scholarly journals Hydraulic and Structural Analysis of Complex Cross-Section Reinforced Concrete Pipes to Improve Sewage Flow in a Combined Sewer System

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3304
Author(s):  
Hyon Wook Ji ◽  
Jeong-Hee Kang ◽  
Dan Daehyun Koo ◽  
Sung Soo Yoo
Keyword(s):  
Reinforced Concrete ◽  
Flow Velocity ◽  
Cross Section ◽  
Sewer System ◽  
Complex Cross ◽  
Complex Cross Section ◽  
Concrete Pipe ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Minimum Criteria

A complex cross-section reinforced concrete pipe that combines a sub-pipe for the flow of sewage in dry weather and a main pipe for the flow of rainwater was developed to reduce sedimentation of the combined sewer system in dry weather. The sub-pipe was designed, considering the flow velocity, constructability, and maintenance. By fitting the sewage data in the dry weather to the normal distribution, the ratio of the cross-sectional area of sewage flow to that of the pipe was determined to be approximately 0.418, which could cover 99.85% of the sewage volume of the target site. Based on this ratio, the diameter of the sub-pipe corresponding to the combined sewer system with a pipe diameter between 450 and 1300 mm was determined. The hydraulic performance analysis results showed that the flow velocity increased by 11 to 12% compared to the circular pipe based on the full sub-pipe and by more than 15% depending on the water level. The shear stress increased by more than 16.5%, and higher tractive force was observed. Structural safety was determined as the crack load and failure load far exceeded the minimum criteria, thereby verifying the feasibility and field applicability of the complex cross-section reinforced concrete pipe.

scholarly journals Analysis of the Flow Performance of the Complex Cross-Section Module to Reduce the Sedimentation in a Combined Sewer Pipe

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3291
Author(s):  
Hyon Wook Ji ◽  
Sung Soo Yoo ◽  
Dan Daehyun Koo ◽  
Jeong-Hee Kang
Keyword(s):  
Flow Velocity ◽  
Cross Section ◽  
Roughness Coefficient ◽  
Cross Sectional ◽  
Complex Cross ◽  
Complex Cross Section ◽  
Combined Sewer ◽  
Manning's Equation ◽  
Manning’S Equation ◽  
Rainy Days

The difference in the amount of stormwater and sewage in a combined sewer system is significantly large in areas where heavy rainfall is concentrated. This leads to a low water level and slow flow velocity inside the pipes, which causes sedimentation and odor on non-rainy days. A complex cross-section module increases the flow velocity by creating a small waterway inside the pipe for sewage to flow on non-rainy days. While considering Manning’s equation, we applied the principle where the flow velocity is proportional to two-thirds of the power of the hydraulic radius. The flow velocity of a circular pipe with a diameter of 450 mm and the corresponding complex cross-section module was analyzed by applying Manning’s equation and numerical modeling to show the effects of the complex cross-section module. The tractive force was compared based on a lab-scale experiment. When all conditions were identical except for the cross-sectional shape, the average flow velocity of the complex cross-section module was 14% higher while the size of the transported sand grains was up to 0.5 mm larger. This increase in flow velocity can be even higher if the roughness coefficient of aging pipes can be decreased.

Reducing Pollutant Loads from Philadelphia's Combined Sewer System with Green Stormwater Infrastructure

2012 ◽  
Vol 2012 (5) ◽  
pp. 952-965 ◽  
Author(s):  
Matthew J. Vanaskie ◽  
Jim Smullen ◽  
Rajesh Rajan ◽  
Mark Maimone ◽  
Marc Cammarata
Keyword(s):  
Sewer System ◽  
Pollutant Loads ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Green Stormwater Infrastructure

Cesium and strontium loads into a combined sewer system from rainwater runoff

2016 ◽  
Vol 183 ◽  
pp. 1041-1049 ◽  
Author(s):  
Nao Kamei-Ishikawa ◽  
Daiki Yoshida ◽  
Ayumi Ito ◽  
Teruyuki Umita
Keyword(s):  
Sewer System ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Rainwater Runoff

scholarly journals High-Throughput Particle Concentration Using Complex Cross-Section Microchannels

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 440 ◽  
Author(s):  
Asma Mihandoust ◽  
Sajad Razavi Bazaz ◽  
Nahid Maleki-Jirsaraei ◽  
Majid Alizadeh ◽  
Robert A. Taylor ◽  
...  
Keyword(s):  
Cross Section ◽  
High Throughput ◽  
Cross Sections ◽  
Particle Concentration ◽  
Separation Efficiency ◽  
Channel Cross Section ◽  
Total Width ◽  
Particle Focusing ◽  
Complex Cross ◽  
Complex Cross Section

