Environmental Science and Engineering
2026 · Paper 1
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Complete GATE ES 2026 Paper 1 overview, original pages and practice · Timed previous-paper practice
Questions 61–63 of 65. Imported answers require review unless explicitly marked reviewed.
Question 61
Open questionESNAT2 marksNeeds review
An anaerobic digestion system is operated for methane gas generation from organic fraction of municipal solid waste (OFMSW). The moisture content and volatile solids (VS) content of OFMSW are 20% and 90%, respectively. The biodegradable volatile solids (BVS) in the VS is 70%, and the BVS conversion efficiency to methane gas is 85%.
If the methane gas generation in the system is 12 m
per kg of BVS converted, the total volume of gas produced from one kilogram of OFMSW is _____ m
(rounded off to two decimal places).Log in to check the answer
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Open questionESNAT2 marksNeeds review
The characteristics of two types of solid waste are given in the table.
The quantity of sludge to be added to leaves to achieve a C/N ratio of 25 (on dry basis) for the mixed waste is _____ kg of sludge/kg of leaves (rounded off to three decimal places).
Type of solid waste | Moisture content (%) | Nitrogen content (%) | Carbon to Nitrogen (C/N) ratio |
|---|---|---|---|
Leaves | 50 | 0.7 | 50 |
Sludge | 75 | 5.6 | 6.3 |
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 63
Open questionESNAT2 marksNeeds review
The concentration of chemical A in ambient air is 50 μg/m
and the toxicological index limit for a threshold health effect for this chemical is 5 mg.If the average breathing rate is 4 L/min, the minimum time of exposure that can lead to any health effect is _____ days (rounded off to one decimal place).
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