Action Plan as a potential model for other regions is appraised.
The Impact of the EC Urban Waste Water Treatment Directive
Authors: WRIGHT P.
Published: July 2007

During the last two years significant policy and legislative developments have taken place in the UK and in the EC in respect of sewage treatment and disposal and the dumping of sewage sludge at sea. Details of the UK Government's sewage‐treatment initiative and its decision to stop the dumping of sewage sludge at sea by 1998 are described. An outline is given of the provisions of the EC urban waste water treatment Directive, in particular those provisions concerned with sewage treatment, trade effluent discharges from prescribed industrial sectors, and the termination of dumping of sewage sludge at sea. The implications of these developments for Scottish sewerage authorities are summarized and provisional estimated costs of meeting these new obligations are given. The opportunities available to contractors and equipment manufacturers are highlighted.
A Survey of Cryptosporidium Oocysts in Surface and Groundwaters in the UK
Authors:   THE NATIONAL CRYPTOSPORIDIUM SURVEY GROUP
Published: July 2007

The Badenoch Group of Experts on Cryptosporidium recommended that a survey should be made of river and borehole sources to assess the incidence of oocysts. This paper presents the results of a national survey of three river stretches and six boreholes carried out between January 1990 and March 1991. A total of 1754 samples were analysed and 266 (15%) of these were subjected to independent checks in reference laboratories. The results show a low incidence of oocysts in the sources (range 0–4 oocysts/1). One river stretch gave consistent positive results but with low concentrations (range 0.04–3 oocysts/1, n = 318). Parallel epidemiological studies showed a low incidence of cases in the community, none of which could be related specifically to water supplies. The concentrations of oocysts found are generally lower than those found in studies in the US particularly in comparison with published results for large industrialized rivers.
National Rivers Authority Initiatives in the Development of Portable Monitoring Equipment
Authors: ADAMS J. R. W. , DOLBY J. C. , WILLIAMS P. N.
Published: July 2007

The use of automated equipment for monitoring water quality is a concept which has received considerable impetus since the Water Act 1989 was introduced. This paper reports on two initiatives by the National Rivers Authority to develop systems for use in their role as the guardians of the water environment. Portable systems have been developed for detection of episodic pollution events and instantaneous spot measurement of water quality.

This paper outlines the principal activities of the development of the systems and their use.
Water Quality and Management Strategies in London's Docklands
Authors: DAWSON J. B. , GUGANESHARAJAH K. , THAKE BRENDA
Published: July 2007

Regeneration and changes in land use in London's Docklands have resulted in new water quality requirements. Areas previously occupied by docks now form part of redevelopment projects which have made a feature of the water.

The paper describes a project to provide water that is aesthetically pleasing and of a quality suitable for water contact recreational activities.

An extensive programme of water sampling and analysis was carried out to gain an understanding of the processes affecting water quality, including the monitoring of algal growth. The river is the main source of nutrients in the docks, which results in large concentrations of algal biomass and bacterial contamination. The principal strategy is to limit light via artificial mixing systems supplemented by limiting the inflow of nutrients from the river.

The results from the water sampling programme have been used to build a 3D computer model with a supporting graphic information system to attain (a) qualitative evaluations of management and development options, and (b) short‐term predictions of changes in water quality.
Experiences of Biological Iron and Manganese Removal in Finland
Authors: SEPPÁNEN H. T.
Published: July 2007

Even though groundwater resources in Finland are adequate, and theoretically the total water consumption could be supplied from this source, in practice only about 50% of the total consumption is from groundwater. There are thousands of unconnected small aquifers dispersed all over the country, and the use of these as water supplies is not economically possible.

Biological iron and manganese removal systems appear to be a promising alternative to chemical treatment. In Finland the following biological treatment systems are in use: (i) VYREDOX method; (ii) overland flow method; (iii) slow sand filtration; (iv) re‐infiltration; and (v) biological reactors.

