Stormwater Management
DocumentsDate added
Authors
K. Osei, R.Y.G. Andoh, J. MacKinnon and M.G.Faram
Abstract
Laboratory testing of stormwater separators can overcome many of the technical challenges associated with field testing. With laboratory testing, sediment characteristics and the flow rates at which a device is tested are known and measurable before, during, and after the test. This controlled environment ensures that test programmes can be set up to meet specific objectives, and data can be obtained in a repeatable and timely fashion. However there are differences in laboratory test protocols that can have a significant bearing on test results which, if overlooked, can result in invalid comparisons being made between different systems. This paper looks at two protocols for testing separators in the laboratory, normally referred to as the Direct Test Method and the Indirect Test Method. The test methodologies are described and the similarities and differences shown. Results from tests on a stormwater treatment separator using the two protocols are presented. The results show that for the same sediment gradation and flow rate, a difference of over 20% in measured removal efficiency is possible. They also show that the Direct Test Method produces outputs that are more consistent, conservative and representative of the removal efficiencies expected for stormwater treatment separators.
Authors: Robert Pitt, Uday Khambhammettu, Robert Andoh, Lisa Lemont, Kwabena Osei, and Shirley E. Clark
Abstract:
Authors
J. P. LeCornu, M. G. Faram, D. S. Jarman,
Authors
D.A. Phipps, R.M.Alkhaddar, E. Loffill, R.Y.G Andoh and M.G. Faram
Abstract
The factors affecting the overall efficiency for the removal of a solid from an influent stream of water by an HDVS (Hydrodynamic Vortex Separator) have been examined using a combination of solids capture/washout experiments and dye tracer studies. The overall solids removal efficiency of the device is a function of loading rate (overall flow). The efficiency can be considered in terms of the balance between initial capture of the sediment and any subsequent re-entrainment. Tracer studies have shown that a well-designed device offers almost complete separation into a mobile and quiescent zone, with slow exchange between the two. This enhances both sediment capture and its subsequent retention.
Authors
Amos Kabo-Bah, Robert Andoh, Samuel Nii Odai and Kwabena Osei
Abstract
Rainwater Harvesting, a traditional practice in parts of Ghana many centuries ago, has received very little attention in recent times. The paper describes a collaborative research effort aimed at the adaptation and development of affordable technologies for capturing and retaining rainwater runoff including that from roof tops; and using this as a valuable source of water to supplement the water needs of households in Northern Ghana. The project also ultimately seeks to address issues of flooding and erosion caused by the lack of adequate drainage through the effective capturing, retention and controlled release of rainwater. The Project will verify the extent to which adoption of the adapted technologies could help greatly in conserving water resources in the Sahel and other semi-arid regions in developing countries and at the same time helping to alleviate poverty by improving the quality of life of women and children in these regions. The rainwater harvesting systems will be designed and implemented adopting an integrated approach utilizing expertise from a collaborating team comprising engineers, agriculturists, economists, sociologists and a practitioner of rainwater harvesting (and other water conservation technologies). It is envisaged that the systems would enable poor households in the community to supplement their water supply needs as well as engage in small scale backyard gardening; extend their cropping seasons through improved security of water resources, ultimately enhancing food security and contributing to poverty reduction.
