bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental River Engineering
Authors: HEY R. D.
Published: July 2007

In the past, river engineering works have often caused channel instability and adversely affected the river's conservation and amenity value. Recent guidelines have advocated a more natural approach to river engineering practice which retains habitat diversity within the river system. While a more natural approach is desirable, geomorphological guidance is required to ensure that the advocated changes are feasible and sustainable, both in the long and short term. The key requirement for sound environmental river engineering is a basic understanding of the natural processes controlling channel shape and dimensions. Examples are given in the paper to illustrate how such knowledge can be used to (a) stabilize rivers, (b) design environmentally‐acceptable and stable flood‐alleviation schemes, and (c) restore previously canalized rivers. The basis of the geomorphological input in the assessment and design process is a river survey which determines the factors controlling channel characteristics and how it will respond to planned changes.
Isle of Wight Water Metering Trial
Authors: SMITH A. L. , ROGERS D. V.
Published: July 2007

The Isle of Wight water metering trial is one of twelve being conducted in England and Wales. The paper describes the consultations that were undertaken, leading up to the design of a metered tariff to meet local requirements. The trial was designed to investigate the problems which a large‐scale implementation of water metering would have and specifically examines meters placed either within a property or laid at the property boundary. The particular problems that arose are discussed, and the problems associated with electrical earthing are briefly described.

The trial, which commenced in the autumn of 1988, involves installing a water meter in all 53 000 Island properties. Southern Water Services Ltd engaged Southern Projects (a sister company within the Southern Water Group) to organize the installation work.

The paper outlines the principal activities of how the trial was planned and executed, with some thoughts on the problems arising during the installation phase.
Network Management ‐ The Bradford Experience
Authors: WHITAKER R. P. , NEWSOME C. D. , PARVIN M. R.
Published: July 2007

The paper reviews the concept of network management in the Western Division of Yorkshire Water and looks closely at its implementation in the Bradford area, together with the role played by an integrated team of staff from Yorkshire Water and Parkman Consulting Engineers.

The individual initiatives which have been integrated into the network‐management programme are identified, and progress on the major ones ‐ network analysis, leakage control, pressure reduction, and telemetry ‐ is discussed together with the details of planned future extensions and developments.
River Catchment Planning for Land Drainage, Flood Defence and the Environment
Authors: GARDINER J. L.
Published: July 2007

The paper describes the changing face of river engineering. The environmental assessment procedure implicit in the Water Act 1989 and explicit in other recent legislation requires review of traditional methodology in the context of the entire river catchment environment. Local deficiencies in performance levels, especially in urbanizing catchments, must be interpreted in this light.

This approach has been made possible by advances in analytical and computational techniques matched by hardware design. Investigations of problem areas can now be specified as part of a developing integrated river catchment plan, supported by adaptable models and capable of playing an increasingly confident role in strategic land‐use planning.
The Use of Audit Surveys in River Maintenance
Authors: EXTON DENISE M. , CROMPTON JUDITH L.
Published: July 2007

The use of river corridor surveys (RCS) prior to major river maintenance works is now widely accepted within the water industry as a means of integrating the requirements for nature conservation with river‐management practices. This paper outlines the audit procedures introduced by the National Rivers Authority (NRA), Wessex Region.

The introduction of follow‐up or audit surveys in 1988 allowed an assessment of the effectiveness of RCS in protecting and enhancing habitats. The method and results of the audit are discussed, confirming the usefulness of audit in ensuring success in the most cost‐effective manner. The audit also identified training needs and failures in implementing enhancement recommendations. Audit has led to a more consistent standard of environmentally‐sensitive maintenance work. A revised method for audit surveys is detailed.
Precast Concrete Blocks for High‐Velocity Flow Applications
Authors: BAKER R.
Published: July 2007

Precast concrete blocks can be used as erosion protection to a surface subjected to high‐velocity water, for example a dam spillway.

The paper describes model testing carried out on flat and wedge‐shaped blocks in a purpose‐designed facility at the University of Salford, where an open channel discharge intensity of 0.5 m2/s can be accelerated to a velocity of 7.5 m/s.

The failure modes of tied and untied flat concrete blocks have been investigated under different laying and bedding conditions. The model results are compared to the findings from prototype studies. Results from experiments on wedge‐shaped blocks of a Soviet design are also presented and confirm the Russian experience that the wedge shape is inherently stable at large discharges, a block of 100‐m thickness being stable under a discharge intensity of 20 m2/s.
Pollution from Fish Farms
Authors: JONES J. G.
Published: July 2007

Fish farms are continuing to grow in numbers and in size. They cause concern because of their location in areas of high‐quality water, frequently in the headwaters where there is little dilution for large volumes of effluent. This jeopardizes the water quality, and may affect the ecology of the river ‐ migratory fish in particular.

