Tag: wastewater story

Questions Related to wastewater story

Solids which remain dissolved in sewage is known as

biology wastewater story origin of waste products waste generation waste and its types

  1. Settaleable Solids

  2. Colloidal Solids

  3. Suspended solids

  4. Dissolved Solids

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Correct Option: D

Which is the most common source of eutrophication?

biology wastewater story origin of waste products waste generation waste and its types

  1. Industrial effluent

  2. Textile effluent

  3. Sewage water

  4. Both B and C

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Correct Option: C
Explanation:

Contamination of water reservoir with sewage water leads to increased level of phosphate in water. Due to increased level of phosphate algae starts growing on it. This decreases the dissolved oxygen level in water thus all the aquatic lives can't survive and leads to mortality. This is called eutrophication.

Find the odd one out:

biology wastewater story origin of waste products waste generation waste and its types

  1. Electrodialysis

  2. Ion exchange chromatography

  3. Reverse osmosis

  4. Electrostatic precipitator

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Correct Option: D
Explanation:

Water gets contaminated due to industrial effluents, sewage water, radio biological pollutants etc. These can be purified by several techniques like electodialysis, Ion exchange chromatography, Reverse osmosis etc.

I. Sewage water treatment plants are setup for controlling water pollution.
II. BOD level increases after sewage treatment.

biology wastewater story origin of waste products waste generation waste and its types

  1. I and II are true

  2. I and II are false

  3. I is true and II is false

  4. I is false and II is true

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Correct Option: C
Explanation:

Sewage treatment constitutes of 3 stages primary, secondary and tertiary. BOD i.e biological oxygen demand decreases during secondary stage. This makes water permissible to let into natural water resources.

______ is the most dangerous soil contaminant.

biology wastewater story origin of waste products waste generation waste and its types

  1. Organic waste

  2. Radioactive waste

  3. Chemical fertilizer

  4. Both A and B

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Correct Option: B
Explanation:

Radioactive substances resulting from explosions of nuclear testing laboratories and industries giving rise to nuclear dust radioactive wastes, penetrate the soil and accumulate giving rise to land/soil pollution.

Wastewater released from home, industries, hospitals is called as

biology wastewater story origin of waste products waste generation waste and its types

  1. Sludge

  2. Potable water

  3. Freshwater

  4. Sewage

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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. 
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  1. (i) and (ii)

  2. (ii) and (iv)

  3. only (iv)

  4. (ii) and (iii)

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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)

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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.