types of sewer

8/2/2019 Types of Sewer

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sewer:A sewer is an underground conduit or drain through which sewage

is conveyed to point of discharge or disposal.

Types of sewers classified on bases of materialsused:1. Asbestos cement sewer.2. Plain or reinforced cement concrete sewer.3. Vitrified clay or stoneware sewer.4. Brick sewer.5. Cast iron sewer.6. Steel sewers.7. Plastic sewers.


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Asbestos cement sewer:These sewer pipes are made from mixture of asbestos fibre,cement and silica.

The asbestos fiber serve as reinforcing material.These pipes are available in various sizes ranging from75mm to 500mm diameter and to 3 to 4m in length.

Advantages:Possess considerable strength against internal pressure.They are light in weight hence handling is easy.They can be easily cut and joined.These pipes offer good resistance to salts, and other cohesive

material normally present in these sewer.The inside surface is relatively smooth. Hence they arehydraulically more efficient.


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Disadvantages:They are brittle. They are weak against impact forces hencecareless handling may result in there breaking.

They have less structural strength against heavy external forces.These are susceptible to sulphide corrosion. Due to thesedisadvantages these are used only as vertical.


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Plain or reinforced cementconcrete :

Cement concrete pipes can either be plain or reinforced.Plain cement concrete are used from 80mm to 450m with theirthickness varying from 25mm to 35mm.for bigger diameter theseare reinforced, consisting of longitudinal and transversereinforcement in the form of rings or elliptical cage.


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Advantages : Cement concrete pipes are equally strong in internal and

external pressures.thus these pipes can withstand bothtensile and compressive stresses. This pipes can be made of any desier strength by proper

design of mix, thickness and reinforcement. This can be easily manufactured at site.

They are economical for medium and large sizedinstallation.

Disadvantages:The biggest disadvantages of this type of sewers are they

get easily corroded and pitted because of corrosive action ofcontents of the sewage.


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Vitrified clay or stonewaresewer:

These pipes are manufactured from clays and shale's ofspecial qualities and grades. In order to make the jointswater tight, the exterior surface of spigot and the interiorsurface of socket are not glazed


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Advantages:They are highly resistance to sulphide corrosion. They possess enough resistance to erosion due to grit

and silt. Because of smooth interior they are hydraulically

efficient.They are highly impervious.They possess good compressive strength.They are cheap and easily available.


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Disadvantages:

They are weak in tension.They are brittle in nature.They are quite bulky and heavy

Cast iron sewers:Cast iron pipes possess high strength. They arestructurally strong to withstand tensile ,compressiveas well as bending stresses.

They are available in diameter ranging from 150mmto 750mm and lengths up to 3 to 3.5m


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Advantages :They are suitable at places where heavy external loads exist.They are preferred when sewage flows under pressure.

They are preferred for sewers laid under cement concrete roadsWhere it is not possible to disturb the road surface for frequentrepairs of the sewers.

They prevent the contamination of ground water as these are100% leak proof.


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Disadvantages:They are very costly.They have to protected with paint or cement concrete.

Steel sewers :Steel sewers are used at those location where highexternal and internal pressures are encountered.


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Advantages:

They are perfectly impervious.They are light in weight. Because of there flexibility they can absorb vibrationsand shock loads.

They are used for mains , outfall, and trunk sewers

having large diameter.They can be easily welded.


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Disadvantages:They are very costly in comparison with cast iron

pipe.


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Thank you

types of sewer

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