Anna University, Chennai
Fifth Semester
(Regulation 2008)
PART-B
|
| Year | Population | Increase in population | Incremental increase |
| 1911 | 40185 | ----- | -------- |
| 1921 | 44522 | 4337 | -------- |
| 1931 | 60395 | 15873 | +11536 |
| 1941 | 75614 | 15219 | -654 |
| 1951 | 98886 | 23272 | +8053 |
| 1961 | 124230 | 25344 | +2072 |
| 1971 | 158800 | 34575 | +9231 |
| TOTAL | 118620 | 30238 | |
| AVERAGE | 19770 | 6040 |
The population at the end of the various decades shall be as follows:
| Year | Expected Population |
| 1981 | 158800+(19770+6040)*1= 184610 |
| 1991 | 158800+(19770+6040)*2=210420 |
| 2001 | 158800+(19770+6040)*3= 236230 |
2. Explain laboratory procedure to find out physical, chemical and biological characteristics of water.
1. Physical characteristics:
a. Turbidity
b. Color and temperature c. Taste and odour
2. Chemical characteristics
In the chemical analysis of water , these tests are done that will reveal the sanitary quality of the water. Chemical tests involve the determination of the total solids, PH value, Hardness of the water, Chloride content etc.
3. Biological characteristics:
a. Plant count test
b. M.P.N. Test ( Most Probable Number)
c. Water Borne Diseases
3. Explain the different sources of water and their characteristics with respect to turbidity, Hardness, Chloride content and Microbiology.
1. Surface sources
· Rivers, streams
· Lakes
· Ponds
· Reservoirs
2. Sub surface sources
· Springs
· Infiltration galleries
· Wells
ü shallow wells
ü deep wells
4. i) List out 10 parameters of Water quality Standards as per the Tamilnadu pollution Control Board Standards.
Water for domestic use should be
· Colourless, clear, free from suspended particles.
· Free from odour and taste good.
· Soft in Nature.
· Free from disease producing bacteria and organisms.
· Free from harmful salts.
Normally the standards of quality of drinking water are sufficient for most of the industrial water supplies.
The quality standards are followed in most of the industries. Some of them given below:
ü Paper industry
ü Textile industry
ü Cement concrete products
ü Manufacture of ice
ü Tanning industry
ü Laundries
ü Steel rolling mills
ii) Write a notes on types of water demand.
The various types of water demand for a city or town may be divided into the following five categories.
| 1. | Domestic water demand | = 135 liters/day | |
| 2. | Commercial and industrial water demand | = | 40 liters/day |
| 3. | Demand for public uses | = | 25 liters/day |
| 4. | Fire demand | = | 15 liters/day |
5. Loss and waste of water = 55 liters/day
------------ Total 270 liters/day
5. Discuss the factors that affect the rate of water demand.
or town.
The following are the main factors affecting per captia demand of the city
a) Climatic conditions b) Size of the city
c) Pressure in the distribution system d) System of water supply
e) Cost of water
f) Policy of water meter
g) Industrial and commercial activities h) Living standard of the people
6. i) What are the classification of intakes based on source also explain with a neat sketch any one of the intakes.
Intakes are of four major types.
Ø Canal intakes
Ø Reservoir intakes
Ø River intakes and
Ø Lake intakes
It also may be grouped under following three types.
· Intake towers
· Submerged intakes
· Portable intakes
ii) What are the different pipe materials used in the water transmission?
There are ten types are pipes are available as given below i. Cast iron pipes
ii. Wrought iron pipes iii. Steel pipes
iv. Asbestos cement pipes v. Cement concrete pipes vi. Galvanized iron pipes vii. Copper pipes
viii. Lead pipes ix. Wood pipes x. Plastic pipes
7. What are the requirements of pipe joint? Explain the various pipe joint with neat sketches.
Requirements:
Ø It should be water tight.
Ø It should be strong.
Ø It should be durable.
Ø It should be economical. Types:
i. Socket and spigot joint or Bell and spigot joint ii. Flanged joint
iii. Dresser coupling
iv. Victaulic coupling v. Flexible joint
vi. Ring-tite coupling or Simplex joint
vii. Cement collar joint viii. Screwed socket joint ix. Expansion joint
8. What are the types of pumps? Discuss the factors influencing the selection of a pump?
Types:
1. Positive displacement pumps
2. Rotodynamic pumps
3. Miscellaneous pumps
Factors for selecting a pump:
The general requirements for selection of a pump for water supply schemes are as indicated below:
ü Capacity
ü Efficiency
ü Reliability of operation
ü Power requirement
ü Cost
ü Suitability of pump for particular situation of service
9. Discuss the sedimentation by coagulation process using alum and state the merits and demerits of using alum
Plain sedimentation is not suitable for setting the particle with mud particles, and sedimentation with coagulation is used to remove these particles also.
1. Alum (Al2So4. 18 H2o)
2. Coppers (FeSO4. 7 H2o)
3. Chlorinated copperass
4. Sodium aluminate (Na2Al2O4)
10. With the help of the diagram, explain the process of Rapid Sand filter.
Rapid gravity filter are open tanks where water passes through a filter medium, usually sand, by gravity. Water is supplied to the top of a bed of sand. the depth of tank may vary between 2.5 to3.5m. each unit may have a surface area of
20 to 50m2. The length to width ratio is normally maintained between 1.25 to 1.35.
Filter medium:
The sand filter medium should satisfy the following criteria:
ü The sand should be of hard and resistant quartz and free of clay, fine particles, soft grains and dirt.
ü Ignition loss should not be exceed 0.7 percent.
ü Soluble fraction in hydrochloric acid should not exceed 5%
by weight.
ü Wearing loss should not exceed 3%.
11. Explain conventional method used to disinfect water.
Methods of disinfection
ü Boiling the water
ü Treating by Ultra-violet rays
ü Treating by the use of ozone
ü Addition of lime
ü Treating by potassium permanganate
ü Treating with silver or electro-katayan process
ü Treating with iodine and bromium
12. What is aerators ? Explain different type of aerator with sketches.
Aeration is defined as the physical process in which the water is contacted with air, in order to absorb oxygen and to remove carbon-di-oxide (CO2) gas. this process also kills bacteria to some extent.
Aerators fall into two general categories. They either introduce air into water or water into air.
The aeration of water can be carried out in the following ways.
ü By using spray nozzles.
ü By permitting water to tickle over cascades.
ü By air diffusers.
ü By using trickling beds.
13. Discuss with neat sketches the various types of layout of distribution system.
The main function of a water distribution system is to give the required pressure at the water taps. The method of water distribution system is based on the following three factors.
1. R.l. of the water source
2. Topography of the area
3. Locality of the area and local considerations.
Based on the above three factors, water is distributed in three ways,
ü Gravity system
ü Pumping system
ü Combined gravity and pumping system.
14. Explain the various system of pipe network.
generally pipes are laid down the road pavements and layout are the layout of roads.
Pipe networks:
follows:
Pipe networks are grouped under following four main categories as
1. Radial system
2. Dead end system
3. Grid iron system
4. Circulation system
15. Explain the various appurtenances used in water distribution system.
For the purpose of testing, inspection, cleaning, repairing and mainly for regulating the flow of water appurtenances are used. The commonly used appurtenances for the water distribution system are,
1. Sluice valve or gate valve
2. Non return valve
3. Air valve
4. Drain valve
5. Safety valve or pressure relief
6. Fire Hydrants
7. Water meters
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