Active iron and manganese bacteria play the most essential role in all these applications, and different methods of removal are discussed in detail in the paper.
Speciation as an Aid to Understanding the Chemistry of Water Treatment
Authors: KERR C. A. , BUCKLEY C. A.
Published: July 2007

The deliberate formation of solid precipitates is a treatment process commonly used to remove undesirable ions from solution. Where the chemistry of the water to be treated is complex, a knowledge of the chemical species present, and their concentrations, can be an effective tool in evaluating the effectiveness of the treatment process and in optimizing reagent dosage and operator control. The use of chemical equilibrium speciation computer programs offers a relatively rapid method to determine the type and concentrations of chemical species present at equilibrium. Some sulphate‐rich waters of significance to South Africa have been speciated using the MINTEQA2 computer program. The effects of treating these waters with barium carbonate have been evaluated. The computer predictions of treated water quality have been experimentally verified.
Cryptosporidium and Water: A Review
Authors: SMITH H. V.
Published: July 2007

Infection with the protozoan parasite Cryptosporidium parvum is now recognized to cause acute self‐limiting gastroenteritis in immunocompetent human beings, and in certain groups of immunocompromised individuals symptoms can persist indefinitely. There is no effective specific drug treatment for cryptosporidiosis. Transmission of Cryptosporidium sp. oocysts via the waterborne route has received attention recently because of the outbreaks which have occurred both in the US and the UK, affecting large numbers of people. This paper reviews the disease in humans, the significance of the waterborne route of infection, and identifies gaps in our current knowledge which the National Cryptosporidium Research Programme attempts to address.
Biological Wastewater Treatment under the Influence of Pressure
Authors: ELLIS K. V. , MORTIMER G. H. , BERKTAY A.
Published: July 2007

An investigation is reported into the effect of pressures of up to 6 bar on the operation of a laboratory‐scale rotating biological contactor. All results are compared with those of an identical reactor operating at atmospheric pressure. Few previous results relating to the effect of pressure on biological wastewater treatment could be found in the literature. Although improved BOD and COD removal (compared to that of the reference unit) was evident as the pressure was increased, the principal benefits of increasing pressure were recorded as being (a) significantly improved nitrification, and (b) a decrease in the sludge yield coefficient. Both these factors improved regularly with increasing pressure, although there is some indication that the production of total oxidized nitrogen might have been affected at the highest pressure employed.
Effect of the EC Urban Wastewater Treatment Directive on Marine Treatment Practice
Authors: HUNTINGTON R. , CHAMBERS B. , DEMPSEY P.
Published: July 2007

The EC Directive on urban wastewater treatment will have a considerable impact on the methods used for the treatment and disposal of sewage at coastal locations. The Directive requires the natural processes involved in marine treatment to be enhanced by the use of land‐based treatment to meet the same standards.

This paper discusses the implications of this change, in particular the problems involved in constructing and operating conventional treatment plants at coastal locations. Planning problems, both locally and on a catchment basis, are considered. It is concluded that these difficulties point to a need for new thinking in catchment planning and in the design and construction methods used for treating wastewaters in coastal communities. This is illustrated with UK and continental examples.

In addition, the implications in terms of outfall design are discussed. It is shown that the change of emphasis towards land‐based treatment does not necessarily reduce the need for a high degree of dilution and dispersion in the sea in order to meet environmental standards. As a result, sound planning, design and operation of long sea outfalls remain as important as ever.
EC and UK Legislation on Environmental Assessment and its Effect on the UK Water Industry
Authors: TURPIN T. , BSc FRANCES FREARS
Published: July 2007

The development of the practice and purpose of environmental assessment (EA) both in the UK and overseas is reviewed, and the implementation of European Commission EA legislation into the UK planning system is examined, together with its relevance to the water industry. The effects and obligations on the industry are discussed with reference to practice prior to and since the introduction of EA legislation. The process of EA is illustrated by reference to the River Avon Sluices Scheme being undertaken by NRA (Severn Trent), and the environmental statements being prepared in accordance with SI 1217. Likely future developments in EA are suggested.
Development of a Decision Support System for Drought Management within North West Water
Authors: WALKER SUSAN , JOWITT P. W. , BUNCH A. H.
Published: July 2007

Whilst droughts, by their nature, are not frequently occurring events, it is essential, for prudent management of water‐resources systems, to have analytical tools available for the effective management of the risks to water supplies when such events do occur.

