LANDFILL GAS: GENERATION MODELS AND ENERGY RECOVERY - Energy Recovery - page 74

Figure 3.. Graphical representation of LFG production over a five-year period from the rapidly and
slowly decomposable organic materials in landfill (Tchobanoglous et al., 1993).

Analytically, the LFG production rate in the Triangular model can be described as a
function of time as it follows:

Q = 0 t ≤ t

LFG , t , i i 0 , i

t − t

i 0 , i

growing phase : Q = Q , t ≤ t ≤ t

LFG , t , i LFG , max, i 0 , i i max, i

t − t

max, i 0 , i

t − t

(2)

max, i i

decreasing phase : Q = Q , t ≤ t ≤ t

LFG , t , i LFG , max, i max, i i end , i

t − t

end , i max, i

Q = 0 t ≥ t

LFG , t , i i end , i

where:
Q LFG,t,i = LFG production rate at year t for waste placed at year i [m 3 /(t · year)]
t max,i = time at which LFG production reaches the peak for waste placed at year i [year]

In order to estimate the current emissions from waste placed in all years, Equation 1 and
Equation 2 can be solved for all values of R i and the results summed:

(3)

t

∑

Q = Q

LFG , t LFG , t , i

i = initial year