Erosion mechanisms in combined sewers and the potential for pollutant release to receiving waters and water treatment plants

2002 ◽  
Vol 45 (3) ◽  
pp. 61-69 ◽  
Author(s):  
T.D. Mcllhatton ◽  
R. Sakrabani ◽  
R.M. Ashley ◽  
R. Burrows
Keyword(s):  
Initial Period ◽  
Suspended Sediments ◽  
Field Studies ◽  
Sediment Concentration ◽  
Storm Event ◽  
Receiving Waters ◽  
Using Data ◽  
Erosion Mechanisms ◽  
Maintenance Requirements

The problems associated with solids in sewerage systems result in common difficulties such as blockages and flooding and the subsequent maintenance requirements have been well documented. Concerns regarding pollutant release have also been demonstrated, with the contribution from in-sewer solids to the quality of the flow during a storm event being especially significant. These events known as “foul flushes” in combined sewers typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants are significantly higher than at other times. Traditionally impacts from these events have been related to the suspended solids phase of the flow passing through a CSO structure. It is now apparent that much of the suspended load originates from solids eroded from the bed. The “near bed solids” which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. The influence of these eroded solids and their potential impact on receiving waters and treatment plants will be reviewed using data obtained from field studies carried out in the main Dundee interceptor sewer in Scotland. This paper describes some of the methods employed to investigate the characteristics of the pollutants associated with solids erosion in combined sewers.

Improved formulations for rapid erosion of diverse solids in combined sewers

2005 ◽  
Vol 52 (5) ◽  
pp. 143-150 ◽  
Author(s):  
T.D. McIlhatton ◽  
R.M. Ashley ◽  
S.J. Tait
Keyword(s):  
Urban Areas ◽  
Suspended Sediment Concentration ◽  
Peak Flow ◽  
Initial Period ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Storm Event ◽  
Flow Conditions ◽  
Combined Sewer Overflows ◽  
Combined Sewer

For more than a decade, research carried out in Scotland has investigated the movement of sediment in sewers and the associated pollutant release. Pollution by discharges from combined sewer overflows can adversely affect watercourses, particularly those in urban areas. Solids and dissolved contaminants, many derived from in-sewer deposits during a storm event, can be especially significant. This phenomenon can occur during events known as ‘foul flushes’. In combined sewers these typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants is significantly higher than at other times. It has become apparent that much of the suspended load originates from solids eroded from the bed. The ‘near bed solids’ which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. This paper describes some of the methods employed to investigate the solids eroding in combined sewers during peak flow events. The work examined the potential for sediment re-suspension under high flow conditions both in the laboratory and in the field.

Dynamics of Coastal Fluid Muds in Low-, Moderate-, and High-Tide-Range Environments

1983 ◽  
Vol 40 (S1) ◽  
pp. s130-s142 ◽  
Author(s):  
John T. Wells
Keyword(s):  
Wave Attenuation ◽  
High Tide ◽  
Suspended Sediments ◽  
Tidal Energy ◽  
Field Studies ◽  
Sediment Concentration ◽  
Fluid Mud ◽  
Incoming Wave ◽  
Wide Range ◽  
High Concentrations

Field studies of intertidal and subtidal fluid muds in low-, moderate-, and high-tide-range environments have revealed several similarities in process-response behavior despite the wide range in tidal energy. Using data from Louisiana (tide range 0.5 m), Surinam (tide range 2.0 m), and South Korea (tide range 5–9 m), examples are given for the unifying characteristics of (1) extreme wave attenuation, (2) high suspended-sediment concentration, and (3) rapid migration and "shifting" of soft muds. The loss of incoming wave energy results in natural protection to shorelines that are fronted by fluid muds. The opportunity thus exists to predict areas of future progradation and erosion from knowledge of fluid mud behavior. Fluid muds can be easily resuspended by small waves, and the high concentrations of suspended sediments in regions of mudshoals suggest that net transport rates can be enormous even under relatively weak currents. In addition to serving as temporary and transitory storehouses for littoral sediments, intertidal mudflats and subtidal mudshoals can become "welded" to the shoreline and colonized by vegetation in a single season.Key words: fluid mud, fine-grained sediments, wave attenuation

Effect of networks on product innovation: empirical evidence from Indonesian SMEs

2013 ◽  
Vol 1 (2) ◽  
pp. 140-158 ◽  
Author(s):  
Nurul Indarti ◽  
Theo Postma
Keyword(s):  
Empirical Evidence ◽  
Product Innovation ◽  
Dynamic Effects ◽  
Depth Of Knowledge ◽  
External Knowledge ◽  
Software Firms ◽  
Using Data

Innovative companies generally establish linkages with other actors and access external knowledge in order to benefit from the dynamic effects of interactive processes. Using data from 198 furniture and software firms in Indonesia, this study shows that the quality of interaction (i.e. multiplexity) as indicated by the depth of knowledge absorbed from various external parties and intensity of interaction (i.e., tie intensity) are better predictors of product innovation than the diversity of interaction.

Use of Biomonitoring to Control Toxics in the United States

1988 ◽  
Vol 20 (10) ◽  
pp. 101-108 ◽  
Author(s):  
Nelson A. Thomas
Keyword(s):  
Water Quality ◽  
Chronic Toxicity ◽  
National Policy ◽  
Single Species ◽  
Field Studies ◽  
The United States ◽  
Toxicity Tests ◽  
Toxic Pollutants ◽  
Receiving Waters ◽  
Biological Field

A biomonitoring program has been developed in support of the National Policy for the Development of Water Quality-Based Permit Limitations for Toxic Pollutants. The program focuses on the use of laboratory toxicity tests on aquatic plants and animals to predict ecosystem impact caused by toxic pollutants. Both acute and chronic toxicity tests were developed to test effluents and ambient waters. Laboratory and biological field studies were conducted at nine sites. Single species laboratory toxicity tests were found to be good predictors of impacts on the ecosystem when two or more species were used. Biomonitoring can be undertaken either on effluents and/or on the receiving waters. In that toxicity related to seeps, leachates and storm sewers has often been found upstream from dischargers, it is beneficial to conduct both effluent and ambient biomonitoring.

