Environmental Biotechnology Multiple Choice Questions on “Aerobic Treatment of Solid Wastes – Composting”.
1. Which of the following is known to decompose the organic matter of wastes?
a) Composting
b) Cooking
c) Decomposing
d) Burning
Answer: a
Clarification: Composting is the method used to decompose the organic matter of wastes by biological degradation, whereas, decomposing is the process, burning is not used in this process and cooking is preparing food which generates wastes.
2. Which of the following is not an objective of composting?
a) Reduction of mass
b) Elimination of toxic substances
c) Stabilization
d) Incineration
Answer: d
Clarification: Reduction of mass, elimination of toxic substances, stabilization, drying etc. are the objectives of composting but incineration is done by burning of wastes. As, when composting starts, it leads to Reduction of mass of the actual mass that has been decomposed. Elimination of toxic substances is one of the major objective of composting. Stabilization is required after and before composting.
3. Pre-treatment of the wastes by composting leads to greenhouse effect.
a) True
b) False
Answer: b
Explanation Pre-treatment of the wastes by composting that is biological degradation of the organic matter helps to control the release of greenhouse gases into the environment as the organic matter is degraded before using in the landfills.
4. What of the following microorganisms have a major role in compositing?
a) Bacteria
b) Fungi
c) Plants
d) Actinomycetes
Answer: c
Clarification: Bacteria, fungi and actinomycetes are the microorganisms that have a major role in compositing as they help to biologically degrade the organic matter present in the wastes, where plant is not a microorganism.
5. Which of the following components are present in the waste air of aerobic respiration?
a) Ammonia
b) Nitrous oxide
c) Carbon dioxide
d) Methane
Answer: d
Clarification: Ammonia, nitrous oxide, carbon dioxide and water are various components present in the waste air of aerobic respiration but methane is an end product anaerobic metabolism but aerobic respiration.
6. Which of the following methods cannot be used for gas exchange in the heap?
a) Releasing the rotting material
b) Forced aeration
c) Maintaining the oxygen demand
d) Tightening the rooting material
Answer: d
Clarification: Tightening the rooting material would lead to more rotting and strong emission of odor, whereas, releasing the rotting material, forced aeration, maintaining the oxygen demand leads to better gas exchange in the heap.
7. Which of the following mechanism can optimize the input of hazardous metals?
a) Hydrolysis
b) Addition of heavy metals
c) Conditioning
d) Solubilisation
Answer: b
Clarification: Conditioning and preparing the materials before composting leads to removal of hazardous metals from the waste whereas, Hydrolysis, solubilisation of the salts present in the waste and biological degradation are the methods that can be used to regulate the transfer of mass from waste to leaching water and addition of heavy metals leads to toxicity.
8. Post processing of the compost leads to increase in quality.
a) True
b) False
Answer: a
Clarification: Post processing of the compost is also an important step that leads to increase in quality of the compost that further increases its marketability. So, for a product to be ready to be sold in the market, it has to have certain standards that would increase its marketability. So, Post processing of the compost adds to the quality of the product.
9. Which of the following method is not a post processing activity?
a) Sieving
b) Landfill sealing
c) Drying
d) Disintegrating clumps
Answer: b
Clarification: Drying, disintegrating clumps, sieving are the methods used for removing impurities and to increase the quality of product to increase its marketability whereas, landfill sealing is an environmental monitoring method used for measuring the landfill process efficacy in a long term basis.
10. Which of the following methods leads to increase of surface area for microorganisms to act?
a) Vermicomposting
b) Disintegration
c) Incineration
d) Recycling
Answer: b
Clarification: Disintegration before composting leads to removal of bulky wastes thereby, increasing the surface area for microorganisms to act whereas, recycling, vermicomposting and incineration are methods used to degrade the solid wastes.
11. Which of the following methods enhance the intensity of disintegration?
a) Velocity of degradation
b) Time of process
c) Composting process
d) Recycling
Answer: d
Clarification: Velocity of degradation, time of process, composting process methods enhance the intensity of disintegration thereby producing better compost, whereas, recycling is used to recycle the wastes and not produce compost.