Waste Water Engineering Question Paper on “Methods for Treatment of Wastewater – 2”.
1. What is the method of treatment used when the TSS in the sample is high?
a) Ultrafiltration
b) High rate solid contact clarifier
c) Pressure Sand filter
d) Activated Carbon filter
Answer: b
Clarification: High rate solid contact clarifier is used to treat samples with very high TSS. The other methods namely ultrafiltration and pressure sand filter cannot treat samples with very high TSS. This is because the filters will get clogged.
2. Which type of treatment does clarification fall in?
a) Secondary treatment
b) Primary treatment
c) Preliminary treatment
d) Tertiary treatment
Answer: b
Clarification: Clarification is classified as Primary treatment. Influent with high TSS can be treated here. The COD associated TSS also gets reduced in this stage.
3. Which of these remove coarse materials?
a) Coarse screen
b) Grit chamber
c) Fine screen
d) Commutors
Answer: a
Clarification: Coarse screens remove coarse materials. The size of the coarse screen is 6mm-25mm. These coarse screens maybe manual or mechanically driven.
4. Which type of treatment is the coarse screen?
a) Preliminary treatment
b) Primary treatment
c) Secondary treatment
d) Tertiary treatment
Answer: a
Clarification: Coarse screens are classified as preliminary treatment. This is mainly to remove grit, sand particles. This prevents clogging of the pipe and pump.
5. Tube settlers are classified as which type of treatment?
a) Tertiary treatment
b) Secondary treatment
c) Preliminary treatment
d) Primary treatment
Answer: b
Clarification: Tube settlers are classified as secondary treatment. These are used mainly to remove TSS. Tube settlers will be followed generally after a clarifier and a flocculator.
6. Activated Carbon is classified as which type of treatment?
a) Preliminary treatment
b) Primary treatment
c) Secondary treatment
d) Tertiary treatment
Answer: d
Clarification: Activated Carbon is classified as tertiary treatment. This works on the principle of adsorption. Pressure sand filter is usually prior to the activated carbon filter.
7. Which of these is used to remove odour?
a) Ultrafiltration
b) Pressure sand filter
c) Activated carbon
d) Nano filter
Answer: c
Clarification: Activated carbon filters are used to remove odour. This is also used to reduce COD by removing organics. The treatment process works on the principal of adsorption.
8. Reverse Osmosis is which type of treatment?
a) Primary treatment
b) Preliminary treatment
c) Secondary treatment
d) Tertiary treatment
Answer: d
Clarification: Reverse Osmosis is classified as tertiary treatment. This is mainly used to remove ions. This results in the reduction of total dissolved salts.
9. Which is usually prior to reverse osmosis?
a) Ultrafiltration
b) Activated carbon filter
c) Clarifier
d) Tube settler
Answer: a
Clarification: Ultrafiltration is usually prior to reverse osmosis. This is to remove the TSS present in the sample. Reverse osmosis reduces the total dissolved solids in the water sample.
10. What does zero discharge actually refer to?
a) There is zero discharge of ions
b) The reject is recycled from every part of the treatment plant
c) The reject is not rejected out. Influent equals effluent
d) 100 percent efficient plant
Answer: b
Clarification: Zero discharge usually refers to the treatment plant in which the reject from each part of the treatment plant is recycled. The reject is fed as the influent and once again treated. The removal efficiency of the pollutants is approximately 97-98%.
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