25 – Wastewater Conveyance System Design April, 23, 2013 Professor Doran CEE 410

Learning goals for today are to improve understanding of: Typical building and service connections Types of collecting sewer systems Key design approach for gravity sewers SizeSlopeCover MHsDetailsDrawings Typical gravity sewer layout concepts

Learning goals for today are to improve understanding of: Typical building and service connections Types of collecting sewer systems Key design approach for gravity sewers SizeSlopeCover MHsDetailsDrawings Typical gravity sewer layout concepts

Learning goals for today are to improve understanding of: Typical building and service connections Types of collecting sewer systems Key design approach for gravity sewers SizeSlopeCover MHsDetailsDrawings Typical gravity sewer layout concepts

Learning goals for today are to improve understanding of: Typical building and service connections Types of collecting sewer systems Key design approach for gravity sewers SizeSlopeCover MHsDetailsDrawings Typical gravity sewer layout concepts

Building Connection

Sewer Alternatives Gravity Sewer Septic Tank Pumping Pressure Systems Vacuum Systems

Alternatives - STEP System

Alternatives – Pressure System

Alternatives - STEP System Centrifugal type Grinder Pump Curve

Alternatives – Pressure System

Pumping Rate (gpm) Discharge Head (ft) Moineau Type Pump Curve (e.g., E-One)

Alternatives – Vacuum System

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Gravity Collecting Sewer Layout Hypothetical Vertical Distances Required For Gravity Collector 9-12 ft m S = 0.02

Gravity Collecting Sewer Layout

Manhole Requirements: At Upstream End of Sewer Where Connecting to Another Sewer At Change of Grade or Direction At Change of Size At Least Every 400 ft Normally no service connections

Gravity Collecting Sewer Layout 100 year flood + 1 ft Flood Proof MH Drop MH of > 2ft difference in elevation

Gravity Collecting Sewer Layout

Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Gravity Collecting Sewer Layout Hydraulics of Gravity Sewers Minimum velocity (self-cleansing velocity) = 0.6 m/s (2.0 ft/s) Maximum velocity = 3.5 m/s (11.5 ft/s) Minimum pipe diameter = 205 mm (8”) Sanitary sewers up to 375 mm diameter (15”) should be designed to run half full Larger pipes may run three-fourths full Manning’s “n” of normally used Allow for minor losses at MHs

Regulations will specify minimum slope From WI NR Gravity Collecting Sewer Layout

Regulations will specify minimum slope From WI NR Gravity Collecting Sewer Layout Use greater slope if possible.

Use Hydraulic Elements Table or Chart Gravity Collecting Sewer Layout

Layout of collection network makes advantage of topography Gravity Collecting Sewer Layout

Layout of collection network makes advantage of topography Gravity Collecting Sewer Layout Normally locate in Public ROW Access for Maintenance

Alternative approach using back yards Gravity Collecting Sewer Layout

Alternative approach using back yards Gravity Collecting Sewer Layout Difficult physical access for maintenance Easement-Access issues Landowners may build over sewer

Alternative approach using back yards Gravity Collecting Sewer Layout

Drop Sewer used for > 2 ft difference in invert elevations

Gravity Collecting Sewer Layout When diameter increases, match at crowns or 0.8 depth

Gravity Collecting Sewer Layout When diameter increases, match at crowns or 0.8 depth 0.8 D u 0.8 D D

Typical Submersible Pump Sta

1A 1B 1C 1D 1E 1F 1G 1H 1I 1K 1L 11A 11B 11C 111A 111B 11D 1111A 1111B 111C 12A 12B 12C 12E 12D 121A 121B 122B 122A 123A 123B Branch MH Numbering Scheme

A B C D 123

A2a