The use of chemicals for the treatment of disease is causing concern, particularly if the river is used for potable abstraction. Little information is available on the low‐level effects and the detection of chemicals such as antibiotics and hormones. The chemicals are not controlled nationally, the only control being through consents.

With the continued growth of the fish‐farm industry, problems are likely to increase in the future unless a responsible attitude to their development is adopted.
Flood Frequency Analysis for the 1988 Truro Floods
Authors: ACREMAN M. C. , HORROCKS R. J.
Published: July 2007

In January 1988 the city of Truro experienced a severe flood from the River Kenwyn. The return period of this event was initially estimated at 350 years using the methodology recommended in the Flood Studies Report1. In October of the same year a second flood, of even greater magnitude, occurred. The subsequent investigations employed a variety of flood frequency estimation techniques including one which uses descriptive information on the history of flooding, obtained from local newspapers and journals, in addition to recent flow records. The return periods of the two events were reassessed to be 50 and 100 years respectively. This flood frequency behaviour was found to be markedly different from the regional average for the South West of England.
Galvanic Corrosion of Lead Solder in Copper Pipework
Authors: GREGORY R.
Published: July 2007

The galvanic corrosion potentials of thirty‐eight different waters were measured on site, using ‘Oliphant’ corrosion cells, for lead‐tin solder coupled to copper. A wide range in corrosion potential was found, and the chloride‐sulphate ratio had the most significant effect on corrosion potential. Tests to reduce corrosion potentials by dosing sulphate, silicate, zinc and orthophosphate were carried out. Zinc dosing, especially in combination with ortho‐phosphate, was the most effective treatment for all waters, but posed problems.

Contamination of tapwater by galvanic corrosion of lead solder occurs early in the life of new plumbing, and risk of exposure to contamination can be reduced by flushing before drawing dietetic water. Best‐of‐all, lead‐tin solder should not be used.
The Application of a Computer‐Based System in the Development of Objective River Maintenance
Authors: FITZSIMONS J. , PIMPERTON A. J.
Published: July 2007

During recent years the need for more objective ways of planning river maintenance work has been highlighted by (a) a greater emphasis on justifying budgets, (b) the requirement to provide ‘levels of service’ indicators, and (c) the growing concern from conservationists. This has prompted the development of a computer system within the Severn Trent Authority, known as the Rivers Information and Maintenance System (RIMS), which is described in this paper. This system allows engineers who are responsible for the maintenance of about 3500 km of main river in the STWA area to assess the costs, benefits, and ultimately the environmental impact, of carrying out such works as dredging, tree work and weed control.
The Impact of Intensive Dairy Farming Activities on River Quality: The Eastern Cleddau Catchment Study
Authors: SCHOFIELD K. , SEAGER J. , MERRLMAN R. P.
Published: July 2007

Pollution from farm wastes has been one of the principal causes of deterioration in river quality in recent years. However, little is understood of how, and which, farming activities affect the chemical and biological quality of rivers. To address this problem, a field study has been initiated in the Eastern Cleddau catchment, West Wales, to investigate relationships between land use, farm waste management practices and river quality.

Water quality of small tributaries in this area is poor, and intensive chemical monitoring has shown that discharges from farmyards are a major source of pollution. Rainfall has been shown to exacerbate this effect either through field runoff or wastes washing directly from the farmyards. The status of benthic macroinvertebrate communities in these tributaries is poor and, typically, only a few pollution‐tolerant species are present.

Small tributaries from farms appear to affect both the water chemistry and biology of larger watercourses, although this effect may be quite localized.

Future research will look at ways to reduce the impact of farm wastes on river quality. This will provide the basis for producing recommendations and guidelines for catchment management aimed at minimizing pollution of rivers from farming practices.
The Application of Physicochemical Treatment to an Overloaded Sewage Works
Authors: JONES K. , SMITH D. E. , THOMAS C.
Published: July 2007

The application of physicochemical treatment (PCT) to an overloaded sewage‐treatment works is described. Two methods were evaluated: (i) the ‘Clariflow’system marketed by Energy and Waste Systems Ltd, and (ii) an ‘in‐house’system of dosing chemicals into existing tanks. Both methods increased the efficiency of primary sedimentation, thereby reducing the organic load applied to biological filters and improving final effluent quality. Some indication of the cost‐benefit relationships was obtained.
The Production of High‐Quality Effluents in Sewage Treatment Using the Biocarbone Process
Authors: LILLY W. , BOURN G. , CRABTREE H. , UPTON J. , THOMAS V.
Published: July 2007

The Biocarbone process is a new system for water and effluent purification in which biological treatment and physical filtration take place in the same reactor. Because the use of the process for tertiary treatment of sewage effluent had not been fully investigated, a pilot‐scale evaluation was undertaken at Severn Trent's Wigston sewage‐treatment works. This paper presents the results.

