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

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Presentation on theme: "25 – Wastewater Conveyance System Design April, 23, 2013 Professor Doran CEE 410."— Presentation transcript:

1 25 – Wastewater Conveyance System Design April, 23, 2013 Professor Doran CEE 410

2 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

3 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

4 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

5 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

6 Building Connection

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9 Sewer Alternatives Gravity Sewer Septic Tank Pumping Pressure Systems Vacuum Systems

10 Alternatives - STEP System

11 Alternatives – Pressure System

12 Alternatives - STEP System Centrifugal type Grinder Pump Curve

13 Alternatives – Pressure System

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

15 Alternatives – Vacuum System

16 http://www.roevac.com/page/ en/page_ID/42?PHPSESSID=d1 265aa3cfe97b116960cb0ce1d6 5499

17 Gravity Collecting Sewer Layout Hypothetical Vertical Distances Required For Gravity Collector 9-12 ft 2.7-3.7 m S = 0.02

18 Gravity Collecting Sewer Layout

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20 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

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

22 Gravity Collecting Sewer Layout

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24 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 0.013-0.015 normally used Allow for minor losses at MHs

25 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 0.013-0.015 normally used Allow for minor losses at MHs

26 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 0.013-0.015 normally used Allow for minor losses at MHs

27 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 0.013-0.015 normally used Allow for minor losses at MHs

28 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 0.013-0.015 normally used Allow for minor losses at MHs

29 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 0.013-0.015 normally used Allow for minor losses at MHs

30 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 0.013-0.015 normally used Allow for minor losses at MHs

31 Regulations will specify minimum slope From WI NR 110.13 Gravity Collecting Sewer Layout

32 Regulations will specify minimum slope From WI NR 110.13 Gravity Collecting Sewer Layout Use greater slope if possible.

33 Use Hydraulic Elements Table or Chart Gravity Collecting Sewer Layout

34

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

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

37 Alternative approach using back yards Gravity Collecting Sewer Layout

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

39 Alternative approach using back yards Gravity Collecting Sewer Layout

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44 Drop Sewer used for > 2 ft difference in invert elevations

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

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

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48 Typical Submersible Pump Sta

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54 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

55 A B C D 123

56 A2a


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