bluuebunny/crossref_metadata_2025 huggingface dataset:
Creating a Wetland Using Rainwater as Mitigation for Loss of Waterfowl Habitat
Authors: Wells M. J. , Turpin T.
Published: July 2007

A major onshore hydrocarbon terminal was constructed on coastal fields at Point of Ayr on the Welsh side of the Dee Estuary which is protected under national and international environmental legislation and conventions as a wetland of major importance ‐ especially for birds. A scheme is described which was implemented to increase the carrying capacity for waterfowl in an area of farmland adjacent to the terminal. The main method for enhancing the habitat involved bringing a core area of the farm to ‘field capacity’(saturation with water) by surface wetting. Various potential water sources for the scheme were explored. The chosen system entailed the collection of rainwater runoff in a system of drains and reservoirs during the winter and the distribution of the water to bunded irrigation areas in the following autumn. The early successes of commissioning experiments are briefly described, and the key issues for further investigation are identified.
Enhanced Chemiluminescence as an Indicator of Water Quality
Authors: Sawcer K. E. , Yeomans W. E. , Thorpe G. H. G.
Published: July 2007

The enhanced chemiluminescence test is based upon monitoring the emission of light from an enhanced chemiluminescence reaction in the presence of an environmental sample and comparing it with a similar reaction using a de‐ionized water control sample. The presence of polluting materials can be detected by changes in the intensity and the kinetics of light emission. This trial demonstrated that the effects of components within a sewage‐works' effluent are detected by enhanced chemiluminescence and that this test has moderately close correlation with parallel bacterial determinations. A high correlation was achieved between the performances of two commercially available enhanced chemiluminescence reagents, and these reagents responded consistently to the effects of a sewage‐works' effluent on the quality of a small river.
Catalytic‐Iron Filters for Effective and Low‐Cost Treatment of Odorous Air
Authors: Boon A. G. , Boon K.
Published: July 2007

Several methods are available to remove hydrogen sulphide and volatile organic sulphides from ventilated air at sewage‐treatment works. Some methods use alkaline and oxidative chemical scrubbers which may have high capital and operational costs. Other methods, such as bio‐scrubbers and bio‐filters, are used to biochemically oxidize sulphides. Biological scrubbers have the advantage of low operating costs, but their performance may be adversely affected by a high concentration of sulphide (> 100 ml/m3).

This paper describes the development of a novel, compact and low‐cost ‘rusty‐iron’ chemical filter which catalyzes the oxidation of hydrogen sulphide and organic sulphides to colloidal sulphur and water. Operating costs are relatively low, with no need for routine maintenance. Full‐scale demonstration of the effectiveness of such filters was carried out over two years at several treatment works, the results of which are described and discussed together with details of capital costs. The overall percentage removal of hydrogen sulphide by compact multistage filters was found to exceed 95%, irrespective of inlet sulphide concentrations which varied from 34 to 500 ml/m3 (ppm).
The Use of Software for a Risk‐Based Approach to the Planning and Operation of Water‐Resource Systems
Authors: Stahl G.
Published: July 2007

Software for water‐resources planning has been in use in the Anglian region of the UK since the mid‐1970s. However, new technical solutions (such as network flow programming) have recently emerged and may offer more appropriate tools to respond to the growing challenges faced by the water industry. These have been explored and implemented by Essex and Suffolk Water and the Environment Agency through the ‘drought reliable output program’(DROP) project. The needs and benefits of a more user‐friendly platform are reviewed, and issues relating to the lack of a general quantifiable measure of reliability (both in yield assessment for planning purposes and the optimization of operation of water‐resource systems) are discussed.
Flood‐Plain Mapping of the River Leam and River Itchen
Authors: Harris E. , Archer D.
Published: July 2007

As part of the requirements of s. 105 of the Water Resources Act 1991, the Environment Agency is producing flood‐plain maps of all major rivers. Where no historic data are available for a large flood event, mathematical models are used to simulate 100‐year design flood flow events, which allows the definition of flood‐prone areas. These maps, together with a database of the water levels and flows, will form part of a national Flood Plain Information System.

This paper describes the development and generation of flood‐plain maps for the Rivers Leam and Itchen in Warwickshire. The data collection and review of topographic and hydrometric data are outlined. Procedures for combining information from gauged data, historical flood data and methods based on catchment characteristics form the basis for estimating design input flows to hydraulic models. Modelling principles and data requirements of two different hydraulic models, used to estimate peak water levels of design return period, are described.
On‐Line Toxicity Monitoring Using Amtox
Authors: Hayes E. , Upton J.
Published: July 2007

As environmental legislation around the world becomes more stringent, it is vital that biological systems are able to treat the effluents which are discharged from wastewater‐treatment plants. Conventional treatment such as BOD removal has been achieved successfully for many years, but the requirements for toxicity removal are more onerous. The Amtox system, which was designed to give operators of wastewater‐treatment plants a tool for assessing the toxicity/treatability, uses an immobilized culture of nitrifying bacteria, maintained in a heated aerobic reactor, to determine whether or not a waste is degradable. The system has a broad range of applications from treatability tests to process monitoring and toxicity tracing and, by changing the culture, effluent toxicity monitoring.