The study corroborates performance information published by the manufacturer. It shows that the process is an alternative to conventional technology for producing fully‐nitrified tertiary effluents having low biochemical oxygen demand (BOD) and suspended solids (SS) concentrations.
Identifying Land Contaminated by Chlorinated Hydrocarbon Solvents
Authors: EASTWOOD P. R. , LERNER D. N. , BISHOP P. K. , BURSTON M. W.
Published: July 2007

This paper provides a method of identifying land contaminated with chlorinated hydrocarbon solvents by sampling and analysing soil gas. Relationships are presented which enable levels of soil gas contamination to be related to levels of soil and groundwater pollution. Two case studies are presented. Soil gas surveying of an industrial site with severe groundwater pollution demonstrated that standards for contaminated land are insufficient to protect groundwater. Solvent levels in groundwater were one to two orders of magnitude higher than UK permitted concentrations in drinking water, whereas soil contamination values did not reach polluted levels. Surveying of a site occupied by a disused fire station showed significant differences in patterns of soil gas and groundwater pollution. This is explained by direct pollution of groundwater though the well at the site and/or possible flow of polluted groundwater to the site from adjacent areas.
The Effect of Hydrogen Sulphide on CHP Engines at Countess Wear Sewage‐Treatment Works, Exeter
Authors: FULTON A. C.
Published: July 2007

The combined heat and power (CHP) system at Countess Wear sewage‐treatment works, Exeter, has been very successful. However, there is a persistent operational problem caused by the acidification of engine lubricating oils by hydrogen sulphide present in digester gas.

The background to the problem is described, and particular emphasis is placed on the use of ‘total base number’(TBN) as a monitoring parameter and the application of ferric chloride as a gas‐scrubbing agent. The economics of CHP are questioned at sites where the hydrogen sulphide level in the digester gas exceeds 2000 ppm.
Greenock/Gourock/Port Glasgow Drainage Scheme and Long Sea Outfall Design
Authors: HUNTER J. C. , SCOTT A. Y.
Published: July 2007

The paper describes the design and construction of a comprehensive drainage scheme which is based on a system of intercepting sewers, headworks, and a long sea outfall. Details are given of the fabrication, discharge arrangements and construction of the outfall, together with measures used for long‐term protection of the pipeline. The layout and design of the headworks and the changes made to the original design to meet changing environmental requirements are given. The paper briefly outlines the existing sewerage system and goes on to describe the proposed interceptor sewerage system for the connection of the flow from the existing outfalls to the headworks. Difficulties encountered in construction are highlighted.

The authors indicate their view on the suitability of the present design, and recognition is given to the likelihood that additional facilities may be required in future. The difficulties which could arise in the provision of such facilities are also highlighted.
Insights into Domestic Demand from a Metering Trial
Authors: RUSSAC D. A. V. , RUSHTON K. R. , SIMPSON R. J.
Published: July 2007

Detailed metering trials together with a survey of property type, household size, and appliance ownership have provided an opportunity to study domestic demand in detail. The data are presented in a number of alternative ways to highlight the relationship between demand and features of the individual households. The uncertainties inherent in using small samples to estimate demands for an area are discussed, and the usefulness of ACORN classifications to characterize an area is examined.
The Liability of Engineers in Design and Construction under English Law: An Engineer's View
Authors: JERRAM D. S.
Published: July 2007

Actions by employers against their professional advisers are on the increase. With the recent changes in the water industry it is possible that the trend will continue, if only because the new private owners can be expected to be less tolerant than their predecessors. This development is compounded by the complicated technical progress with which water engineers are required to be familiar in an industry which demands skills of a high order.

The paper reviews some of the situations in which professional liability can arise, with reference to appropriate case law. The present state of the law in this field is the product of accidental and haphazard development of litigation, with a period of great uncertainty having now become more settled by some recently decided cases.
Probabilistic Modelling in the Water Industry
Authors: METCALFE A. V.
Published: July 2007

The water authorities in England and Wales, which have now become water companies, recently had to provide anticipated costs for maintaining the water supply and sewerage systems over the next 20 years. Probabilistic models and statistical inference provide an opportunity to quantify the uncertainty in such exercises. Their use in a study undertaken by a water authority in the north‐east of England is described and illustrated with interim data which were available at an early stage in the exercise.
Cyanobacterial (Blue‐Green Algal) Toxins and their Significance in UK and European Waters
Authors: LAWTON LINDA A. , CODD G. A.
Published: July 2007

The cyanobacteria (blue‐green algae) which commonly produce mass developments in fresh and saline waters are capable of producing toxins. These compounds have been responsible for the deaths of animals, birds and fish in many countries, and have been linked with several forms of human illness through skin contact and ingestion. Evidence has accumulated over the past decade that cyanobacterial toxins occur commonly in European waters which contain cyanobacterial mass growths. This paper summarizes the recent published occurrence and types of cyanobacterial toxins found in European waters with reference to poisoning incidents.

