Process for the purification of industrial waste-waters

• US 5,405,532 A
• Filed: 04/29/1994
• Issued: 04/11/1995
• Est. Priority Date: 05/05/1988
• Status: Expired due to Fees

• Current Assignee: Sandoz Inc. (Novartis Ag)
• Original Assignee: Sandoz Inc. (Novartis Ag)
• Inventors: Loew, Richard, Samhaber, Wolfgang, Wyss, Anton
• Primary Examiner(s): WYSE, THOMAS G
• Application Number:
  US08/236,761
• Time in Patent Office: 347 Days
• Field of Search: 210/631, 210/638, 210/639, 210/650-652, 210/663, 210/668, 210/669, 210/670, 210/694, 210/759, 210/763, 210/908, 210/909
• US Class Current: 210/631
• CPC Class Codes: C02F 1/281 using inorganic sorbents
• CPC Class Codes: C02F 1/283 using coal, charred products, or inorganic mixtures containing them
• CPC Class Codes: C02F 1/285 using synthetic organic sorbents
• CPC Class Codes: C02F 1/42 by ion-exchange ion-exchange in general B01J
• CPC Class Codes: C02F 1/442 by nanofiltration
• CPC Class Codes: C02F 1/722 Oxidation by peroxides
• CPC Class Codes: C02F 1/725 by catalytic oxidation
• CPC Class Codes: C02F 1/76 with halogens or compounds of halogens C02F1/4674 takes precedence
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 3/02 Aerobic processes
• CPC Class Codes: C02F 3/1231 Treatments of toxic sewage
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage
• CPC Class Codes: Y10S 210/908 Organic

Abstract

The invention relates to a process for treating industrial waste water which comprises either: (a) pre-treating the waste water with at least two different pre-treatments selected from adsorption, membrane filtration and oxidation and then, biologically purifying the waste water or, (b) neutralizing and biologically purifying the waste water and then after-treating the waste water either by membrane filtration in combination with adsorption or oxidation or, by oxidation optionally in combination with adsorption or filtration on a nanofiltration membrane or, by filtration on a nanofiltration membrane.

Claims

1. A process for purifying a waste-water stream of organic contaminants, comprising the steps of neutralization and biological treatment followed by a treatment which comprises:

(1) contacting the waste water stream with at least one nanofiltration membrane under conditions of pressure and temperature sufficient to form a permeated stream which has reduced organic carbon content relative to the feed stream, and recovering the permeated stream, said nanofiltration membrane being characterized by retention of organic substances with a molecular weight of about 500 Daltons or greater, and a retention coefficient for NaCl of about 0% and for Na₂ SO₄ of about 20%; and

(2) treating the waste water stream with hydrogen peroxide in the presence of a catalytic amount of a cation selected from copper, aluminum, zinc and iron.

2. A process according to claim 1 wherein the hydrogen peroxide treatment is carried out in the presence of Fe⁺⁺ at pH 3 to 5 and at a temperature of from 20°

to 40°

C.

3. A process according to claim 1 wherein neutralization and biological purification are carried out in a waste water purification plant.

4. A process according to claim 1, in which the cation is Fe⁺⁺ as provided by FeSO₄.7H₂ O.

5. A process according to claim 4, in which the molecular ratio between H₂ O₂ (35% V/V) and FeSO₄.7H₂ O is from 30:

1 to 3;

1.

6. A process according to claim 5 wherein filtration is effected under a pressure of 10 to 40 Bar, at a temperature of 5°

to 95°

C.