Patent ID: 8137547

Claim:
A fluid treatment tank for use in a well fluid processing system, the tank comprising: at least three compartments, including: an oil treatment compartment for receiving oil from a separator vessel of the well fluid processing system so as to allow stabilization and/or final separation and treatment of the oil; a reject treatment compartment for receiving reject fluid from one or more water treatment units of the well fluid processing system so as to allow gravitational separation of heavier and lighter components of the reject fluid; and a water treatment compartment for receiving de-oiled water from one or more water treatment units of the well fluid processing system so as to allow degassing and/or final separation of the water, wherein the reject treatment compartment comprises an outlet at a lower part, wherein the outlet is connected to an inlet of the water treatment compartment so as to allow fluid withdrawn from the lower part of the reject treatment compartment via said outlet to be introduced in the water treatment compartment via said inlet, and wherein the oil treatment compartment comprises an outlet at a lower part, wherein the outlet is connected to the inlet of the water treatment compartment so as to allow fluid withdrawn from the lower part of the oil treatment compartment via said outlet to be introduced in the water treatment compartment via said inlet.