This paper details two case studies: (i) in an abattoir where an Amtox monitor was used to diagnose the source of toxicity, and (ii) on the River Trent.
Floating Filters for Particle Removal in Sewage Treatment
Authors: Ødegaard H. , Helness H.
Published: July 2007

This paper describes experiments which were carried out on a high‐rate secondary‐treatment plant which incorporate a moving‐bed biofilm and floating filter. The same cylindrically shaped plastic elements were used both as a biofilm carrier and as a filter medium in the floating filter.
Customer Service and Operational Efficiency as Drivers for Distribution Capital Investment
Authors: Armstrong R.
Published: July 2007

In order to realize the maximum improvement in customer service and operational efficiency from infrastructure improvement, a rational, integrated and structured approach to capital investment planning is required. This involves undertaking an operational review and predictive study based upon a full understanding of the hydraulic behaviour of the water supply and distribution system, and considers wider issues such as consequences of (a) long‐term future demands, (b) environmental issues, and (c) external regulatory pressures.

The methodology has been demonstrated in work carried out for East of Scotland Water as part of their ‘integrated network management strategy’.
Contaminated‐Land Information and Guidance: User Evaluation
Authors: Petts J. , Butler B.
Published: July 2007

This paper discusses a survey of users of contaminated‐land information and guidance. The survey was designed to assist in the understanding of user needs in the context of the developing risk‐based approach to decision‐making. Environment Agency staff, local authority officers, consultants and specialists within major industrial companies contributed. The results suggest that, whilst highly qualified in their specific environmental and scientific disciplines, people are faced with many issues (in relation to contaminated land) with insufficient technical background and assistance. The potential impact of such deficiencies is discussed, together with possible solutions.
The Two‐Stage Moving‐Bed/Activated‐Sludge Process: An Effective Solution for High‐Strength Wastes
Authors: Sunner N. , Evans C. , Siviter C. , Bower T.
Published: July 2007

The paper describes a moving‐bed bioreactor which was used as the first stage of a two‐stage process to provide an effective and simple means of reducing the biochemical oxygen demand of a wastewater prior to further treatment in a conventional second‐stage activated‐sludge plant.

At Corby, a scheme was required to (a) meet the requirements of a more stringent effluent consent and (b) provide capacity for further anticipated growth in industrial effluent loads. The original works comprised conventional primary sedimentation tanks, biological filters and humus tanks, followed by an activated‐sludge oxidation ditch and further settlement tanks. A pilot plant has been in operation at Corby for two years, and the results were used to design a moving‐bed bioreactor to replace the existing filters.

At Pyewipe, a new coastal treatment plant was required and, following the change in status from a ‘high natural dispersion area &, a ‘normal’ programme was initiated to achieve the required completion date. A value‐management workshop was held which identified the two‐stage moving‐bed bioreactor/activated‐sludge process, and a pilot plant was operated for eighteen months. A full‐scale plant is now under construction and incorporates a number of innovative features.
A New Generation of Biological Aerated Filters
Authors: Bigot B. , Tallec X. Le , Badard M.
Published: July 2007

Biological filters with fixed submerged beds are normally used for secondary or tertiary treatment and are recognized for their good performance. These processes are designed to meet, simultaneously, strict requirements of quality and operation. The achievement of the discharge consent requires the use of fine media which features a large support surface for the growth of biomass. On the other hand, the achievement of long filter run times is intrinsically related to the use of coarse media. Nowadays, all biological filters have mono‐media, which offers a compromise between these two conflicting criteria.

The B2A process is a newly developed compact filter which ensures high filtration performance and long filter run times, even when used for crude sewage. The technology has been in use since 1992 for nitrification/ denitrification using an applied load of 0.7 kg/m3. d to obtain an effluent quality of 20 mg/l total nitrogen. Further tests have proved its efficiency in the removal of carbonaceous pollution.

The B2A process is the first compact filter capable of treating screened crude sewage yet producing effluent qualities which are equal to that from conventional biological filters receiving settled sewage.
The Changing Picture of Water Consumption By Power Stations
Authors: Martin P. C. , Todd I. J.
Published: July 2007

Recent advances in open‐cycle gas‐turbine technology have resulted in station thermal efficiencies which are comparable with the large fossil‐fired stations built in the 1970s. The combination of a steam cycle to the gas turbine culminating in the ‘combined cycle gas turbine’ station has led to even greater generating efficiencies. These advances in power‐station design have led to reductions in water demand per megawatt of electricity generated. However, water usage still contributes significantly to increasing fuel efficiency in (a) the electrical generating process, (b) reducing atmospheric emissions from stations burning fossil fuels, and (c) utilizing gas turbines. Considerations arising from the competitive electricity market and wider issues of sustainability and environmental improvements, in general, suggest that water will continue to be required for power generation in the foreseeable future.
Optimizing Nitrification On Biological Filters
Authors: Pearce P. A. , Foster D. M.
Published: July 2007

