The solvent waste will be burnt up.
If the solvent waste contains halogen then the smoke gas will contain the corresponding halogen acids. Since no acidic gas may be released into the environment the gas has to be washed neutral.
Therefore it is more effort to burn a halogen-containing solvent.
There is no difference if the waste contains halogenated solvents or if halogenfree solvents are contaminated with halogen-containing reagents. Even the presence of sodium chloride changes a mixture of non-halogenated solvents into halogencontaining solvent waste.
It is OK, if a waste is labelled as "halogen-containing", but there is no halogen present.
But the institute will run into trouble if on the other hand halogen-containing waste is labelled as halogen-free, because then it seemes to the staff of the disposal company that special treatment of the smoke gas ist not needed.
In any case avoid this!