Patent ID: 6875351

Claim:
A water treating system for treating produced water containing suspended solids and emulsified oil, the water treating system comprising: a dissolved gas floatation clarifier system to remove suspended solids and emulsified oil as sludge, the dissolved gas floatation clarifier system adapted to separate the produced water into clarified water and sludge of suspended solids and emulsified oil, and an oil demulsification and separation system to demulsify and remove oil remaining in the clarified water from the dissolved gas floatation clarifier system, in which the dissolved gas floatation clarifier system comprises: a dissolved gas floatation clarifier having a manifold, a clarified water outlet, and a sludge collection chamber to collect sludge, the dissolved gas clarifier being enclosed; a storage tank for collecting clarified water exiting the outlet of the dissolved gas floatation clarifier; a pressurized gas supply in fluid communication with the dissolved gas floatation clarifier to supply pressurized gas to the dissolved gas clarifier; a recycle pressure aeration system adapted to pressurize the clarified water from the storage tank with a recycling pump; a dissolved gas generator adapted to dissolve gas from the dissolved gas clarifier into the pressurized clarified water from the recycle pressure aeration system to form a fluid saturated with dissolved gas to serve as emulsified oil diluent and to supply flotation bubbles to the dissolved gas flotation clarifier; a water pump adapted to pressurize the produced water; and a liquid-liquid fluid mixer adapted to mix the pressurized produced water from the water pump with the fluid saturated with dissolved gas exiting the dissolved gas generator to dilute the emulsified oil and form a mixture of demulsified oil and excess dissolved gas with water, the liquid-liquid fluid mixer providing the mixture to the manifold of the dissolved gas floatation clarifier, wherein the dissolved gas floatation clarifier separates the mixture from the liquid-liquid mixer into sludge and clarified water, the sludge being collected in the sludge collection chamber, the clarified water collected in the storage tank.