Combined Sewer Overflow Articles

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

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

Report to Congress: Combined Sewer Overflows to the Lake Michigan Basin

The U.S. Environmental Protection Agency (EPA) is transmitting this Report to Congress on combined sewer overflows (CSOs) in the Lake Michigan basin. CSOs can occur in combined sewer systems (CSSs), which are defined as collection systems that carry both wastewater and storm water in the same pipe. A CSO is defined as “the discharge from a CSS at a point prior to the publicly-owned treatment ...

Nov. 22, 2007

By US EPA - Environmental Protection Agency

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

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 ...

Sep. 29, 2015

By IWA Publishing

The evaluation of rainfall influence on combined sewer overflows characteristics: the Berlin case study

The present study aims to explore the relationship between rainfall variables and water quality/quantity characteristics of combined sewer overflows (CSOs), by the use of multivariate statistical methods and online measurements at a principal CSO outlet in Berlin (Germany). Canonical correlation results showed that the maximum and average rainfall intensities are the most influential variables ...

Dec. 19, 2013

By IWA Publishing

Micropollutants in stormwater runoff and combined sewer overflow in the Copenhagen area, Denmark

Stormwater runoff contains a broad range of micropollutants. In Europe a number of these substances are regulated through the Water Framework Directive, which establishes Environmental Quality Standards (EQSs) for surface waters. Knowledge about discharge of these substances through stormwater runoff and combined sewer overflows (CSOs) is essential to ensure compliance with the EQSs. Results from ...

Jan. 1, 2011

By IWA Publishing

Constructed wetlands for combined sewer overflow treatment in a Mediterranean country, Portugal

The use of constructed wetlands as a valuable and attractive method for combined sewer overflow (CSO) treatment has been demonstrated in several studies. In Portugal, a Mediterranean country having usually a long dry period, there are still no applications of this technology. The purpose of this research is to gather information and know-how required for the design and management of this type of ...

Jun. 21, 2013

By IWA Publishing

Combined sewer overflow control with LID based on SWMM: an example in Shanghai, China

Although low impact development (LID) has been commonly applied across the developed countries for mitigating the negative impacts of combined sewer overflows (CSOs) on urban hydrological environment, it has not been widely used in developing countries yet. In this paper, a typical combined sewer system in an urbanized area of Shanghai, China was used to demonstrate how to design and choose CSO ...

Apr. 27, 2015

By IWA Publishing

Modelling sewer sediment deposition, erosion, and transport processes to predict acute influent and reduce combined sewer overflows and CO2 emissions

Understanding of solids deposition, erosion, and transport processes in sewer systems has improved considerably in the past decade. This has provided guidance for controlling sewer solids and associated acute pollutants to protect the environment and improve the operation of wastewater systems. Although measures to decrease combined sewer overflow (CSO) events have reduced the amount of ...

Nov. 1, 2010

By IWA Publishing

Multifaceted sewer improvements program eliminates sewer connection moratorium and system overflows

The sewer system serving Borough of Jewett City, Connecticut dates from the late 1800’s and was originally constructed as a combined sewer system with the discharges directed to the area rivers. In the 1970’s, the raw sewage discharges from the Borough system were removed from the rivers and redirected to a newly constructed wastewater treatment facility. However, the overflows from the ...

Oct. 13, 2007

By Water Environment Federation (WEF)

City of Portland Bureau of Environmental Services Deep Tunnels for Combined Sewer Overflow Storage and Transport – Portland, Oregon

BACKGROUNDThe Bureau of Environmental Services (BES) of Portland, Oregon, began a major program to mitigate combined sewer overflows (CSOs) into the Willamette River and Columbia Slough in 1991. The Program was organized into three major phases: Cornerstone projects to reduce stormwater entering the combined sewer system, ...

