“Design of Water Supply and Sewer Systems” Teaching language: English Main TopicsMain Topics A.Design of Water Supply Systems I.Water Demand and Plan of

““Design of Water Supply and Sewer Systems”Design of Water Supply and Sewer Systems”

• Teaching language: English• Main TopicsMain Topics

A. Design of Water Supply Systems

I. Water Demand and Plan of the Distribution System (Drawing 1)

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

““Design of Water Supply and Sewer Systems”Design of Water Supply and Sewer Systems”

Advised LiteratureAdvised Literature

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

2. Ignatova, Sl., Tutorial Notes (Power Point slides), UACG, Sofia, 2008

3. Бойчев, Ст., Ръководство за упражнения по водоснабдяване, Техника, 1981

4. Иванов, Сл., Калинков П., Рулев, Д., Ръководство по водоснабдителни мрежи и съоръжения, УАСГ, 1993, 2001

5. Иванов, Ив., др., Наръчник по водоснабдяване, Техника, 1982

6. Гиргинов, Т., Ръководство за проектиране по канализация, Техника, 1992

7. Кузуджийски, К., Ив. Иванов, Наръчник по канализация, Техника 1964, 1977

I. Water Demand and Plan of the Distribution SystemTopic I.1 Water Demand of the Settlement

Elements of the Water Supply

System

1 - intake ( spring )2 - external pipelines3 - pump station4 - water tank

(service reservoir)5 - feeder6 - main branches7 - distribution

branches

Fig.1


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.


Calculation of the water demand

Average daily demand of a consumer type

dmqN

Q dav3

, 1000

.

Maximum daily demand of a consumer type

dmQKQ davdd3

,,max

Maximum hourly demand of a consumer type

hmQKQK

Q havhdh

h3

,,max

,max .24

.

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 f315

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 /3 dm /3 dm /3

N q

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.


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

Qdav

set

hloss3,

, 24

2.0


Average daily demand

What is a Plan of the Distribution System?

It is a drawing (at a scale of 1:2000), made on the cadastral plan of the settlement, showing the route of the main and distribution branches of the water supply network with the desired direction of

water movement.

Basic requirements to the distribution system

Reachability of any consumer

Continuous supply of water in case of normal operation or in case of failure of some branches

Most economical solution

I. Water Demand and Plan of the Distribution SystemTopic 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

Plan of the Distribution System Plan of the Distribution System (Drawing 1)(Drawing 1)


Contents 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 desired direction of flow

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

The numeration of the branches (of the main branches in Roman numbers; of the distribution branches in Arabic numbers, according to the order of their origin from the mains)

The fire hydrants The stop valves


Rules for drawing of the main branches

The direction of the water movement in the main branches must follow the general direction from the source to the settlement

The main branches must cover uniformly the area of the settlement

The main branches must have looped outline The number of main branches is determined according to

the requirement: the loops must be elongated following the general direction of water flow; the longer size of the loops must 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 the localized consumers

When possible, they must be traced along the higher level streets


Rules for drawing of the distribution branches

The distribution branches must form loops, just like the mains.

The direction of water movement in them must follow the general direction from the source to the settlement. Some exceptions are possible for meeting the requirement of the closest crossroads.

The branches must have minimal length; it means that the water must be supplied to each consumer from the nearest crossroads where the main branch passes.

No water should be returned from the distribution branches to the mains.


Rules for situating of the fire hydrants

The fire hydrants have to be situated mainly on the distribution branches. Some exceptions are allowed for long distance sections of the main branches.

Maximum distance between two fire hydrants – 150 m (optimal distance 100 – 120 m).

Recommended position of the hydrants – close to the crossroads (to be easily found by the fire brigades in case of fire).


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


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

beg

inn

ing

end

I. Water Demand and Plan of the Distribution System

Vocabulary of the Terms

appurtenance арматура

average daily demand среден денонощен разход

branch клон

cadastral plan кадастрален план

coefficient of daily variability of

consumption

коефициент на денонощна

неравномерност

coefficient of hourly variability of

consumption

коефициент на часова

неравномерност

design проект

dimensioning оразмеряване

distributed consumers разпръснати консуматори

distribution branch разпределителен клон

distribution system водопроводна мрежа

external pipeline външен водопровод

failure of a branch авария на клон

feeder главен водопровод

fire hydrant пожарен хидрант

flowrate водно количество

intake водовземане, каптаж

localized consumers концентрирани консуматори

loop пръстен



main branch главен клон

maximum daily demand максимален денонощен разход

maximum hourly demand максимален часов разход

normal operation нормална работа

plan of the distribution system идейно решение на

водопроводната мрежа

potable (drinking) water питейна вода

pump station помпена станция

repair of a branch отстраняване на авария на клон

sewer system канализационна система

sewerage канализация



spring извор

stop valve спирателен кран

wastewater treatment пречистване на отпадъчни води

water consumption norm водоснабдителна норма

water demand водопотребление (разход)

water for fire extinguishing противопожарен разход

water source водоизточник

water supply водоснабдяване

water supply system водоснабдителна система

water tank (service reservoir) изравнителен резервоар

water treatment пречистване на природни води



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“Design of Water Supply and Sewer Systems” Teaching language: English Main TopicsMain Topics A.Design of Water Supply Systems I.Water Demand and Plan of