UPSC Prelims 2024 · GS Paper I
Question 46: Environment and Ecology
Consider the following materials :
- 1.Agricultural residues
- 2.Corn grain
- 3.Wastewater treatment sludge
- 4.Wood mill waste
Which of the above can be used as feedstock for producing Sustainable Aviation Fuel ?
AnswerUPSC’s answer is (c).
Sustainable Aviation Fuel can be made from many renewable feedstocks. Agricultural residues, wood mill waste and wastewater sludge can be converted by processes such as gasification with Fischer-Tropsch synthesis or by hydroprocessing, and corn grain can be turned into jet fuel by the ethanol-to-jet route. All four materials can serve as feedstock, though food crops such as corn raise food-versus-fuel concerns.
- 1. Agricultural residues are a standard SAF feedstock.
- 2. Corn grain can be converted to SAF through the ethanol-to-jet route.
- 3. Wastewater treatment sludge can be processed into SAF.
- 4. Wood mill waste is a forestry residue used as SAF feedstock.
How you could have got this
- If you were sure statement 2 is correct, (b) and (d) go: each of them leaves 2 out.
What you needed to know: Corn grain can be converted to SAF through the ethanol-to-jet route.
- Then, if you were sure statement 3 is correct, (a) goes: it leaves 3 out.
What you needed to know: Wastewater treatment sludge can be processed into SAF.
Only (c) is left. You didn’t need statements 1 or 4.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: wastewater sludge and wood mill waste can also be used.
- (b) Wrong: agricultural residues and corn grain can also be used.
- (c) Right: all four can be feedstock for sustainable aviation fuel.
- (d) Wrong: corn grain can also be used.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.