Oct. 22, 2006

By Water Environment Federation (WEF)

Estimation of combined sewer overflow discharge: a software sensor approach based on local water level measurements

Combined sewer overflow (CSO) structures are constructed to effectively discharge excess water during heavy rainfall, to protect the urban drainage system from hydraulic overload. Consequently, most CSO structures are not constructed according to basic hydraulic principles for ideal measurement weirs. It can, therefore, be a challenge to quantify the discharges from CSOs. Quantification of CSO ...

Sep. 30, 2016

By IWA Publishing

Modelling of <italic>E. coli</italic> distribution in coastal areas subjected to combined sewer overflows

Modelling of E. coli distribution in coastal areas subjected to combined sewer overflows

Rivers, lakes and the sea were the natural receivers of raw urban waste and storm waters for a long time but the low sustainability of such practice, the increase of population and a renewed environmental sensibility increased researcher interest in the analysis and mitigation of the impact of urban waters on receiving water bodies (RWB). In Europe, the integrated modelling of drainage systems ...

Sep. 16, 2013

By IWA Publishing

Model evaluation of faecal contamination in coastal areas affected by urban rivers receiving combined sewer overflows

Odaiba seaside park is one of the most popular waterfronts in Tokyo Bay, but is easily affected by wet weather pollutant loads through combined sewer overflows (CSOs). The monitoring data of Escherichia coli clearly showed high faecal contamination after a rainfall event on 9–11 November 2007. We estimated the amounts of discharge volume and E. coli pollutant loads of ...

Aug. 7, 2014

By IWA Publishing

The Use of Computational Flow Modeling to Determine Disinfection Efficacy of an Advanced Hydrodynamic Vortex Combined Sewer Overflow Treatment System

The ProblemA number of cities in Northeastern US are investigating the installation of new combined sewer overflow (CSO) treatment units utilizing an Advanced Hydrodynamic Vortex Separator (HDVS) with a self-cleansing screen. Hydrodynamic Vortex systems have traditionally been utilized as high-rate solids liquid separators and only recently have their potential use as contact chambers for ...

Oct. 21, 2006

By Water Environment Federation (WEF)

Determining Water Quality Impacts of Combined Sewer Overflow on the Mississippi River Using Full Factorial Analysis

ABSTRACTThe City of Rock Island, Illinois is completing a Combined Sewer Overflow Long Term Control Plan as part of a Consent Decree with the U.S. EPA. The Consent Decree includes a requirement that Rock Island document existing water quality so that CSO impacts could be identified and potential improvements with various CSO could be assessed. Because of complex river morphology, large flow rate ...

Oct. 22, 2006

By Water Environment Federation (WEF)

Predicting combined sewer overflows chamber depth using artificial neural networks with rainfall radar data

Combined sewer overflows (CSOs) represent a common feature in combined urban drainage systems and are used to discharge excess water to the environment during heavy storms. To better understand the performance of CSOs, the UK water industry has installed a large number of monitoring systems that provide data for these assets. This paper presents research into the prediction of the hydraulic ...

Mar. 19, 2014

By IWA Publishing

Estimating inflow to a combined sewer overflow structure with storage tank in real time: evaluation of different approaches

The performance assessment of storage tanks and combined sewer overflow (CSO) structures in sewer systems requires knowledge of the total inflow from the catchment during rainfall events. Many structures are, however, only equipped with sensors to measure water level and/or outflows. Based on the geometry of the tank, expressed as a level-storage relationship, inflow can be calculated from these ...

Oct. 20, 2014

By IWA Publishing

Impact of Water Quality and Pretreatment upon UV Inactivation of MS-2 Bacteriophage in Combined Sewer Overflow

The disinfection of MS-2 bacteriophage by low pressure and medium pressure UV was evaluated in three different source waters: raw wastewater, storm water runoff and a synthetic combined sewer overflow prepared from a 50:50 mix of raw wastewater and storm water runoff. Each of the source waters were pretreated by dissolved air floatation and vortex separation prior to UV exposure. Source water and ...

Oct. 21, 2006

By Water Environment Federation (WEF)

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