A recently developed nitrification model for biological filters has been applied to the design of three sites to increase nitrification. The first site was upgraded by the installation of a dedicated recirculation facility, the second by reconfiguration to double filtration, and the third by the installation of a chemical pre‐precipitation plant. All three sites responded well to the modifications and achieved compliance with ammoniacal nitrogen consents of 3–5 mg/l on a 95%oile basis. The key influence of hydraulic load on nitrification capacity and reliability was demonstrated on all three plants. The ability to upgrade existing biological filter installations to meet stringent ammoniacal nitrogen consents allows a significant reduction in environmental impact and revenue costs when compared with energy‐intensive options such as the activated‐sludge process.
Water Supply and Demand Balances: Converting Uncertainty Into Headroom
Authors: Carnell J. , Lawson J. D. , von Lany P. H. , Scarrott R. M. J.
Published: July 2007

This paper reports on research into the development of a standard procedure for calculating headroom. Headroom is a legitimate planning allowance to account for uncertainties in the supply/demand balance in a water‐resource plan. Prior to this research, the UK water industry did not have an agreed method for calculating headroom, which resulted in inconsistencies in regulatory submissions. The research built on previous studies to define an approach that would be practical and easy to apply. A pragmatic methodology using a series of forms with clear guidelines was developed. The methodology has been applied in the 1998 supply/demand balance submissions to the regulatory authorities as part of the Asset Management Plan 3 periodic review.
Direct Use of Spent Distillery Wash Liquor on Paddy Fields in Thailand
Authors: Phanapavudhikul S.
Published: July 2007

Spent wash liquor (or stillage) from the Excise Department's distillery plant at Ubonratchathani Province, Thailand, has a flow‐rate of 550 m3/d. About 100 m3/d of the liquor are fed to an anaerobic digester by the ‘upflow anaerobic sludge blanket’ process ‐ the remainder being transferred directly to a large storage lagoon. The digested liquor is then diluted and pumped during the dry season (December to July) to 400 ha of paddy fields; this has resulted in a 2–3 fold increase in rice yield. Also, the liquor serves as an oxygen‐depletion aid which inhibits the growth of thrips and eradicates insect pests. In return, the farmers save 66–80 p/m3 in terms of equivalent chemical fertilizer and insecticides. This direct use of spent wash liquor is a promising trend towards sustainable development in developing countries.
Implementing a Sustainable Flood‐Defence Strategy for London's Tidal Thames
Authors: Penrose J‐P. , Fry C. M.
Published: July 2007

The tidal flood defences in London protect the city and its citizens from potentially catastrophic flooding. In recent years there has been increased recognition of the environmental value of the tidal Thames; however, this environmental renaissance has been matched by increased river‐side development, creating intense pressures upon the tidal Thames environment.

Building on the application of environmental assessment at the project level, the Environment Agency is developing new tools to evaluate the cumulative environmental impact of‐works to individual frontages. Using current case studies, this paper describes practical examples of these approaches which aim to provide sustainable and economically justifiable flood defences and contribute to the enhancement of the tidal Thames.
Submerged Biotower Technology for Tertiary Nitrification of Poultry Abattoir Wastewater
Authors: Dale C. J.
Published: July 2007

The paper describes the design and operation of a submerged biotower, i.e. flooded upflow reactor which utilises a random‐packed polypropylene medium for supporting the biomass. The process can be used for carbonaceous removal or nitrification. In the application which is described, the process has been used for tertiary nitrification of a poultry abattoir wastewater as an extension to the existing effluent‐treatment plant. Details of process commissioning at low temperatures are given and results from twelve months’operation are discussed. Operating costs are compared with other processes.
Life‐Cycle Assessment of a Sewage‐Treatment Plant in South‐East Asia
Authors: Zhang Z. , Wilson F.
Published: July 2007

This paper analyses the environmental impacts of a large‐scale sewage‐treatment plant and identifies opportunities for environmental performance improvements over the three life‐cycle phases of construction, operation and demolition. Results show that nearly 70% of energy consumption occurred during the operation phase, which was lower than the normal energy consumption level of the conventional activated‐sludge process. The results of the life‐cycle assessment may have implications in material selection, energy management, process design, supplier and contractor management, and environmental policy making.
Thermochemical Treatment of Sewage Sludge
Authors: Furness D. T. , Hoggett L. A. , Judd S. J.
Published: July 2007

Technologies for the thermochemical treatment of sewage sludge are appraised with reference to their efficacy in terms of (a) operational parameters, (b) pre‐and post‐treatment requirements, and (c) the extent of their use for the application. Particular attention is given to the characteristics of the solid and gaseous products and how such characteristics affect post‐treatment, reuse or disposal – this being dictated by environmental legislation.