Within North West Water Limited, modelling techniques have been developed and applied over a number of years, which allow water‐supply managers to be provided with information concerning risks to supply within the Company's water‐resources systems.

The paper describes how these modelling techniques have been integrated within a decision support system for drought management. Two different approaches have been used. Firstly, enhancement by the implementation of a user‐friendly interface and, secondly, the development of a knowledge‐based system. The problems and benefits of each approach are discussed.
Operational Aspects of Three ‘Selectors’in Relation to Aeration Tank Ecology and Stable Foam Formation
Authors: FOOT R. J. , ROBINSON M. S. , FORSTER C. F.
Published: July 2007

The use of ‘selectors’to control the filamentous bacteria which promote bulking in activated sludge is a well‐established concept. However, their use as a control measure for stable foams is still to be optimized. This paper presents the results of a preliminary investigation into the use of selectors at three sewage‐treatment works where stable foams occurred regularly. Chemical and biological data are reported together with the redox potentials in the selector zones. Taken overall, the results suggest that selectors cannot be designed or built on an ad hoc basis if the foam‐producing filaments are to be controlled.
Sustainable Development for River Catchments
Authors: GARDINER J. L.
Published: July 2007

This paper deals with some of the strategic issues arising from the consideration of the sustainable development of river catchments. Principles and best practice are discussed, both in general terms and as challenges to professionals involved with the coordinated planning and management of river catchments.

Points are illustrated with reference to experience in the highly developed River Thames catchment, where the many demands made on the water environment require complex multifunctional decision‐making.

Sustainability offers a new paradigm and common language to support decision‐making for sustainable development. The appropriate institutional and legislative framework will be supported by tools such as environmental appraisal, strategic environmental assessment and economic instruments. Within this context, the implicit partnership between asset management planning, catchment management planning and land‐use planning has the potential to deliver sustainable development for the water environment, through a process which may be called ‘total’ catchment planning.

It is suggested that source control will play a major role in the search for ‘prevention rather than cure’ as a basic principle of sustainability.
Operation of Submerged Filters by Anglian Water Services Ltd
Authors: MEANEY B.
Published: July 2007

Since the introduction of submerged filters for sewage treatment in Europe, process improvements have been rapid. Downflow submerged filters using natural medium have been superseded by upflow filters using synthetic floating medium. Many advantages have been claimed for these systems and Anglian Water have investigated the operation of the Biobed and Filtabed submerged filters for carbonaceous oxidation, nitrification and suspended‐solids removal. The process is based on the use of a bed of floating plastic beads (2–5 mm) through which the sewage flows in an upward direction. The reactor is aerated or non‐aerated according to the required application. Results have shown the process to be capable of producing an effluent containing less than 2 mg/l amm.N and 5 mg/l SS. Backwash water requirements are less than 1%. The Biobead/Filtabead systems are designed to be competitive with regard to area, capital and operating costs.
A Gradual Rehabilitation Programme for Combined Sewerage Systems
Authors: KIRYU T.
Published: July 2007

The Kannai‐Yamashita district, which is Yokohama's administrative and economic heart, was the first part of the city to be installed with a modern sewerage system. This district is served by combined sewers, many of which have extensive pipe deterioration, shallow covering, and insufficient capacity. Whilst rehabilitation of these sewers has therefore been an urgent priority, flood alleviation has been given even greater precedence.

