ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTThere 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 sit

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTLee Valley Water plc has, in a joint study with the University of Birmingham, been reassessing the reliable yields of its existing chalk sources in order to make maximum use of the available groundwater resources. An approach to yield assessment was developed which took into account the hydrogeology and flow processes in the vicinity of pumping stations, and within the contributing area. The yield of many sources was found to be very dependent on regional water level conditions. Initial estimates of potential yields were made but future monitoring should aim to clarify the interrelationship between source output and aquifer state.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTThe selection of clean‐up methods for contaminated land depends upon the nature and degree of contamination and on standards for clean up. There have been two approaches to clean‐up standards, namely ‘multifunctionality’, where the site is cleaned up to a standard suitable for any use, and the ‘end use’approach, as used in the UK, where clean up is to a standard suitable for the immediate use proposed for the site.Clean‐up options fall into four categories: (i) excavation and off‐site removal; (ii) encapsulation and cover; (iii) retention of contaminated soil on site after treatment; and (iv) removal of contaminants from soil and reuse of cleaned soil on site.In the UK, clean up has been dominated by off‐site disposal and encapsulation/cover, while soil treatment techniques have been used mainly in the US and some European countries such as the Netherlands. This is largely as a result of the availability and relatively low cost of landfill in the UK and the lesser importance attached to date to groundwater considerations.Soil treatment processes include biological, physicochemical, and thermal processes, all generally of

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTA study of two major environmental issues in upland water management is presented. Discolouration and reservoir sedimentation are seen to affect water managers on different timescales and to different degrees. Rates of reservoir sedimentation, adjusted for empirically derived trap efficiency, are measured and found to be higher than previously believed. A link between sediments found within the reservoir basin and the generation of colour is described.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTMuch has been written in recent years about the potential threats posed by increasing greenhouse gas concentrations. This paper summarizes the implications of global warming for hydrological processes in general and river flow characteristics in the UK in particular, emphasizing the present high degree of uncertainty. Current climate change scenarios for the UK imply that rainfall between autumn and spring will increase, and this may have beneficial implications for UK water resources. However, the effect of this increase may be outweighed by higher evapotranspiration. Average annual runoff in a catchment in southern UK may be reduced by around 5% by the middle of the next century, but this estimate is very uncertain: runoff may reduce by 30% or increase by 30%. Runoff in northern and western UK is likely to show a slight increase (but with similarly large confidence intervals). It is probable that river flows in the UK will be much more concentrated in winter than at present. The effect of a given climate change scenario on monthly flow regimes depends on the current summer water balance and on catchment geological conditions.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTInfection with the protozoan parasiteCryptosporidium parvumis now recognized to cause acute self‐limiting gastroenteritis in immunocompetent human beings, and in certain groups of immunocompromised individuals symptoms can persist indefinitely. There is no effective specific drug treatment for cryptosporidiosis. Transmission ofCryptosporidiumsp. oocysts via the waterborne route has received attention recently because of the outbreaks which have occurred both in the US and the UK, affecting large numbers of people. This paper reviews the disease in humans, the significance of the waterborne route of infection, and identifies gaps in our current knowledge which the National Cryptosporidium Research Programme attempts to addres

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTIn spite of many aquifers still being in good condition, groundwater pollution is becoming a serious problem in some areas of continental and insular Spain, although it is not always recognized. Irrigated agriculture is an important source of pollutants, but industrial, mining and urban‐related problems also exist. These go in parallel with serious salinity problems of diverse origin. The degree of knowledge with regard to these problems is still poor, and in many instances low priority is given to studies, prevention, control and remedial action. Water quantity aspects still receive most of the attention and economic resources. A new Water Act includes provisions for dealing with groundwater quality and pollution; they seem adequate to cope with existing problems, but their effectiveness, feasibility and willingness to be applied is still uncertain. The success not only depends on scientific and technical issues, but mainly in achieving an administration and management structure capable of coping with real problems and able to obtain the trust and cooperation of water user

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTThis 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.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

ABSTRACTAn investigation is reported into the effect of pressures of up to 6 bar on the operation of a laboratory‐scale rotating biological contactor. All results are compared with those of an identical reactor operating at atmospheric pressure. Few previous results relating to the effect of pressure on biological wastewater treatment could be found in the literature. Although improved BOD and COD removal (compared to that of the reference unit) was evident as the pressure was increased, the principal benefits of increasing pressure were recorded as being (a) significantly improved nitrification, and (b) a decrease in the sludge yield coefficient. Both these factors improved regularly with increasing pressure, although there is some indication that the production of total oxidized nitrogen might have been affected at the highest pressure employe

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1992.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY