PTU B.Tech CIVIL 6th Semester May 2019 71087 ENVIRONMENT ENGINEERING II Question Papers

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Roll No.

Total No. of Pages : 02

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Total No. of Questions : 09

B.Tech.(CE) (2011 Onwards) (Sem.-6)

ENVIRONMENT ENGINEERING-II

Subject Code : BTCE-606

M.Code: 71087

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Time: 3 Hrs.

Max. Marks : 60

INSTRUCTIONS TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students have to attempt any FOUR questions.

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3. SECTION-C contains THREE questions carrying TEN marks each and students have to attempt any TWO questions.

SECTION-A

Q1. Answer briefly :

1. Differentiate between separate sewer and combined sewer
2. What is meant by Dry weather flow (DWF)? How is it different from WWF?

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3. How does the sewage flow fluctuate during 24 h period? How does this fluctuation affect design of sewers?
4. What is meant by self cleansing velocity in sewers? How is it important?
5. Differentiate between lamp holes and man holes.
6. Give any two unit operations and unit processes from wastewater treatment.
7. Differentiate between Ejectors and Pumps

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8. What is meant by biological solids retention time? How is it different from hydraulic retention time?
9. What is meant by relative stability?
10. "Septic tank can only be considered as a primary treatment and the effluent needs treatment before disposal". Why?

SECTION-B

Q2. A main sewer is to be designed to receive a flow from 1 km² area of a community where population density is 200 persons/ha. The average flow is 150 lpcd. What is the design flow for the main sewer?

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Q3. Sketch and explain the construction and working of inverted siphons.

Q4. What are the different measures of organic content in wastewater? Discuss the importance of BOD/COD ratio.

Q5. A channel - type grit chamber has a flow through velocity of 0.25 m/s, a depth of 0.8 m and a length of 10 m. For inorganic grit particles with specific gravity 2.5, determine the particle size that can be removed with 100 percent efficiency, (assume v = 1.01 × 10-² cm²/s).

Q6. Differentiate between oxidation pond and oxidation ditch.

SECTION-C

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Q7. Compare the advantages and disadvantages of aerobic and anaerobic systems of wastewater treatment. Use at least two examples from each to substantiate your point.

Q8. a) Calculate the surface area required for a stabilization pond to serve a population of 1 lakh sewage flow of 189 lpcd. BOD is 200 mg/L hydraulic loading of 250kg BOD/d.ha. if the average liquid depth 1.5m. Calculate the retention time of the sewage based on influent flow. Sketch the process diagram.

b) A trickling filter has a diameter of 20m and depth 2.5m. it is operated with a direct circulation ratio of 1.5 and influent sewage rate of 2 million litres per day. Influent BOD into the filter is 200 mg/L and effluent BOD is 30 mg/L. Calculate the hydraulic loading rate and organic loading rate. What is the efficiency of the filter?

Q9. Write short notes differentiating the following :

1. One Pipe system and two pipe system of plumbing

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2. Grease trap and Grit chamber
3. Pump capacity and pump efficiency
4. Stabilization pond and constructed wet land

NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any page of Answer Sheet will lead to UMC against the Student.

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