Non-emulsifying products facilitate the desorption of the pollutant by the rocks, thus allowing recovery downstream.
Emulsifying products also facilitate the desorption of the pollutant by the rocks, then help to disperse the pollutant in the natural environment.
In France, the test methods for surface washing agents have been standardised to include a measurement method for the product's emulsifying power (NF.T.90-348) and another for its cleaning power (NF.T.90-364). The products are classified according to:
- an emulsifying power test, to determine whether or not the product is emulsifying
- efficiency (cleaning power) and toxicity tests, and for emulsifying products a biodegradability test (NF.T.90-346).