It was consequently decided (a) to construct supplementary storm trunk sewers and a stormwater pumping station to mitigate flooding, and (b) to implement a systematic rehabilitation of the sewers on a gradual basis. Studies of branch sewer rehabilitation also used a surcharge model in the interest of achieving an economical and efficient design.
Developments in European Water Policy
Authors: ZABEL T. F.
Published: July 2007

Significant changes to the existing European Community (EC) legislation for the protection of the aquatic environment are being contemplated by the EC Commission. In addition, the emphasis on sustainable development in the Fifth EC Environmental Action Programme will focus attention on economic instruments to be applied in support of legislation. The EC eco‐labelling and auditing schemes, although voluntary, will lead to more environmentally acceptable products and processes. The paper discusses the likely future EC regulatory system for the protection of the aquatic environment and how the supporting EC initiatives will contribute to environmental improvements.
Guessing or Assessing the World's Water Resources?
Authors: RODDA J. C
Published: July 2007

It is something of a paradox that, at this time when the global demand for water is rising faster than ever before, knowledge of the world's water resources is waning. The networks of instruments which provide the basis for this knowledge are considered, with the errors of measurements involved. Work on reducing these errors, particularly the introduction of total quality management, is discussed. The conclusion is reached that a reliable assessment of the world's water resources is some distance away. This presents problems to bodies involved in their development and management and to those organizations who wish to provide the United Nations' Commission for Sustainable Development with an assessment of global water resources for its session in 1997 ‐ an assessment which will then be presented to a special session of the UN General Assembly.
Aeromonads in Drinking‐Water Supplies: Their Occurrence and Significance
Authors: HOLMES P. , NICOLLS L. M.
Published: July 2007

Traditionally, bacteriological monitoring of drinking‐water supplies has focused on the detection of Escherichia coli and related coliform bacteria. However, attention has recently been given to the occurrence of biofilms and associated organisms which occur in distribution systems. One group of bacteria which have been isolated from water supply systems are the Aeromonads. This group is gaining increased recognition as they have been implicated as causal agents of gastro‐enteritis in humans and are indicators of regrowth potential. In order to obtain a better insight into these organisms and their relationship with other parameters, a number of laboratory and field‐based studies were undertaken. These included (a) comparison of isolation media, (b) examination of biofilms, (c) temperature growth studies, (d) toxicity testing, and (e) sampling and analysis at treatment works and in distribution systems.
Changes in the Distribution of Annual Rainfall in the British Isles
Authors: MAYES J. C.
Published: July 2007

The spatial distribution of annual rainfall in the British Isles is analysed from 1881 to 1990 with reference to changes in the frequency of airflow types. The influence of more frequent westerly airflows earlier this century is evident in higher rainfall in western areas. Changes from 1941 to 1970 show no evidence of a reversal of this change despite a reduction in the dominance of westerlies. Evidence for an abrupt return to a more vigorous westerly circulation since the mid‐1970s, and associated wetness in north‐west Britain, is found to have parallels with scenarios of future climates produced by recent climate models caused by a strengthening of the temperature gradients which drive the mid‐latitude westerly circulation.
Research and Development in Methods of Soakaway Design
Authors: Pratt C.J.
Published: July 2007

Soakaways have been a traditional method of disposal of stormwater for decades, and their usage has mainly been determined by the absence of a convenient watercourse, drain, or sewer into which to discharge runoff arising from roofs and paved surfaces. Today, soakaways are still being installed at a rate of tens of thousands per annum, despite the extensive storm‐sewer systems in the UK. It is therefore surprising that little systematic research and development has been undertaken into their design and performance, or into the appropriate forms of maintenance to be conducted to extend operational life.

