De or het orderbehandeling?

The correct Dutch article is:

de orderbehandeling

Rule Words ending in -ing: almost always de. See the rule

How to use orderbehandeling

the orderbehandelingde orderbehandeling
this orderbehandelingdeze orderbehandeling
that orderbehandelingdie orderbehandeling
our orderbehandelingonze orderbehandeling
your orderbehandelingjouw orderbehandeling
every orderbehandelingelke orderbehandeling
which orderbehandeling?welke orderbehandeling?
a big orderbehandeling / the big orderbehandelingeen grote orderbehandeling, de grote orderbehandeling