Method of removing water soluble organics from oil process water with an organic acid and a mineral acid having a plurality of pKa's

A method of removing water soluble organics from oil process water containing cations that tend to form scale upon exposure to phosphoric acid, comprising the steps of

• a) adjusting the pH of the water to within the range of about 2-6 by incorporating in the water an organic acid and a mineral acid selected from the group consisting of phosphoric acid, phosphorous acid, sulfuric acid and sulfurous acid, in an organic acid to mineral acid molar ratio of from about 99:1 to about 1:99, the organic acid having a pKa and the mineral acid have a plurality of pKa's, at least one of which is higher than the pKa of the organic acid, the organic acid being added in an amount sufficient to form water soluble salts with said cations thereby to inhibit scale formation in the water after addition thereto of the mineral acid, the organic acid being incorporated into the water simultaneously with or prior to the incorporation of the mineral acid into the water thereby to form acidified water;
• b) thereafter or simultaneously contacting the acidified water intimately with oil with the result that the content of water soluble organics in the water is substantially reduced by migration from the water to the oil;
• and
• c) separating the oil and the water.