MCQOPTIONS
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MCQOPTIONS
This section includes 43 Mcqs, each offering curated multiple-choice questions to sharpen your Municipal Solid Waste knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Water samples (X and Y) from two different sources were brought to the laboratory for the measurement of dissolved oxygen (DO) using modified Wrinklier method. Samples were transferred to 300 ml BOD bottles. 2 ml of MnSO4 solution and 2 ml of alkaliodide-azide reagent were added to the bottles and mixed. Sample X developed a brown precipitate, whereas sample Y developed a white precipitate. In reference to these observations, the correct statement is |
| A. | Both the samples were devoid of DO |
| B. | Sample X was devoid of DO while sample Y contained DO |
| C. | Sample X contained DO while sample Y was devoid of DO |
| D. | Both the samples contained DO |
| Answer» D. Both the samples contained DO | |
| 2. |
Match the following Group IGroup 2P. Thickening of sludge1. Decrease in volume of sludge by chemical oxidation Q. Stabilization of sludge2. Separation of water by heat or chemical treatmentR. Conditioning of sludge3. Digestion of sludgeS. Reduction of sludge4. Separation of water by flotation or gravity |
| A. | P- 4, Q-3, R-1, S-2 |
| B. | P- 3, Q-2, R-4, S-1 |
| C. | P- 4, Q-3, R-2, S-1 |
| D. | P- 2, Q-1, R-3, S-4 |
| Answer» D. P- 2, Q-1, R-3, S-4 | |
| 3. |
Column IColumn IIP. Grit chamber1. Zone settlingQ. Secondary settling tank2. Stoke s lawR. Activated sludge process3. AerobicS. Trickling filter4. Contact stabilisationThe correct match of Column I with Column II is |
| A. | P-1, Q-2, R-3, S-4 |
| B. | P-2, Q-1, R-3, S-4 |
| C. | P-1, Q-2, R-4, S-3 |
| D. | P-2, Q-1, R-4, S-3 |
| Answer» C. P-1, Q-2, R-4, S-3 | |
| 4. |
If the BOD5,30 of waste is 150 mg/L and the reaction rate constant (to the base 'e') at 20 C is 0.35/day, the ultimate BOD in mg/L is |
| A. | 97.5 |
| B. | 181.5 |
| C. | 212.9 |
| D. | 230.2 |
| Answer» C. 212.9 | |
| 5. |
A portion of wastewater sample was subjected to standard BOD test (5 days, 20 C), yielding a value of 180 mg/1. The reaction rate constant (to the base 'e') at 20 C was taken as 0.08 per day. The reaction rate constant at other temperature may be estimated by kr = (k 20 (1.047)T-20. The temperature at which the other portion of the sample should be tested, to exert the same BOD in 2.5 days, is |
| A. | 4.9 C |
| B. | 24.9 C |
| C. | 31.7 C |
| D. | 35.0 C |
| Answer» E. | |
| 6. |
The following data are given for a channel-type grit chamber of length 7.5 m. (i) flow through velocity = 0.3 m/s (ii) the depth of wastewater at peak flow in the channel = 0.9 m (iii) specific gravity of inorganic particles = 2.5 (iv) g = 9.80 m/s , m = 1.002 10 3 N/s/m at 20 C, pw 1000 kg/m Assuming that the stokes is valid, the largest diameter particle that would be removed with 100 parent efficiency is |
| A. | 0.01 mm |
| B. | 0.21 mm |
| C. | 1.92 mm |
| D. | 6.64 mm |
| Answer» C. 1.92 mm | |
| 7. |
In a certain situation, wastewater discharged into a river,mixes with the river water instantaneously and completely. Following is the data available: Wastewater: DO = 2.00 mg/L Discharge rate = 1.10 m /s River water DO = 8.3 mg/L Flow rate = 8.70 m /s Temperature = 20 C Initial amount of DO in the mixture of waste and river shall be |
