GATE CE 2023 Set 2 — Question 49

MSQ+2 / -0HardCompostingMunicipal Solid WasteEnvironmental EngineeringSludge DisposalEffluent & Sludge Management

Environmental Engineering → Effluent & Sludge Management → Composting

Last updated 5 September 2026

Question

Which of the following statements is/are TRUE for the aerobic composting of sewage sludge?

Correct answer (B) Leachate can be generated during composting; (C) Actinomycetes are involved in the process Solution 1. Statement (A): Bulking agents (such as wood chips, shredded tires, or straw) are added to sewage sludge to increase the porosity and provide structural integrity to the pile, ensuring better air distribution. Thus, (A) is incorrect. 2. Statement (B): Composting involves the decomposition of organic matter with high moisture content. Excess water can drain from the composting mass, forming leachate. Thus, (B) is correct. 3. Statement (C): Actinomycetes are a group of filamentous bacteria that are particularly active during the thermophilic and curing stages of composting, breaking down tough organic materials like cellulose and lignin. Thus, (C) is correct. 4. Statement (D): In-vessel composting systems can be designed to operate in various flow regimes, including plug-flow (where material moves through the vessel as a discrete mass) or completely mixed. Thus, (D) is incorrect. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (B) Leachate can be generated during composting; (C) Actinomycetes are involved in the process Solution 1. Statement (A): Bulking agents (such as wood chips, shredded tires, or straw) are added to sewage sludge to increase the porosity and provide structural integrity to the pile, ensuring better air distribution. Thus, (A) is incorrect. 2. Statement (B): Composting involves the decomposition of organic matter with high moisture content. Excess water can drain from the composting mass, forming leachate. Thus, (B) is correct. 3. Statement (C): Actinomycetes are a group of filamentous bacteria that are particularly active during the thermophilic and curing stages of composting, breaking down tough organic materials like cellulose and lignin. Thus, (C) is correct. 4. Statement (D): In-vessel composting systems can be designed to operate in various flow regimes, including plug-flow (where material moves through the vessel as a discrete mass) or completely mixed. Thus, (D) is incorrect.

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