Q. No.What would happen if oxygen availability to activated sludge flocs is reduced?
| 1. | It will slow down the rate of degradation of organic matter. |
| 2. | The center of flocs will become anoxic, which would cause death of bacteria and eventually breakage of flocs. |
| 3. | Floes would increase in size as anaerobic bacteria would grow around floes. |
| 4. | Protozoa would grow in large numbers. |
The amount of oxygen required by the microbes in the decomposition of organic matter is called:
1. Chemical oxygen demand
2. Biochemical oxygen demand
3. Total oxygen demand
4. Dissolve oxygen
The primary treatment of sewage involves:
1. Digestion
2. Decomposition
3. Sedimentation and filtration
4. None of these
Given below are three statements (A-B) each with one or more blanks. Select the option which correctly fills the blanks in the statements Statements:
| A. | Bioactive molecule, ________ is used as immunosuppressive agent in organ transplant patients, It is produced by the fungus ________. |
| B. | Primary treatment of sewage involves physical removal of small and large particles through ________. |
1. A - Antibiotic, Trichoderma polysporum; B - filtration and sedimentation
2. A - Cyclosporin A, Trichoderma polysporum; B - filtration and sedimentation
3. A - Cyclosporin A, Trichoderma polysporum; B - Centrifugation and sedimentation
4. A - Antibiotic, Trichoderma polysporum; B - Centrifugation and sedimentation
Filteration and sedimentation are the components of -
1. Primary treatment
2. Secondary treatment
3. Tertiary treatment
4. Quaternary treatment
What gases are produced in anaerobic sludge digesters?
1. Methane and CO2 only
2. Methane, Hydrogen sulphide and CO2
3. Methane, hydrogen sulphide and O2
4. Hydrogen sulphide and CO2
Secondary sewage treatment is mainly a
(1) mechanical process
(2) chemical process
(3) biological process
(4) physical process
During secondary treatment, major part of activated sludge is pumped into tanks called
1. Aerobic sludge digesters.
2. Anaerobic sludge digesters.
3. Primary sludge digesters.
4. Settling tanks.
High value of BOD (Biochemical Oxygen Demand) indicates that
1. Water is pure
2. water is highly polluted
3. water is less polluted
4. Consumption of organic matter in the water is higher by the microbes
Microorganisms are used during which stage of the purification of the sewage water?
(1) Primary treatment
(2) Secondary treatment
(3) None of the above
(4) Both (1) and (2)
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