The colleagues from ifeu Heidelberg explained as follows:

(translation by pbeilschmidt)

It is the amount of seepage water that is created from the waste directly originating a) partly from organic decomposition and b) partly from the discharge of water bound in the waste itself:

a) is calculated using the C content that is decomposed (L01*L02*0,5), and for each kg C decomposed it is assumed that 1,25 kg water is created/discharged

b) is calculated as follows: the water content of the waste (L01*30/100), and it is assumed that again 30% of it results in a seepage water discharge.

The whole water is furthermore assigned with 24% to diffuse seepage water and with 76 % to controled (collected) seepage water. 24% and 76% are rounded values for the effective collection rate in the old situation there were 85% of landfills with seepage water collection and 90 % of the (seepage water) anount could actually be collected 0,85*0,9 = 0,765. Consequently, there were 15% of landfills without seepage water collection plus the above 10% diffuse seepage water emissions from landfills with seepage water collection which leads to the (inverse) value of 0,235