摘要:

ABSTRACTThe reconstruction of 8.1 km of dilapidated sea wall protecting the Hampshire coast of the Western Solent, near Lymington, presented the National Rivers Authority (Southern Region) with particular problems and substantial extra costs in coping with the needs of conservation. The resulting scheme, however, can be seen not only to have preserved but also enhanced the conservation value of its immediate surroundings in addition to the wider area of protected land.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01153.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe Sankey Brook catchment lies in the heart of the Mersey basin. As part of a major study into development issues in the Sankey Brook catchment, a hydraulic model was constructed and successfully used to simulate the river system and to assist in the derivation of discharge control policies.The background to the study and the subsequent hydrological and hydraulic modelling are described, particularly in relation to the more complex systems in the lower reaches of Sankey Brook.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01154.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTIncreasing restrictions on sewage sludge disposal routes and the tightening of treatment requirements have led to an escalation of sludge‐disposal costs which are out of proportion to other sewage‐treatment costs: consequently reducing sludge volume is becoming increasingly cost‐effective. Consolidation of anaerobically digested sludge has traditionally been difficult and takes many weeks in secondary digesters or deep storage tanks. Pre‐aeration of the sludge using the Aercon process can enable consolidation to take place in days instead of weeks.This paper reports the results of a pilot‐scale plant designed to investigate further the mechanism by which aeration speeds up consolidation. It was concluded that the rate of consolidation depended on aeration intensity and cooling of the sludge. Inhibition of anaerobiosis was more important than gas stripping in enhancing cons

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01155.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTUsing regional statistics of daily rainfall, a simple water‐balance model was employed to generate runoff sequences with which to simulate the yield/storage behaviour of reservoirs in south‐east England, in north‐west England, and North Wales. Similarly sequences of recharge to an unconfined aquifer in eastern England were the basis of deriving its yield/storage behaviour. Then, taking scenarios of the year 2030 rainfall and evaporation, provided by the University of East Anglia's Climatic Research Unit, reductions in yield were calculated to be 5–15% below present‐day values. For direct supply reservoirs, greater percentage reductions in yield were found to apply to the south‐east region, as compared to the north‐west. The results from the aquifer example are interpreted on a novel basis which allows an immediate comparison with the surface reservoir examples.Coastal sea‐water intrusion was modelled for three common geological conditions (i) the Grimsby Chalk (confined), (ii) the Brighton Chalk (unconfined), and (hi) the Otter Valley Sandstone (unconfined). In all three cases the effect of a possible 0.6 m rise in mean sea level was shown to have only a marginal effect on sustainable yields, which reduced by about 1.5%.Estuarine fresh‐salt water interfaces are important to the abstraction regime of freshwater intakes in the lower reaches of rivers. The effect of a 0.6‐m sea‐level rise on the saline interface location at high tide was evaluated by hydrodynamic computational models. Only a minor inland shin of the interface was found, less man 800 m in the Thames tideway and less than 500 m in the Lune estuary. The Severn estuary is exceptional in having its saline interface move 3.5 km landwards for the same 0.6‐m

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01156.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTBritish Gas owns over 900 sites within the UK with a total land area in excess of 5500 ha. Many of the sites are former gasworks, chemical works or associated holder stations.Although serious attempts were made to remove contamination during the last three decades, the operating and demolition standards previously considered to be adequate may no longer be acceptable and may have given rise to sites with the potential to contaminate adjacent land, surface waters and ground‐water. As a result, further actions may now be required on these sites to reach new environmental standards, thereby reducing any chance there may be of legal liability on the Company.This paper describes the advantages and disadvantages of several qualitative and quantitative risk‐assessment methods which can be used to prioritize potentially contaminated sites for further investigation. The use of site investigation data to accurately target risk reduction in site remediation proposals is also discus

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01157.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTOsaka has nearly completed its sewerage system, and twelve sewage‐treatment works are now in operation. Tsumori and Ebie works, the two oldest, were commissioned in 1940. For these works, full‐scale reconstruction has just commenced.This paper reports on the reconstruction of the Tsumori works, and outlines the plan for future reconstruction of the city's sewage‐treatment

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01158.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTChemical investigations of contaminated land can be expensive and yet still leave the landowner unaware of his/her full environmental liability. An approach to an effective means of planning chemical investigations is described by a case study of a contaminated site near London. This approach limits environmental liability in a cost‐effective manner.One of the main problems encountered in assessing the degree of contamination of land for the purposes of technical design, and ultimately for developer confidence, is the lack of recognized UK standards for acceptable levels of contaminants.Using a second case study relating to a large contaminated site in the Midlands, the paper describes how a set of site‐specific standards, for soil and water, was derived and used to develop a reclamation strategy for an 81‐ha site. The case study also demonstrates the approach which was adopted in handling a large amount of analytical data and other quantitive information needed to produce a set of ‘constraint models’. From these constraint models, the strategy for reclaiming the site has been

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01159.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe development of groundwater modelling techniques is reviewed, from analogue and early digital models to current commercial software packages. The parallel development of the application of groundwater modelling as a tool for evaluating the impact of developments and structures on hydrogeological systems is also examined. Formerly, new model programs were written for each application, requiring that the user had programming skills as well as hydrogeological expertise, and model development periods were measured in months or years. Now, a knowledge of the program details is not necessarily a prerequisite for a satisfactory model, which may be designed, constructed, calibrated and used in days or weeks. However, a thorough understanding of the conceptual model underlying a software package, and of the numerical methods used to generate the output, is as important as ever. Examples are given in the paper of the exploitation of commercial packages to produce rapid assessments of the impact on groundwater of proposed mineral workings and similar developments.

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01160.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTDuring the long‐distance pressure transportation of sewage, the interior of a rising main tends to become anaerobic, thereby producing a large amount of hydrogen sulphide at manholes and terminals. High concentrations of hydrogen sulphide have become a serious environmental and maintenance problem.In order to prevent the production of hydrogen sulphide in rising mains, the City of Kobe (in Japan) introduced a system to inject air directly into the main.This paper describes the results of studies on the effect of air injection on hydrogen sulphide inhibition and the relationship between water quality and the amount of air injecte

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01161.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe paper outlines how consent standards are normally calculated in Scotland for both river systems and tidal waters. A background is given to the reason why a more statistical approach has been adopted in England and Wales where the use of combining distribution methods is more widespread. Comparison of the two approaches is made, particularly with regard to their potential impact on resources required for treatment plants, and also the problems of taking enforcement action. The setting of standards under the EC urban waste water treatment Directive is considered where, in addition to the implications of primary, secondary and more stringent treatment, consideration is given to storm‐sewage overflows and industrial discharge

ISSN:1747-6585    

DOI:10.1111/j.1747-6593.1994.tb01162.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY