A Study on Spatial Growth of Beijing's Central Urban Area from 1950s to 2005 Supported by Spatial Information Technology

1. Introduction According to the National Bureau of Statistics of China, the urban population and urbanization rate of China have increased very rapidly in recent years (see Fig. 1). In     

The Production of High-Quality Effluents in Sewage Treatment Using the Biocarbone Process

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.     

The Development of Ion Chromatography for Metals Analysis in Saline Waters

Previous attempts to utilize ion chromatography for the analysis of sea water samples have failed through chronic interference by the major ions (na, Mg, Ca) during the preconcentration stage. As part of ongoing research into ion chromatography, a technique has been developed to overcome these interferences, using a two-stage preconcentration step, prior to separation on a cation-exchange column. This has made it possible to detect μg/l quantities of trace metals in samples containing g/l concentrations of sodium, magnesium and calcium. A modified commercially-available ion chromatographic system was used to analyse copper, nickel, zinc, cobalt and manganese in saline waters. Detection limits were typically less than 1 μg/l, with relative standard deviation of less than 10%. Hence this new method has the potential to provide an inexpensive multi-elemental sea water analysis with the minimum of handling. In addition, the simplicity and sensitivity of the technique may make it suitable for unattended use as a remote monitor of metals.     

Design and Construction of an Ion-Exchange Denitrification Plant in South Staffordshire

Increasing concern about rising levels of nitrate in groundwater supplies and their subsequent removal to comply with EC drinking water standards has led to the construction of the first full-scale ion-exchange nitrate-removal plant in the UK by the South Staffordshire Waterworks Company.
This paper describes the development of the project from concept, through pilot-plant studies to final design, installation and commissioning. It explains the role of ion-exchange technologies, the use of recently developed nitrate-selective resins and the development of a novel dual regeneration system. The initial performance of the full-scale plant is discussed.     

Changes in Plant community at Foxcote Reservior Following Use of Ferric Sulphate to Control Nutrient Levels

I n an attempt to control planktonic algal growth in I n an attempt to cosntrol planktonic algal growth in Foxcote water supply reservoir, which is supplied by eutrophic waters from the river Great Ouse, ferric sulphate has been used to reduce ortho-phosphate concentrations in the pumped inlet water. Internal recycling of sediment-bound nutrients retarded the expected algal control for almost three years. During the third year, a marked change in the ecology of the reservoir occurred, and planktonic algae were largely replaced by prolific growths of filamentous species and rooted macrophytes. While the changed flora have caused their own problems, the reservoir is now less prone to closure due to intractable water treatment problems.     

Groundwater Model of Conditions in Liverpool Sandstone Aquifer

T his study considers the groundwater conditions for the period 1948–82 in the Permo-Triassic Sandstone aquifer of the Liverpool area. During this period, significant changes have occurred in the abstraction patterns and a new railway tunnel has been constructed below sea level in Central Liverpool. To understand the flow conditions within the aquifer, detailed studies have been carried out into the aquifer properties, the influence of rivers and tunnels, and the estimation of recharge. It is found that conventional rainfall recharge accounts for only one-third of the total recharge.
Numerical model solutions were used to check the adequacy of the understanding of the flow processes and the solutions have confirmed that the rising water levels in Central Liverpool result from high recharge and a reduction in abstraction. Having validated the model by comparisons with field data, the model was then used to predict the probable future water level changes.     

Managing and Engineering Rivers for the Benefit of Man

F rom earliest times flood, famine and drought have been scourges of mankind. River engineers alleviate floods, drain the land for agriculture, and conserve water resources. They construct engineering works, guide planners and developers, and provide warnings to minimize damage caused by storms over catchments and coasts. As the country becomes more developed, problems of reconciling conflicting interests require a flexible approach. This paper examines ways of providing the basic services in a climate of increasing public clamour for wildlife and landscape protection, and recreation.     

Controlling Nitrate Leaching in Water Supply Catchments

S prings from a catchment to the north east of Bath to provide up to 80 per cent of the water supply to a population of 96 000. A review in 1984 suggested that within a few years nitrate concentrations in these sources could exceed the limit for drinking water (11.3 mg N/1). Nitrate was being leached from agricultural land and when an opportunity arose to alter the largely arable farming on part of the catchment, guidelines were devised to reduce nitrate leaching. This paper describes the guidelines and the effects of their implementation.