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 the death of bacteria and eventually breakage of flocs. |
3. | Flocs would increase in size as anaerobic bacteria would grow around flocs. |
4. | Protozoa would grow in large numbers. |
During which stage of the sewage treatment are the microbes used?
1. | Primary | 2. | Secondary |
3. | Tertiary | 4. | Quaternary |
Biogas is a mixture of:
1. | Methane, Carbon dioxide, and Hydrogen sulfide |
2. | Methane, Carbon dioxide, and Ammonia |
3. | Methane, Ammonia, and Hydrogen sulfide |
4. | Ammonia, Carbon dioxide, and Hydrogen sulfide |
‘Toddy’, a traditional drink of some parts in southern India, is made by fermenting sap from:
1. | Soyabean | 2. | Bamboo shoots |
3. | Palms | 4. | Sugarcane |
The ‘Roquefort cheese’ is ripened by:
1. | A fungus | 2. | A bacterium |
3. | An algae | 4. | Lichens |
With reference to human beings, antibiotics are actually:
1. | Anti life | 2. | Pro-life |
3. | Irrelevant to life | 4. | Defining life |
Which of the following human diseases cannot be treated by antibiotics?
1. | Plague | 2. | Diphtheria |
3. | Leprosy | 4. | Mumps |
In the secondary treatment or biological treatment of sewage water, the primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and the air is pumped into it. This allows:
1. vigorous growth of useful aerobic microbes into flocs
2. the decrease in the number of aerobes in the water
3. rapid increase in the count of methanogens
4. a dramatic decrease in the anaerobic methanogens
The part of the complex stomach of ruminants that has methanogens present is the:
1. | Omassum | 2. | Abomasum |
3. | Rumen | 4. | Reticulum |
The major problem with the use of chemicals to control plant diseases and pests is:
1. High cost
2. Ineffectivity against most pathogens
3. Difficulty in production
4. Non-specific nature