An economic analysis is needed for a new municipal solid waste landfill.

This includes determining the potential economic benefit from the gas

that is generated when solid waste decomposes. The landfill is proposed

at $14$ acres, with a design capacity of $1$ million cubic yards of capacity.

The final capping system will require a $3-$foot layer over the $14$ acres,

and the waste flow rate is $120,000$ tons per year. Calculate:

$($a$)$ The life of the landfill.

$($b$)$ The average annual methane production $($assume all methane

production has ceased by $15$ years after landfill closure$).$

$($c$)$ The dollar value of annual methane converted to electricity $($neglect

collection and energy production costs$).$