Although EN**0 covers numerous fuel characteristics, water content
is the most relevant contaminant for fuel maintenance. To comply
with EN**0, fuel can contain no more than **0mg of water per kg of
fuel.
This is an extremely demanding standard. **0mg of water per kg of
fuel represents just 0.*2% water contamination. Because modern
biodiesel blends absorb water naturally (i.e. they are hygroscopic)
it is practically impossible to adhere to the standard without
regular testing and the use of a water extraction process such as a
polishing system or regular tank cleaning.