Model Questions Paper with Answer 2

MODEL QUESTION PAPER - II

PART A

 

1. Write in brief about recharge of ground water.

Groundwater recharge (or) deep drainage is a hydrologic process where water moves downward from surface water to groundwater. Groundwater recharge is the primary method through which water enters on Aquifer. Ground water recharge also encompasses water moving away from the water table farther into the saturated zone.

 

2. List functions of intake structures.

The main function of intake is to provide highest quality of water from source.

To protect pipes and pumps from damaging (or) clogging by wave action/ floating bodies and submerged aquatic lives.

To help in safely withdrawing water from the source over predetermined pool levels and then to discharge this water into the withdrawal conduit.

 

3. Mention the basic for the selection of types and capacity of pumps.

 

4. Write the nature of any four coagulants.

i) Alum

Most common and universal coagulant. Alum requires presence of alkalinity in water to form floc. Alum dissolves in water hyderolyze into aluminium hyderoxide. The aluminium hyderoxide floc so formed in insoluble in water. Alum reduces turbidity, taste and odour. It produces crystal clear water.

ii) Chlorinated Copperas:

Hydrated ferrous sulphate is called copperas. Copperas are effective in removing colour. Ferric chloride is effective over pH 3.5 to 6.5 and above 8.5.

iii) Ferrous sulphate and lime:

Lime is added with ferrous sulphate to increase the reaction rate. The ferric hydroxide is a heavier floc. Ferrous sulphate is effective at a pH range above 8.5 Agin 000 abiloa babnis

iv) Magnesium Carbonate and lime

When magnesium carbonate and lime are dissolved in water, magnessium hyderoxide, Calcium carbonate is formed. Both Mg(OH), and CaCO, are soluble in water resulting in formation of sludge which is slurry.

 

5..Distinguish between Ultrafiltration and Nanofiltration.

 

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. State the discharge standards for any two parameters for treated sewage.

Tolerance limit for industrial effluents discharge into public sewers as per IS 3306-1974

(i) BOD5 -m500 mg/L

(ii) COD -  ­-

(ii) pH value - 5.5 to 9.00

(iv) Total suspended solids - 600 mg/L

(v) Chromium – 2mg/L

 

8.What do you mean by UASB?

Uplow Anaerobic sludge Blanket: It is an anaerotric reactor in which sewage flaws upward through the sludge led (or) aggregates. The UASB reactor maintains a high concentration of biomass through the formation of highly settleable microbial sludge aggregate.

Some of the merits are:

 (i) Three phase (gas-liquid-solid) seperation

 (ii) Biogas recovery

(iii) Sludge granules acts like a filter media.

 

9. How do you remediate sewage sickness.

The remedial measures for sewage sickness.

(i) Primary treatment of sewage

(ii) Choice of land

(iii) Under-drainage of soil

(iv) Giving rest to the land

(v) Rotation of crops

(vi) Applying sewage to shallow depths.

 

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

a) Give a detailed account on the selection of pumps and pipe materials suitable for the conveyance system.

Refer Section 3.9

b) 12. (b) What is intake structure? Explain with neat sketches, the various type of intake structures based on sources.

Refer Section 1.7

12. a) Describe in detail about the principle and mechanism of desalination process.

Refer Section 2.12

(b) (i) Explain the design principles of flash mixer and flocculator.  (6)

Refer Section 2.3

(ii) Design a clarifier for a population of 60000 persons. Percapita demand is 150 Lped. Peak demand 180% of average demand. Assume suitable data if necessary. (7)

Refer Section 2.4

13. (a) Find the flow in each pipe in the Loop shown in Fig. 15 (a). Use Hardy Cross method for analyzing the Loop. Consider CH as 1 10 for all pipes.

Refer Section 3.6

(b) Explain the important aspects associated with the house service connection.

Refer Section 3.10

14. (a) Enumerate and explain the various physico-chemical characteristics of sewage and state their environmental significance.

Refer Section 4.3 and 4.5

 (b) From a topographic map and field survey, the area of the drainage basin upstream was found out to be 35 hectares. Determine the maximum rate of run-off for a 10 year. The length of overflow slope is 45 meter with an average overland slope of 2%. The length of main basin channel is 700 meter with a slope of 1.8%. Ratio of area and perimeter is found out to be 0.6 meters. Take mannings roughness coefficient to be 0.09 and total runoff coefficient to be 0.35

elei Refer Section 4.7

15. (a) Design a high rate trickling filter from the following data:

Design flow  - 40 ML/d

Recirculation ratio -1.5

BOD of raw sewage - 250 mg/L

Desirable effluent BOD - 20 mg/L

Refer Section 5.3

(b) Write short notes on lagooning dumping landfilling and incineration fo solid wastes.

Refer Section 5.13 

 

PART C

16. (a) Design the rapid gravity sand filter for a flow of 20 MLD. Assume suitable design parameters.

Refer Section 5.2

 (b) A waste treatment plant is required to digest a sludge in such a way that gig lie the moisture content is reduced to 95% from the initial value of 96%. The inflow of sludge initially contains 70% volatile matter in the solid portion and during digestion only 60% of the volatile matter is destroyed. The specific gravity of volatile matter is 1.2 and that of fixed solid is 2.5. Calculate the volume of sludge before and after digestion if the inflow contains 2500 kg dry solids per day. Assuming 100 kg/m2/year solids loading rate, design the sludge drying bed required for dewatering 10 zoites operation.

Refer Section 5.12