Lesson 12: MSW Landfills
The airspace a landfill occupies is approximately the shape of a truncated pyramid.
This airspace is not only occupied by waste. Daily and intermediate cover materials, gas collection wells, and leachate recirculation devices are a few of things which may also occupy space within the landfill. It is therefore necessary to first estimate the amount (volume) of waste which will be landfilled during the design life then, an estimate of the percentage (usually 20 to 40%) of the landfill occupied by materials other than waste should be made. The landfill volume is then increased accordingly. When estimating the volume of landfilled waste it is important to account for density changes due to compaction occurring during waste placement (See: Table 11-24, pp. 474).
Once the total volume of the landfill has been estimated, the areal dimensions and final height of a landfill may be estimated using simple geometric concepts:
Area = Length(avg)*Width(avg)
Volume = Area(avg)*Height(avg)
Area(avg)=0.5*[Area(base)+Area(top)]
L(top)=L(base)-2*(Height)*N
W (top)=W(base)-2*(Height)*NN = slope of landfill sides, (rise:run, 1:N), typical values are 3 to 4
Review: Text, Example Problem
4-1 (pp.113)
Review: Text, Example Problem 4-2 (pp.114-115)
Think:
Write an equation for the sizing of a landfill which will have a rectangular base. Assume that the length of the base will be twice the width.
Review: MSW Management: Landfill Airspace: a Holistic Approach by Neal Bolton (March-April 2013)