The paper briefly describes the recent research into, and design approaches for, the sizing of soakaways. An example is given of the use of Building Research Establishment Digest 365 to review alternative soakaway designs and to assess the cost implications. Some field data are reported which (a) illustrate the seasonal variability and difficulties of determination of the soil infiltration rate, and (b) provide some insight into the pollution issues from the use of soakaways.
Water and Wastewater Minimization: the Aire and Calder Project
Authors: Edwards A. M. C. , Johnston N.
Published: July 2007

The reduction of the waste of raw materials at source using clean technologies, recycling, and good housekeeping has considerable benefits for both the environment and industry. A demonstration project on wastewater minimization was completed in 1995 in the Aire and Calder catchments of West Yorkshire. The findings indicated cost savings for eleven firms of over $3 million/annum and further opportunities which, when implemented, could realize another $1 million/annum. The reduction in the amount of wastewater discharged either to sewer or river was 27%, with a potential to increase to over 40%. The payback period for 63% of the waste minimization opportunities is less than one year and many involve only a small initial investment. Waste minimization when widely adopted has prospects for cutting industry's costs, reducing demand for water and reducing the volume of effluent produced.
The Bacterial Quality of an Upland Stream
Authors: Tranter J. , Hunter C. , Gunn J. , Perkins J.
Published: July 2007

Faecal coliform concentrations were determined at stream and water inflow sampling sites within an upland catchment in North Derbyshire containing rough, semiimproved and improved pastures. The results indicated that, during its passage through the catchment, the faecal indicators of the stream increased, and this may constitute a health risk to cavers using a popular recreational cave into which the stream drains. The decline in streamwater quality suggests that a semipermanent store of bacteria existed in catchment soils, and hydrological processes operated to transfer bacteria from the land to the stream channel. Contrary to expectations, intra‐catchment differences in the bacterial quality of water at inflow and stream sampling sites could not be related to the intensity of agricultural land use in adjacent areas. This is explained with reference to changes in the nature of hydrological transport pathways associated with the improvement of pastures.
Tritium Levels in Leachates and Condensates from Domestic Wastes in Landfill Sites
Authors: Robinson H. D. , Gronow J. R.
Published: July 2007

An extensive review study of leachate composition, from landfills which have received mainly domestic wastes in the UK, has been carried out by Aspinwall & Company on behalf of the Department of the Environment. This work has provided detailed information on concentrations of a wide range of determinands. One set of analyses which has produced particularly interesting results comprises the determination of tritium. Tritium is a natural isotope of hydrogen (3H), with a half‐life of 12.43 years, which decays radioactively to form stable 3He atoms, releasing beta particles. Although tritium concentrations can be measured accurately as tritium units (TU), these represent extremely low levels of activity, and concentrations of tritium well in excess of 100 000 TU would be needed before acceptable levels of radio‐activity in drinking water were exceeded.

Background levels of tritium in UK rainfall rarely now exceed 50 TU although, in the 1960s, values of up to 3000 TU in rainfall were associated with atmospheric testing of atomic weapons. It was somewhat surprising, therefore, to discover that relatively high concentrations of tritium (>10 000 TU) were widespread in leachates from landfills which had received primarily domestic wastes. This paper presents results from samples taken at 30 representative UK sites, and discusses potential sources of tritium.
Environmentally Persistent Oestrogen‐like Substances in UK River Systems
Authors: Montagnani D. B. , Puddefoot J. , Davie T. J. A. , Vinson G. P.
Published: July 2007

The paper describes (a) the research into substances with oestrogenic properties in river systems, (b) the background on why and how these substances are present in river systems, (c) the potential harm which they have through endocrine disruption, and (d) the different techniques for their detection. Results are presented form a preliminary study on the overall oestrogenic potential of sewage effluent being discharged into a river. These results show high levels of oestrogenic potential in the effluent and also in stream water upstream from any sewage‐treatment works. The implications for the management of rivers which contain recycled water and possible future research directions in this field are discussed.
Control of Coliform Growth in Drinking Water Distribution Systems
Authors: Parent A. , Fass S. , Dincher M. L. , Reasoner D. , Gatel D. , Block J. C.
Published: July 2007

