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

Which of the following statements about control of particular pollution is/are not correct?

  1. Gravity settling chamber removes larger particles from the air.
  2. In electrostatic precipitator, the particulates acquire positive change, they are then attracted by the negative electrodes and removed.
  3. Cyclone collector removes fine particles in the diameter range 5-20 micron.
  4. Wet scrubbers are used to wash away all types of particulates.

  1. 1 and 2

  2. 1 and 3

  3. 2 only

  4. 4 only

  5. 2 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because particulates acquire negative charge and are attracted by the positive electrodes.

Multiple choice

Which of the following is not a step involved in the primary treatment stage of the sewage? a. Passage of liquid through sedimentation tanks. b. Treatment of liquid with chlorine to kill disease causing organisms. c. Passage of liquid through a tank to remove dirt and sand.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Treatment of liquid with chlorine to kill disease causing organisms, is not a step involved in the primary treatment stage of sewage. The liquid is treated with chlorine at the last stage, which is called tertiary treatment.

Multiple choice

Which of the following statements is/are false?

a. Treating the sludge with anaerobic bacteria is a step in the secondary treatment of sewage. b. The biogas that is produced at the end of the second stage in the treatment of sewage is methane. c. During the third stage of treatment of sewage, disinfection of water is done by using calcium.

  1. Only a

  2. Only a and b

  3. Only b

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

During the third stage of treatment of sewage, disinfection of water is done by using calcium, is a false statement. Thus, it is a correct option. During the third stage of treatment of sewage, disinfection of water is done by using ozone or chlorine.

Multiple choice

Which of the following is the full form of WWTP?

  1. World Waste Treatment Plant

  2. Waste Water Treatment Plant

  3. World Workers Talent Programme

  4. Water World Treatment Plant

  5. World Wide Transport Programme
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option. Waste Water Treatment Plant is the full form of WWTP.

Multiple choice

Which of the following methods can be effective for controlling pollution?

  1. Sewage treatment

  2. Control of soil pollution

  3. Installation of tall chimneys with filters

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

Sewage treatment, soil pollution control, and the use of filters in chimneys are all standard and effective methods for mitigating various types of environmental pollution.

Multiple choice

'Chlorination' is

  1. a process of converting chlorides into chlorine

  2. adding small amount of chlorine to contaminated water

  3. a chemical reaction in which chlorine is formed

  4. the formation of a salt containing chlorine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chlorination is the process of adding chlorine or chlorine compounds to water to kill bacteria and other pathogens, making it safe for drinking.

Multiple choice

Pure water can be obtained from sea water by the process of

  1. filtration

  2. distillation

  3. evaporation

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

Distillation is the process of heating sea water to create steam, which is then condensed to form pure water, leaving salts behind. Filtration and evaporation are not sufficient to remove dissolved salts effectively.

Multiple choice

The working principle of a washing machine is

  1. dialysis

  2. centrifugation

  3. diffusion

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

A washing machine uses the principle of centrifugation, where rapid rotation forces water and dirt out of the fabric through the holes in the drum.

Multiple choice

Which of the following statements about control of particular pollution is/are not correct?

  1. Gravity settling chamber removes larger particles from the air.

  2. Cyclone collector removes fine particles in the diameter range 5-20 micron.

  3. Wet scrubbers are used to wash away all types of particulates.

  4. Both 2 and 3

  5. In electrostatic precipitator, the particulates are made acquire positive change, which are then attracted by the negative electrode and removed.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because particulates acquire negative charge and are attracted by the positive electrode.

Multiple choice

In a waste water treatment plant, when biological processes are used to purify water, it is called ___.

  1. preliminary treatment

  2. primary treatment

  3. secondary treatment

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

Secondary treatment is called the activated sludge process. Air pumped into large aeration tanks mixes the waste water and sludge, that stimulates the growth of oxygen-using bacteria and other tiny organisms, that are naturally present in the sewage. These beneficial microorganisms consume most of the remaining organic materials, that are polluting the water and this produces heavier particles, that will settle later in the treatment process.

Multiple choice

Which of the following methods is not used to control water pollution?

  1. Lagoon system

  2. Use of clarifier

  3. Proper solid waste management

  4. Proper recycling of materials
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is a very important method for the prevention of soil pollution. An efficient system of disposal should be developed to deal with domestic solid waste. Industrial wastes can be treated physically, chemically and biologically, until they are less hazardous.

Multiple choice

 Which of the following is not used as disinfectant?

  1. Formalin

  2. Phenol in lower concentration

  3. Aqueous solution of chlorine in low concentration

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 This is correct option as Phenol is not used as disinfectant in lower concentration.