SPSC 2011 Assistant Engineer / Assistant Executive Engineer (Civil) BPS-17, Engineers Cadre CCE (2011) — Water Supply & Sanitary Engineering Paper

Assistant Engineer / Assistant Executive Engineer (Civil) BPS-17, Engineers Cadre CCE (2011) — Water Supply & Sanitary Engineering. Combined Competitive Examination for Engineers Cadre · Tuesday 22 March 2011, 2:00 pm to 5:00 pm · Max marks 100. Attempt any 05 questions.

1. 1(a) State the various investigations one would make and the data that would be collected for preparation of water supply project for a town. What drawings would be prepared to present a scheme for the supply of water? (10) (b) How is rainfall measured? Explain the meaning of the term "Mean Annual Rainfall" of a place. Discuss its variations, and point out its practical applications. (10)

2. 2A drainage district has an area of 14 hectares with 30 houses per hectare. The average area of the roof is 84.0 sq. m per house; take K₁ = 0.9 as impervious factor. The roads occupy 25 percent of the total area. The main roads are tarred and the interior ones are water bound macadam; K₂ for roads could be taken as 0.6. The remaining area is open space whose value for K₃ equals 0.12. Determine the impervious factor for the entire district. If the rainfall record shows that the intensity of an ordinary rain storm is 4.5 cm per hour, what will be the discharge from this district? (20)

3. 3Design an isolated lavatory block to serve a secondary school with 500 boys and 200 girls. Drainage from the lavatory block is to be connected to a city sewer at a depth of 12 feet. The sewer is located at a distance of 300 ft from the site of lavatory. (20)

4. 4(a) What are the salient features of Water Supply Scheme and its need? (08) (b) Estimate the water demand for a small town having probable population as 10,000 (after three decades). Assume reasonable data. (08) (c) What do you mean by per capita water demand and fluctuation of demand? (04)

5. 5(a) What are the factors considered while estimating the quantity of the Dry Weather Flow (DWF) and Wet Weather Flow (WWF)? (10) (b) A 1 km long storm water sewer collects water from a catchment area of 200 hectares, where 30% of the area is covered by roofs (I = 0.90), 20% by pavements (I = 0.8) and 50% by open land (I = 0.13). Determine the average I and the diameter of the storm water sewer line assuming: (i) time of entry = 2 minutes; (ii) time of flow = 4 minutes; (iii) velocity of full flow = 2 m/s; (iv) n = 0.013 and slope = 0.002. (10)

6. 6(a) What are the sources of water pollution? State the common impurities in water. (10) (b) State the necessity of water treatment and what is the function of Sedimentation and of Coagulation-flocculation processes. (10)

7. 7(a) Describe, with sketch, the construction, working, cleaning, rate of filtration, and efficiency of a rapid sand filter. (12) (b) Explain the action of Chlorine when mixed with water and how it is applied in water. (08)

8. 8(a) Describe how the solid waste is collected and removed. (12) (b) What do you mean by Integrated waste Management? Explain with examples. (08)