The occurrence of coliforms in drinking water distribution systems may be explained by (i) inadequate water treatment, (ii) post‐treatment contamination, or (iii) coliform growth in the network. In order to confirm the third hypothesis, a 24 h‐starved dense suspension of Escherichia coli was injected into an experimental water distribution system. Results from this experiment clearly indicate that E. coli may find ecological conditions in drinking water distribution systems which will allow growth, particularly in the biofilm phase. Chlorination is an appropriate tool to limit coliform much more easily than the total heterotrophic bacterial biomass. However, in all cases, biofilm associated bacteria are more difficult to kill than suspended bacteria, because of chlorine consumption by the pipe material, and because of a diffusion‐limited reaction between chlorine and the biofilm.
Metering for Demand Management: The Cambridge Experience
Authors: Kay S. B.
Published: July 2007

In March 1991, the Cambridge Water Company imposed the first hosepipe ban in its 138‐year history. Peak summer flows had increased to the extent that large‐scale investment was required to meet customers’demands for water. At the time of the ban the company had over 5% of households registered to use garden sprinklers and 23% registered to use a hosepipe. The company decided to meter all sprinkler users, compulsorily, as part of its strategy to reduce peak summer demands. The meters were installed before the summer of 1993, and lower peak flows during the hot periods in 1995 and 1996 offer some evidence for the success of the strategy.
Tunnel Composting at Ipswich
Authors: Barnes L. M.
Published: July 2007

The composting of sewage sludge, either in isolation or in admixture with other biodegradable wastes, is widely practised in the USA and mainland Europe. However, until recently, it has not found favour in the UK. This paper describes the background of a project which led to the construction of the first Gicom tunnel co‐composting system in this country, and the formation of the company ‘Compost Development Venture’(CDV) Ltd – a jointly owned subsidiary of Anglian Water and Ipswich Borough Council. The rationale for choosing tunnel composting above other technologies is outlined, and a brief description of the biology of the composting process is included. The tunnel‐composting method is explained, and operating experience over the first six months is followed by brief accounts of the role of the regulator, operating costs, and future developments for the plant.
Assessing the Adequacy of Wright's Model Reconstructed Stream‐Flow Data for Reservoir Storage‐Yield‐Reliability Analysis
Authors: Adeloye A. J. , Nawaz N. R.
Published: July 2007

As a method of reconstructing long stream‐flow data records for consistent yield analysis, the Environment Agency in England and Wales has adopted the catchment model of Wright. However, to date none of the calibrated models has been verified using criteria directly linked to the intended purpose of the reconstructed data. This paper reports the findings of a simulation study carried out to assess the adequacy of Wright's model reconstructed stream‐flow data for reservoir storage‐vield‐reliability analysis.
The Effect of Ozonation on Particle Removal in Drinking‐Water Treatment
Authors: Bourgine F. P. , Chapman J. I. , Bastiment R. J. , Gennery M. G. , Green J. G.
Published: July 2007

The effect of the introduction of additional process stages in a surface‐water treatment plant was studied in order to investigate how particle removal could be optimized. Particle counting is considered to be a useful indicator of treatment performance. This paper is based on results which were obtained from trials on a water‐treatment plant treating surface water; these consisted of a combination of modifications to existing full‐scale plant and a specially constructed pilot plant.
Milestones in the Development of the Activated‐Sludge Process Over the Past Eighty Years (Abridged)
Authors: Cooper P. F. , Downing A. L.
Published: July 2007

The biological filter was introduced during the latter part of the last century but, in 1913, a radical new process was developed which resulted in a four‐fold reduction in the size of sewage‐treatment plants. This new method was called the ‘activated‐sludge process', and whilst biological filters are still in use ‐ especially for small works ‐ activated sludge is now the dominant secondary treatment process and is the ‘engine’around which modern treatment systems are constructed.

