Design Of Sanitary Sewers Research Articles

Issues in Hydraulic Design of Sanitary Sewers

AbstractVarious protocols are used in the hydraulic design of sanitary sewers, with key differences related to the assurance of self-cleansing, and the selection of Manning’s n. Analyses reported i...

Integrating water‐saving schemes in the design of sanitary sewers

AbstractUrbanisation and climate change worsen the ever‐increasing gap between demand and the supply of water. Closing the gap between water demand and supply remains a global challenge that influences the growing uptake of water‐saving schemes (WSSs) to reduce the threat to water security. This study proposes a method for simultaneous design of sanitary sewers (SSs) and the selection of WSSs. An integrated design approach (or problem) that matches SSs with WSSs was formulated and solved as a multi‐objective optimisation problem. The two objectives considered are: (1) minimisation of the total cost and (2) maximisation of the cost benefits of interventions. The main constraints considered include the sanitary sewer technical and hydraulic performances. The problem was solved using the well‐known NSGA2 optimisation technique. The proposed method was demonstrated using a subsystem of the Tsholofelo Extension sanitary sewer in Gaborone. The results obtained from the integrated approach suggest that WSSs influence designs of the sanitary sewer (SS) and the other way round.

Discussion of “Tractive Force Design for Sanitary Sewer Self-Cleansing” by LaVere B. Merritt

In the original paper, Merritt presents a detailed summary ofChapter 5 of the 2007 edition of the joint ASCE MOP 60-WaterEnvironment Federation (WEF) FD-5 Manual, Gravity SanitarySewer Design and Construction (ASCE-WEF 2007). He endorsesthe manual’s recommendation to use the unit tractive force (TF)method to calculate the minimum slope of sanitary sewers carryingthe minimum flow at the beginning of the design period. He alsoreproduces the method to calculate such a flow, by using criteriapresented in Chapter 3 (ASCE-WPCF 1970, 1982; ASCE-WEF2007).In Merritt’s literature review, he fails to mention that the TFmethod to attain self-cleansing in sewers carrying settleableparticles was proposed as early as 1954 by Fair and Geyer,who suggested that to have self-cleansing conditions at all flowrates, the unit tractive force must be equal to that generated in asewer running full at a minimum velocity of 0:6m∕s(Fair andGeyer 1954). This minimum velocity was considered for manyyears sufficient to provide self-cleansing in a sanitary sewer run-ning full, without regard to particle size. The unit tractive force,in this case, can be calculated by using the following equation(La Motta 1996):T ¼ 0:571464γn

Sanitary sewer design using EPA storm water management model (SWMM)

AbstractTraditional sanitary sewer design uses detailed design tables that contain all the necessary information to complete the design. An alternative approach is to use modeling software, such as the EPA SWMM model. This paper details the application of the EPA SWMM model to design the sanitary sewer system of a proposed 62 lot development. Typically SWMM is thought of almost exclusively as a storm water system analysis tool, but this application shows how it can also be used for sanitary sewer analysis and design. The paper details how the SWMM model parameters were set to handle infiltration and inflow as well as base residential sanitary flows. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 203–212, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20124

Discussion of “ Graphs for Hydraulic Design of Sanitary Sewers ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Discussion of “ <i>Graphs for Hydraulic Design of Sanitary Sewers</i> ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Closure to “ Graphs for Hydraulic Design of Sanitary Sewers ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Closure to “ <i>Graphs for Hydraulic Design of Sanitary Sewers</i> ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Discussion of “ Graphs for Hydraulic Design of Sanitary Sewers ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Discussion of “ <i>Graphs for Hydraulic Design of Sanitary Sewers</i> ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Discussion of “ Graphs for Hydraulic Design of Sanitary Sewers ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Discussion of “ <i>Graphs for Hydraulic Design of Sanitary Sewers</i> ” by Venkateswarlu Swarna and Prasad M. Modak (May/June 1990, Vol. 116, No. 3)

Graphs for Hydraulic Design of Sanitary Sewers

Graphs are developed based on the concept of feasible diameter set for the rapid design of sanitary sewers. They are developed for various hydraulic criteria, such as full flow and best hydraulic cross section, taking into account the hydraulic constraints such as velocity and partial depth of flow. These graphs can be used by practicing engineers to perform quick and improved designs, thereby eliminating any need for trial‐and‐error procedures. Procedures for preparation of the graphs are detailed. An illustrative example describing the application of design graphs is included.

Designing Sanitary Sewers with Microcomputers

A program titled Sanitary Sewer Design (SSD) has been developed for the Apple II microcomputer. SSD is a heuristic program that attempts to find the least costly design of a sanitary sewer network or pipeline. The program computes velocities, water depths, pipe slopes, and inverts corresponding to inputted diameters, flows, pipe lengths, ground elevations, and design criteria. SSD was used to find the least costly design of a 3.25 mile sewer trunk line in Chapel Hill, N.C., for the Orange Water and Sewer Authority (OWASA). It was also used to perform a sensitivity analysis, which evaluated the effect that design criteria, uncertainty in flows, and alteration of pipe diameters have on the cost of a sewer system. The sensitivity analysis indicated that: (1) Costs can be reduced 20‐25% by relaxing the pipe size progression criterion; and (2) sewer design was relatively sensitive to flow uncertainty.