“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 (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”
Advised Literature
1.
2.
3.
4.
5.
6.
7.
Arsov, R., Lecture Notes (Power Point slides), UACЕG, Sofia,
2003
Ignatova, Sl., Tutorial Notes (Power Point slides), UACG, Sofia,
2008
Бойчев, Ст., Ръководство за упражнения по водоснабдяване,
Техника, 1981
Иванов, Сл., Калинков П., Рулев, Д., Ръководство по
водоснабдителни мрежи и съоръжения, УАСГ, 1993, 2001
Иванов, Ив., др., Наръчник по водоснабдяване, Техника,
1982
Гиргинов, Т., Ръководство за проектиране по канализация,
Техника, 1992
Кузуджийски, К., Ив. Иванов, Наръчник по канализация,
Техника 1964, 1977
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
Elements of the
Water Supply
System
1 - intake ( spring )
2 - external
pipelines
3 - pump station
4 - water tank
(service
reservoir)
5 - feeder
6 - main branches
7 - distribution
branches
Fig.1
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
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.
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
Calculation of the water demand
 Average daily demand of a consumer type
Q av , d
N. q

1000
m d 
3
 Maximum daily demand of a consumer type
Q max, d  Kd Q av , d
m d 
3
 Maximum hourly demand of a consumer type
Q max, h 
K h . Q max, d
24
 K h .Qav , h
m h 
3
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
N is the number of consumers of a specific type
q is the water consumption norm of the consumer
Kd
is the coefficient of daily variability of consumption
Kh
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 f 15 dm3 s

Table of settlement demand
№ Consumer
N
q
Q av , d
m / d 
K d Q max, d
m / d 
3
Kh
3
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
1.0
1.0
6b drinking
35
1.0
2.5
6c shower
50
1.0
-----
Settlement
m / h
3
1
6a technology
Qmax, h
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
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.
I. Water Demand and Plan of the Distribution System
Topic I.1 Water Demand of the Settlement
Water demand of the whole settlement
Average daily demand
Qav,d
Q set av , d 
m
3
d

1, 2, 3, 4, 6 a
Maximum daily demand (used for sizing of 1,2,3 and 4 – see Fig.1)
Q set max, d 
Qmax,d  Qloss ,d
1, 2, 3, 4, 6 a
Qloss ,d  0.2Q set av,d
m
3
d

m d 
3
Maximum hourly demand (used for sizing of 5,6 and 7 – see Fig.1)
Q set max, h 
Qmax,h  Qloss ,h
1, 2, 3, 4, 6 a
Qloss ,h
0.2Q set av,d

24
m h 
3
m h 
3
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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 System
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
Plan of the Distribution System (Drawing 1)
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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.
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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).
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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
I. Water Demand and Plan of the Distribution System
Topic I.2 Plan of the Distribution System
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
end
beginning
Symbols, used for the branches and appurtenances
Branch
Stop Valve
Fire Hydrant
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 коефициент
consumption
на
денонощна
неравномерност
coefficient of hourly variability of коефициент
на
consumption
неравномерност
design
проект
dimensioning
оразмеряване
distributed consumers
разпръснати консуматори
часова
I. Water Demand and Plan of the Distribution System
Vocabulary of the Terms
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
I. Water Demand and Plan of the Distribution System
Vocabulary of the Terms
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
I. Water Demand and Plan of the Distribution System
Vocabulary of the Terms
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