The standard applies to all types of sludge, unless the test is not possible due to practical objections, such as foam formation, floating layer or an extremely high dry residue of the undis olved components. The determination of the extraction time is used as a quick simple method for characterizing the dewatering rate of sludge.
NEN 6689-1983 history
1983NEN 6689-1983 Sludge - Determination of the suction time in vacuüm filtration