Development and testing of a new design procedure for the control of aesthetic pollutants at combined sewer overflows

1999 ◽  
Vol 39 (2) ◽  
pp. 53-60
Author(s):  
D. J. Balmforth ◽  
J. R. Blanksby ◽  
C. Brown ◽  
C. Rogerson
Keyword(s):  
Software Development ◽  
Design Procedure ◽  
Cost Effective ◽  
Research Projects ◽  
Combined Sewer Overflows ◽  
Design Guide ◽  
Combined Sewer ◽  
The Subject ◽  
Sewer Overflows ◽  
Selection Of

Two research projects identified the need for a new design guide and software to facilitate the design of combined sewer overflows. The purpose of the design guide and software is to enable the selection of the most cost effective arrangement of overflow and screens according to local circumstances. Strategies were developed to minimise the risk of those testing the design guide and software. Tests took place on a number of projects, one of which is the subject of an ongoing pre and post construction appraisal. The experience gained from the test projects is being fed back into the software development.

Pilot-Scale Study of Satellite Treatment Options for the Control of Combined Sewer Overflows

1997 ◽  
Vol 32 (1) ◽  
pp. 169-184 ◽  
Author(s):  
J. SCHMIDT ◽  
P. SETO ◽  
D. Averill
Keyword(s):  
Treatment Options ◽  
Cost Effective ◽  
Pilot Scale ◽  
Combined Sewer Overflows ◽  
International Joint Commission ◽  
Pollution Problem ◽  
Combined Sewer ◽  
Vortex Separator ◽  
Sewer Overflows ◽  
Screen Performance

Abstract Combined sewer overflows (CSOs) have been recognized for many years as a pollution problem within the Great Lakes ecosystem. CSOs were identified as a source of contamination in 10 of the 17 Canadian “Areas of Concern” designated by the International Joint Commission, and were considered a major problem in Hamilton Harbour and the Metropolitan Toronto Waterfront. Satellite treatment systems (located upstream in the sewerage system) were identified as being significantly more cost effective than other CSO control options in a feasibility study conducted for Metropolitan Toronto. Consequently, a multi-agency initiative was established in 1993 to examine the treatment of CSOs at a pilot-scale facility in the City of Scarborough. The technologies evaluated during two experimental seasons in 1994 and 1995 included a vortex separator, a circular clarifier, a horizontal-flow plate clarifier and an inclined rotary drum screen. Performance of the technologies is being assessed against a draft policy proposed by the Ontario Ministry of Environment and Energy. Results to date have indicated that the vortex separator and the plate clarifier under “best conditions” were capable of 50% TSS removal and 30% BOD5 removal and should be capable of satisfying the policy.

Optimization of Storage/Treatment Scheme for Combined Sewer Overflows

1994 ◽  
Vol 29 (1-2) ◽  
pp. 401-408
Author(s):  
Adel Ashamalla ◽  
Ted Bowering ◽  
Mario Parente
Keyword(s):  
Cost Effective ◽  
Combined Sewer Overflows ◽  
Treatment Rate ◽  
Family Of Curves ◽  
Precipitation Record ◽  
Storage Volume ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
Pumping Rates ◽  
Set Up

The evaluation of various schemes to eliminate Combined Sewer Overflows (CSO) from the City of Toronto to the lower Don River and the shores of Lake Ontario resulted in the selection of a storage tunnel system, from which flows are pumped to a treatment facility before discharge to the receiving waters. This paper discusses the procedure used and the results obtained to optimize the combination of the storage volume and treatment rate to meet the required objectives. To analyze the effectiveness of this scheme in reducing the number of overflow events and the total volume of the CSO, long term simulations were carried out. The City's Quantity-Quality Simulation model (QQS model, developed by Dorsch Consult) was calibrated and run for four years of rainfall record. These years were selected as two average precipitation years, a dry year and a wet year representing the last twenty years of precipitation record. The model was used to predict the frequency of overflows resulting from different storage volumes (represented by tunnel sizes) and different treatment rates (represented by pumping rates from the tunnel). A family of curves was plotted using the QQS results, to present the relationship between the storage volume and the treatment rate vs. the effectiveness of the scheme presented by the resulting number of CSO events per year, and the percentage reduction in the overall annual CSO volume. To optimize the scheme the total cost of the storage and treatment was estimated, and a family of curves was produced among alternative schemes consisting of combinations of storage sizes and treatment rates, their effectiveness and their overall cost. The curves were plotted to present the effectiveness in the entire waterfront area, as well as the effectiveness in separate areas, since different water quality objectives were set up according to the water use activities in those areas. The procedure then identified the most cost effective combination of tunnel sizes and treatment capacity to meet the objectives in the different areas.

London Tideway Tunnels: tackling London’s Victorian legacy of combined sewer overflows

2011 ◽  
Vol 63 (1) ◽  
pp. 80-87 ◽  
Author(s):  
G. B. Thomas ◽  
D. Crawford
Keyword(s):  
Cost Effective ◽  
Tidal River ◽  
Public Consultation ◽  
The European Union ◽  
Design Development ◽  
Combined Sewer Overflows ◽  
Environmental Objectives ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
River Thames

It takes a few millimetres of rainfall to cause the 34 most polluting combined sewer overflows (CSOs) to discharge into the River Thames. Currently, in a typical year, spillages to the tidal reaches of the River Thames occur about 60 times, with an estimated spill volume of 39 million cubic metres. Both the UK Government and the European Union have determined that the CSO discharges have an adverse environmental impact on fish species, introduce unacceptable aesthetics and elevate the health risks for recreational users of the Thames, with a frequency of discharge which is in breach of the Urban Wastewater Treatment Directive. Studies have established that the environmental objectives can be fully met on the most cost-effective basis by completing both quality improvements to treatment works and by the provision of a storage and transfer tunnel to intercept unsatisfactory CSOs. Extensive modelling has been undertaken to develop an optimised solution. In parallel with the design development a rigorous and comprehensive site selection methodology has been established to select sites and consult stakeholders and the public on the preferred sites and scheme, with the first stage of public consultation planned for later in 2010. The London Tideway Tunnels are an essential part of the delivery of improvements to the water quality of the tidal River Thames, and this ambitious, historic scheme represents a vital strategic investment in London’s infrastructure.