Of specific interest is the off‐gas treatment, which can contribute significantly to operating and capital costs of incineration. On the other hand, gasification and pyrolysis generate a combustible product for use in heat and/or power generation. Available information, although limited, suggests that gasification offers significant advantages over the conventional incineration process, yielding a combustible gaseous product (which can be directly utilised on site) and a solid char product (which is less prone to leaching of toxic metals).
Ultrasonic Sludge Pretreatment for Enhanced Sludge Digestion
Authors: Clark P. B. , Nujjoo I.
Published: July 2007

During recent decades, the anaerobic digestion process has been extensively studied and various methods for process enhancement have been explored. These methods include heat treatment, alkali addition, phase separation and membrane enhancement. In general, whilst technically feasible, the methods have not proved to be economically competitive.

The pretreatment of sludges with high‐power ultrasound has been investigated as part of a twelve‐month research project funded by six UK water utilities. Cell lysis and particle‐size reduction (caused by ultrasonic cavitation) are thought to be the key parameters through which the digestion process is enhanced. A series of laboratory‐scale anaerobic digesters has been operated and significant increases in biogas yield have been noted following ultrasonication. Experiments have been completed with a variety of ultrasonic devices (of different geometries and construction materials) and sludge types (e.g. primary, secondary and co‐settled). Current experiments are investigating methods through which the technology can be successfully scaled‐up and applied on a full‐scale plant.
Water Pollution Control Issues in an Independent Ukraine
Authors: Nazarov N. , Cook H. F. , Woodgate G.
Published: July 2007

Water‐quality monitoring in the Ukraine is intended to control pollution and enforce water‐protection legislation. The control is both state and institutional, with institutional control being predominant. Despite the fact that the country has a good scientific and technical background for effective water‐quality monitoring, there are failures in the operation of state environmental law enforcement inspectorates. This appears to be due to the economic crisis in the country; as a result, there are serious water pollution problems. The only long‐term solution is considered to be an improved performance in the Ukranian economy, which would allow society to pay for enhanced ‘environmental goods’.
Developments in Structured‐Wall Plastics Sewer Pipes and a Method of Testing Their Resistance to Damage
Authors: Rasbash J.
Published: July 2007

Structured‐wall plastics sewer pipes rely upon the structural configuration of their walls to enhance their stiffness, whilst saving on material. Their properties and performance vary widely with the type and material from which they are made, and opinion is divided as to the acceptability of these products for sewerage systems. The UK water industry and the Committee for European Normalisation are actively developing standards for them, but there are a number of performance‐related concerns which need to be addressed if they are to be accepted in the UK.

A test, which measures a pipe's resistance to being damaged, has been developed at the University of East London, and preliminary results confirm a wide variation in performance.
A Realistic Basis for an International Comparison of Real Losses from Public Water‐Supply Systems
Authors: Lambert A. O.
Published: July 2007

The paper considers the subject of physical (real) losses from pressurised systems which are used for public water supply. To date, attempted comparisons of leakage management performance between water undertakings world‐wide have been severely compromised because there have been no standard methods of defining and calculating real losses. Performance indicators, which have been traditionally used for comparisons, have been too simplistic. Limitations of existing performance indicators are identified in the paper by reference to key factors which should be incorporated in objective comparisons of real losses.

The paper describes an improved methodology which was developed by an International Water Association Task Force, based upon logical concepts using local key parameters, calibrated using auditable assumptions, and tested against twenty‐seven diverse sets of data from twenty countries.
Statistical Analysis of the Performance of a Biological Nutrient‐Removal Plant
Authors: Williams S. , Hardy P. , Green D. , Wilson I.
Published: July 2007

Thames Water operated a demonstration‐scale biological nutrient‐removal plant for two years to investigate the feasibility of retrofitting it into existing activated‐sludge plants. The plant was operated with and without the addition of short‐chain fatty acids to the anaerobic zone. The results from the trial showed that phosphorus removal was possible, but that performance was not consistently good. The data show that the key parameters which affect the effluent soluble phosphorus concentration are (i) the soluble phosphorus and oxidised nitrogen concentrations at the end of the aeration lane, and (ii) the sludge‐blanket depth. Further analysis of the data suggests that secondary release of phosphorus was marked when the concentration of short‐chain fatty acids in the anaerobic zone was low, even if the sludge blanket was shallow and when oxidised nitrogen was present in the return sludge. In contrast, secondary release of phosphorus was limited when the concentration of short‐chain fatty acids in the anaerobic zone was high.
Estimating Pipe Reticulation Losses in a Municipal Water‐Supply System
Authors: Stent A. F. , Harwood N.
Published: July 2007

Domestic water consumption in the city of Dunedin, New Zealand, is unmetered. Recently, the Council's Water Department adopted sampling methods to estimate domestic water consumption and system losses, consistent with the recent reports on managing leakage produced by the UK water industry. This paper describes the exercise (which is ongoing), including the treatment of practical issues which arise in applying the methodology. System losses were estimated to increase substantially over the initial two years of the study, leading to the investigation of an assignable cause. The data reflect the effects of the corrective action, lending considerable support to the validity of the method.
Low‐Cost Separation of Arsenic from Water: With Special Reference to Bangladesh
Authors: Mamtaz R. , Bache D. H.
Published: July 2007

The main objective of the study was to develop a low‐cost technique for the removal of arsenic from contaminated groundwater, as found in Bangladesh. It was shown that arsenic can be removed by co‐precipitation with the naturally occurring iron which is found in groundwater. Tests showed that the removal rate was largely controlled by the arsenic concentration, the iron/arsenic ratio, and pH. Iron precipitation was induced by aeration and mixing through manual shaking.

