INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

CASE STUDY # 183

1. Headline: Poly Vinyl Alcohol Recycling in the Process of

"Sizing" Cotton Fibers in the Textile Industry

2. Background: See below.

3. Cleaner Production Principle: internal recycling

4. Description of Cleaner Production Application: Recycling,

reuse and reclamation: This technology involves the use

of a closed-loop recycling including a ultra-filtration

membrane process to capture poly vinyl alcohol (PVA).

Case Study Summary

Process and Waste Information: Poly vinyl alcohol (PVA),

polyacrylates (PAA) and starch are used in the textile

industry for "sizing" cotton fibers; a process where

applied chemicals confer strength to the fiber and protect

it during the weaving process. The PVA, PAA and starch

are removed from the cloth after weaving by washing it in

hot water in a "desizing" operation resulting in an

aqueous effluent containing these chemicals.

A ultra-filtration process to reduce the amount of PVA and

starch in the effluent followed by a closed-loop recycling

operation was tested for 16 months in a pilot plant. The

ultra-filtration membrane used in this process recovered

PVA successfully. Starch is enzymatically solubilized

prior to desizing and, therefore, can not be recovered.

The film forming characteristics of the PAA during testing

were impaired by the formation of a calcium-polyacrylate

complex.

State of Development: The process was tested for 16 months

in a pilot plant.

5. Economics

Investment Costs: The capital cost for the

ultra-filtration plant is $600,000.

Operational and Maintenance Costs: Operating costs for

ultra-filtration plant was $61,000.

Payback Time: The payback period is 15 months.

6. Advantages:

Economic benefits were calculated in terms of raw material

savings based on 4DE 6 meters/year cloth production:

a) PVA sizing - $ 420,000/year

b) Enzymes - $ 100,000/year

c) Steam - $ 20,000/year

This resulted in a net savings of $ 485,000/year from

reduced waste generation (900 tons/year) and raw material

purchasing needs.

7. Constraints: No information provided.

8. Contacts and Citation

Type of Source Material: Journal

Citation: Buckley, C.A. 1982. The Performance of an

Ultrafiltration Recycling of Textile Desizing Effluents.

Water Science and Technology 14:705-713.

9. Keywords: South Africa, textile, cotton, sizing,

recycling, poly vinyl alcohol, ultrafiltration, starch,

ISIC 2211.

10. Reviewer's Comments: This case study was originally

compiled by the UNEP Working Group of Textiles. It

underwent a UNEP IE funded technical review in 1994 for

quality and completeness. It was edited for the ICPIC

diskette in July of 1995.

( Docno UNEP 11: DOCUMENT NOT AVAILABLE 11-13 )