Study Bg 538 1 Demand Plan

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Design of Water Supply and Sewer Systems

Teaching language: English

Main Topics

A. Design of Water Supply Systems

I. Water Demand and Plan of the Distribution System (Drawing1)

II. Dimensioning of the Water Supply Distribution System(Drawing 2)

III. Design of Water Tank (Drawing 3)

B. Design of Sewer Systems

V. Plan of the Sewer System (Drawing 4)

VI. Design Requirements and Dimensioning of the Sewer

System


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Design of Water Supply and Sewer Systems

Advised Literature

1. Arsov, R., Lecture Notes (Power Point slides), UACG, Sofia,2003

2. Ignatova, Sl., Tutorial Notes (Power Point slides), UACG, Sofia,

2008

3. ,., ,

, 1981

4. , ., ., , ., ,, 1993, 2001

5. , ., ., , ,

1982

6. , ., ,

, 1992

7. , ., . , ,

1964, 1977


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I. Water Demand and Plan of the Distribution System

Topic I.1 Water Demand of the Settlement

Elements of theWater SupplySystem

1 - intake ( spring )

2 - external

pipelines3 - pump station

4 - water tank

(service

reservoir)

5 - feeder6 - main branches

7 - distribution

branches

Fig.1


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Consumption of potable water in the settlement

A. Distributed consumers:

Population

Cattle

Sheep and Goats

B. Localized consumers:

Hospital

Restaurant

Factory:

- water for production technology- drinking water for the workers during the shift

- water for taking shower after the shift

C. Water for fire extinguishing

Possible burst of fire somewhere in the settlement.


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Calculation of the water demand

Average daily demand of a consumer type

dmqNQ dav 3,1000

.

Maximum daily demand of a consumer type

dmQKQ davdd3

,,max

Maximum hourly demand of a consumertype

hmQKQK

Q havhdh

h

3

,

,max

,max .24

.


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N

is the number of consumers of a specific type

is the water consumption norm of the consumer

is the coefficient of daily variability of consumption

is the coefficient of hourly variability of consumption

Dimension of q:

[dm3/consumer.day] for 1,2,and 3

[dm3/patient.day] for 4, [dm3/person.visit] for 5

[dm3/worker.shift] for 6b and 6c.

Water for fire extinguishing requirements:

q

dK

hK



sdmQ f3

15


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Table of settlement demand

Consumer

1 Population 180 1.45 1.65

2 Cattle 50 1.8 2.5

3 Goats, sheep 10 1.8 2.5

4 Hospital 180 1.45 2.45

5 Restaurant 25 1.0 1.0

6 Factory

6a technology 1.0 1.0

6b drinking 35 1.0 2.5

6c shower 50 1.0 -----

Settlement

hK hQ ,maxdK dQ

,maxdavQ ,

hm /3dm /3dm /3N q


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Additional Information

The water for technology production is given directly as a

water flowrate.

The whole amount of water for taking shower is consumed

in the first hour after the end of the shift.

The water amount for the restaurant and the workers is

included in the norms of the population.




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Water demand of the whole settlement

dmQQa

davdavset 3

6,4,3,2,1

,,

dmQQQ dlossa

ddset 3

,

6,4,3,2,1

max,,max

Maximum daily demand (used for sizing of 1,2,3 and 4

see Fig.1)

dmQQ davset

dloss3

,, 2.0

Maximum hourly demand (used for sizing of 5,6 and 7

see Fig.1)

hmQQQ hlossa

hhset 3

,

6,4,3,2,1

max,,max

hmQ

Q dav

set

hloss 3,

,24

2.0



Average daily demand


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Topic I.2 Plan of the Distribution System

Main factors, influencing the preparation of the plan

The regulation plan of the settlement

The situation of the localized consumers

The relief of the area

The availability of natural and artificial obstacles

The location of the water sources


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Plan of the Distribution System (Drawing 1)


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Topic I.2 Plan of the Distribution SystemContents of the Plan

The numeration of the quarters (in the center of the

quarters)

The numeration of the crossroads (in the numerator)

The elevations of the crossroads (in the denominator, in m)

The main and distribution branches with the desireddirection of flow

The length of the branches between the crossroads (in m)

The numeration of the branches (of the main branches inRoman numbers; of the distribution branches in Arabicnumbers, according to the order of their origin from themains)

The fire hydrants

The stop valves


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Rules for drawing of the main branches

The direction of the water movement in the main branchesmust follow the general direction from the source to thesettlement

The main branches must cover uniformly the area of thesettlement

The main branches must have looped outline

The number of main branches is determined according tothe requirement: the loops must be elongated following thegeneral direction of water flow; the longer size of the loopsmust vary from 400 to 800 m, and the shorter one from 300

to 600 m The main branches should be traced through the areas of

the highest population density and pass just next to thelocalized consumers

When possible, they must be traced along the higher level

streets


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Rules for drawing of the distribution branches

The distribution branches must form loops, just like themains.

The direction of water movement in them must follow thegeneral direction from the source to the settlement. Some

exceptions are possible for meeting the requirement of theclosest crossroads.

The branches must have minimal length; it means that thewater must be supplied to each consumer from the nearest

crossroads where the main branch passes.

No water should be returned from the distribution branchesto the mains.


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Rules for situating of the stop valves

The valves operate at two positions: completely open

and completely closed. Usually they are used to

disconnect failed branches from the rest of the

distribution system and allow for repairs.

Stop valves on the main branches:

At the entrance of the feeder in the settlement

At the points of main branches deviations

At a distance of 300 to 400 m from each other


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Stop valves on the distribution branches:

At all deviations from the main branches

Placed in such a way, that in case of fire a group of several

distribution branches could be isolated, but in this group no

more than five fire hydrants must be situated

Symbols, used for the branches and appurtenances

Branch

Stop Valve

Fire Hydrant

beginning

en

d


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Vocabulary of the Terms

appurtenance

average daily demand

branch

cadastral plan

coefficient of daily variability ofconsumption

coefficient of hourly variability of

consumption

design

dimensioning

distributed consumers


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distribution branch

distribution system

external pipeline

failure of a branch

feeder

fire hydrant

flowrate

intake ,

localized consumers

loop




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main branch

maximum daily demand

maximum hourly demand

normal operation

plan of the distribution system

potable (drinking) water

pump station

repair of a branch

sewer system

sewerage




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spring

stop valve

wastewater treatment

water consumption norm

water demand ()water for fire extinguishing

water source

water supply

water supply system

water tank (service reservoir)

water treatment



Documents

Study Bg 538 1 Demand Plan