Q1. What is the primary principle behind bioremediation?
- Use of chemicals to neutralize pollutants
- Use of microorganisms to degrade pollutants
- Use of machinery to extract pollutants
- Use of plants to absorb radiation
Correct Option: 2. Use of microorganisms to degrade pollutants.
Explanation: Bioremediation refers to the process of using living organisms—mainly bacteria, fungi, and other microbes—to break down hazardous pollutants into less harmful or non-toxic forms. These organisms utilize the contaminants as a source of energy or nutrients, thereby cleaning up the environment naturally. It’s a sustainable and eco-friendly alternative to chemical or mechanical clean-up methods.
Q2. Which of the following is an in situ bioremediation technique?
- Landfarming
- Biopiles
- Bioventing
- Bioreactor
Correct Option: 3. Bioventing.
Explanation: In situ bioremediation techniques treat the contaminated material directly at the site, without excavation. Bioventing involves supplying air and nutrients through wells to contaminated soil to stimulate the activity of native microbes. It is particularly effective for treating simple hydrocarbon pollutants located deep underground. Other options (1, 2, 4) are ex situ methods requiring the removal of contaminated material.
Q3. Which technique involves injecting air below the water table to increase groundwater oxygen?
- Biosparging
- Bioaugmentation
- Bioventing
- Rhizofiltration
Correct Option: 1. Biosparging.
Explanation: Biosparging is a method where air (sometimes oxygen-enriched) is injected under pressure directly into groundwater to increase the oxygen concentration. This promotes the aerobic degradation of contaminants like petroleum hydrocarbons by native microbes. It is especially useful in saturated zones, i.e., below the water table.
Q4. What is the role of “Oilzapper” developed by TERI?
- To purify drinking water
- To treat industrial wastewater
- To degrade oil spills using bacteria
- To clean heavy metals from soil
Correct Option: 3. To degrade oil spills using bacteria.
Explanation: “Oilzapper” is a microbial consortium developed by TERI (The Energy and Resources Institute) for bioremediation of oil-contaminated sites. It contains oil-degrading bacteria that break down hydrocarbons in crude oil into non-toxic by-products. It’s used to clean up oil spills in a cost-effective and environmentally friendly way.
Q5. Which of the following is not a phytoremediation technique?
- Phytostabilization
- Phytoextraction
- Rhizofiltration
- Bioventing
Correct Option: 4. Bioventing.
Explanation: Bioventing is a microbial technique and not related to phytoremediation, which uses plants to clean up contaminants from soil and water. Phytostabilization, phytoextraction, and rhizofiltration are all techniques where plants absorb, degrade, or stabilize pollutants.