Authors

Lisa Glennon, Marcus Mumford, Uday Khambhammettu, Robert Pitt

Abstract

Runoff from urban drainage areas is a major source of diffuse pollution containing high concentrations of pollutants such as phosphorus and silts (sediments in the 3.9 to 62.5 μm range). Urban drainage areas such as parking lots, vehicle fueling and maintenance stations, and public works storage areas have been dubbed critical source areas due to the observation that runoff from these areas may contain high pollutant loadings of varying diffuse pollutant classifications, including trash and other debris, coarse and fine sediment, hydrocarbons, toxic trace metals, nutrients such as phosphorus and nitrogen, pathogens, and/or other toxicants (Bannerman, et al. 1993; Pitt, et al. 1995; Claytor and Scheuler 1996). One approach to stormwater treatment is to treat urban runoff at end-of-pipe, once runoff from critical source areas has mixed with runoff from less polluted areas. An alternative approach is to use small-footprint treatment devices upstream at critical source areas before the runoff mixes with larger volumes of less polluted runoff. Treatment devices installed at critical source areas need to incorporate several treatment processes, such as sedimentation, screening, and filtration, to target the different classifications of pollutants and respond to the inherent variability of runoff quality from different types of critical source areas (Pitt, et al. 1999). An upflow filter device equipped with a pre-settling sump and a coarse screening system has undergone a full-scale field evaluation at a site near the City Hall in Tuscaloosa, Alabama as part of a Small Business Innovative Research (SBIR) project funded by the United States Environmental Protection Agency (US EPA). This paper presents results of ongoing comprehensive characterization and performance evaluation of the upflow filtration unit tested under controlled laboratory conditions at Hydro International's hydraulics facility in Portland, ME, and compares the results to the field data collected by the University of Alabama (Pitt, et al. 2005; Khambhammeettu 2006).

Authors

R.Y.G. Andoh1, R.M. Alkhaddar , M.G. Faram and P. Carroll

Abstract

Several configurations of proprietary ‘flow-through’ stormwater treatment devices have evolved to address the need for compact and effective systems that remove sediment and other pollutants from stormwater runoff. Whilst a number of these systems have been the subject of several field monitoring and independent laboratory studies, differences between design methodologies, unit sizes and capacity, test protocols and site conditions in the field have made direct comparisons of results very difficult. Most studies to date have focused mainly on the pollutant removal efficiency (effectiveness) of these systems.

Authors

R.Y.G. Andoh, A.J. Stephenson and P. Collins

Abstract

The need for a more holistic approach in the development of solutions to wet-weather induced problems in urban drainage systems is advocated. A review of current approaches to resolving problems of premature overflows and flooding is presented outlining a case example of the successful application of non-conventional approaches, techniques and devices that assist in the better management and control of wet-weather flow sources. This involves the seeking of solutions within the upstream portions of drainage systems by intercepting, containing, controlling and treating excess wet-weather flows before they cause hydraulic and water quality problems in downstream areas (sections of the drainage system). These approaches have been found to be more cost-effective than conventional solutions and involve the implementation of distributed/decentralised schemes which in turn offer improved opportunities for wider community and other stakeholder involvement leading to the realisation of amenity and other non-structural benefits.

Authors

LeCornu, J.P. and Faram, M.G.

Abstract

The ability to accurately and reliably control flows in drainage and sewerage systems is critical for the effective operation of such systems. The use of inaccurate or unreliable flow controls can lead to adverse effects including flooding. Conventional methods for the calibration of flow controls are time consuming and can suffer from poor repeatability.

This paper describes work carried out with the aim of developing new, improved methods, to both enhance accuracy and improve repeatability, while also reducing test times. In order to achieve the objectives, a PROFIBUS based instrumentation and control system was fitted to existing hydraulic test facilities, operated by Hydro International. The new methods, applied to the calibration of vortex flow controls and orifice plates, show potential to reduce test times by a factor of more than ten, while also increasing the accuracy and repeatability of results.

Authors

D.S. Jarman, M.G. Faram, G. Tabor

Abstract

The current climate of interest in water-environmental issues has lead to increased use of advanced computer-based simulation techniques in the evaluation and improvement of water management systems. This paper reviews the usage history of computational fluid dynamics (CFD) techniques by a supplier of technologies for urban water management, leading to the development of insights and guidance on the adoption of such tools, presented in the context of a number of practical case studies. The paper finds that CFD methods offer genuine opportunities and can yield direct tangible benefits. However, this is reliant on organ isations having a realistic understanding of what such approaches can offer, their limitations, and also having an appreciation of the long-term commitment that is required to achieve maximum value.