Process for the purification of greasy and soiled water using a heavy solvent, and apparatus for its implementation

Claim 2

A process for purifying waste water containing grease and soil which comprises: mixing waste water containing greasy matter and soil with a heavy solvent in a mixing device in a solvent to water ratio of 1 part solvent to 3 to 8 parts water to form an emulsion; centrifuging the emulsion to obtain degreased water, a small quantity of water-solvent emulsion and solvent containing greasy matter and soil; separating the soil from the solvent containing greasy matter and drying the soil; azeotropically distilling the solvent containing greasy matter in the presence of water to recover pure solvent as the head product and a tail product containing greasy matter; and centrifuging the tail product to isolate the greasy matter.

Claim 3

A process according to claim 1 in which the waste water containing greasy matter is from wool soaking and the degreased water is evaporated to recover suint.

Claim 4

A process according to claim 2 in which the suint is combined with the dried soil.

Claim 5

A process as claimed in claim 1, wherein, before treatment with the solvent, the waste water is evaporated to adjust its grease content to a value in the range of from 5 to 15 g/liter.

Claim 6

A process as claimed in claim 4, wherein the grease content is adjusted to from 9 to 10 g/liter.

Claim 7

A process as claimed in claim 1, wherein the solvent-water ratio is substantially 1 : 5.

Claim 8

A process as claimed in claim 1, wherein part of the clarified solvent before azeotropic distillation is recycled by mixing with the waste water to be treated.

Claim 9

A process as claimed in claim 7, wherein the solvent is perchloroethylene and two thirds of it is recycled, the remaining third being distilled in the presence of 30% of water under a vacuum of from 30 to 40 cm Hg.

Claim 10

A process for purifying waste water containing grease and soil which comprises: (A) mixing wool-soaking water containing greasy material and soil with a heavy solvent in a mixing device in a solvent to water ratio of 1 part solvent to 3 to 8 parts water to form an emulsion; centrifuging the emulsion to obtain degreased water, a small quantity of water-solvent emulsion, and solvent containing greasy matter and soil; evaporating the degreased water to recover suint; separating the soil from the solvent containing greasy matter to give a first solvent body containing greasy matter and drying the soil; (B) mixing wool-washing water containing greasy matter with a heavy solvent in a mixing device in a solvent to water ratio of 1 part solvent to 3 to 8 parts water to form an emulsion; centrifuging the emulsion to obtain degreased water, a small quantity of water-solvent emulsion, and solvent containing greasy matter and soil; separating the soil and the solvent containing greasy matter to give a second solvent body containing greasy matter; (C) combining the first and second solvent bodies containing greasy matter from (A) and (B) and clarifying the resulting mixture; subjecting the resulting clarified solvent mixture containing grease to an azeotropic distillation in the presence of water to recover pure solvent as the head product and a tail product containing greasy matter; and centrifuging the tail product to obtain wool grease.

Claim 11

A process for purifying waste water containing grease and soil which comprises: (A) mixing wool-soaking water containing greasy material and soil with a heavy solvent in a mixing device in a solvent to water ratio of 1 part solvent to 3 to 8 parts water to form an emulsion; centrifuging the emulsion to obtain degreased water, a small quantity of water-solvent emulsion, and solvent containing greasy matter and soil; evaporating the degreased water to recover suint; separating the soil from the solvent containing greasy matter to give a first solvent body containing greasy matter and drying the soil; (B) mixing wool-washing water containing greasy matter with a heavy solvent in a mixing device in a solvent to water ratio of 1 part solvent to 3 to 8 parts water to form an emulsion; centrifuging the emulsion to obtain degreased water, a small quantity of water-solvent emulsion, and solvent containing greasy matter and soil; separating the soil and the solvent containing greasy matter to give a second solvent body containing greasy matter; (C) combining the first and second solvent bodies containing greasy matter from (A) and (B) and clarifying the resulting mixture; subjecting the resulting clarified solvent mixture containing grease to an azeotropic distillation in the presence of water to recover pure solvent as the head product and a tail product containing greasy matter; and centrifuging the tail product to obtain wool grease.

Claim 12

A process as claimed in claim 9, wherein the degreased water obtained from the treatment of wool-washing water is mixed with wool-rinsing water and purified by physico-chemical means.

Claim 13

A process as claimed in claim 10, wherein the physico-chemical purification is a flocculation-decantation process.

Claim 14

Apparatus for purifying waste water containing grease and soil which comprises (i) a multi-action evaporator, an emulsifier, a disc centrifuge, another multi-action evaporator and a storage means for the suint, connected in that sequence; (ii) an emulsifier, a disc centrifuge, a clarifier, a distillation tower, a Florentine separator and a device for storing and recycling the solvent, connected in that sequence, the clarifier also being connected to the disc centrifuge mentioned under (i); (iii) a centrifuging separator and a storage means for the greasy matter, connected in that sequence to the distillation tower mentioned under (ii); and (iv) a device, connected to the clarifier, for drying and storing the soil separated from the anhydrous solvent in the clarifier.

Claim 15

Apparatus for purifying waste water containing grease and soil which comprises (i) a multi-action evaporator, an emulsifier, a disc centrifuge, another multi-action evaporator and a storage means for the suint, connected in that sequence; (ii) an emulsifier, a disc centrifuge, a clarifier, a distillation tower, a Florentine separator and a device for storing and recycling the solvent, connected in that sequence, the clarifier also being connected to the disc centrifuge mentioned under (i); (iii) a centrifuging separator and a storage means for the greasy matter, connected in that sequence to the distillation tower mentioned under (ii); and (iv) a device, connected to the clarifier, for drying and storing the soil separated from the anhydrous solvent in the clarifier.

Claim 16

Apparatus as claimed in claim 12, which includes a device for mixing the suint with soil which has been separated from the clarifier and dried.