Model Questions Paper with Answer 1

MODEL QUESTION PAPER - I

PART A

 

1. State the various reasons for water demand in the recent times.

The various reasons for water demand in the recent timer are:

i) Climatic conditions

ii) Expansions of the city limits

iii) Increase in population

iv) Quantity of water available for domestic purposes

v) System of sanitation

 

2. State the factors governing the selection of particular water source.

The factors governing the selection of a particular water sources are :

i) Quantity of available water sufficient to meet the demand throughout the year.

ii) Quality of available water.

iii) Distance of source of supply

iv) Topography of intervening area.

v) Elevation of source.

 

3. Highlight the criteria required for the pipe materials in the water supply system.

Following are the basic criteria's required for a pipe material in a water supply system.

i) A good pipe material should be capable of withstanding internal and external pressures.

ii) A good pipe material be easily jointed.

iii) A good pipe material should be durable.

iv) A good pipe material should not react with water.

v) Head loss due to friction should be minimum

 

4. What are flocculators?

Flocculators are generally rectangular tanks with paddles operated by electric motors. The paddles rotate at 2 to 3 rpm. speed. The purpose of the flocculator is to facilitate to 'floc' formation. The flocculator provides energy and gentle mixing to induce particle collisions that form large flocs.

 

5. Distinguish between Ultrafiltration and Nanofiltration.

Ultrafiltration

Ultrafiltration are microprocess membranes which remove suspended small size particles by physical separation.

They are low pressure processes.

Nanofilteration

Nanofilteration remove dissolved salts ions by osmosis.

Nanofilteration is also a low pressure reverse osmosis.

 

6. Mention the the important components needed for the water distribution to buildings.

i) Valves

a) Sluice valve, b) Check valves, c) Air valves, d) Drain valves

ii) Ferrule

iii) Goose neck

iv) Seevice pipe

v) Stop cock

vi) Water meter

vii) Water taps

 

7. Define BOD.

Biological Oxygen Demand: Measure of oxygen required to oxidise biologically active basa ve organic matter in sewage by micro-organisms.

Significance of BOD:

1. Quantity of O2 required for biological stabilization of organic matter in sewage.

2. Size of treatment facilities.

3. Measure of efficiency of treatment

8. What are small bore systems?

Small bore sewer is a water tight small diameter waste water collection pipe that provides servicing with superior operational and environmental performance at a significance lower cost as compared to conventional gravity sewage.

 

9. What is meant by sludge volume index?

Slude volume index is defined as the volume occupied in ml by 1 gm of solids in the mixed liquor after settling for 30 minutes. Sludge volume index indicates the sludge concentration in system and settallility characteristics of sludge.

 

10. What is meant by sludge conditioning?

Sludge conditioning is a treatment process which improves the drainability of digested sludge. The addition of chemical such as alum, poly electrolyles, ferric salt to improve the dewatering characteristic of sludge is called as sludge conditioning.

 

PART B

11. a) Describe in detail about the hydraulics of flow in pipes.

Refer Section 1.2

b) (i) Write down the water quality standards for drinking purpose as per B.I.S.

Refer Section i.6.1

(5)

(ii) Discuss, the factors influencing the selection of a pump. viral

Refer Section 1.7.

12. a) Explain about the process carried out in sedimentation tanks and sand filters during water treatment operation.

Refer Section 2.1

(b) (i) Explain the design principies of flash mixer and flocculator.

Refer Section 2.3

(6)

(ii) Design a clarifier for a population of 60000 persons. Percapita demand is 150 Lpcd. Peak demand 180% of average demand. Assume suitable data if necessary.

(7)

Refer Section 2.4

13. (a) Brief about few recent and possible advancement in water filtration techniques.

Refer Section 2.12

 (b) Elaborate how are defluoridation and demineralization carried out in the advanced water treatment process?

Refer Section 2.10

14. (a) Explain various systems of sanitary plumbing and write down their main characteristics of each system.

Refer Section 4.16

14. (b) Expand UASB and draw the schematic diagram of UASB. Given that the influent to UASB reactor has following characteristics: flow rate = 8000 m3/day, depth of sludge blanket = 2.2 m, reactor height (including settler) = 5 m, effective coefficient (ratio of sludge to total volume in sludge blanket) = 0.85, and average concentration of sludge = 70 kg/m3. Determine HRT and reactor area. Take BOD removal efficiency as 80% and sludge age as 30 days.

Refer Section 5.5

15. (a) What do you mean by sludge thickening process? Explain Gravity thickening and air flotation unit with a neat diagram.

Refer Section 5.12

(b) Draw a neat sketch of a high rate two-stage anaerobic sludge digster and explain its working principle.

Refer Section 5.2

 

PART C

16. (a) Briefly discuss about the various physic-chemical test on water and write their limitation for domestic and industrial purpose.

Refer Section 5.12

(b) It is preposed to treat 18 ML/d of primary treated sewage with the help of a ASP system. The BOD of raw sewage is 280 mg/L. Design the various components of ASP system by assuming the following parameters.

MLVSS in the reactor = 2500 mg/L

Return sludge Concentration (VSS)= 800 mg/L

MCRT = 8 d

Yield coefficient = 0.45

Decay coefficient =0.05 d-1

Refer Section 5.2