US 6,306,303 B1Granted

Washing process with waste water recycling

AssigneeHenkel Kommanditgesellschaft auf Aktien

InventorsIrmhild Goebel, Walter Guhl, Hans-Josef Wieser

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Abstract

A process for washing fat- or dye-soiled materials involving: (a) providing a fat- or dye-soiled material; (b) providing an aqueous detergent-containing liquor; (c) contacting the fat- or dye-soiled material with the aqueous detergent-containing liquor, thus forming a washed material and wash wastewater; (d) providing a source of rinse water; (e) rinsing the washed material with the rinse water, at least once, thus forming rinsed material and rinse wastewater; (f) collecting both the wash and rinse wastewater; (g) chemically pretreating the collected wash and rinse wastewater by contacting it with a compound selected from the group consisting of a demulsifier, an oxidizing agent and mixtures thereof to form waste particles; (h) mechanically removing the waste particles from the collected wash and rinse wastewater by flotation or sedimentation to form prepurified wash and rinse wastewaters; (i) biologically treating the prepurified wash and rinse wastewater by introducing it into a fixed-bed reactor containing activated sludge to form a mixture of treated wastewater and sludge; (j) separating the treated wastewater from the sludge; and (k) recirculating the treated wastewater back into the aqueous detergent-containing liquor, the rinse water, or both.

Claims15

Dependent claims

A process for washing fat- or dye-soiled materials comprising:

(a) providing a fat- or dye-soiled material;
(b) providing an aqueous detergent-containing liquor;
(c) contacting the fat- or dyesoiled material with the aqueous detergent-containing liquor, thus forming a washed material and wash wastewater;
(d) providing a source of rinse water;
(e) rinsing the washed material with the rinse water, at least once, thus forming rinsed material and rinse wastewater;
(f) collecting both the wash and rinse wastewater;
(g) chemically pretreating the collected wash and rinse wastewater by contacting it with a compound selected from the group consisting of a demulsifier, an oxidizing agent and mixtures thereof, to form chemically pretreated wash and rinse wastewater containing waste particles dispersed therein;
(h) mechanically removing the waste particles from the chemically pretreated wash and rinse wastewater by flotation or sedimentation to form prepurified wash and rinse wastewaters;
(i) biologically treating the prepurified wash and rinse wastewater by introducing it into a fixed-bed reactor containing activated sludge to form a mixture of treated wastewater and sludge;
(j) separating the treated wastewater from the sludge;
and
(k) recirculating the treated wastewater back into the aqueous detergent containing liquor, the rinse water, or both.

9 more elements

Dependencies are inferred from the claim text.