2. [landfills, reduction of GWP emissions] A paper mill landfills 50 metric tonnes per day of solid waste composed primarily of sludge/solids from wastewater treatment plant, ash, and other miscellaneous waste typical of a kraft mill. The mill generates solid waste for 350 days a year. The landfill has been in use for 20 years and remains active. The decay of the solid waste in the landfill produces a biogas rich in methane. The amount of methane generated can be estimated by using the simplified first order decay equation given in the supplementary information. a) The landfill does not have a collection and recovery system for the biogas and the methane is released to the atmosphere. Calculate the amount of greenhouse gases emitted to the atmosphere due to the methane release from the landfill. Use the most recent GWP value for methane (IPCC AR5 value) in your calculations and answer in tonnes of CO2 equivalents per year, t CO₂e/y. [Ans: = 15,780 t CO₂e/y]
2. [landfills, reduction of GWP emissions] A paper mill landfills 50 metric tonnes per day of solid waste composed primarily of sludge/solids from wastewater treatment plant, ash, and other miscellaneous waste typical of a kraft mill. The mill generates solid waste for 350 days a year. The landfill has been in use for 20 years and remains active. The decay of the solid waste in the landfill produces a biogas rich in methane. The amount of methane generated can be estimated by using the simplified first order decay equation given in the supplementary information. a) The landfill does not have a collection and recovery system for the biogas and the methane is released to the atmosphere. Calculate the amount of greenhouse gases emitted to the atmosphere due to the methane release from the landfill. Use the most recent GWP value for methane (IPCC AR5 value) in your calculations and answer in tonnes of CO2 equivalents per year, t CO₂e/y. [Ans: = 15,780 t CO₂e/y]
for part a) can someone show how we get from 35265405 moles to 564.24tonne/year
Transcribed Image Text:2. [landfills, reduction of GWP emissions] A paper mill landfills 50 metric tonnes per day of solid waste
composed primarily of sludge/solids from wastewater treatment plant, ash, and other miscellaneous waste
typical of a kraft mill. The mill generates solid waste for 350 days a year. The landfill has been in use for
20 years and remains active. The decay of the solid waste in the landfill produces a biogas rich in methane.
The amount of methane generated can be estimated by using the simplified first order decay equation
given in the supplementary information.
a) The landfill does not have a collection and recovery system for the biogas and the methane is released
to the atmosphere. Calculate the amount of greenhouse gases emitted to the atmosphere due to the
methane release from the landfill. Use the most recent GWP value for methane (IPCC AR5 value) in
your calculations and answer in tonnes of CO2 equivalents per year, t CO₂e/y.
[Ans: = 15,780 t CO₂e/y]
b) Consider that the landfill is fitted with a "collection + combustion" system to harness the calorific value
of the generated methane and reduce CH4 emissions. The system has a collection efficiency of 75%
and 10% of the uncollected meth is oxidised before escaping to the atmosphere. collected
methane is burned.
i. Calculate the amount of greenhouse gases emitted solely due to the methane that still escapes
from the landfill.
[Ans: = 3,550 t CO2e/y]
ii. Assuming perfect combustion of the collected methane, calculate the percentage net reduction in
greenhouse gas emissions that is attained by fitting the "collection + combustion" system.
[Ans: = 70% net reduction in GHG emissions]
Supplementary information:
• Assume that the methane is generated and collected or released/emitted always at 0°℃ and 1atm.
• CH₁ generated from waste in landfill (m³/year) = R L₁ (e-kC – e-kT)
with: R = average amount of waste sent to landfill per year (t/y)
Lo = ultimate methane generation potential = 100 m³ of CH4/t of waste
k = methane generation rate constant = 0.03 y¹
C = time since landfill stopped receiving waste (y)
T = time since landfill opened (y)
R = 8.31446 J K-¹ mol1¹ = 0.082057 L atm K-1 mol¹; 1 atm = 101325 Pa.
Transcribed Image Text:сни
per year (m³/year) - RL. (eke e-kr)
C = 0
T= 20 years
17500
R= 50x350
17500 X100 (1-0-5488)
ided
gas equation
ما
La = 100
-789579.63 m ²³ / year
0.5488) = 789579-63
PV = nRT
101325 x 789579.68 = nx8.31x273
n = 35265405 moles.
564.24 T/year
GWP value of methane over 20 years = 28
Tonne esuivalent of co
= 28x 564-24 = 15780-15798.72
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![2. [landfills, reduction of GWP emissions] A paper mill landfills 50 metric tonnes per day of solid waste
composed primarily of sludge/solids from wastewater treatment plant, ash, and other miscellaneous waste
typical of a kraft mill. The mill generates solid waste for 350 days a year. The landfill has been in use for
20 years and remains active. The decay of the solid waste in the landfill produces a biogas rich in methane.
The amount of methane generated can be estimated by using the simplified first order decay equation
given in the supplementary information.
a) The landfill does not have a collection and recovery system for the biogas and the methane is released
to the atmosphere. Calculate the amount of greenhouse gases emitted to the atmosphere due to the
methane release from the landfill. Use the most recent GWP value for methane (IPCC AR5 value) in
your calculations and answer in tonnes of CO2 equivalents per year, t CO₂e/y.
[Ans: = 15,780 t CO₂e/y]
b) Consider that the landfill is fitted with a "collection + combustion" system to harness the calorific value
of the generated methane and reduce CH4 emissions. The system has a collection efficiency of 75%
and 10% of the uncollected meth is oxidised before escaping to the atmosphere. collected
methane is burned.
i. Calculate the amount of greenhouse gases emitted solely due to the methane that still escapes
from the landfill.
[Ans: = 3,550 t CO2e/y]
ii. Assuming perfect combustion of the collected methane, calculate the percentage net reduction in
greenhouse gas emissions that is attained by fitting the "collection + combustion" system.
[Ans: = 70% net reduction in GHG emissions]
Supplementary information:
• Assume that the methane is generated and collected or released/emitted always at 0°℃ and 1atm.
• CH₁ generated from waste in landfill (m³/year) = R L₁ (e-kC – e-kT)
with: R = average amount of waste sent to landfill per year (t/y)
Lo = ultimate methane generation potential = 100 m³ of CH4/t of waste
k = methane generation rate constant = 0.03 y¹
C = time since landfill stopped receiving waste (y)
T = time since landfill opened (y)
R = 8.31446 J K-¹ mol1¹ = 0.082057 L atm K-1 mol¹; 1 atm = 101325 Pa.](https://content.bartleby.com/qna-images/question/de55ad6b-27eb-44c5-bca1-afdb32f2dfc7/0d3646cc-948b-468b-b1b7-6e45b64c7d25/hazi3eg_processed.png)
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