Bench‐scale tests demonstrated that up to 88% of the arsenic (III) in water could be removed by settlement over a period of 24 h. This was better than the removal rate achieved by filtration. It was found that the removal rate was mainly independent of the mode of mixing. For solid‐liquid separation, draw‐off arrangements were studied. It was found that the sample should be drawn off with a slow flowrate (<0.5 l/min). In such conditions the treated water quality is not seriously impaired for the particular design of the container which was examined.

From maps of the known distributions of arsenic, iron and pH, it was evident that 63% of the area in Bangladesh complied with the Bangladesh standard for arsenic. By interpreting the maps and applying the potential removal identified in the study, it was estimated that a further 9% of the area would comply with the Bangladesh standard, freeing 8 million people from arsenic contamination.
Development of a Methodology to Set Up Odour‐Quality Objectives for Sewage‐Treatment Plants in Flanders
Authors: Van Broeck G. , Van Langenhove H.
Published: July 2007

On the basis of elaborate odour studies around three sewage‐treatment plants, the relationship between modelled 10 mins average odour concentrations in combination with exceedence frequencies (percentiles) and annoyance near the sewage‐treatment plants, was investigated. Annoyance was measured by means of a telephone survey in the vicinity of the odour source. The odour concentrations were determined using sniffing measurements in combination with short‐term and long‐term dispersion model calculations – over a period of one year.
New Insights into the Appraisal of Flood‐Alleviation Benefits: (2) the Broader Context
Authors: Penning‐Rowsell E. C. , Green C.
Published: July 2007

During the last twenty‐five years, new approaches to the appraisal of flood‐alleviation investment have developed. This paper (a) identifies some of the key data inputs to this process, (b) evaluates the impact of these on decision choices, and (c) explores the issues concerning the relationship between flood losses and flood probability.
Modelling the Soil Moisture Deficits Developed under Grass and Deciduous Woodland: the Implications for Water Resources
Authors: Finch J. W.
Published: July 2007

The area of deciduous woodland in the UK is increasing as a result of Government policy, and studies suggest that this might result in reduced streamflow and groundwater recharge. Measurements of soil water content were carried out (a) at a site on a sandy loam soil, (b) under land covers of grass, and (c) in deciduous woodland. The data show that both the field capacity and wilting point of the soils were much less under the woodland than those under grass. In 1997, soil moisture deficits were developed down to a depth of 1 m under grass and in excess of 3 m under the deciduous woodland. A simple daily water‐balance model was able to simulate the observed soil water contents and emphasised the importance of interception losses from the deciduous woodland canopy. For a 25‐year period, the model predicted that the mean annual runoff and soil drainage for the woodland was less than half those for grass.
The Use of High‐Rate Nitrification for the Pretreatment of Ammoniacal Digested Sludge Liquors
Authors: Barnes L. M.
Published: July 2007

Anaerobic sludge digestion reduces most of the organic nitrogen in raw sludge to ammonia. Where the digested sludge is dewatered, the ammonia in the liquors can represent up to 25% of the total ammonia load on the receiving wastewater‐treatment plant. This can cause problems with compliance and also limit the throughput of the digestion plant. The paper describes how Anglian Water addressed this problem at Cliff Quay wastewater‐treatment plant, Ipswich by installing the AmtreatTM high‐rate nitrifying process. The reasons for the necessity to reduce the ammonia load to the plant are presented and the rationale behind the selection of this solution is outlined. The AmtreatTM plant is described and its performance is evaluated. The Cliff Quay site is the first application of this process to a municipal wastewater‐treatment plant in the UK, although there are several installations operating with industrial effluents.
Leakage Targets and Socio‐Economic Efficiency
Authors: Bouchart F. J‐C. , Salleh H. M. , Sawkins J. W. , Jowitt P. W.
Published: July 2007

During the last few years, the introduction of mandatory leakage targets for UK water companies has had the positive effect of reducing levels of leakage, while requiring the companies to operate at an economic level of leakage. Unfortunately, the determination of company‐specific economic levels of leakage have been a source of disagreement between the water companies and the Government, with the Government view that water companies are not using the true long‐term marginal costs of water abstraction, and therefore are not safeguarding the environment.

