Abstract: A method for dehydrating a waste hydrocarbon sludge, includes the steps of: (a) providing a waste hydrocarbon sludge in the form of an emulsion of water and oil having a water content greater than or equal to about 10% vol; (b) providing a solution of a clarifying agent in formation water; (c) mixing the waste hydrocarbon sludge with the solution so as to provide a sludge-water mixture having a ratio of water to hydrocarbon of at least about 1:1; (d) adding a demulsifier to the sludge-water mixture to provide a sludge-water-demulsifier mixture; (e) heating the sludge-water-demulsifier mixture to a sufficient temperature and holding for a time sufficient to provide a hydrocarbon phase having a water content of less than or equal to about 1% vol.