combined sewer overflow Articles

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. 24, 2008

By US EPA - Environmental Protection Agency

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 ...

Jul. 31, 2010

By IWA Publishing

 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. 12, 2007

By Water Environment Federation (WEF)

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 ...

Dec. 31, 2010

By IWA Publishing

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 ...

Dec. 31, 2010

By IWA Publishing

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 ...

Jan. 31, 1999

By IWA Publishing

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 ...

Jan. 31, 2011

By IWA Publishing

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. 3, 2013

By IWA Publishing

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. 20, 2006

By Water Environment Federation (WEF)

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 ...

Jan. 31, 1999

By IWA Publishing

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 ...

Dec. 31, 2010

By IWA Publishing

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 ...

Jan. 31, 1999

By IWA Publishing

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 ...

Nov. 30, 2011

By IWA Publishing

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. 21, 2006

By Water Environment Federation (WEF)

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 ...

Feb. 28, 2011

By IWA Publishing

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 ...

Dec. 31, 2010

By IWA Publishing

A bromine disinfection technology currently utilized in Japan for Combined Sewer Overflow (CSO) disinfection was piloted by the City of Akron, Ohio. Bromochlorodimethylhydantoin (BCDMH) is a biocide in powdered form that, when dissolved in water, hydrolyzes to hypobromous acid, hypochlorous acid (the active biocides) and Dimethylhydantoin. This unique combination in active biocides can yield ...

Oct. 20, 2006

By Water Environment Federation (WEF)

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 ...

Feb. 28, 2011

By IWA Publishing

As a representative urban stream in Korea, the Gwangju (GJ) stream suffers from chronic fecal contamination. In this study, to characterize levels of fecal pollution in the GJ stream, the monthly monitoring data for seven years (from 2001 to 2007) and the hourly monitoring data from two field experiments were examined with respect to seasonal/daily variations and spatial distribution under wet ...

May 31, 2010

By IWA Publishing

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. 3, 2013

By IWA Publishing