Since dirts and soils are emulsified and rinsed off in aqueous cleaning, aqueous baths that are not treated have to be replaced frequently.
In contrast, solvent can be recycled indefinitely via the distillation unit, which is built within the vapor degreasing system or as a separate additional system.
The continuous distillation and re-purification of the solvent significantly increases solvent lifespan and cuts down on waste volume. This again leads to reduced solvent consumption and solvent costs (therefore a lower cost per-cleaned-part).
If there is a large amount of oils to be cleaned off, the opportunity to separate solvent from oils (via distillation) can be a particular advantage, since solvent can be effectively recovered, leaving only very little solvent residues in the waste.
Generally, the higher the difference in boiling point/range between solvent and the oil, the better they can be separated in the distillation.
As an example, given that the boiling point of Perchloroethylene is significantly lower than that of oils (>250 °C), the solvent can be most effectively separated from oils in the distillation sump. Solvent content in the waste can be as low as just 1% (or even lower).