CE 2304 - ENVIRONMENTAL ENGINEERING Two Marks Questions With Answers 2015

Anna University, Chennai

Anna_University,_Chennai_logo

 

Fifth Semester

clip_image001 Civil Engineering CE 2304 - ENVIRONMENTAL ENGINEERING

(Regulation 2008)

PART-B

Year

1911

1921

1931

1941

1951

1961

1971

Population

Solution:

40185

44522

60395

75614

98886

124230

158800

1. The population figures of a city as per census records are given below for the years 1911 to 1971. Find out the population after one, two and three decades beyond the last known decades by using incremental increase method.

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