Sean Edward Paquette
Homework Number 4
March 6, 2014
Problem4-1:
For your own community, calculate how many years it would take to fill a football field 20ft deep.
Include the necessary earth cover.
After extensive online searching for average quantities of refuse for the town of Rocky Hill, I was unable
to collect actuals. Therefore, the following are assumptions: Miscellaneous Paper 50% by weight
(Compacted bulk density 3.81 lb/ft3), Plastic 20% by weight (Compacted bulk density 35 lb/ft3), Garden
waste 10% by weight (Compacted bulk density 4.45 lb/ft3), Glass 10% by weight (Compacted bulk
density 18.45 lb/ft3) and metal 10% by weight (Compacted bulk density 50 lb/ft3).
Problem 4-2
Estimate the life of a landfill for a user population of 10,000. The available area for the area-type landfill
is 10 acres. The water table is estimated at 20ft below the ground surface. The pit must have a side
slope of 1:3, and the final surface must have a slope of 1:4. Assume that the soil occupies 20% of the
compacted volume.
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Problem 4-3
Assume the following fraction, by weight, of material in a refuse:
(A) Estimate the in-place density of this refuse, using the bulk density values listed in Table 4-1.
(B) If the following materials are recovered in a materials recovery operation, estimate the bulk
density of the remaining refuse going into the landfill.
(C) If the life of the landfill for this community was originally calculated as 10 years, what is the
expected life if the materials listed in part (b) are recovered?
Sean Edward Paquette
Homework Number 4
March 6, 2014
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Problem 4-4
You are the engineer hired by a community trying to side a modern landfill. At the public hearing, one of
the neighbors of the proposed landfill asks you if her well water might become contaminated by the
landfill leachate.
(A) How would you answer her? Take your time and give a full answer.
(B) The town hired you to site the landfill. Is the town your client, or do you have a higher
professional responsibility?
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Problem 4-5
A landfill initially receives 1000 tons/day of waste. This receipt rate increases 10% per year. The landfill
is closed at the end of the fourth year. Using the EPA exponential model, calculate the yearly gas
production for 20 years after opening. What is the peak gas production in m3/yr?
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Problem 4-6