GTU BE 2019 Summer Question Papers || Gujarat Technological University
Subject Code:2164010 Date:21/05/2019
Subject Name: Water and Wastewater Treatment Technologies
Time:10:30 AM TO 01:00 PM Total Marks: 70
Seat No.: Enrolment No.
GUJARAT TECHNOLOGICAL UNIVERSITY
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BE - SEMESTER-VI(NEW) —- EXAMINATION - SUMMER 2019Subject Code:2164010 Date:21/05/2019
Subject Name: Water and Wastewater Treatment Technologies
Time:10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
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- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
| MARKS | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q.1 (a) A town has an existing horizontal flow sedimentation tank with an overflow rate of 17 m³/day/m², and it is desirable to remove particles that have settling velocity of 0.1 mm/sec. Assuming the tank is an ideal sedimentation tank, Find the percentage of particles removal. | 03 | ||||||||||||||
(b) Ion concentrations obtained for a groundwater sample (having pH = 8.1) are given below:
--- Content provided by FirstRanker.com --- Find the total hardness, carbonate and non-carbonate hardness in the above water sample. | 04 | ||||||||||||||
| (c) The following data refers to an ASP: (i) sewage discharge = 3500 m³/day (ii) volume of tank 10900 m³ (iii) Influent BOD = 250 PPM (iv) Effluent BOD = 20 PPM (v) MLSS = 2500 PPM (vi) Effluent suspended solids = 30 PPM (vii) Waste sludge suspended solids = 9700 PPM (viii) quantity of waste sludge = 220 m³/day. Find (i) HRT (ii) F/M ratio (iii) Efficiency (iv) Residence time (v) SVI if settled volume is 150 ml/liter (vi) sludge return ratio | 07 | ||||||||||||||
| Q.2 (a) Explain the process of determination of alkalinity of water sample? | 03 | ||||||||||||||
| (b) Write short notes on: (1) Hardness (2) Turbidity | 04 | ||||||||||||||
| (c) For a circular sewer and a rectangular sewer to be hydraulically equivalent, find the relation between the depths of the rectangular sewer. Take the width of the rectangular sewer as 1.5 times the depth and assume that only three sides of rectangular sewer are wetted. | 07 |
OR
| (c) Calculate the diameter and discharge of a circular sewer laid at a slope of 1 in 500 when running half full, and with a velocity of 2 m/sec. Take N = 0.012 in Manning's formula. | 07 |
| Q.3 (a) What is coagulation and flocculation? | 03 |
| (b) Describe in briefly the various types of coagulants available in market for treating the water. | 04 |
| (c) A water treatment plant treat 10 MLD of raw water, the dose of alum is 18 ppm. Find the quantity of alum per year. Total quantity of CO2 gas produced per year. Total quantity of floc per year. Total quantity of hardness. | 07 |
OR
| Q.3 (a) What is sedimentation? Explain the various types of sedimentation | 03 |
| (b) Write briefly the construction of slow sand filter with neat sketches. Explain the advantage and disadvantage of slow sand filter. | 04 |
| (c) A water treatment plant treats 10 MLD of raw water. The dose of alum is 30 ppm. The raw water consist of alkali equal to 5 ppm of calcium carbonate. Find: (i) Total quantity of alum required (ii) Total quantity of calcium carbonate required (iii) Extra quantity of calcium carbonate required to be added (iv) Extra quantity of quick lime required having impurity 5%. | 07 |
| Q.4 (a) What do you mean by screening and aeration? | 03 |
| (b) Draw the flow chart of waste water treatment plant. | 04 |
| (c) The BOD of a sewage incubated for one day at 30°C has been found to 100 mg/L. What will be the 5 day 20°C BOD. Assume K = 0.12 (Base 10) at 20°C. | 07 |
OR
| Q.4 (a) Define the following: BOD, COD and THOD. | 03 |
| (b) Differentiate between the slow sand filter and rapid sand filter. | 04 |
| (c) Calculate the diameter of a rectangular plain sedimentation tank to treat 12 x 106 lit/day. Assume a detention period of 8 hours and the velocity of flow as 20 cm per minute i.e. 3.33 mm per sec. | 07 |
| Q.5 (a) Explain briefly: Oxidation pond and septic tank? | 03 |
| (b) For a waste water sample, 5 day BOD at 20°C is 200 mg/L and is 67% of the ultimate. What will be 4 day BOD at 30°C? | 04 |
| (c) Calculate the diameter required for single stage trickling filter which is to be effluent BOD of 20 mg/L when treating settled domestic sewage of BOD 120 mg/L. Waste water flow is 2200 m³/day and recirculation discharge is 4000 m³/day. Depth of tank is 1.5 m. | 07 |
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OR
| Q.5 (a) Write short notes on: Activated sludge process and skimming tank | 03 |
| (b) Explain with neat sketch the construction and working principle of trickling filter. | 04 |
| (c) Population of town is 30,000, Domestic sewage produced is 120 lpcd having BOD of 200 mg/L. Industrial sewage produced is 3 X 106 lit/day having BOD 800 mg/L. Design high rate single stage trickling filter with following data: BOD removed in PST: 35% Organic loading rate: 10,000 kg/Ha.m/day (excluding recirculation) Hydraulic loading rate: 170 X10³ lit/Ha/day (Including recirculation) --- Content provided by FirstRanker.com --- Recirculation ratio: 1Find the efficiency of trickling filter and effluent BOD. | 07 |
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