This paper (a) reviews the milestones in the evolution of the activated‐sludge process from 1913 to 1954, centering on reliable removal of BOD and suspended solids, (b) highlights the improvements in design capabilities (1955‐74), with the emphasis on the attainment of consistent nitrification, and (c) discusses the removal of nitrogen and phosphorus (1975‐97), with brief reference to computer modelling and the control of sludge properties.
The Development of Nutrient‐Removal Processes (Abridged)
Authors: Barnard J. L.
Published: July 2007

The earliest references to the loss of nitrogen and phosphorus in activated‐sludge systems indicated an awareness, but no particular interest, in the use of biological processes for the removal of nutrients. The development of extended‐aeration processes in general, and of channel systems in particular, intensified the interest in denitrification as a means of reducing nitrogen in an effluent. Observations of simultaneous nitrification and denitrification led to the proposal of separate anoxic zones for optimal nitrogen removal. The discovery that biological nitrogen and phosphorus removal could be synergistic, led to an explosion of processes, differing in all but the basic underlying biochemistry, for the removal of both nitrogen and phosphorus. The development of computer models, to accurately describe the complex and inter‐related reactions, makes it possible to fully exploit biological systems to achieve cost‐effective nutrient removal.
The Effects of Motorway Runoff on Watercourses in South‐West Scotland
Authors: McNeill A. , Olley S.
Published: July 2007

The paper examines the potential pollution of rivers due to surface‐water discharges from newly‐built sections of the A74(M) motorway in south‐west Scotland. A method for assessing the theoretical risks of pollution of road drainage is compared with the results of discharge monitoring. The impact of motorway runoff on the invertebrate fauna of watercourses is also investigated.
The Affordability of Water in an African Town
Authors: Morris N. G. , Parry‐Jones S. A.
Published: July 2007

This paper examines (a) the ability of consumers in a typical medium‐sized African town to pay for a piped water supply, and (b) the implications for the financial viability of the local water undertaking. It demonstrates that, at present, people are paying about 10% of their income for water, and this appears to be near their limit of affordability. However, it is shown that it is possible for the water company to improve its revenue, whilst maintaining its present tariffs, by providing more private connections. Furthermore, the aim of improving water‐company revenues is compatible with providing improved services to its urban customers.
A Pipeline Testing Facility for the Examination of Pipe‐Wall Deposits and Red‐Water Events in Drinking Water
Authors: Smith S. E. , Ta T. , Holt D. M. , Delanoue A. , Colbourne J. S. , Chamberlain A. H. L. , LIoyd B. J.
Published: July 2007

Field surveys of Thames Water's distribution mains found the occurrence of ‘red water’ to be highly variable and localized. To model the many inter‐related factors identified in the field, a controlled pipeline‐testing facility was required to simulate conditions in a ‘live’ network, but on a pilot‐scale. This was achieved by incorporating a specialized red‐water testing facility into an existing experimental pipeline.

This paper describes the hydraulic and material design features, including the addition of a ‘dead‐end’ section operated on a stagnation and flow regime, quantified using computational fluid dynamics. Following commissioning, the facility has provided detailed, time‐sequenced observations on corrosion‐deposit development and red‐water generation under different hydraulic regimes.
The Fate of Enteric Bacteria in Relation to Suspended Particles in Sea Water
Authors: Alkan U.
Published: July 2007

The investigation was carried out to determine the effect of suspended particles on the survival of selected enteric bacteria (i.e. Escherichia coli and enterococci) which are important indicators of faecal pollution in marine waters. Rates of bacterial removal under varying experimental conditions (i.e. particle concentration, sewage content, and degree of mixing) were determined. The combined effect of the factors concerned with the removal rate of bacteria was evaluated by statistical analyses carried out on the experimental data utilizing the ‘complete factorial’ experimental design, and a good correlation between bacteria and particles was obtained.
Integrated Environmental Planning for Sustainable Development: The Environment Agency's Role
Authors: Carroll B. A. , Howes H. R.
Published: July 2007

The Environment Agency is midway through a programme of ‘local environment agency plans’ for all of England and Wales by the Millennium. To complement them, the Agency has published two overarching plans ‐ one of which is regional and the other sub‐regional in scale. ‘Thames Environment 21’ and ‘The North Wessex Plan’ deal with the potential impact of development pressures and their consequent implications for the environment. Both give practical expression to the Agency's environmental strategy for the Millennium, which concentrates on issues of direct concern to local planning authorities, e.g. addressing climate change, improving air quality, managing water resources, managing waste and enhancing biodiversity.
A Nitrification Model for Mineral‐Media Trickling Filters
Authors: Pearce P. , Williams S.
Published: July 2007