Implementation of Hamilton-Wentworth Region’s Pollution Control Plan

1996 ◽  
Vol 31 (3) ◽  
pp. 453-472 ◽  
Author(s):  
M. Stirrup
Keyword(s):  
Wastewater Treatment ◽  
Pollution Control ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Control Measures ◽  
Storm Events ◽  
Combined Sewer Overflows ◽  
Control Plan ◽  
Combined Sewer ◽  
Sewer Overflows

Abstract The Regional Municipality of Hamilton-Wentworth operates a large combined sewer system which diverts excess combined sewage to local receiving waters at over 20 locations. On average, there are approximately 23 combined sewer overflows per year, per outfall. The region’s Pollution Control Plan, adopted by Regional Council in 1992, concluded that the only reasonable means of dealing with large volumes of combined sewer overflow in Hamilton was to intercept it at the outlets, detain it and convey it to the wastewater treatment plant after the storm events. The recommended control strategy relies heavily on off-line storage, with an associated expansion of the Woodward Avenue wastewater treatment plant to achieve target reductions of combined sewer overflows to 1–4 per year on average. The region has begun to implement this Pollution Control Plan in earnest. Three off-line detention storage tanks are already in operation, construction of a fourth facility is well underway, and conceptual design of a number of other proposed facilities has commenced. To make the best possible use of these facilities and existing in-line storage, the region is implementing a microcomputer-based real-time control system. A number of proposed Woodward Avenue wastewater treatment plant process upgrades and expansions have also been undertaken. This paper reviews the region's progress in implementing these control measures.

A STRATEGY FOR MONITORING THE IMPACTS OF COMBINED SEWER OVERFLOWS ON THE OHIO RIVER

1994 ◽  
Vol 30 (1) ◽  
pp. 167-175
Author(s):  
Alan H. Vicory ◽  
Peter A. Tennant
Keyword(s):  
National Policy ◽  
The United States ◽  
Ohio River ◽  
Combined Sewer Overflows ◽  
Treatment Technology ◽  
Design Storm ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
Definition Of ◽  
And Control

With the attainment of secondary treatment by virtually all municipal discharges in the United States, control of water pollution from combined sewer overflows (CSOs) has assumed a high priority. Accordingly, a national strategy was issued in 1989 which, in 1993, was expanded into a national policy on CSO control. The national policy establishes as an objective the attainment of receiving water quality standards, rather than a design storm/treatment technology based approach. A significant percentage of the CSOs in the U.S. are located along the Ohio River. The states along the Ohio have decided to coordinate their CSO control efforts through the Ohio River Valley Water Sanitation Commission (ORSANCO). With the Commission assigned the responsibility of developing a monitoring approach which would allow the definition of CSO impacts on the Ohio, research by the Commission found that very little information existed on the monitoring and assessment of large rivers for the determination of CSO impacts. It was therefore necessary to develop a strategy for coordinated efforts by the states, the CSO dischargers, and ORSANCO to identify and apply appropriate monitoring approaches. A workshop was held in June 1993 to receive input from a variety of experts. Taking into account this input, a strategy has been developed which sets forth certain approaches and concepts to be considered in assessing CSO impacts. In addition, the strategy calls for frequent sharing of findings in order that the data collection efforts by the several agencies can be mutually supportive and lead to technically sound answers regarding CSO impacts and control needs.

The Role of Computer Modeling in Combined Sewer Overflow Abatement Planning

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1831-1840 ◽  
Author(s):  
L. A. Roesner ◽  
E. H. Burgess
Keyword(s):  
System Modeling ◽  
Cost Effective ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
New Techniques ◽  
Hydraulic Simulation ◽  
Continuous Simulation ◽  
Combined Sewer ◽  
The U.S

Increased concern regarding water quality impacts from combined sewer overflows (CSOs) in the U.S. and elsewhere has emphasized the role of computermodeling in analyzing CSO impacts and in planning abatement measures. These measures often involve the construction of very large and costly facilities, and computer simulation during plan development is essential to cost-effective facility sizing. An effective approach to CSO system modeling focuses on detailed hydraulic simulation of the interceptor sewers in conjunction with continuous simulation of the combined sewer system to characterize CSOs and explore storage-treatment tradeoffs in planning abatement facilities. Recent advances in microcomputer hardware and software have made possible a number of new techniques which facilitate the use of computer models in CSO abatement planning.

Methods of Estimating the Discharge of Gross Solids from Combined Sewer Systems

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1295-1304 ◽  
Author(s):  
C. Jefferies
Keyword(s):  
Research Centre ◽  
Combined Sewer Overflows ◽  
Water Research ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
The Uk

Visible pollution discharged from two combined sewer overflows were studied using passive Trash Trap devices and the UK Water Research Centre Gross Solids Sampler. Relationships are presented for the number of visible solids and the mass of gross solids discharged during an event. The differences in the behaviour of the overflow types are reported on and they are categorised using the Trash Traps.

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