Patent ID: 7678280

Claim:
A method of cleaning slop water, wherein the slop water comprises a water component emulsified with an oleaginous component, the method comprising: feeding the slop water and an emulsion breaker into an emulsion breaking tank of an apparatus for recycling drilling fluid, wherein the apparatus for recycling drilling fluid comprises: the emulsion breaking tank, which comprises an agitator, a means for the addition of the emulsion breaker, a means for the addition of the drilling fluid, and a means for removing at least a portion of a demulsified water; a water treatment tank, which comprises an agitator, a means for adding the at least portion of demulsified water, a means for adding flocculation materials for producing a treatment water and a treatment sludge, a means for removing the treatment water, wherein the emulsion breaking tank is in fluid connection with the water treatment tank; and hydrocarbon filters for filtering the treatment water, wherein the water treatment tank is in fluid connection with the hydrocarbon filters; mixing the slop water with the emulsion breaker in the emulsion breaking tank, wherein the emulsion breaker is selected from the group consisting of a non-ionic surfactant, an anionic surfactant, and an alkyl polyglycoside; separating the water component of the slop water from the oleaginous component of the slop water; mixing the water component in the water treatment tank with the flocculation materials to produce a treatment sludge and a treatment water; skimming the treatment water from the water treatment tank; passing the treatment water through the hydrocarbon filters; and discharging the treatment water.