Combined Sewer Overflow Management
DocumentsDate added
Authors
Professor Robert Y.G. Andoh
Abstract
The conventional approach to the rehabilitation and improvement of collection system service levels has been to enhance system capacity and transfer increased flows to central wastewater treatment facilities, which in turn often results in the need for upgrading the treatment works to handle increased flows. The paper highlights why the implementation of satellite treatment systems within the collection systems (away from end of pipe) provides significant benefits from both a process and public health standpoint compared with the conventional approach.
Aspects of wastewater characterization, in particular settling velocity distributions, and its relevance on the performance of physical unit processes such as sedimentation and filtration are described and used to explain why satellite treatment makes sense. The satellite CSO treatment facilities at Columbus, Georgia which have undergone more than 5 years of peer reviewed intensive monitoring are described and used as a case example to highlight the benefits and significant cost savings that accrue from implementing satellite treatment systems within collection systems.
Authors
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.
Use of computational fluid dynamics to assess the disinfection performance of a sewer overflowhot!
08/22/2005
Authors
D.A. Egarr, M.G. Faram, I. Guymer, T. O’Doherty, N.Syred
Abstract
The fluid residence time characterisation of a 3.4m diameter Hydrodynamic Vortex Separator (HDVS) has been carried out over a range of flowrates. Computational Fluid Dynamic (CFD) modelling has also been undertaken for the same conditions and validated against the experimental results, for which reasonable correspondence has been found. Using the results from the CFD modelling and batch inactivation results from the disinfection of secondary treated wastewater, it is shown that the theoretical performance of a HDVS as a contact vessel for disinfection can be predicted.
EVOLVING METHODS FOR THE CALIBRATION OF FLOW CONTROLS FOR STORMWATER AND WASTEWATER MANAGEMENThot!
09/26/2006
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.
