Abstract: A process for treating feedwater with a microfiltration or ultrafiltration membrane unit and a downstream reverse osmosis unit. An aluminum salt coagulant is added and mixed with the feedwater upstream of a membrane separation unit. An aluminum salt coagulant is added and mixed with the wastewater upstream of the membrane separation unit. The membrane separation unit produces a permeate that is directed to the reverse osmosis membrane. The concentration of aluminum in the permeate is controlled by controlling the hydraulic residence time for aluminum salt reaction products in a concentrate loop associated with the membrane separation unit.

Abstract: A process for treating feedwater with a microfiltration or ultrafiltration membrane unit and a downstream reverse osmosis unit. An aluminum salt coagulant is added to the feedwater upstream of a membrane separation unit. The aluminum salt coagulant is mixed upstream of the membrane separation unit. A sufficient amount of the aluminum salt coagulant is mixed with the feedwater for a sufficient residence time to control the concentration of the aluminum in the permeate emitted by the membrane separation unit.

Abstract: A method of recovering oil from an oil-bearing formation including recovering an oil-water mixture from the oil-bearing formation and separating produced water from the oil-water mixture. The produced water includes phosphonate anti-scalant compounds. An oxidant is mixed with the produced water to deactivate the phosphonate anti-scalant compounds, thereby permitting dissolved solids in the produced water to precipitate. After deactivating the phosphonate anti-scalant compounds, the produced water is directed into a ceramic membrane which filters the produced water, producing a permeate stream and a retentate stream having suspended solids and precipitants therein.