Tag: wastewater treatment - need and methods

Questions Related to wastewater treatment - need and methods

Pollution can be checked through

zoology waste water story sewage treatment wastewater treatment - need and methods wastewater story

  1. Reducing discharge of waste

  2. Increasing industrial development

  3. Throwing wastes in open spaces

  4. All of the above

Show answer
Correct Option: A
Explanation:

With development and advancement, industries, factories and other establishments have become necessary reality, the pollution can be mitigated by adopting measures as to the treatment of waste at generating source before it is exposed in the environment, reducing the generation of waste material and recycling the waste over and again wherever possible. Preventing the discharge that contaminates the fresh drinking water source.

Hence, the correct answer is 'Reducing discharge of waste'.

22$^{nd}$ March is celebrated as

zoology waste water story sewage treatment wastewater treatment - need and methods wastewater story

  1. World environment day

  2. World water day

  3. World AIDS day

  4. None of the above

Show answer
Correct Option: B

Which of the following increases the scarcity of freshwater?

zoology waste water story sewage treatment wastewater treatment - need and methods wastewater story

  1. Pollution

  2. Population growth

  3. Industrial development

  4. All of the above

Show answer
Correct Option: D

Study the given differences between primary sludge and activated sludge and select the incorrect ones. 

Primary Sludge Activated sludge
(i) It is sludge formed during primary sewage treatment. It is sludge formed during secondary sewage treatment.
(ii) It possesses flocs of decomposer microbes.  It does not possess flocs of decomposer microbes.
(iii) It does not require aeration.  Formation of activated sludge requires aeration.
(iv) A lot of decomposition occurs during formation of primary sludge.  Very little decomposition occurs during formation of activated sludge. 
biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. (i) and (ii)

  2. (ii) and (iv)

  3. only (iv)

  4. (ii) and (iii)

Show answer
Correct Option: C
Explanation:

The primar sludge is formed during primary sewage treatment, while activated sludge is a sludge during secondary sewage treatment, little decomposition occurs during primary sludge formation, while lot of decomposition occurs during activated sludge.

So, the correct option is 'only (iv)'.

Select the correct statement regarding activated sludge formed during secondary sewage treatment.

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. A small part of it is rapidly pumped back from sedimentation to aeration tank.

  2. It absorbs pathogenic bacteria present in waste water while sinking to the bottom of the settling tank.

  3. A major part of it Is anaerobically digested.

  4. Both (a) and (c)

Show answer
Correct Option: D
Explanation:
A small part of activated sludge is pumped back  from sedimentation to aeration tank. But it dos not absorb pathogenic bacteria.
A major part of activated sludge is anaerobically digested by methanogens.
So, the correct option is 'Both (a) and (c)'

____________  is the first step of sewage treatment.

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. Precipitation

  2. Chlorination

  3. Sedimentation

  4. Aeration

Show answer
Correct Option: C
Explanation:

Primary treatment in sewage treatment involves physical removal of particles (large and small) from the sewage through filtration and sedimentation. Initially floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation. 

Study the following statements and select the incorrect ones.


(i) Physical removal of large and small particles through filtration and sedimentation is called primary sewage treatment.
(ii) Secondary sewage treatment is mainly a mechanical process.
(iii) Activated sludge sediment in a sewage treatment plant is a rich source of aerobic bacteria.
(iv) Biogas, commonly called as gobar gas, is pure methane.

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. A-(iii), B-(i), C-(iv), D-(ii)

  2. A-(i), B-(iii), C-(iv), D-(ii)

  3. A-(iii), B-(ii), C-(iv), D-(i)

  4. A-(iii), B-(i), C-(ii), D-(iv)

Show answer
Correct Option: B
Explanation:

Secondary treatment is also called biological treatment or microbial degradation. It is mainly a biological process. Biogas is a mixture of gases, containing predominantly methane (50-70%), $CO _2$ (30-40%) and traces of hydrogen, $H _2S$ and nitrogen.

During the primary treatment of sewage, solid particles that settle down are called

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. Flocs

  2. Primary sludge

  3. Activated sludge

  4. Anaerobic sludge

Show answer
Correct Option: B
Explanation:

Primary or physical treatment is the process of removal of small and large, floating and suspended solids from sewage through two processes of filtration and sedimentation. First floating and suspended matter is removed through sequential filtration with progressively smaller pore filters. The sediment is called primary sludge while the supernatant is called effluent. The primary sludge traps a lot of microbes and debris. It is subjected to composting, land fill or anaerobic digestion to produce biogas and manure. 

So, the correct answer is 'Primary sludge'.

Which of the following could be a substance found in waste water that floats on the top and is removed in the Primary Treatment of water?

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. Oil and grease

  2. Human faeces

  3. Hair

  4. Plastic

Show answer
Correct Option: A
Explanation:

  • Primary treatment removes material that will either float or readily settle out by gravity. It includes the physical processes of screening, comminution, grit removal, and sedimentation.
  • Human faeces, hair and plastic settle down at bottom while Oil and grease are immiscible in water and are found floating on top.
So, the correct option is 'Oil and grease'.

Read the following statements & about waste water treatment how many of them are correct

(i) In Primary treatment First, floating debris of waste is  removed by sequence filters
(ii) The Soil and small pebbles are removed by sedimentation in settling tanks
(iii)The sediment is called primary sludge and supernatant is effluent.
(iv) The Sludge is taken for Secondary treatment.
(v) Lower the B.O.D., higher Is water pollution.
(vi)When DDT enters the food chain then they reach water and are easily degradable.
(vii)Discharge of sewage water into river water will decrease its B.O.D.
(viii) Chlorine is added to disinfect drinking water

biology wastewater story basics of water pollution sewage treatment wastewater treatment - need and methods personal and public cleanliness who will do this? water borne disease hygiene - a key to healthy life

  1. (i), (ii), (iii), (iv)

  2. (i), (ii), (iii), (vii)

  3. (i), (ii) (iv), (v)

  4. (i),(iv),(v), (viii)

Show answer
Correct Option: A
Explanation:
  • Treatment of wastewater is done by the heterotrophic microbes naturally present in the sewage. 
  • This treatment is carried out in two stages: 
  1.  Primary treatment: These treatment steps basically involve physical removal of particles large and small from the sewage through filtration and sedimentation. Initially, floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation. All solids that settle form the primary sludge and the supernatant forms the effluent. The effluent from the primary settling tank is taken for secondary treatment.
  2. Secondary treatment or Biological treatment: The primary effluent is passed into large aeration tanks. 
  • Hence, (i) In Primary treatment First, floating debris of waste is removed by sequence filters (ii) The Soil and small pebbles are removed by sedimentation in settling tanks (iii)The sediment is called primary sludge and supernatant is affluent. (iv) The Sludge is taken for Secondary treatment following statements & about wastewater treatment are correct. 

  • So, the correct answer is '(i), (ii), (iii), (iv)'.