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प्रश्न
List the events that reduce the Biochemical Oxygen Demand (BOD) of a primary effluent during sewage treatment.
उत्तर १
Primary effluent is taken in large aeration tanks where it is continuously agitated mechanically and air is pumped into it. This allows the growth of a large number of aerobic bacteria and fungi (flocs). Growing flocs start consuming organic matter present in the effluent. This decreases the biological oxygen demand (BOD) of the effluent. Sewage is treated till the BOD is significantly reduced.
उत्तर २
Events that lead to biogas production from wastewater with reduced BOD are:
- Wastewater is sent into a settling tank for sedimentation once its BOD has decreased considerably.
- Most of the sedimented material, activated sludge (bacterial floes), is poured into huge anaerobic sludge digesters from the settling tank. At the same time, a tiny portion is fed back into the aeration tank to act as an inoculum.
- These tanks produce biogas, a blend of methane, hydrogen sulphide, and carbon dioxide resulting from bacteria and fungi anaerobically digesting the sludge. Because biogas is combustible, it can be used as an energy source.
संबंधित प्रश्न
With the help of a flow-chart exhibit the events of eutrophication.
Write critical notes on Eutrophication
Write critical notes Groundwater depletion and ways for its replenishment
Plenty of algal bloom is observed in a pond in your locality.
(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure.
What is Biochemical Oxygen Demand significance in an aquatic ecosystem?
Answer the following question:
While on a visit to a pond in the city-neighborhood, the visitors were delighted to find a large expanse of water covered with colorful algal mass.
As a student of biology, do you agree with their delight? Give reasons in support of your answer.
The expanded form of DDT is ______.
Match the items in column I and column II and choose the correct option:
| Column I | Column II |
| A. UV | i. Biomagnification |
| B. Biodegradable Organic matter | ii. Eutrophication |
| C. DDT | iii. Snow blindness |
| D. Phosphates | iv. BOD |
The correct match is:
Match the following and choose the correct option.
| Column I | Column II | |
| A. | Environment Protection Act | i. 1974 |
| B. | Air Prevention & Control of Pollution Act | ii. 1987 |
| C. | Water Act | iii. 1986 |
| D. | Amendment of Air Act to include noise as an air pollutant | iv. 1981 |
The correct matches is;
Match the following and choose the correct option.
| Column I | Column II | ||
| A. | Environment Protection Act | i. | 1974 |
| B. | Air Prevention & Control of Pollution Act | ii. | 1987 |
| C. | Water Act | iii. | 1986 |
| D. | Amendment of Air Act to include noise as an air pollutant | iv. | 1981 |
The correct matches is;