Cyanobacterial blooms were particularly abundant in the warm dry summer of 1989 in the UK. The deaths of sheep and dogs and the cases of human illness that were ascribed to cyanobacterial toxins were followed by a more intensive and wider investigation into the extent of cyanobacterial toxicity in UK waters than had hitherto been undertaken. Of the cyanobacterial blooms sampled from over 90 freshwaters, approximately two‐thirds were toxic (lethal) according to mouse bioassay. Short‐term and long‐term needs for the recognition, quantification and management of problems which can be caused by potentially toxigenic cyanobacteria in water‐bodies used for recreation, aquaculture and potable supply are briefly discussed.
Development of a New Water Supply for Fort William
Authors: JOHNSTONE J. M. C. , RENNIE G. M.
Published: July 2007

The development of a new water supply source for the Fort William/Corpach and Caol area in the West Highlands of Scotland is described with particular reference to the hydrological and groundwater investigations. Attention is given to a study to reduce the level of leakage and to the analysis of improvements in water quality between well and direct river abstraction. The effect on fisheries in the River Lochy is described, and a preliminary design identified for the recommended scheme.
Contaminated Land: Implications for Water Pollution
Authors: FLAVIN R. J. , HARRIS R. C.
Published: July 2007

The water environment is often neglected in the assessment of the impact of contaminated land and its redevelopment. The lack of effective legislative controls over derelict contaminated land areas and the poor appreciation of water pollution by developers and planning authorities in the undertaking and controlling of site redevelopment has severely hindered effective clean‐up and protection of groundwater and surface waters.

The formation of the National Rivers Authority, the publication of the House of Commons Environment Committee's report and the implementation of the Environmental Protection Act 1990 have given the subject a new impetus. The preparation of registers by local authorities, which identify contaminated land areas, could be enhanced by the National River Authority's assessment of key sites. It is hoped to initiate clean‐up by cooperation, but the testing of legislative powers has been encouraged by the Government, if only to reveal their inadequacies.
Recently Recognized Concerns in Drinking Water Microbiology
Authors: WATKINS J. , CAMERON SHONA A.
Published: July 2007

A wide range of pathogenic micro‐organisms may be found in wastewater and effluents associated with animals. Bacterial indicators may not always be adequate to demonstrate their presence in raw and treated waters. Some pathogens have only recently been recognized as causing problems in water, either by their resistance to disinfection or their ability to grow in aquatic systems. Much time and effort is being spent on improving existing methods and developing new methods which will improve (a) our ability to detect pathogens, (b) our understanding of their distribution in the environment, and (c) the efficacy of water treatment in removing them.
Vacuum Sewerage – The Four Crosses Experience
Authors: ASHLIN D. E. , BENTLEY S. E. , CONSTERDINE J. P.
Published: July 2007

The paper describes the installation of a vacuum sewerage system in a village on the Welsh border west of Shrewsbury. Reasons are given for the choice of system, design criteria, and installation experience, together with observations on the system's performance over the last four years.

The scheme is self‐contained in that it has a dedicated sewage‐treatment works in the form of a proprietary rotating biological contactor, and it is about to be extended in a second phase of vacuum sewerage.
The Roadford Scheme: Planning, Reservoir Construction and the Environment
Authors: GILKES P. W. , MILLMORE J. P. , BELL J. E.
Published: July 2007

Roadford reservoir completes South West Water's major three reservoir strategy quadrupling storage in the region.

The paper examines how environmental issues have impacted on the scheme and demonstrates how effective planning and management can minimize effects and concerns on a major civil engineering project.

Strategy changes from river regulation to gravity water mains have given reduced environmental impact on rivers and a lowering of power costs, also giving environmental gain. The setting of strict environmental protection measures within contracts and a determined policing policy during construction have produced low levels of pollution incidents during construction.

The paper highlights the benefits of working with environmental groups to secure a successful conclusion not only of the construction element but how that construction can be blended into its local environment. Costs are identified and the authors point to the substantial public relations benefits that can be gained with the successful management of environmental issues.
The UK's Environmental Strategy and Its Likely Impact
Authors:   THE ENVIRONMENTAL PROTECTION CENTRAL DIVISION, DEPARTMENT OF THE ENVIRONMENT
Published: July 2007

The Environment White Paper entitled ‘This Common Inheritance’, published in September 1990, set out for the first time a comprehensive statement of the Government's environmental policies and its strategy for their implementation. It established a number of principles on which that strategy is based, the key one being that we have a duty to hand on our world in good order to future generations.

Another principle is that we must only act on the best available scientific evidence, but if that evidence is inconclusive we must take precautionary action. In applying this principle, the Government is aware of the need to promote scientific research to ensure that the results are given wide and clear dissemination.

