Denmark's National Inventory Report 2005 - Submitted under the ...

account a correction for the contribution from the industry.
Table 3E.8 The gross-emission data based on raw (original) TOW data
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The uncertainty on BOD data are estimated to be higher than for COD data due to differences
in methodologies of measurements from year to year caused by reporting of varying BOD
data measured as modified, unmodified and sometimes reported as the average of the two
measurement methods. Therefore, it has been decided to use the regression line based on
COD derived gross emission data as shown in Figure 3.E.1 below.
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y = 0.5705x - 1119.2
R 2 = 0.2811
1989 1991 1993 1995 1997 1999 2001 2003
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Figure 3.E.1. The open triangles and circles represent the country-specific gross emission derived from measured
BOD and COD values, respectively. The grey triangles represent the gross emission based on the IPCC GL default
value for Europe of 18250 kg BOD/1000 persons/yr. The black triangles and circles represent the country-specific
gross emission derived from measured BOD and COD values, respectively, where the industrial contribution to the
influent TOW has been subtracted. The data point from 1993 indicated that the industrial contribution to the TOW
at the WWTPs might have been underestimated.
For data gap filling backward it is assumed reasonable to use the interpolated linear regression
equation. For future trend analyses it may be considered to use a correction for nonlinearity
depending on the national statistics on TOW. At this stage, the gross emission estimates
of methane are based on an average of the above regression equation and the default
IPCC methodology using a constant contribution from the industry of 0.417; an average of the
contribution from 1997 and forward where the industrial contribution seems to have stabilised.
The results of the regression approach and the adjusted default IPPC approach are given