Patent ID: 7935261

Claim:
A method of treating a waste drilling mud comprising a bulk emulsion and a drilling mud solid, wherein the bulk emulsion comprises an organic emulsifier an hydrophobic phase and an aqueous phase, the method comprising: (a) separating a fraction of the drilling mud solid from the waste drilling mud, the fraction comprising particles above a predetermined diameter; (b) demulsifying the bulk emulsion by adjusting the pH of the waste drilling mud to 4.5-5.3, adding an oxidant sufficient to degrade said organic emulsifier, and heating the waste drilling mud to about 140-200° F., to break the emulsion and form a demulsified hydrophobic phase and a demulsified aqueous phase; and (c) separating the demulsified hydrophobic phase from the demulsified aqueous phase in a three-phase centrifuge, to create an aqueous product and an oil product, wherein the oil product comprises a water content and a solids content suitable for reuse.