Everyone is involved in protecting and improving the environment. Many businesses are already investigating ways of reducing damage to the environment that, in fact, make good commercial sense. Local authorities, voluntary groups and individuals can and do help.
Treatment and Disposal Scheme for the Sewage of Athens
Authors: ANDREADAKIS A. D. , CHRISTOULAS D. G.
Published: July 2007

The sewage from the Greater Athens area is discharged without treatment to the nearby Saronicos Gulf. Recently the Greek government decided to implement an appropriate treatment and disposal scheme, on the basis of a study of the hydrodynamic behaviour of the Gulf and the fate of the discharged pollutants. The study was conducted with the aid of suitable hydrodynamic and water quality models for a number of alternative treatment schemes, ranging from primary treatment to biological treatment with seasonal nitrogen removal, combined with outfalls of different lengths. The results indicate that, although none of the examined schemes will lead to an immediate substantial impact, the scheme that includes biological treatment with seasonal nitrogen removal can eliminate the danger of serious ecological disturbances at a reasonable cost.
Evaluation of Methods for Nitrogen and Phosphorus Control in Sewage Effluents
Authors: HARREMOËS P. , SINKÆ O. , HANSEN J. L.
Published: July 2007

The design parameters for the City of Copenhagen sewage‐treatment works were established on an experimental basis, and parallel studies of six pilot plants were made over a two‐year period. The key parameters are (a) the rate of nitrification and denitrification, (b) temperature, and (c) BOD: N ratio in the influent. The data obtained from different methods had to be normalized with respect to the fraction of nitrifiers, temperature, and concentrations of substrates in order to achieve consistent results. The results indicated a substantial inhibition of the nitrifiers, i.e. a 20–30% reduction of the reaction rate. Significant savings were made possible by a comprehensive analysis of the temperature conditions.
New Technologies in the Belgian Drinking Water Sector
Authors: DESMED A.
Published: July 2007

The internationalization of the European market means that the new technologies used in the Belgian water supply sector are very similar to those used in other European countries. Belgian experience of the following new technologies is described in this paper: denitrification, automation, remote reading of water meters, network cartography, directional drilling, leak detection, and experiments with new materials and equipment.
Fluvial Redistribution of Chernobyl Fallout: Reservoir Evidence in the Severn Basin
Authors: ROWAN J. S. , BRADLEY S. B. , WALLING D. E.
Published: July 2007

Sediments in the Chelmarsh pump‐storage reservoir have provided a valuable record of the 137Cs levels associated with suspended particulates transported by the River Severn since 1965. The presence of Chernobyl‐derived 137Cs and 134Cs within the sedimentary record of the site, despite the absence of any direct fallout on the local area, confirmed that radiocaesium from the Ukrainian reactor accident has been mobilized from the upper reaches of the Severn basin where atmospheric deposition was relatively high. The incorporation of Chernobyl radiocaesium within these sediments can be used to date the 1986 fallout episode, and the established geochronology indicated variable rates of post‐1986 sediment accumulation. As radiocaesium is strongly bound to fluvial particulates, this mechanism of redistribution has not adversely affected the quality of the drinking‐water source at the site which was studied.
The Development of an Automatic Soil Sampler
Authors: SNEATH R. W. , PHILLIPS V. R. , INSKIP P. E. , HALL J. E. , PRICE J. S.
Published: July 2007

A recently introduced EC Directive requires that soils receiving sewage sludge should be sampled to a greater depth (250 mm) than previously.

The Water Research Centre foresaw the difficulties that could arise for responsible Authorities if they were to cope with the extra workload and maintain the quality of sampling, and therefore it funded the development of an automatic sampler.

This report traces the development of the sampler which was mounted on an all‐terrain vehicle, and illustrates its suitability for the task by reporting one year's operating experiences. Work rates have been up to eight times those with hand sampling.

A production machine from the first batch is also described.
Use of the Streaming Current Detector at Langsett Water‐Treatment Works
Authors: BISHOP S.
Published: July 2007

A major capital programme is being undertaken by Yorkshire Water to rebuild its water‐treatment plants.

Despite good process design, more stringent standards mean that process control, in particular chemical dosing, has become increasingly important.

This paper describes the investigation of chemical dosing control using streaming current detection, which was initially applied at Langsett water‐treatment works as a means of controlling the ferric sulphate dose in the clarification process.

Following this successful application, further evaluation was carried out using streaming current detection to control the polyelectrolyte dose in the sludge thickening process.
The Sirofloc Process at Redmires Water‐Treatment Works
Authors: HOME G. P. , STOCKLEY M. , SHAW G.
Published: July 2007

The first use of the Sirofloc process in an operational water‐treatment works, outside Australia, was commissioned in 1988 by Yorkshire Water at Redmires, Sheffield. The plant represents a major advancement in the development of a new type of treatment process for drinking water.

