De or het milieuhandhaving?

The correct Dutch article is:

de milieuhandhaving

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

How to use milieuhandhaving

the milieuhandhavingde milieuhandhaving
this milieuhandhavingdeze milieuhandhaving
that milieuhandhavingdie milieuhandhaving
our milieuhandhavingonze milieuhandhaving
your milieuhandhavingjouw milieuhandhaving
every milieuhandhavingelke milieuhandhaving
which milieuhandhaving?welke milieuhandhaving?
a big milieuhandhaving / the big milieuhandhavingeen grote milieuhandhaving, de grote milieuhandhaving