GATE ES Municipal solid waste management PYQs & Answers — Page 2

Questions 11–20 of 23. Imported answers require independent review unless marked reviewed.

Food waste, paper waste and plastic waste have typical densities of 280 kg/m

, 80 kg/m

, and 50 kg/m

, respectively. The mixed waste is composed of 70% food waste, 20% paper waste and 10% plastic waste. The density of the mixed waste is ______ kg/m

(rounded off to 2 decimal places). Neglect compaction effect.

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For a biodegradable waste with a chemical formula C

N, the maximum theoretical methane production per ton of waste is ______ kg (rounded off to 2 decimal places). Assume 100% anaerobic conversion. Atomic weights of C-12; H-1; O-16; N-14

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Read the following statements about aerobic composting of organic fraction of municipal solid waste

I. The majority of the odor problem in aerobic composting process is due to the development of anaerobic conditions within the compost pile.

II. All organic carbon present in the waste will completely biodegrade in 14 days.

III. At high C/N ratio, ammonia would be released and biological activity may also be impeded.

IV. Optimum moisture content for aerobic composting process would be 50–60%. Lower moisture would slow down the biological process. Excessive moisture will make it difficult to maintain aerobic conditions.

The correct choice(s) is/are

Your answerSelect all correct options. You can choose more than one.

I and IV are correct

II and III are incorrect

I is correct; IV is incorrect

II is correct; IV is incorrect

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A city generates on average 1000 metric tonnes/day of municipal solid waste and follows integrated waste management system. 15% of the total waste is recycled, 40% of the total waste is used to produce compost. 25% of the total waste is converted to refuse derived fuel (RDF) with 80% efficiency. Remaining is disposed of in a sanitary landfill. The calorific value of the RDF is 15 MJ/kg, which is further used to generate electricity. The electrical energy that could be generated from the RDF with a thermal to electrical energy conversion efficiency of 20% is ______________(in MWh/d, rounded off to two decimal places).

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Ultimate analysis of a municipal solid waste sample is given below:

Percent by weight
Carbon	Hydrogen	Oxygen	Nitrogen	Ash
48	6	35	6	5

For 1 kg of the municipal solid waste burnt, assuming that air contains only nitrogen and oxygen, maximum CO₂ emitted is ______________(in kg, rounded off to three decimal places).

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Leachate generated from a legacy municipal solid waste dumping site has to be collected and managed carefully. Which one of the following statements is correct in the context of treatment of leachate from such a site?

Your answerChoose one option.

Setting chamber followed by micro-filtration units are required.

Modular treatment units targeting dissolved organic matter and salts are required.

Only biological treatment units like AS with extended aeration are required.

Only a combination of anaerobic-aerobic treatment units is required.

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Biodegradable wastes like vegetable peels from kitchen are usually processed by composting techniques. Which of the following option(s) regarding the process of biodegradable wastes is/are correct?

Your answerSelect all correct options. You can choose more than one.

Vermi-composting is relatively faster than window composting, however vermi-composting is not frequently used on large commercial scale.

The window height should be as short as possible as large window height may cause compaction due to the self-weight.

The window height should be as large as possible as that will help to ensure appropriate temperature within the window.

Earthworms facilitate the growth of microorganisms and break down complex organic molecules to simpler ones using enzymatic secretions.

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As per the Solid Waste Management Rules of 2016 (Govt. of India), which of the following statement(s) is/are correct?

Your answerSelect all correct options. You can choose more than one.

Biodegradable waste should be processed biologically preferably in decentralized facilities at the sources of generation.

Biodegradable waste should be processed biologically preferably in centralized facilities away from the sources of generation.

Used sanitary pads and napkins should be wrapped and disposed into the domestic hazardous waste containers.

Non-biodegradable components with a heat content more than 1500 kcal/kg should be used for power generation or Refuse Derived Fuel (RDF) manufacture.

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Choose the correct order of biodegradability (highest to lowest) of the following municipal solid waste components.

Your answerChoose one option.

Food waste > Newspaper > Polyvinyl Chloride (PVC)

Newspaper > Food waste > Polyvinyl Chloride (PVC)

Food waste > Polyvinyl Chloride (PVC) > Newspaper

Polyvinyl Chloride (PVC) > Food waste > Newspaper

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In proximate analysis, when a 10 kg moisture-free solid sample is heated in a furnace at 950 °C in the absence of air, its mass is reduced by 6 kg. If the same 10 kg moisture-free solid sample is heated in the furnace at the same temperature in the presence of air, its mass is reduced by 7 kg. The percentage of fixed carbon in the sample is __________.

Your answerChoose one option.

20 %

60 %

10 %

30 %

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GATE ES Municipal solid waste management PYQs

Question 61

Question 62

Question 45

Question 60

Question 63

Question 24

Question 31

Question 49

Question 13

Question 14