RIVM report xxxxxx xxx

page 74 of 142 RIVM report 773301 001 / NRP report 410200 051
For k we use as GHIDXOWVN DQG, depending on the regions. In practice the value can
vary between 0.005-0.4 year. N = 0.95 when using k = 0.21; doubling or halving the k-value gives the
range for N of 0.90-0.98 (the extremes mentioned give 0.82-1.00 as range).
To calculate the actual emissions in year W the methane generated should be corrected for any
amount recovered 5 (e.g. used energetically or flared) and the fraction of methane 2; that is oxidised
in the upper layers of waste and in the site cover material, before it is released to the atmosphere:
where:
R(t) = Recovered amount of CH 4 [Gg/yr]; GHIDXOW
OX = Oxidation factor [fraction]; H[FHSW IRU2(&'DQG(,7 (IPCC default is 0)
Results of this model are presented in Fig. 4.6.
Emissions E(t) = [G(t) - R(t)] * (1 - OX)
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According to our analysis, global total net landfill emissions increased from 15 to 23 Gg in the 1970-
1995 period. This includes the effect of increasing amounts of methane being recovered and
combustion for energy purposes or flared, which increased from virtually 0 to 2.5 and 4.3 Gg in 1990
and 1995, respectively (see Table 4.9). Figure 4.6 clearly shows the impact on emissions from the
USA in the early '90s. Table 4.12 shows how the amount of waste deposited into landfills has
increased over time but started to decrease in the 1990's in the USA and in the countries of the former
USSR.