SPSC 2014 Assistant Engineer (Civil) BPS-17, Public Health Engineering Department (2014) — Sanitary Engineering & Water Supply Paper

Assistant Engineer (Civil) BPS-17, Public Health Engineering Department (2014) — Sanitary Engineering & Water Supply. Competitive examination for the post of Assistant Engineer (Civil) BPS-17 in PHED, Government of Sindh · Tuesday 28 January 2014, 2:00 pm to 5:00 pm · Max marks 100. In combination with Group-II of Part-I only. Attempt any five questions. All questions carry equal marks.

1. 1Distinguish between the following: (i) Sewage and Sullage (ii) Dry Weather Flow and Wet Weather Flow (iii) Sanitary Sewage and Industrial Sewage (iv) Raw Sewage and Septic Sewage (v) Vent Pipes and Waste Pipes.

2. 2(i) Describe an Artesian Well, and how is it formed? (ii) What is a river intake? What are the factors which govern the location of an intake? (iii) What are the common sources of water for a water supply scheme? State the factors that govern the final selection.

3. 3In a 4-storeyed building each storey is 3.5 m high; the plinth is 0.75 m above and the underground tank is 0.75 m below GL respectively. The height of the storage tank is 1.2 m and in each floor the number of fixtures are: wash basins = 2, water closets = 2, showers = 2, kitchen sinks = 2. Design the piping system.

4. 4Write short notes on any five of the following: (i) Water supply pipe joints and their losses (ii) Oxidation Ponds (iii) Septic Tanks (iv) Sewer Appurtenances (v) Composting (vi) Incinerators (vii) Infiltration Gallery and Infiltration Well.

5. 5(a) What are the fundamental principles of sanitation? Mention the points of importance in any public sanitary project and discuss them. (b) What are the aspects to be considered at the time of selection of site and design of a sewage treatment plant?

6. 6Sketch a conventional sequence of various unit operations in a complete Municipal Sewage Plant. What do you understand by the Primary and Secondary Processes of Sewage Purification Treatment? Design a septic tank for 100 users. Average rate of sewage flow is 100 lpcd. Assume data where necessary.

7. 7Define the process of purification of sewage through trickling filters. How would you compare Standard Rate and High Rate trickling filters? Design the high rate trickling filter for the following data: (i) Flow = 30 mld (ii) Recirculation = 1.5 (iii) BOD of raw sewage = 200 mg/l (iv) Final effluent BOD desired = 60 mg/l.

8. 8(a) What are the factors considered while estimating the quantity of the Dry Weather Flow (DWF) and Wet Weather Flow (WWF)? (b) A 1 km long storm water sewer collects water from a catchment area of 50 hectares, where 35% of the area is covered by roofs (I = 0.90), 20% by pavements (I = 0.8) and 45% by open land (I = 0.5). Determine the average I and the diameter of the storm water sewer line assuming: (i) time of entry = 3 minutes; (ii) time of flow = 10 minutes; (iii) velocity of full flow = 1.5 m/s; (iv) n = 0.013 and slope = 0.002.