This paper describes the new treatment process and the method and reasons adopted in developing a full‐scale plant. The first four months of operation are reviewed, with particular attention to the water quality produced and the performance of the plant. Further areas for development in improving the performance of the process are identified.
Design and Implementation of the River Sheaf Comprehensive Flood‐Alleviation Scheme
Authors: YOUNG D. R. , CROSS J. G.
Published: July 2007

The River Sheaf Comprehensive Flood‐Alleviation Scheme is a flood‐defence scheme promoted by the Yorkshire Region of the National Rivers Authority. The scheme will improve 5.2 km of main river from a 1‐in‐5 year standard to a 1‐in‐50 standard at an overall cost of £3.1 million over the next four years. The hydrological, hydraulic and benefit/cost analyses have been carried out by the National Rivers Authority. Balfour Maunsell were commissioned to carry out the detailed structural design, prepare and administer contracts and supervise construction. The paper covers the preliminary design work and the detailed design of Phase I of the scheme.
Environmental Control Measures at Greengairs Landfill Site
Authors: PHILPOTT M. J. , REID R. C. , DAVIES J. N. , LAST S. D. , BOLDON J. M.
Published: July 2007

The paper describes a programme of infilling, the first phase of which will bring an immediate improvement to the amenity of Greengairs village and will screen the subsequent filling operations from view. The landfill is technically advanced, being designed as an engineered leachate attenuation site but including full back‐up control facilities. These take the form of a full underdrainage blanket under the first two phases, which will collect attenuated leachate and allow confident predictions of the site's behaviour for the design of subsequent phases.

A landfill gas‐collection and control system was incorporated in accordance with laid‐down guidelines.

Other factors which have significant environmental effects are the control of site surface waters and their interaction with groundwater, mine drainage, and the receiving waters.
Diversion of the River Calder at Welbeck: An Engineering and Environmental Challenge
Authors: McDONALD C. , RICKARD C. E.
Published: July 2007

The Welbeck reclamation and landfill project (near Wakefield) is reclaiming over 1.5 km2 of former aggregate and colliery workings through the creation of a new landform. This is to incorporate millions of tonnes of colliery spoil and controlled (i.e. household, trade) wastes, and to avoid the need for disposal on less suitable sites elsewhere.

The scheme is already under way, but the proposed diversion of the River Calder to one side of the site would more than double its capacity for landfill. In environmental terms, the project has been seen as the creation of a new river corridor, rather than simply the diversion of a river channel.

The paper outlines the engineering of the river diversion, which is routed for about 2 km through varied and difficult ground conditions, and gives a number of examples of the priority attached to landscape and after‐use factors, and their intrinsic importance in design.
Waste Stabilization Ponds: A Viable Alternative for Small Community Treatment Systems
Authors: MARA D. D. , MILLS S. W. , PEARSON H. W. , ALABASTER G. P.
Published: July 2007

Waste stabilization ponds are widely used in many European countries, such as France and Germany, for the treatment of wastewater from mainly small communities. There would seem to be no reason why they should not also be a suitable treatment process for populations of under 2000 in the UK. The relative advantages and disadvantages of ponds are compared to other small community treatment systems, such as rotary biological contactors, biological filters and reed‐bed systems, particularly in relation to effluent standards with respect to algae, nutrient removal and relative costs.
Plumbosolvency Effects and Control in Hard Waters
Authors: COLLING J. H. , CROLL B. T. , WHINCUP P. A. E. , HARWARD C.
Published: July 2007

A laboratory lead‐pipe rig has been used to support Anglian Water's successful orthophosphate dosing programme to reduce plumbosolvency. The hard waters in the region generally fall into low or high plumbosolvency categories according to the types of crystalline deposit formed. To improve the cost‐effectiveness of plumbosolvency control, the effects of temperature, phosphate doses, blending and alternation of these waters were investigated.

Initial phosphate concentrations must be above 0.6 mg P/l (as phosphorus) to establish plumbosolvency control. Subsequently, phosphate doses may be reduced, provided that dosing is continuous and sufficient phosphate reaches the extremities of the distribution system. When high and low plumbosolvency waters are blended before distribution, both (or the mixture) must be phosphate dosed. However, where waters alternate in distribution, laboratory studies have shown that low plumbosolvency deposits are more stable, resulting in low lead concentrations. The high plumbsolvency of some hard waters may be due to the presence of low concentrations of humic substances.
Land‐Surface Zoning for Groundwater Protection
Authors: ADAMS B. , FOSTER S. S. D.
Published: July 2007

A procedure for land‐surface zoning, related to the protection of groundwater against both point and diffuse pollution, is described. The procedure is based upon two independent elements:

(i) Division of the entire land surface on the basis of the aquifer pollution vulnerability, which relates to protection of groundwater resources; and

(ii) A series of special protection areas for individual sources, in which various potentially polluting activities are either prohibited or strictly controlled.