Trickling filters represent the biological treatment component of about 70% of sewage works in the UK. Increasingly, they are being required to achieve a high degree of nitrification consistent with 95 percentile compliance with effluent discharge consents as low as 2 mg/1 of ammoniacal nitrogen. The available design models for the simultaneous removal of BOD and ammoniacal nitrogen are poor and have led to a lack of confidence in the ability of the process to comply with such standards.

This paper describes the development and application of an empirical model based upon the performance of eleven sets of trickling filters at five sites covering a wide range of organic and hydraulic loading.
Driffield Sewerage and Sewage‐Treatment Projects
Authors: Westoll T. G.
Published: July 2007

The town of Driffield (in the East Riding of Yorkshire) has several combined‐sewer overflows which cause nuisance during rainfall. A new interceptor sewer has been laid and the sewage‐treatment works has been reconstructed to improve the water quality in the receiving watercourse. The sewerage scheme was mainly constructed using trenchless technology to reduce the risk of ground settlement in the narrow streets and to avoid contamination of the underlying aquifer. The existing biological filters were replaced with a new four‐basin cyclic activated‐sludge plant. This process achieves biological treatment within a single reactor basin which operates typically on six 4‐h cycles per day and without the need for separate primary and final settlement tanks.
The Treatment of Pumped Minewater at Woolley Colliery, West Yorkshire
Authors: Laine D. M.
Published: July 2007

Woolley pumping station controls the level of underground minewater over about 100 km of abandoned coal workings in West Yorkshire. Pumping prevents the overflow of potentially contaminated minewater from many old drainage adits. On‐site treatment at the adits would be difficult because of land‐ownership problems, topographical constraints, and lack of capacity in adjacent watercourses. The treatment facilities at Woolley were adequate for the volume of minewater during the operational life of the colliery; however, a predicted 500% increase in volume made it essential to extend the plant if the consent standard was to be attained.

The paper describes the options which were adopted, i.e. (a) improvements to the settlement ponds and cascades, (b) the use of cloth filters, and (c) the construction of a large wetland. Further research into the use of wetlands for the reduction of amm. N is now being carried out.
Problems Caused by Filamentous Bacteria in Pilot‐Scale Nutrient‐Removal Activated‐Sludge Plants
Authors: Baxter‐Plant V. S. , Hayes E. , Forster C. F.
Published: July 2007

Sludges from two pilot‐scale nutrient‐removal activated‐sludge plants (a modified three‐stage Bardenpho process and a Phostrip plant) were analysed and the results examined, primarily, in relation to the formation of stable foam. The survey showed that both units produced stable foam, but this did not appear to be related either to temperature or to the more conventional operational parameters (sludge age, F:M ratio). The dominance of the sludge by Microthrix parvicella was related to the amount of uronic acids in the extracellular polymers produced by the sludge. The results also indicated that (a) the addition of fermenter elutrient, which was used to produce supplementary readily degradable COD, stimulated foam formation, and (b) the degree of phosphorus removal might also be implicated in the production of foam – and requires further scrutiny.
An Investigation of Sanitary Indicator Bacteria in a Macrophyte Wastewater‐Treatment System
Authors: Perkins J. , Hunter C.
Published: July 2007

During recent years, many studies have attempted to determine the efficiency of macrophyte systems in removing a wide range of chemical substances and in the amelioration of wastewaters to attain effluent‐quality standards. However, despite the importance of microbiological indicators of water quality for determining the suitability of water for recreational and public‐supply purposes, little research has focused on the dynamics of sanitary indicator bacteria in macrophyte systems. This study reports the initial findings of such an investigation for a macrophyte raft‐lagoon system which was used in the treatment of sewage at Sowerby Bridge, West Yorkshire, England.