This paper (a) reviews the model which was used to define the economic level of leakage, (b) argues the case for resource management based on the impact of water abstractions on the socio‐environmental quality of a resource rather than the myopic focus on leakage reductions, (c) presents the concepts of effectiveness and efficiency in relation to socio‐environmental quality, and (d) proposes a new methodology which allows the determination of water abstraction rates while maintaining a desired level of socio‐environmental quality.
Seasonal Forecasting of River Flows in the British Isles Using North Atlantic Pressure Patterns
Authors: Wilby R. L.
Published: July 2007

A potentially useful forecasting relationship is demonstrated between the North Atlantic Oscillation index in winter (January‐February) and the following summer (July‐September) monthly mean flows for selected rivers in the British Isles. The relationship was strongest in August when up to 40% of the variance in monthly mean flow may be explained. For two rivers in southern and eastern England, positive phases of the winter North Atlantic Oscillation index were found to precede summer flows which were nearly 50% of long‐term average. A regression equation which was established to predict August flows in the Great Stour produced a correlation score of 0.6 at a lead time of six months. Further research is needed to determine the significance of catchment characteristics and geographic location relative to forecasting skill.
A Coastal Strategy for Edinburgh
Authors: Wallis B.
Published: July 2007

This paper describes the development of a coastal strategy which is designed to meet (a) regulatory requirements, (b) customer aspirations, and (c) environmental needs of a capital city. The strategy was developed taking into account the needs and views of all stakeholders, and a holistic approach was taken to ensure that the principles of sustainable development are met. The strategy requires a substantial phased capital investment of more than £175 million, and it was essential that a ‘value for money’approach was taken without compromising the achievement of the required standards. This was ensured by the use of ‘value management’, detailed environmental studies, and consultation with customers and other stakeholders.
Development, Flood Risk and the Urban Environment: Experiences from the River Tame
Authors: Webster P. , West J. R. , Gurnell A. M. , Petts G. E. , Sadler J. P. , Forster C. F.
Published: July 2007

Experience and knowledge of river‐restoration schemes are generally available at the reach scale. However, there are problems with the application of this knowledge at the scale of large urbanised catchments which relate to understanding the system and predicting the impact of management strategies. This paper considers problems of developing a perceptive and efficient rehabilitation strategy for a large urbanised catchment, with specific reference to the River Tame in the West Midlands. Consideration is given to (a) rainfall‐runoff relationships, (b) assessment of water quality and ecological status, and (c) predicting the impact of various management strategies.
The Promotion of a Planned Indirect Wastewater Re‐use Scheme in Essex
Authors: Walker D.
Published: July 2007

During the last eighty years, Essex and Suffolk Water has had to resort to various innovative water‐storage and river‐transfer schemes to satisfy increasing demands for water in the driest part of the UK. Recently, a series of droughts has emphasised the need for more water. To help meet this need, the company intends to recycle 35 MI/d of Chelmsford treated wastewater, using an £8 million plant to reduce pollutants. In April 2000, the company was granted discharge and abstraction licences by the Environment Agency for the recycling scheme. This paper includes (a) some of the results from several years of pre‐impact baseline data, (b) an outline of pilot trials of the recycling processes, and (c) a brief description of the public consultation which was necessary to promote the scheme.
A Practical Assessment of the Use of Particle Counters for Monitoring the Risk of Cryptosporidium and Giardia
Authors: Wilson R. , Morse A.
Published: July 2007

The paper describes a project which was carried out to establish whether particle counts can be used to predict the risk of Cryptosporidium and Giardia breakthrough at a large water‐treatment works. The project was based at a direct river‐abstraction works which treats up to 120 MI/d. On‐line particle counters were installed following three of the rapid‐gravity filters, and a fourth counter was used to measure particles in spot samples of raw and clarified water.

There was a clear relationship between particle counts and the occasional low‐level (oo)cyst (crypto oocysts and giardia cysts) occurrence in the filter samples, and no (oo)cysts were found in the final water. There appear to be complex inter‐relationships between particle counts and other parameters such as raw‐water conditions, environmental factors and treatment‐plant variables.
Managing the Impact of Tourism on the Environment
Authors: Reeves N.
Published: July 2007

Tourism is now the world's largest industry, generating earnings of £285 billion/annum. In recent years, the tourism sector has become a significant contributor to the wealth of the UK and represents about 7% of the workforce. Greater mobility and more leisure time has led to greater car use, many more short‐term movements of people, and increasing pressure on the transport infrastructure. Consequently, there is real concern about the effect of increased tourist activity on the environment and how the challenge of sustainable tourism can be achieved. This paper examines how the tourism industry is addressing that challenge by balancing the benefits of tourist activity without compromising the environment. In Wales, the Wales Tourist Board is committed to sustainable tourism, and its approach is offered as an example of achievement and how conflicting demands can be resolved.
The Use of Biosolids and Other Organic Substances in the Creation of Soil‐Forming Materials
Authors: Chambers B. , Royle S. , Hadden S. , Maslen S.
Published: July 2007

