Q. No.High value of BOD (Biochemical Oxygen Demand) indicates that:-
(1) water is pure
(2) water have heavy metal
(3) water is less polluted
(4) consumption of organic matter in the water is higher by the microbes
What gases are produced in anaerobic sludge digesters?
1. Methane and CO2.
2. Methane, Hydrogen sulphide and CO2.
3. Methane, Hydrogen sulphide and CO.
4. Hydrogen sulphide and CO2.
Masses of bacteria associated with fungal filaments to form mesh like structures is called as
1. Flocs
2. Primary sludge
3. Sewage
4. Biofertiliser
| 1. | The amount of oxygen required by aerobic microorganisms to decompose organic matter in water. |
| 2. | The oxygen content available in the air. |
| 3. | The efficiency of oxygen production by photosynthesis in plants. |
| 4. | The amount of carbon dioxide absorbed by water bodies. |
Measuring Biochemical Oxygen Demand (BOD) is a method used for
(1) Measuring the activity of Saccharomyces cervisae in producing curd on a commercial scale
(2) Working out the efficiency of R.B.Cs. about their capacity to carry oxygen
(3) Estimating the amount of organic matter in sewage water
(4) Working out the efficiency of oil driven automobile engines
During sewage treatment a small part of the activated sludge is pumped back into the aeration tank to
1 Serve as inoculum
2 Serve as nutrient medium
3 Produce biogas
4 Produce CO
| 1. | Eutrophication occurs: algal bloom, oxygen depletion, fish death |
| 2. | Water quality improves |
| 3. | Water becomes potable |
| 4. | Aquatic life flourishes |
The growth of Flocs is facilitated by
(1) Constant agitation mechanically
(2) Air is pumped
(3) Both A and B
(4) Filaments of algae
| 1. | To decompose heavy metals in the sewage. |
| 2. | To act as an inoculum, promoting the growth of aerobic microbes for further BOD reduction. |
| 3. | To ensure that harmful gases are removed from the sewage before discharge. |
| 4. | To increase the oxygen concentration in the effluent. |
1. Primary
2. Secondary
3. Tertiary
4. Quaternary
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