William M Herring

US Patent:

40000656, Dec 28, 1976

Filed:

Nov 18, 1974

Appl. No.:

5/524806

Inventors:

Kamal K. Ladha - Riverview MI
William M. Herring - Trenton MI
Joseph F. Louvar - Lincoln Park MI

Assignee:

BASF Wyandotte Corporation - Wyandotte MI

International Classification:

B01D 3100
B01D 1300

US Classification:

210 23H

Abstract:

Aqueous streams contaminated with minor amounts of organic materials are separated into an aqueous fraction which is concentrated with respect to the organic contaminants and a water fraction relatively free of the organic contaminants by a method which includes a unique combination of reverse osmosis (RO) and ultrafiltration (UF). The organic contaminants include substances having molecular weights of less than 10,000 which are soluble in the aqueous stream initially but have limited solubility ranges and are precipitated therefrom upon concentration. The contaminated aqueous stream is circulated from the high pressure compartment of a RO unit to the high pressure compartment of an UF unit, then to the low pressure compartment of the UF unit, and then back to the high pressure compartment of the RO unit. The contaminants are concentrated in the high pressure compartment of the RO unit, and a portion thereof is precipitated or otherwise rendered amenable to removal along with the UF concentrate upon passing the RO concentrate from the high pressure compartment of the RO unit to the high pressure compartment of the UF unit. Soluble organic contaminants remaining in the aqueous stream are removed in the UF permeate and are recycled back to the high pressure compartment of the RO unit for further concentration and precipitation, followed by recycling to the high pressure compartment of the UF unit for removal.