High throughput particle/cell concentration is crucial for a wide variety of biomedical, clinical, and environmental applications. In this work, we have proposed a passive spiral microfluidic concentrator with a complex cross-sectional shape, i.e., a combination of rectangle and trapezoid, for high separation efficiency and a confinement ratio less than 0.07. Particle focusing in our microfluidic system was observed in a single, tight focusing line, in which higher particle concentration is possible, as compared with simple rectangular or trapezoidal cross-sections with similar flow area. The sharper focusing stems from the confinement of Dean vortices in the trapezoidal region of the complex cross-section. To quantify this effect, we introduce a new parameter, complex focusing number or CFN, which is indicative of the enhancement of inertial focusing of particles in these channels. Three spiral microchannels with various widths of 400 µm, 500 µm, and 600 µm, with the corresponding CFNs of 4.3, 4.5, and 6, respectively, were used. The device with the total width of 600 µm was shown to have a separation efficiency of ~98%, and by recirculating, the output concentration of the sample was 500 times higher than the initial input. Finally, the investigation of results showed that the magnitude of CFN relies entirely on the microchannel geometry, and it is independent of the overall width of the channel cross-section. We envision that this concept of particle focusing through complex cross-sections will prove useful in paving the way towards more efficient inertial microfluidic devices.

scholarly journals Analysis of the residual nutrient load from a combined sewer system in a watershed of a deep Italian lake

2019 ◽  
Vol 571 ◽  
pp. 202-213 ◽  
Author(s):  
Laura Barone ◽  
Marco Pilotti ◽  
Giulia Valerio ◽  
Matteo Balistrocchi ◽  
Luca Milanesi ◽  
...  
Keyword(s):  
Nutrient Load ◽  
Sewer System ◽  
Combined Sewer ◽  
Combined Sewer System

scholarly journals Air flow model development and application in a complex combined sewer system

2020 ◽  
Vol 82 (8) ◽  
pp. 1687-1700 ◽  
Author(s):  
Hasan Zobeyer ◽  
David Z. Zhu ◽  
Stephen Edwini-Bonsu
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Air Flow ◽  
Model Development ◽  
Iterative Solution ◽  
Momentum Equation ◽  
Air Flow Rate ◽  
Sewer System ◽  
Combined Sewer ◽  
Combined Sewer System

Abstract A steady-state air flow model was developed and applied in a complex combined sewer system in the city of Edmonton, Alberta, Canada. The model solves the continuity at each junction and the momentum equation for the links coupled with dropshaft and other manholes. The dropshaft pressure gradient is computed using the dropshaft equation and air flow rate through manhole pickholes is computed considering the opening as an orifice. A leakage factor is used as a calibration parameter to represent the area through which air can leak from the manholes into the neighborhood. The model uses an iterative solution algorithm with a forward sweep for the continuity and backward sweep for the momentum equation. An underrelaxation is applied to update pressure in each iteration for model stability. The model was calibrated and validated by using the measured air flow rate and manhole pressure in the sewer network, with good results. An analysis of the air flow characteristics shows that a significant amount of air is brought into the system due to a large headspace in the upstream trunk but over 70% of this air is released into the neighborhood due to reduced headspace in the downstream trunk.

Settleable Solids in a Combined Sewer System, Settling Characteristics, Heavy Metals, Efficiency of Storm Water Tanks

1993 ◽  
Vol 27 (5-6) ◽  
pp. 153-164 ◽  
Author(s):  
S. Michelbach ◽  
C. Wöhrle
Keyword(s):  
Heavy Metals ◽  
Settling Velocity ◽  
Urban Runoff ◽  
Stormwater Treatment ◽  
Sewer System ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Water Tanks ◽  
The Relationship

Sedimentation and transportation of mineral and organic pollutions in combined sewer systems are not completely understood. For better understanding, samples of sediment, slime and urban runoff were taken from the combined sewer system of Bad Mergentheim. The settling velocity of settleable solids was measured with a settling apparatus. Typical settling curves for sediment, slime and wastewater were put together. Some of the samples were analysed for heavy metals and organic micro-pollution. By this the relationship between settling velocity and the load of heavy metals can be shown. The gained data are of interest for the design of clarifier tanks for stormwater treatment.

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