combined sewer overflow Articles

EPA initiates strategic planning for priority enforcement areas, but key elements still needed

OECA has instituted a process for strategic planning in its national enforcement priority areas. It has developed strategic planning guidance and a strategy template to facilitate continual review and improvement of the strategies. The Fiscal Years 2008-2010 strategic plans we reviewed, for air toxics, combined sewer overflows, and mineral processing, contain an overall goal, a problem statement, ...

Sep. 25, 2008

By US EPA - Environmental Protection Agency
A New Method of Predicting Rainfall Dependent Inflow and Infiltration

ABSTRACT There are many hydrological models available to quantitatively characterize rainfall dependent inflow and infiltration (RDII) in a sanitary sewer system, most of which were first derived for quantifying rainfall surface runoff process and later found many applications in studying the issues of combined sewer overflows (CSO). However, it has been long recognized that profound ...

Oct. 13, 2007

By Water Environment Federation (WEF)
Washoff behavior of in-sewer deposit in combined sewer system through artificial flushing experiment

In-sewer deposits in combined sewer systems (CSSs) are closely related with the behavior of first foul flush and combined sewer overflows. However, the research paying attention to the role of in-sewer deposits is quite rare, furthermore, their contributions for the washoff patterns of each pollutant including pathogenic microorganisms are almost never discussed so far. The artificial flushing ...

Aug. 1, 2010

By IWA Publishing
An application of Austrian legal requirements for CSO emissions

The Austrian standard for designing combined sewer overflow (CSO) detention basins introduces the efficiency of the combined sewer overflows as an indicator for CSO pollution. Additionally criteria for the ambient water quality are defined, which comprehend six kinds of impacts. In this paper, the Austrian legal requirements are described and discussed by means of hydrological modelling. This is ...

Jan. 1, 2011

By IWA Publishing
Evaluation of effectiveness of combined sewer overflow control measures by operational data

The effect of combined sewer overflow (CSO) control measures should be validated during operation based on monitoring of CSO activity and subsequent comparison with (legal) requirements. However, most CSO monitoring programs have been started only recently and therefore no long-term data is available for reliable efficiency control. A method is proposed that focuses on rainfall data for ...

Jan. 1, 2011

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

ABSTRACTTwo 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 ...

Feb. 1, 1999

By IWA Publishing
Experimental study of the performance of a siphon sediment cleansing set in a CSO chamber

Model experiments were conducted to investigate the performance of a siphon sediment cleansing set (SSCS) for preventing sediment deposition on the combined sewer overflow (CSO) chamber bottom. The results confirmed the effectiveness of siphon suction in sediment removal in the chamber. The sediment scour test revealed that the equilibrium scour depth correlated significantly with the ...

Jul. 4, 2013

By IWA Publishing
Using UV to Disinfect Low Quality Wastewater

This paper discusses the issues involved in sizing ultraviolet (UV) disinfection systems for low quality water, such as those found in poor quality wastewater (primary effluents) or wet weather flows (combined sewer overflows). Discussions of UV reactor dynamics and the merits of bioassay validation are ...

Oct. 21, 2006

By Water Environment Federation (WEF)
Emission predictions with a multi-linear reservoir model

ABSTRACTFor the assessment of combined sewer overflows detailed models are not necessary. Physically based conceptual models give an optimal balance between model uncertainty and uncertainty in the input data. Besides, it is important that continuous long term simulations are performed. To prove this, in this paper the calibration of a reservoir model is discussed. The emission results of the ...

Feb. 1, 1999

By IWA Publishing
Determination of the vertical velocity distribution of floatables in CSOs

ABSTRACTControl of floatables, since April 1994, is one of the nine minimum controls required by the U.S.EPA (United States Environmental Protection Agency) for CSO (Combined Sewer Overflows) control policy compliance. Municipalities must control and intercept floatables at their overflow sites. Efficient interception of these floatables requires prior characterisation. To accomplish this ...

Feb. 1, 1999

By IWA Publishing
The use of CFD modelling to optimise measurement of overflow rates in a downstream-controlled dual-overflow structure

The measurement of the flow through complex combined sewer overflow structures in the frame of automated monitoring remains difficult. In this paper, a methodology based on the use of computational fluid dynamics (CFD) modelling in order to improve the instrumentation of a downstream-controlled dual-overflow structure is presented. The dual-overflow structure is composed of two combined sewer ...

