During which stage of the sewage treatment are the microbes used?
1. | Primary | 2. | Secondary |
3. | Tertiary | 4. | Quaternary |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
Statement I: | Primary treatment removes material that will either float or readily settle out by gravity. |
Statement II: | Secondary treatment removes the soluble organic matter that escapes primary treatment. |
1. | Statement I is correct but Statement II is incorrect |
2. | Statement I is incorrect but Statement II is correct |
3. | Statement I is correct and Statement II is correct |
4. | Statement I is incorrect and Statement II is incorrect |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
Rivers may be considered severely polluted when BOD values exceed:
1. | 1 mg/L | 2. | 2 mg/L |
3. | 4 mg/L | 4. | 8 mg/L |
The large holes in ‘Swiss Cheese’ are due to the production of a large amount of carbon dioxide by:
1. Propionibacterium shermanii
2. Methylophilus methylotrophus
3. Penicillium roqueforti
4. Penicillium camemberti
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
What is true regarding the activated sludge generated during the secondary treatment of sewage water?
I: | It is made up of aerobic bacteria that sediment down |
II: | A large part of the activated sludge is pumped back into the aeration tank to serve as the inoculum. |
III: | A minor part of the sludge is pumped into large tanks called anaerobic sludge digesters. |
1. | Only I | 2. | Only II and III |
3. | Only I and III | 4. | I, II and III |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
Consider the two statements:
I: | Indirectly, BOD is a measure of the organic matter present in the water. |
II: | The greater the BOD of wastewater, the more its polluting potential. |
1. Both I and II are correct
2. Only I is correct
3. Only II is correct
4. Both I and II are incorrect
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.