MCQOPTIONS
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MCQOPTIONS
This section includes 16 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
If initial Dissolved Oxygen (DO) and final DO after 5 days incubation at 20° C in 1·0% dilution sample are 5·0 mg/L and 4·0 mg/L respectively, what is 5-day BOD of the same sample in mg/L |
| A. | 50 |
| B. | 100 |
| C. | 150 |
| D. | 200 |
| Answer» C. 150 | |
| 2. |
For disinfection of water with ultraviolet rays, the turbidity should not exceed: |
| A. | 15 mg/l |
| B. | 25 mg/l |
| C. | 50 mg/l |
| D. | 75 mg/l |
| E. | 85 mg/l |
| Answer» B. 25 mg/l | |
| 3. |
A solution has 100 mg/L NH3 and 100 mg/L glucose. Calculate theoretical oxygen demand of this solution? |
| A. | 483.14 mg/L |
| B. | 106.67 mg/L |
| C. | 400 mg/L |
| D. | 350 mg/L |
| Answer» B. 106.67 mg/L | |
| 4. |
For a waste, the 5-day BOD at 20° C is 180 mg/l. For the same waste, the 5 - day BOD at 32° C will be |
| A. | Equal to 180 mg/ |
| B. | Less than 180 mg/l |
| C. | More than 180 mg/l |
| D. | Negligible as the bacteria cannot survive at that temperature |
| E. | zero |
| Answer» D. Negligible as the bacteria cannot survive at that temperature | |
| 5. |
An anaerobic reactor, operated at 35°C, treats wastewater with a flow of 200 m3/d and a biological soluble COD (bsCOD) concentration of 500 g/m3. At 90% bsCOD removal and a biomass synthesis yield of 0.04 g Volatile Suspended Solids/g bsCOD used, calculate amount of COD consumed (in kg/d)? |
| A. | 90 |
| B. | 100 |
| C. | 50 |
| D. | 110 |
| Answer» B. 100 | |
| 6. |
Assertion A: The determination of pH value of sewerage is important.Reason R: The efficiency of certain treatment method depends upon the availability of the pH value.Which of the following is correct? |
| A. | A is true but R is false. |
| B. | Both A and R are true, and R is the correct explanation of A |
| C. | A is false but R is true. |
| D. | Both A and R are true, but R is not a correct explanation of A |
| Answer» C. A is false but R is true. | |
| 7. |
An effluent of a flow rate of 2670 m3/day from a sewage treatment plant is to be disinfected. The laboratory data of disinfection studies with a chlorine dosage of 15 mg/litre yield the model Nt = No e(-0.145t) where Nt = Number of organisms remained at any time t (in 'min')and No = Number of initial organisms at time t = 0. The volume of disinfection unit (in m3) required to achieve a 98 % kill of micro-organisms is ______________ |
| A. | 35 |
| B. | 50 |
| C. | 45 |
| D. | 85 |
| Answer» C. 45 | |
| 8. |
If 2% solution of a sewage sample is incubated for 5 days at 20 degrees and depletion of oxygen was found to be 5 ppm, BOD of the sewage is |
| A. | 1000 ppm |
| B. | 300 ppm |
| C. | 250 ppm |
| D. | 10 ppm |
| Answer» D. 10 ppm | |
| 9. |
In chemical Oxygen Demand test, the digested sample is titrated with standard Ferrous Ammonium Sulphate to determine the unreacted amount of |
| A. | Mercuric sulphate |
| B. | Postassium dichromate |
| C. | Silver sulphate |
| D. | Sulphuric acid |
| Answer» C. Silver sulphate | |
| 10. |
Presence of nitrogen in a wastewater sample is due to the decomposition of |
| A. | Carbohydrates |
| B. | Proteins |
| C. | Fats |
| D. | Vitamins |
| Answer» C. Fats | |
| 11. |
Consider the following statements:1. Ammonia nitrogen is a measure of nitrogen present as ammonium hydroxide and ammonium salts. It will progressively decrease as sewage gets treated.2. Organic nitrogen is the total nitrogenous matter in sewages excepting that present as ammonia nitrogen, nitrites and nitrates. It becomes ammonia in anaerobic decomposition and nitrites or nitrates in aerobic decomposition.Which of the above statements is/are correct? |
| A. | 1 only |
| B. | Both 1 and 2 |
| C. | 2 only |
| D. | Neither 1 nor 2 |
| Answer» C. 2 only | |
| 12. |
For an industrial wastewater sample, which of the following conditions satisfy? |
| A. | BOD > COD |
| B. | BOD = TOD |
| C. | BOD = COD |
| D. | BOD < COD |
| Answer» E. | |
| 13. |
Ammonia nitrogen is present in a given wastewater sample as the ammonium ion (NH4+) and ammonia (NH3). If pH is the only deciding factor for the proportion of these two constituents, which of the following is a correct statement? |
| A. | At pH 7.0, NH4+ will be predominant. |
| B. | At pH below 9.25, NH3 will be predominant. |
| C. | At pH below 7.0 NH4+ and NH3 will be found in equal measures |
| D. | At pH 9.25, only NH4+ will be present |
| Answer» B. At pH below 9.25, NH3 will be predominant. | |
| 14. |
Order 4 solutions in decreasing order of their BOD values? |
| A. | Industrial water > river water > tap water > bottled water |
| B. | Tap water > bottled water > river water > industrial water |
| C. | Bottled water > tap water > river water > industrial water |
| D. | River water > industrial water > tap water > bottled water |
| Answer» B. Tap water > bottled water > river water > industrial water | |
| 15. |
A drain carrying 5 m3/s of wastewater with its BOD of 100 mg/l joins a steam carrying 50 m3/s flow with its BOD of 5 mg/l. What will be the value of the BOD of the combined flow after complete mixing? |
| A. | 3.6 mg/l |
| B. | 13.6 mg/l |
| C. | 33.6 mg/l |
| D. | 53.6 mg/l |
| Answer» C. 33.6 mg/l | |
| 16. |
Generally, the period chosen for a standard B. O. D. test is |
| A. | 1 day |
| B. | 5 days |
| C. | 8 days |
| D. | 20 days |
| Answer» C. 8 days | |