The procedure is hydrogeologically based, but not so complex as to be unworkable in practice. For resource protection three classes of formation type are defined, with a further subdivision on the basis of depth to saturated aquifer. In the case of diffuse pollution, it will also be necessary to consider the nature of the soil cover in the area where the polluting activity occurs. For source protection, up to four special protection areas are specified, and the criteria used to define them are discussed.
Physicochemical Aspects of Activated Sludge in Relation to Stable Foam Formation
Authors: KOCIANOVA E. , FOOT R. J. , FORSTER C. F.
Published: July 2007

The presence of stable foams can seriously impair the ability of an activated sludge to produce a high‐quality effluent. This paper examines how the physicochemical characteristics of the solids are related to foam formation and describes how the foaming potential of full‐scale plants can be assessed. It also confirms that Microthrix parvicella can exhibit a variable morphology and shows that these variations are related to the physicochemical properties that characterize foam‐forming solids.
Landfill Lining for Leachate Containment
Authors: SEYMOUR K. J.
Published: July 2007

There is an increasing need for engineered liners to prevent the escape of leachate and to control the migration of landfill gas. This has been influenced by new European and UK legislation and codes of practice.

General principles of site design are explained, followed by a review of the advantages and disadvantages of different liner systems, including mineral liners (natural clay, mudrocks and soil/bentonite admixtures), geomembranes and composite liners.

The need for conservative factors of safety in site design and high standards of quality control, involving full‐time supervision and independent certification of the installation works, are considered essential to ensure the effectiveness of the barrier.

There is no one ideal liner material. Composite mineral/geomembrane liners provide the highest degree of security against leakage and, as such, should be considered as ‘the norm’rather than for use only in particularly high‐risk situations.
Assessing the Health Risks of Sea Bathing
Authors: WHEELER D. , ALEXANDER L. M.
Published: July 2007

This paper considers the scientific basis of epidemiological research into marine bathing water quality in the UK, and places it in the context of policy development for the water industry and regulatory agencies in Europe. Results of the latest UK studies employing internationally recognized methods are reviewed, together with the output of other studies including those based on the use of healthy adult volunteers. It is concluded that methods based on captive volunteer populations may have merit in inland waters used by defined groups of recreational users. However, there is no epidemiologically defensible way of linking the output of such methods to the results of more conventional techniques for assessing risks in marine recreational waters. This observation may have implications for the formulation of new standards for bathing water quality in Europe.
Contamination of the Chalk Aquifer by Chlorinated Solvents: A Case Study of the Luton and Dunstable Area
Authors: LONGSTAFF SARAH L. , ALDOUS P. J. , CLARK L. , FLAVIN R. J. , PARTINGTON J.
Published: July 2007

A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land‐use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.

Low‐level solvent contamination of the Chalk Aquifer was found to be widespread with ‘hotspots’of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.

Clean‐up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.
Hot‐Water Supply System Utilizing Waste Heat from a Sludge Incineration Plant
Authors: KAYANO Y. , SAGAI M. , TAKENAKA K.
Published: July 2007

This paper describes a system for supplying hot water for a small community by utilizing the waste heat generated during the incineration of sludge at a site on Rokko Island, which is a new artificial island built inside the port of Kobe, Japan.

The system was designed to use the heat from the hot water, produced during the cleansing of exhaust gases in the scrubber system of the sludge incineration plant, by recycling it via a heat exchanger in order to supply the occupants of neighbouring apartment complexes with clean hot water. The system has been in operation since 1988. On a yearly average the water supplied is 20° hotter than normal tap water, helping to reduce considerably the use of city gas.
Controlling Diffuse Pollution of Groundwater from Agriculture and Industry
Authors: HARRIS R. C. , SKINNER A. C.
Published: July 2007

The greatest threat of contamination to groundwater resources is posed by pollutants from diffuse sources, yet legislation in the UK has until recently been focused on point sources. The problem of widespread pollution from industrial sources is described and compared with that from agriculture. The legislative controls available under the Water Resources Act 1991 are outlined, and the approach adopted by the National Rivers Authority in its Groundwater Protection Policy is discussed with respect to the concept of groundwater vulnerability.
Long‐Term Experiment of Applying Sludge Fertilizer to Agricultural Land
Authors: NOGUCHI H. , ITO H.
Published: July 2007

Yokohama city has developed facilities to dry and granulate digested sludge, and has been producing and selling sludge fertilizer since 1977. Concurrently, investigations have been carried out on the continuous use of sludge fertilizer with respect to its nutrient value and the influence of heavy metals.

Four types of fertilizer and eight types of crop were used in the test. The nutrient values and other aspects were compared statistically for assessment.