Operations Research on the Female Village-Based Family Planning Worker Program of Pakistan

1998 ◽  
Vol 18 (3) ◽  
pp. 283-305
Author(s):  
Louisiana Lush ◽  
George P. Cernada ◽  
A. K. Ubaidur Rob ◽  
Mohammed Shafiq Arif ◽  
Minhaj Ul Haque ◽  
...  
Keyword(s):  
Family Planning ◽  
Operations Research ◽  
Technical Assistance ◽  
Field Studies ◽  
Family Planning Services ◽  
Training And Supervision ◽  
The Government ◽  
And Training ◽  
Broad Program

This article presents the results of a number of operations research studies (OR) of family planning services provided by a new cadre of female village-based family planning workers in Punjab Province, Pakistan. This cadre of workers, recruited nationwide, have been trained to visit women in their villages to provide information and family planning services. The studies were conducted as part of a broad program of technical assistance to the Government of Pakistan. Surveys investigated the quality of their training as well as attitudes among clients to the new program. They found that the program is developing well but there is room for improvement, particularly in counseling and training. Additional field studies are ongoing and recommendations for change have been incorporated in training and supervision. The program is expanding on a national scale.

Founding Family Ownership and the Selection of Industry Specialist Auditors

2014 ◽  
Vol 28 (2) ◽  
pp. 261-276 ◽  
Author(s):  
Fei Kang
Keyword(s):  
Financial Reporting ◽  
Family Firms ◽  
Structure And Agency ◽  
Founding Family ◽  
Using Data ◽  
Dual Class Shares ◽  
Dual Class ◽  
Selection Of ◽  
Industry Specialist

SYNOPSIS This study examines how family firms' unique ownership structure and agency problems affect their selection of industry-specialist auditors. Using data from Standard & Poor's (S&P) 1500 firms, the results show that family firms are more likely to appoint industry-specialist auditors than non-family firms, which suggests that family firms have strong incentives to signal the quality of financial reporting. Additional analysis indicates that due to the potential entrenchment problems, family firms with family member CEOs or with dual-class shares have even a higher tendency to hire industry-specialist auditors to signal their disclosure quality.

Institutions and Political Support

2017 ◽  
Author(s):  
Shaun Bowler
Keyword(s):  
Political Institutions ◽  
Political Process ◽  
Institutional Reform ◽  
Institutional Arrangements ◽  
Individual Characteristics ◽  
Political Support ◽  
The Political ◽  
General Expectation ◽  
Using Data

This chapter analyzes to what extent variation in political institutions affects political support. The chapter observes that the existing research is not always clear on which institutions should produce what kind of effect, although a general expectation is that institutional arrangements improve political support when they give citizens an increased sense of connection to the political process. In general then, we should expect institutions that strengthen the quality of representation to strengthen political support. This general expectation is specified in six hypotheses that are tested using data from the ESS 2012. The chapter demonstrates that electoral systems that provide voters with more choice about candidates, multiparty governments, and “responsive” legislatures, correlate positively with political support. However, compared to other macro-level factors and individual characteristics, the effects of political institutions on political support are modest. The chapter concludes that the prospects for institutional reform to strengthen political support are limited.

scholarly journals Getting information on suspended sediments in a large river from acoustic backscatter

2018 ◽  
Vol 40 ◽  
pp. 04017
Author(s):  
Adrien Vergne ◽  
Céline Berni ◽  
Jérôme Le Coz
Keyword(s):  
Suspended Sediment Concentration ◽  
Spatial Information ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Large River ◽  
Acoustic Backscatter ◽  
Qualitative Information ◽  
Sediment Size ◽  
The Common

There has been a growing interest in the last decade in extracting information on Suspended Sediment Concentration (SSC) from acoustic backscatter in rivers. Quantitative techniques are not yet effective, but acoustic backscatter already provides qualitative information on suspended sediments. In particular, in the common case of a bi-modal sediment size distribution, corrected acoustic backscatter can be used to look for sand particles in suspension and provide spatial information on their distribution throughout a river crosssection. This paper presents a case-study where these techniques have been applied.

scholarly journals Remote or Removed: Predicting Successful Engagement with Online Learning during COVID-19

2021 ◽  
Vol 7 ◽  
pp. 237802312098820
Author(s):  
Thurston Domina ◽  
Linda Renzulli ◽  
Brittany Murray ◽  
Alma Nidia Garza ◽  
Lysandra Perez
Keyword(s):  
Elementary School ◽  
Student Engagement ◽  
High Speed ◽  
Initial Period ◽  
Learning Opportunities ◽  
Academic Learning ◽  
Socioeconomic Resources ◽  
Using Data ◽  
School Programming ◽  
Remote Learning

Using data from a spring 2020 survey of nearly 10,000 parents of elementary school parents in one large southeastern public school district, the authors investigate predictors of elementary school student engagement during the initial period of pandemic remote learning. The authors hypothesize that household material and technological resources, school programming and instructional strategies, and family social capital contribute to student engagement in remote learning. The analyses indicate that even after controlling for rich measures of family socioeconomic resources, students with access to high-speed Internet and Internet-enabled devices have higher levels of engagement. Exposure to more diverse socioemotional and academic learning opportunities further predicts higher levels of engagement. In addition, students whose families remained socially connected to other students’ families were more likely to engage online.

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