Peter D. Hedges

Analysis of the methods for determining the settling characteristics of sewage and stormwater solids

In order to optimise the design and the management of sewer networks and settling tanks, there is a need to determine the settling velocity characteristics of sewage and stormwater solids. Devices and test methods for measuring settling velocities of these solids have been developed (Chebbo, 1992), (Michelbach and Wohrle, 1993) and (Tyack et al., 1993). In order to quantify the influence of the experimental procedure on the settling velocity grading curves, we have compared three selected methods (Cergrene, Aston, Camp) when tested with the same sample with the method developed by UFT (Michelbach and Wohrle, 1993). The results of the comparative tests indicate that the settling velocities are significantly higher with the UFT test procedure than the other methods. This is mainly explained by the fact that the UFT method takes only settleable solids into account. When the calculations of the four methods are made with the total mass of SS, the study has shown that the settling velocity curves of the same samples are different. The differences vary between the nature of the samples and the test procedures which were compared. The influence of the experimental procedure for separating a sample by settling velocities fractions is demonstrated. In conclusion, we explain the need to develop an international test procedure in order to be able to compare the results.

The Hydrological Sustainability of Constructed Wetlands for Wastewater Treatment

It is argued that there is a need for a hydrological assessment to be undertaken at the design stage of wetlands, which are to be constructed for wastewater treatment, in order to ensure their long-term sustainability. A simple water budget provides a suitable tool for this purpose. The product of an appropriate crop coefficient (Kc), and the reference crop evapotranspiration (ETo) determined from meteorological data, is deemed a suitable procedure for determining the evapotranspiration component of the water budget. The UK and the Czech Republic are taken as case studies, representative of maritime and mid-continent climates, to illustrate a procedure for identifying regions where created wetlands are potentially at most risk from water deficits.

An Approach to the Integration of Communication Skills Development within an Undergraduate Civil Engineering Program.

Graduate engineers in the United Kingdom are frequently criticized for lacking communication skills. In undergraduate courses, such as civil engineering, which are mathematically and technically oriented, it is very difficult to find space within a full timetable for the development of communication skills. At Aston University this work has been integrated successfully into a course on Public Sector Planning. Lectures are complemented by a project which culminates in the students participating in a simulated Public Inquiry—part of the planning process intended to provide a forum for public debate. Not only do the students learn about the planning process, tangible and intangible aspects of a water resource development, but at the same time develop their written, oral, and decision-making skills.

Corporate responsibility reporting of biodiversity in the supply chain

Industrial development, accompanying human population growth, has had a major role in creating the situation where bio-diverse materials and services essential for sustaining business are under threat. A major contributory factor to biodiversity decline comes from the cumulative impacts of extended supply chain business operations. However, within Corporate Responsibility (CR) reporting impacts on biodiversity due to supply chain operations have not traditionally been given equal weighting with other environmental issues. This paper investigates the extent of CR reporting in managing and publicising company biodiversity supply chain issues by reviewing a cross-sector sample of publicly available CR reports. The report contents were examined for suggestions of industrial sectorial trends in the level of biodiversity consideration. The reporting of environmental management system use within company supply chain management is assessed in the samples and is considered as a mechanism for responsible supplier partnership working.

Use of GIS and Remote Sensing in Water Supply: Applications

This Section applies the theory of the preceding Section to the problems of water supply systems. The first section looks at the use of GIS with environmental process models. The second section covers the use of GIS and remote sensing techniques in demand evaluation and forecasting. The third section looks at two current applications of remote sensing for water supplies; the detection of buried objects and leaks, and the assessment of water quality. The last section considers the issues of using GIS and remote sensing in a utilities environment.

Relevant GIS and Remote Sensing Technology: Theoretical Considerations

The Geographical Information System is well suited as a tool for assisting with water supply problems. It not only carries out the inventory functions, as to what lies where, but assists with the manipulation of the data and the extraction of information for modelling and decision making. This section will describe the fundamental features of GIS directly relevant to water supply projects, and the ways that data are stored in a GIS. The Digital Elevation Model (DEM), which is of great importance to hydrology and water supply, will be considered in some detail. In terms of cost for implementing a GIS solution: manpower, data acquisition, software and hardware rank in about that order. Manpower is a very difficult aspect to specify for a project, so it will only be discussed briefly. Manpower depends as much on existing skills, training requirements and workloads for existing staff as on the GIS. The other three aspects are discussed with respect to the current state of the art; however technology is likely to change in the future.