Environmental Studies · Chemistry

Water and Wastewater Treatment

1,423 Questions

This topic deals with water purification, wastewater treatment methods, and industrial effluent management. It includes questions on filtration, disinfection, and water hardness removal. These concepts are tested in environmental science and engineering exams.

Water purificationWastewater treatmentBioremediation strategiesWater hardness removalIndustrial effluent management

Water and Wastewater Treatment Questions

Multiple choice 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

Primary treatment of sewage is also known as

  1. Physical treatment

  2. Chemical treatment

  3. Biological treatment

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Primary treatment basically involves physical removal of particles large and small from the sewage through the filtration and sedimentation. These are removed in stages initially floating debris is removed by sequential filtration.

Multiple choice 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

Chlorine treatment 

  1. Removes all the air pollutants

  2. Disinfects water by killing germs

  3. Removes hardness of water

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorine is a strong oxidizing agent commonly used in water treatment to disinfect water by killing pathogenic microorganisms, such as bacteria and viruses.

Multiple choice 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

In our municipal drinking water purification and supply scheme chlorine is added to water because 

  1. Chlorine gives sweat taste to water.

  2. Chlorine kills harmful bacteria.

  3. Chlorine cools water.

  4. Chlorinated water is now a days fashionable.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorine is used for municipal drinking water purification. It is a strong oxidizing agent, hence it kills pathogenic bacteria by oxidation of organic molecules. Chlorine on hydrolysis produces hypochlorous acid that penetrates the pathogenic surface and disintegrates lipids in its cell wall. It also reacts with intracellular enzymes and proteins and deactivates them. Hence chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery and typhoid. Thus the correct answer is option B.

Multiple choice 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

In water treatment plants, the gas used to kill germs is

  1. Nitrogen

  2. Chlorine

  3. Argon

  4. Krypton
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorine is widely used in municipal water treatment plants as a disinfectant to eliminate harmful germs and ensure the water is safe for consumption.

Multiple choice 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

Secondary sewage treatment is mainly a

  1. Biological process

  2. Physical process

  3. Mechanical process

  4. Chemical process
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sewage pollution can be prevented by treating sewage before passing into water course in sewage or effluent treatment plant.

The sewage treatment involves -
Primary treatment, secondary treatment and tertiary treatment. 
Primary treatment consists of shredding, churning, floatation, screening and sedimentation. 
In Secondary treatment the organic matter is decomposed by microorganisms and through sewage fungus by passing through water hyacinth pond, trickling filter method or activated sludge method. Aeration helps in oxidation of sludge. 
Tertiary treatment is a physico-chemical treatment for removing turbidity and dissolved substances.
So, the correct answer is 'Biological process'

Multiple choice 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

Which of the following filter is used for filtration of wastewater?

  1. Sand filter

  2. Grit filter

  3. Cloth

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In wastewater treatment, both sand filters and grit chambers (or grit filters) are standard components used to remove solid particles and debris from the influent.

Multiple choice 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

When water is passed through filter beds of sand and gravel to remove smaller particles of dust is called

  1. oxygenation

  2. chlorination

  3. sedimentation

  4. filtration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Filtration is the physical process of passing water through layers of sand and gravel to remove suspended solids and smaller particulate matter.

Multiple choice 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

Which of the following chemical is used to disinfect water

  1. Chlorine

  2. washing soda

  3. coal

  4. petrol
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chlorine is the most common chemical used for water disinfection in treatment plants due to its effectiveness in killing pathogenic bacteria.

Multiple choice 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

Which of the following need to be done before chemical treatment and biological treatment?

  1. Screening only

  2. Filteration only

  3. Boiling of water

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Screening and filtration are preliminary physical treatment steps used to remove large debris and suspended solids before the water undergoes more intensive chemical or biological treatment.

Multiple choice 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

In a filtration plant, water is filtered using layers of 

  1. sand

  2. oil

  3. sand and clay

  4. sand, fine gravel and medium gravel
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A standard slow or rapid sand filter in a water treatment plant uses graded layers of sand and gravel to effectively trap and remove impurities from the water.

Multiple choice 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

Water before treatment contains

  1. Nitrogen

  2. Oxygen

  3. Phosphorus

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Untreated water often contains nutrients like nitrogen and phosphorus, which are common pollutants from agricultural runoff and sewage that can lead to eutrophication.

Multiple choice 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

Activated sludge acts as inoculum in:

  1. Primary treatment

  2. Secondary treatment

  3. Tertiary treatment

  4. More that one option
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A.Primary treatment – Removal of large and small particles from sewage through sequential filtration and sedimentation is called primary treatment.

B.Secondary treatment – It involves biological process of microbial degradation of organic matter contained in sewage effluent. In this activated sludge acts an inoculum.

C.Tertiary treatment – There is no occurrence of tertiary sewage treatment.

So, the correct option is ‘Secondary treatment’.    

Multiple choice 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

Which process involved in waste water convertion into drinkable water?

  1. Precipitation

  2. Condensation

  3. Filtration

  4. Nutrient cycle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Filtration is a key physical process in wastewater treatment used to remove suspended solids and impurities. While other processes like sedimentation or chlorination are also used, filtration is a fundamental step in cleaning water.

Multiple choice 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

What involved in wastewater final treatment?

  1. BOD

  2. Chlorination

  3. Sedimentation

  4. All of above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorination is a common final treatment process used to disinfect wastewater by killing pathogens and bacteria before the water is discharged or reused. While BOD and sedimentation are part of the treatment, they occur in earlier stages.