This paper describes an experiment which was carried out at a landfill site in north Lincolnshire to investigate the use of biosolids and other organic materials in soil formation. The following organic amendments were incorporated into the surface of the on‐site geological clay to form ‘topsoil’treatments: (i) nil, (ii) biosolids (digested cake), (iii) waste peat/compost, and (iv) composted green waste. The biosolids were applied at a rate of 70 tDS/ha and all the organic materials were incorporated to a depth of 150 mm. The organic amendments reduced the topsoil bulk density and increased plant available water supply and soil water infiltration rates. Topsoil organic matter, total nitrogen and extractable phosphorus concentrations, biomass nitrogen, readily mineralisable organic nitrogen and soil respiration rates were also increased. Additionally, the biosolids application increased topsoil aggregate stability and soil surface strength.
Development and Application of a Method to Appraise Acid Waters in Wales
Authors: Brookes A.
Published: July 2007

This paper describes an appraisal methodology which has been developed and applied specifically to identify options for alleviating surface‐water acidification in Wales in the short, medium and longer terms. It involves screening and scoping of options, ranging from those that might result in environmental improvement several years on from a policy change, to more immediate measures with results that can be seen on the ground ‐ albeit only at a local level. The method relies on gaining consensus from a wide range of experts and involves (a) identification of options, (b) deciding on decision factors, (c) elicitation of scores for the impacts of each option on particular issues/decision factors, and (d) trade‐off analysis using a non‐parametric statistical technique. It is hoped that the lessons derived from this case study will be of use in further development and application of the methodology.
Drought‐Intensity Duration and Frequency Analysis: A Case Study of Western Uganda
Authors: Rugumayo A. I. , Mwebaze D. B.
Published: July 2007

This paper describes (a) drought occurrences in two selected climatic zones of western Uganda and (b) examines the meteorological aspects of drought where rainfall is the main parameter of interest. Rainfall data from various stations in each climatic zone were checked for consistency using the double mass curve technique, and one representative station from each climatic zone was selected. Two probability distributions: normal and log‐normal were fitted to the data, and the log‐normal distribution provided a better fit in each case. Drought volumes, return periods, intensities, and severity indexes were determined for each climatic zone. The annual potential evapotranspiration was also calculated and plotted against the rainfall to give the soil‐moisture deficit. From the results of the analysis it was observed that droughts of a higher severity occurred in Kasese compared with Mbarara.
Lowland Stream Restoration in Denmark: Background and Examples
Authors: Neilsen M.
Published: July 2007

Since 1982, Danish legislation on streams and drainage has included clauses which make it possible to implement river restoration. In this paper, the Danish shift in policy from drainage to the return of wetlands is described. To illustrate the new beginning on catchment management, two major river‐restoration schemes, i.e. the River Brede demonstration project and the River Skjern Nature project, are presented. Both projects have been implemented and consist of many parts, including (a) returning the straight, regulated rivers back to their former meanders, (b) introducing better hydraulic interaction between the river and its meadows, and (c) establishing former lakes, bogs, ponds and marshes. Also, an increase in security against flooding has resulted, as the regulated ‘water‐motorways’have become more natural, with buffer‐zones and retention of water in the restored features.
Potential for Sewage Sludge Co‐Combustion in the UK Based on German Experience
Authors: Barber W. P.
Published: July 2007

Increasingly strict legislation, escalating costs and external pressures are causing the water industry to look for alternative strategies to agricultural recycling for the disposal of biosolids. Although the development of the ‘safe sludge matrix’has encouraged agricultural recycling, negative press has hampered this outlet and public perception is seen as a major threat. Accordingly, many water companies are looking towards thermal‐reduction technologies and have invested in thermal dryers and sludge incinerators; however, such technology has high capital costs and complex maintenance and operator requirements. An alternative method, i.e. co‐combustion, is becoming more popular in mainland Europe. Unlike incineration/drying, the capital expenditure is low and operator/maintenance risks are minimised.

This paper (i) discusses a case study in which 40 000 dry tonnes of sludge per annum have been successfully combusted since 1996, and (ii) explores how this experience could be applied in a UK situation.
Effectiveness of Secondary Digesters as a Pathogen Controller in Winter
Authors: Le M. S. , Mayhew M. E. , Back P. A.
Published: July 2007

