Hydrophobic contaminants are removed from sludge that has been liquidized by violent shearing, by stirring a hydrophobic sorbent substance material into the sludge. After a period of time in which the contaminants are sorbed into the sorbent, the sorbent substance is separated from the sludge by gravity-settling, centrifuging, etc, where the sorbent is a liquid, or by filtration etc where the sorbent is a solid. Some sorbents have a melting point such that the sorbent can be liquid for good dispersal in heated sludge, and then can be solid when the sludge has cooled, whereby the sorbent can be removed e.g by filtration. Liquefaction by violent shearing causes the biosolids in the sludge to go into solution, which leaves the hydrophobic contaminants more available to be sorbed.