| A. | 5.3 mg/L |
| B. | 6.5 mg/L |
| C. | 7.6 mg/L |
| D. | 8.4 mg/L |
| Answer» D. 8.4 mg/L | |
| 8. |
50 g of CO2 and 25 g of CH4 are produced from the decomposition of municipal solid waste (MSW) with a formula weight of 120 g. What is the average per capita green house gas production in a city of 1 million people with a MSW production rate of 500 ton/day? |
| A. | 104 g/day |
| B. | 120 g/day |
| C. | 208 g/day |
| D. | 313 g/day |
| Answer» E. | |
| 9. |
A wastewater sample contains 10 5.6 m mol/l of OH ions at 25 C. The pH of this sample is |
| A. | 8.6 |
| B. | 8.4 |
| C. | 5.6 |
| D. | 5.4 |
| Answer» E. | |
| 10. |
Determine the correctness or otherwise of the following Assertion (A) and the Reason (R). (A): the crown of the outgoing larger diameter sewer is always matched with the crown of the incoming smaller diameter sewer. Reason (R): It eliminates backing up of sewage in the incoming smaller diameter sewer. |
| A. | Both (A) and (R) are true and (R) is the correct reason for (A) |
| B. | Both (A) and (R) are true and (R) is not the correct reason for (A) |
| C. | Both (A) and (R) are false |
| D. | (A) is true but (R) is false |
| Answer» B. Both (A) and (R) are true and (R) is not the correct reason for (A) | |
| 11. |
The 5-day BOD of a waste water sample is obtained as 190 mg/l (with k = 0.01h 1). The ultimate oxygen demand (mg/l) of the sample will be |
| A. | 3800 |
| B. | 475 |
| C. | 271 |
| D. | 190 |
| Answer» D. 190 | |
| 12. |
If the BOD3 of a waste water sample is 75 mg/l and reaction rate constant k (base e) is 0.345 per day, the amount of BOD remaining in the given sample after 10 days is |
| A. | 3.21 mg/l |
| B. | 3.45 mg/l |
| C. | 3.69 mg/l |
| D. | 3.92 mg/l |
| Answer» D. 3.92 mg/l | |
| 13. |
Water samples (X and Y) from two different sources were brought to the laboratory for the measurement of dissolved oxygen (DO) using modified Wrinklier method. Samples were transferred to 300 ml BOD bottles. 2 ml of MnSO |
| A. | Both the samples were devoid of DO |
| B. | Sample X was devoid of DO while sample Y contained DO |
| C. | Sample X contained DO while sample Y was devoid of DO |
| D. | Both the samples contained DO |
| Answer» D. Both the samples contained DO | |
| 14. |
A sample of domestic sewage is digested with silver sulphate, sulphuric acid, potassium dichromate and mercuric sulphate in chemical oxygen demand (COD) test. The digested sample is then titrated with standard ferrous ammonium sulphate (FAS) to determine the un-reacted amount of |
| A. | mercuric sulphate |
| B. | potassium dichromate |
| C. | silver sulphate |
| D. | sulphuric acid |
| Answer» C. silver sulphate | |
| 15. |
Column IColumn IIP. Grit chamber1. Zone settlingQ. Secondary settling tank2. Stoke s lawR. Activated sludge process3. AerobicS. Trickling filter4. Contact stabilisation |
| A. | P-1, Q-2, R-3, S-4 |
| B. | P-2, Q-1, R-3, S-4 |
| C. | P-1, Q-2, R-4, S-3 |
| D. | P-2, Q-1, R-4, S-3 |
| Answer» C. P-1, Q-2, R-4, S-3 | |
| 16. |
A portion of wastewater sample was subjected to standard BOD test (5 days, 20 C), yielding a value of 180 mg/1. The reaction rate constant (to the base 'e') at 20 C was taken as 0.08 per day. The reaction rate constant at other temperature may be estimated by k |
| A. | 4.9 C |
| B. | 24.9 C |