Jan. 1, 2011

By IWA Publishing
Research of trace metals as markers of entry pathways in combined sewers

Combined sewers receive high toxic trace metal loads emitted by various sources, such as traffic, industry, urban heating and building materials. During heavy rain events, Combined Sewer Overflows (CSO) can occur and, if so, are discharged directly into the aquatic system and therefore could have an acute impact on receiving waters. In this study, the concentrations of 18 metals have been ...

Feb. 1, 2011

By IWA Publishing
Flow measurements in sewers based on image analysis: automatic flow velocity algorithm

Discharges of combined sewer overflows (CSOs) and stormwater are recognized as an important source of environmental contamination. However, the harsh sewer environment and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. An in situ system for sewer water flow monitoring based on video images was evaluated. Algorithms to determine ...

Jan. 1, 2011

By IWA Publishing
CSO management from an operator's perspective: a step-wise action plan

Combined sewer overflows (CSO) are the “ugly ducklings” of urban wastewater infrastructure, rather unknown, rarely loved. Contrary to wastewater treatment plants (WWTP) where, commonly, process parameters are carefully registered, still relatively little is known about the spill behaviour of CSOs. In spite of the considerable bandwidth of pollution magnitude reported in literature, it can be ...

Mar. 1, 2011

By IWA Publishing
Analysing urban floods and combined sewer overflows in a changing climate

Climate change is expected to lead to an increased frequency and intensity of extreme precipitation events. For urban drainage, the primary adverse effects are more frequent and severe sewer overloading and flooding in urban areas, and higher discharges through combined sewer overflows (CSO). For assessing the possible effects of climate change, urban drainage models are run with ...

Dec. 1, 2011

By IWA Publishing
Making Affordability Fit Your Community - A Holistic Approach for Wet Weather Management Programs

ABSTRACTThe City of Columbus, Ohio is under two consent orders from the Ohio Environmental Protection Agency (OEPA) related to wet weather issues. One order deals with combined sewer overflows (CSO) while the other addresses sanitary sewer overflows (SSO). The City recognized that these two issues were related and needed to be dealt with in an integrated approach. This decision led to the ...

Oct. 22, 2006

By Water Environment Federation (WEF)
Chemical pretreatment of combined sewer overflows for improved UV disinfection

The aim of this research was to better understand chemical pre-treatment of combined sewer overflows (CSOs) for subsequent ultraviolet (UV) disinfection. Approximately 200 jar tests were completed. Alum (Al2(S04)3·12H2O) resulted in a higher UV light transmission (UVT), and equivalent total suspended solids (TSS) removal, than ferric chloride (FeCl3). An alum dose of 20 mg/L increased the UVT ...

Sep. 29, 2015

By IWA Publishing
Modeling climate change impacts on combined sewer overflow using synthetic precipitation time series

In the presented study climate change impacts on combined sewer overflows (CSOs) in Baden-Wuerttemberg, Southern Germany, were assessed based on continuous long-term rainfall–runoff simulations. As input data, synthetic rainfall time series were used. The applied precipitation generator NiedSim-Klima accounts for climate change effects on precipitation patterns. Time series for the past ...

Jul. 4, 2013

By IWA Publishing
Priority substances in combined sewer overflows: case study of the Paris sewer network

This study was undertaken to supply data on both priority pollutant (PP) occurrence and concentrations in combined sewer overflows (CSOs). A single rain event was studied on 13 sites within the Paris sewer network. For each sample, a total of 66 substances, including metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, organotins, volatile organic compounds, chlorobenzenes, phthalates and ...

Mar. 1, 2011

By IWA Publishing
CSO Treatment Technologies: A Comprehensive Design and Resource Manual

Increasingly, municipal wastewater authorities are exploring new and innovative treatment technologies specifically designed for Combined Sewer Overflows (CSOs). These technologies, when applied as part of an overall wastewater management strategy, can produce efficient and cost-effective solutions for CSOs. However, like all technologies, theyrequire systematic design and proper operation. In ...

May 9, 2008

By XCG Consultants Ltd.

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