It was found that (a) sludge fertilizer had the same nutrient value as organic fertilizer, (b) there was minimal transfer of heavy metals from sludge to crops, and (c) sludge fertilizer could be used continuously over a long period.
Health‐Risks Assessment of Dinghy Sailing in Avon and Exposure to Cyanobacteria (Blue‐Green Algae)
Authors: PHILIPP R. , BATES A. J.
Published: July 2007

In 1990, the health hazards associated with cyanobacteria attracted widespread interest. In this study, the risks associated with dinghy sailing on two water reservoirs in Avon were examined when the National Rivers Authority concentration threshold for ‘a potential to cause harm’was exceeded at one of these sites. No unusual illnesses were identified and the patterns of reported minor health symptoms were similar at each site. These patterns were also similar to those found amongst freshwater dinghy sailors in Hampshire when the NRA cyanobacteria threshold was exceeded, and similar to patterns of minor morbidity identified amongst dinghy sailors in marine waters when the EC bathing water quality standards are met. The consistency of these findings from three different studies suggests that present Royal Yachting Association guidelines for dinghy sailors are adequate to safeguard their health from cyanobacteria exposure.
Mathematical Models and Engineering Design
Authors: THOMPSON G.
Published: July 2007

The role of mathematical models in engineering design is no longer that of simply automating techniques which were previously carried out manually. Throughout industry models are now becoming accepted as one of the main decision support systems to managers. This is certainly the case in engineering design for managing the environment. We are rapidly moving into the age of expert systems and hydro‐informatics, where the primary aim of most models is decision support. In this paper the role of the models in modern practice is reviewed and illustrated by case histories.
Stage‐Discharge Functions for Two‐Stage Channels: The Impact of New Research
Authors: ACKERS P.
Published: July 2007

Research into two‐stage channels carried out in the large flood channel facility at Wallingford has shown that the conventional approach to their hydraulics over‐estimates their conveyance when in flood. This is because of the interaction between the main channel flow and the slower moving flood plain flows which, traditionally, has been ignored. A new design procedure has therefore been developed allowing for this effect. This has important implications in respect of the stage‐discharge functions for rivers and bermed drainage channels, and especially on the extrapolation of observed flows to greater depths. The newly developed hydraulic design method is provided as an Appendix.
Upgrading Biological Filter Effluents Using the TF/SC Process
Authors: PARKER D. S. , BRISCHKE K. V. , MATASCI R. N.
Published: July 2007

The trickling filter/solids contact process has been shown to be an excellent means of upgrading biological filter plants in North America, and about 100 plants have been built since 1979 in both cold and warm climates, and on both large and small works. A variety of effluent requirements has been satisfied consistently, including monthly average BOD and SS concentrations of 10 mg/l and 10 mg/l respectively. Key design features are described, including the use of an aerated solids contact tank to flocculate dispersed solids. Also, a flocculator‐clarifier with special design features allows the use of high overflow rates and smaller sedimentation tanks.
Treatment and Disposal of Municipal Sludge in The Netherlands
Authors: Van VOORNEBURG F. , Van VEEN H. J.
Published: July 2007

This paper reviews the sludge treatment and disposal operation in The Netherlands where the total volume of sludge is increasing and the sales potential is falling due to stringent quality requirements. The sludge can no longer be recycled to agriculture and has to be dumped on land. The techniques available for this purpose make sludge disposal much more expensive.

A meticulous analysis of the entire sludge chain seems to be necessary to control the costs and minimize the environmental impact, and a start has recently been made on the formulation of ideas in this context.
Assessment of the February 1990 Flooding in the River Tay and Subsequent Implementation of a Flood‐Warning System
Authors: FALCONER R. H. , ANDERSON J. L.
Published: July 2007

Between 4 and 7 February 1990, exceptionally high river flows on the River Tay resulted in widespread flooding of land and property. Roads and railway lines were rendered impassable, and villages and farms were isolated for a prolonged period. In the Tay Valley, 42 km of flood banks were overtopped and 34 km2 of land were inundated.

This paper describes the extent and effects of the flooding and reviews the relevance of various factors in terms of their likely contribution to the magnitude of flooding. Flood‐mitigation measures are discussed with particular attention being given to the implementation of a flood‐warning system for the Tay Valley.
Evaluation and Development of a Thermophilic Aerobic Digester at Castle Donington Sewage‐Treatment Works
Authors: EDGINGTON RACHEL , BSc S. CLAY
Published: July 2007

An investigation into the practicality of thermophilic aerobic digestion has been in progress at Castle Donington since 1989. The work has been carried out in a glassed steel insulated digester of 123 m3 capacity. Both auto‐entraining and blower‐assisted venturi systems have been evaluated.

Both aeration systems were able, under favourable conditions, to remove at least 50% of the sludge COD. It was found that the additional flexibility of the blower venturi combination was necessary to accommodate crude sludges varying from 2% to 12% dry solids.

Originally the plant was intended to operate at above 55C with a 10‐day retention period. In practice retention periods at this temperature have been at least 15 days. The process has proved relatively susceptible to inhibition and requires the air supply to be closely matched to the load.

The revenue costs have been, at best, around 47.3/tDS. This is competitive with small‐scale anaerobic digestion, but not with the large digestion centre approach widely used in the UK. Unless pasteurization becomes a requirement for agricultural disposal, thermophilic aerobic digestion is unlikely to find wide use in this country.