| C. | 31.7 C |
| D. | 35.0 C |
| Answer» E. | |
| 17. |
An analysis for determination of solids in the return sludge of activated sludge process was done as follows: (1) A crucible was dried to a constant mass of 62.485 g. (2) 75 ml of a well-mixed sample was taken in the crucible. (3) The crucible with the sample was dried to a constant mass of 65.020 g in a drying oven at 104 C. The crucible with the dried sample was placed in a muffle furnace at 600 C for an hour. After cooling, the mass of the crucible with residues was 63:145 g. The concentration of organic fraction of solids present in the return sludge sample is |
| A. | 8000 mg/I |
| B. | 25000 mg/1 |
| C. | 33800 mg/1 |
| D. | 42600 mg/1 |
| Answer» C. 33800 mg/1 | |
| 18. |
Setting test on a sample drawn from Aeration Tank liquor of ASP (MLSS = 2800 mg/I) was carried out with I litre sample. The test yielded a settled volume of 200 ml. The value of Sludge Volume Index shall be |
| A. | 14.0 |
| B. | 34.2 |
| C. | 71.4 |
| D. | 271 |
| Answer» D. 271 | |
| 19. |
A Trickling filter is designed to remove |
| A. | Settleable Solids |
| B. | Colloidal Solids |
| C. | Dissolved Organic Matter |
| D. | None of the above |
| Answer» D. None of the above | |
| 20. |
In a domestic wastewater sample, COD and BOD were measured. Generally which of the following statement is true for their relative magnitude? |
| A. | COD = BOD |
| B. | COD > BOD |
| C. | COD < BOD |
| D. | Nothing can be said |
| Answer» C. COD < BOD | |
| 21. |
A circular primary clarifier processes an average flow of 5005 m /d of municipal wastewater. The overflow rate is 35 m /d. The diameter of clarifier shall be |
| A. | 10.5 m |
| B. | 11.5 m |
| C. | 12.5 m |
| D. | 13.5 m |
| Answer» E. | |
| 22. |
The BOD removal efficiency, in percentage, during primary treatment, under normal conditions is about |
| A. | 65% |
| B. | 85% |
| C. | 30% |
| D. | Zero |
| Answer» D. Zero | |
| 23. |
In a certain situation, wastewater discharged into a river,mixes with the river water instantaneously and completely. Following is the data available: |
| A. | 5.3 mg/L |
| B. | 6.5 mg/L |
| C. | 7.6 mg/L |
| D. | 8.4 mg/L |
| Answer» D. 8.4 mg/L | |
| 24. |
Bulking sludge refers to having |
| A. | F/M < 0.3 /d |
| B. | 0.3/ d < F/M < 0.6/d |
| C. | F/ M = zero |
| D. | F/ M > 0.6/d |
| Answer» B. 0.3/ d < F/M < 0.6/d | |
| 25. |
The following data are given for a channel-type grit chamber of length 7.5 m. |
| A. | 0.01 mm |
| B. | 0.21 mm |
| C. | 1.92 mm |
| D. | 6.64 mm |
| Answer» C. 1.92 mm | |
| 26. |
A wastewater sample contains 10 |
| A. | 8.6 |
| B. | 8.4 |
| C. | 5.6 |
| D. | 5.4 |
| Answer» E. | |
| 27. |
The 5-day BOD of a waste water sample is obtained as 190 mg/l (with k = 0.01h |
| A. | 3800 |
| B. | 475 |
| C. | 271 |
| D. | 190 |
| Answer» D. 190 | |
| 28. |
50 g of CO |
| A. | 104 g/day |
| B. | 120 g/day |
| C. | 208 g/day |
| D. | 313 g/day |
| Answer» E. | |
| 29. |
A horizontal flow primary clarifier treats waste water in which 10%, 60% and 30% of particles have settling velocities of 0.1 mm/s, 0.2 mm/s and 1.0 mm/s respectively. What would be the total percentage of particles removed if clarifier operates at a surface overflow rate (SOR) of 43.2 m /m . d? |
| A. | 43% |
| B. | 56% |
| C. | 86% |
| D. | 100% |
| Answer» C. 86% | |
| 30. |