A revision of the Regulations regarding the use of sewage sludge in agriculture has forced a change in emphasis in sludge treatment from stabilisation to achieving pathogen kill. Previous work carried out by United Utilities Service Delivery highlighted temperature as being a key factor in pathogen kill in mesophilic anaerobic digestion and a possible important factor in pathogen destruction in secondary digestion, which is normally carried out in large open tanks where temperature control is not possible. It was found that temperature is a key factor in the rate of pathogen de‐activation under isothermal conditions. However, in the full‐scale secondary digester trial under winter conditions it was found that there was a significant difference between the surface temperature and the bulk temperature within the sludge; at the surface the temperature decreased more quickly. There was no significant difference between the performance of the ‘old’and ‘new’design of concrete tank with respect to wall thickness, cooling rates and E. coli reduction rate. The glass‐coated steel‐tank design showed a marked increase in the cooling rate and, despite the low ambient temperatures and fluctuating sludge temperature, a minimum 1‐log reduction in E. coli was achieved.
A NOVEL CATALYTIC SYSTEM FOR THE OXIDATIVE DESTRUCTION OF TOXIC ORGANIC COMPOUNDS IN INDUSTRIAL WASTEWATERS
Authors: Ishtchenko V. V. , Huddersman K. D. , Vitkovskaya R. F. , Tereschenko L. Y. , Romanova E. P. , Rumynskaya I. G.
Published: July 2007

This work describes a novel heterogeneous oxidation catalyst which is analogous to the homogeneous‐phase Fentons reagent for the successful destruction of a range of organic pollutants. The catalyst is a polyacrylonitrile fibre which was modified to incorporate ligatinggroups, resulting in a transition metal cation being firmly fixed onto the fibre. The novelty of the catalyst resides in its open‐knit mesh structure. In the presence of hydrogen peroxide, the catalyst containing ferric ions (as the active site) is shown to rapidly decompose phenol in addition to (a) the anthraquinone dyes: acid blue 45, carminic acid and reactive blue 19, and (b) the azo‐dye drimarine red K. B. The decomposition reaction was followed by ultraviolet spectroscopy, and the distribution of ferric ions on the external surface of the fibre was examined by a scanning electron microscope. The mechanical properties of the fibre were found to have decreased on modification but were still sufficient for the manufacture and commercial exploitation of the fibre.
WATER CONSERVATION AND ITS PERCEPTION IN PALESTINE: A CASE STUDY
Authors: Mimi Z. A. , Ziara M. , Nigim H. H.
Published: July 2007

This paper describes a pilot project, based upon a specific approach for encouraging effective water use in schools. The project included (a) constructing two low‐cost sewage‐treatment plants for irrigation water re‐use in two schools, and (b) conducting an awareness campaign for effective water use in fifteen schools in the Jenin rural area. Data show that the campaign increased the pupils' knowledge of water and positively impacted on attitudes and practices.

Statistical analysis demonstrates that good knowledge and positive attitudes in students will result in improved effective water use. The schools with pilot sewage‐treatment plants for irrigation water re‐use benefited the most and encouraged students to modify their water‐use practices.
DYNAMICS OF SEDIMENT‐ASSOCIATED METALS IN A HIGHLY URBANISED CATCHMENT: BRADFORD, WEST YORKSHIRE
Authors: Old G. H. , Leeks G. J. L. , Packman J. C. , Stokes N. , Williams N. D. , Smith B. P. G. , Hewitt E. J. , Lewis S.
Published: July 2007

Urban watercourses are potential hazards because of their rapid flow changes, poor water quality and contaminated sediments. This study is a preliminary field investigation into fine sediment‐associated metal contamination and its transport dynamics in a highly urbanised catchment in West Yorkshire, UK. Spatial and temporal changes in the concentration of channel‐bed sediment‐associated metals are investigated, and the fluxes of selected suspended sediment‐associated metals, during an extreme high flow event, are determined. Channel‐bed sediments were more contaminated at the most heavily urbanised sites. Data suggest that contaminated bed sediments could accumulate and possibly become increasingly contaminated between high‐flow events, prior to being flushed from the system. Fluxes of contaminated suspended sediments were very high at the peak of the high flow event. The spatial and temporal dynamics of contaminated fine sediment which were identified in this study could inform planners with regard to future monitoring strategies.
THE RESTORATION OF WOODS MILL LAKE
Authors: Hayes E.
Published: July 2007

Woods Mill Lake is the centrepiece of a nature reserve at Henfield in Sussex, UK. During the last forty years, the lake has undergone a succession of changes, and this has resulted in loss of depth and encroachment of the reed‐bed. In the summer months the large carp population was suffering stress due to shallow water. The problem of silt excavation required extensive discussion with statutory agencies: in addition, the work had to be scheduled around nesting birds, breeding newts and school visits. This paper (a) discusses the complexity of the work which was undertaken, and (b) provides an analysis of the fish population which was removed from the lake.
STORMWATER QUALITY ASSOCIATED WITH A FULL SILT TRAP DISCHARGING INTO AN URBAN WATERCOURSE
Authors: Scholz M. , Zettel S.
Published: July 2007

The aim of this project was to assess the influence of a full silt trap on the quality of stormwater which was discharged into an urban watercourse. The average SS concentrations of the outflow were 2.0 and 34.1 mg/l during dry‐weather and wet‐weather conditions, respectively, and SS concentrations of up to 141.6 mg/l were recorded during storms. Treated stormwater SS concentrations were often high, compared with secondary sewage‐treatment standards of ≤30 mg/l. Pollutants accumulated in the silt trap.