Calculations of Landfill Gas.
From analysis of waste composition the Specific
Gas Production in m3 per ton/yr has been calculated.
It was found that one ton (1000 kg) of
refuse - based on Western European moderate landfill
composition - contains 347 kg of net organic biodegradable
compound, of which:
22 % with a half life time of 5
years
19 % with a half life time of 15
years and
59 % with a half life time of 30
years.
Half life times are moderate values for certain substances in the organic material.
This, calculated with my form, gives a
Table
of Specific Landfill Gas Production
(cubic
meter per ton per year)
Year
SGP
Year SGP
Year SGP
1
11.03
11 5.07
21 2.98
2
10.07
12 4.76
22 2.86
3
9.23
13 4.48
23 2.74
4
8.48
14 4.23
24 2.63
5
7.81
15 4.00
25 2.53
6
7.21
16 3.79
26 2.43
7
6.69
17 3.60
27 2.35
8
6.21
18 3.43
28 2.26
9
5.79
19 3.27
29 2.18
10
5.41
20 3.12
30 2.11
With the amount of refuse, deposited per
year, you can calculate the maximum gas production for 30 years,
par example:
( in thousands cubic
meters per year )
until 2010 .......
T x 1000 1980
1981 1982
1983 1984
1985 etc ....
1980 100
551.5*) 1007
923 848
781 721
etc
1981 100
0 551.5
1007 923
848 781
1982 100 0
0 551.5
1007 923
etc
1983
etc etc
until 2010
------------------------------------------------------------------------------------
Totals
552
1559 2482
......
*) every first
year 50% as the total is reached at the end of the year.
If this model
is put into a spreadsheet and the real figures for years, amount
of refuse/year etc. are filled in then it is supposed
that of the
totals per year, in practice 50% is retractable, because of
losses in the air and solution in leachate water.
Exact values
cannot be guaranteed, but figures give a good indication for
predicting landfill gas production.
Landfill Gas
exploitation can last for 10 to 15 years