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 )