An aerobic reactor receives waste water at a flow rate of 500 m /d having a COD of 2000 mg/l. The effluent COD is 400 mg/l. Assuming that waste water contains 80% biodegradable waste, the daily volume of methane produced by the reactor is |
| A. | 0.224 m |
| B. | 0.280 m |
| C. | 224 m |
| D. | 280 m |
| Answer» C. 224 m | |
| 31. |
The design parameter for flocculation is given by a dimensionless number Gt, where G is the velocity gradient and t is the detention time. Values of Gt ranging from 104 to 105 are commonly used, with t ranging from 10 to 30 mm. The most preferred combination of G and t to produce smaller and denser focus is |
| A. | large G values with short t |
| B. | large G values with long t |
| C. | small G values with long t |
| D. | small G values with short t |
| Answer» B. large G values with long t | |
| 32. |
Two biodegradable components of municipal solid waste are |
| A. | plastics and wood |
| B. | cardboard and glass |
| C. | leather and tin cans |
| D. | food wastes and garden trimmings |
| Answer» E. | |
| 33. |
From amongst the following sewage treatment options, largest land and requirements for a given |
| A. | trickling filter |
| B. | anaerobic pond |
| C. | oxidation ditch |
| D. | oxidation pond |
| Answer» E. | |
| 34. |
Which of the following sewage treatment methods has inherent problem of odour, pending, and fly nuisance? |
| A. | UASB system |
| B. | Activated sludge process |
| C. | Trickling filters |
| D. | Stabilization ponds |
| Answer» D. Stabilization ponds | |
| 35. |
If the BOD |
| A. | 3.21 mg/l |
| B. | 3.45 mg/l |
| C. | 3.69 mg/l |
| D. | 3.92 mg/l |
| Answer» D. 3.92 mg/l | |
| 36. |
A wastewater sample has an initial BOD of 222 mg/L. The first order BOD decay coefficient is 0.4/day. The BOD consumed (in mg/L) in 5 days is |
| A. | 150 |
| B. | 192 |
| C. | 30 |
| D. | 50 |
| Answer» C. 30 | |
| 37. |
What is the average time for which the biomass stays in the system? |
| A. | 5 h |
| B. | 8 h |
| C. | 2 days |
| D. | 8 days |
| Answer» E. | |
| 38. |
What is the hydraulic retention time of the waste water in aeration tank? |
| A. | 0.2 h |
| B. | 4.8 h |
| C. | 10 h |
| D. | 24 h |
| Answer» C. 10 h | |
| 39. |
45. A landfill is to be designed to serve a population of 200000 for a period of 25 years. The solid waste (SW) generation is 2 kg/person/day. The density of the uncompacted SW is 100 kg/m and a compaction ratio of 4 is suggested. The ratio of compacted fill (i.e, SW+ cover) to compacted SW is 1.5. The landfill volume (in million m ) required is __________. |
| A. | 24 million m |
| B. | 21 million m |
| C. | 21.9 million m |
| D. | 22 million m |
| Answer» D. 22 million m | |
| 40. |
The food-to-biomass (F/M) ratio (in kg BOD per kg biomass per day) for the aeration tank is |
| A. | 0.015 |
| B. | 0.210 |
| C. | 0.225 |
| D. | 0.240 |
| Answer» D. 0.240 | |
| 41. |
The mass (in kg/day) of solids wasted from the system is |
| A. | 24000 |
| B. | 1000 |
| C. | 800 |
| D. | 33 |
| Answer» D. 33 | |
| 42. |
What is the solids content (by weight) of the thickened sludge? |
| A. | 3.96% |
| B. | 4.00% |
| C. | 4.04% |
| D. | 4.10% |
| Answer» B. 4.00% | |
| 43. |
What is the density of the sludge removed from the aeration tank? |
| A. | 990 kg/m |
| B. | 1000 kg/m |
| C. | 1011 kg/m |
| D. | 1022 kg/m |
| Answer» D. 1022 kg/m | |