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Ozone Treatment

>From Aarti Sharma, in response to question on treatment of textile
effluents with ozone:

I am posting some information I have on hand on color and COD treatment
from the second and third issues of the TAPP-IN newsletter.  Please post
any other information you would like to share to texnet@clean.rti.org or
directly to me (if you are on the consultant list):

>From the second issue of the TAPP-IN newsletter:
Auburn University has a ten year old program that has involved research
on the use of oxidation technologies to decolorize dye waste water and
reuse the bath.  The original work, funded by Russell Corporation and
the National Textile Center (NTC), started with comparing the use of
chlorine and ozone gases.  Ozone was bubbled through dye waste in a
number of configurations, including a packed column, which increased
efficiency substantially compared to a standard bubble tower.   The
research has yielded a great deal of data on the effect of dye type and
the presence of auxiliaries on the kinetics of the process.  A pilot
trial, funded by the Electric Power Research Institute (EPRI) and the
Southern Company, was started about two years ago.  In the pilot work,
ten pound lots of knitted cotton fabric were dyed with a number of
current industrial reactive dye formulations. The mixed waste was
decolorized and the water was successfully reused for subsequent
dyeings.  This process was recently tested successfully on full scale
plant equipment at Russell Corporation. The project involved piping from
two dye machines to several storage tanks and an industrial scale
ozonator.  Auburn Researchers also looked at decolorizing spent dyebaths
with hydrogen peroxide, catalyzed by trace metals or by high and low
intensity ultraviolet irradiation.  This was successful and comparable
in effectiveness and cost to the ozone methods.  Products of
decomposition from oxidative destruction of the dye were also examined
for chemical structure and toxicity.  Although the products were
slightly more toxic than the original dyes, the total toxicity was
considered low. The trial showed that commercial dyebaths could be
reused with favorable economics.  However, only reactive dyes were used
and economics for other dye types have not been evaluated.  
For further information on this work, contact William K. Walsh
(Department Head, Textile Engineering, Auburn University, 334-844-5452,
wwalsh@eng.auburn.edu)  or Glynn E. (Ed) Fouche (Manager, EPRI
Industrial Processes, College of Textiles, North Carolina State
University, Raleigh, NC 27695-8301).

>From third issue:
The Color Cracker Oxidation Reactor, a technology developed by Tex-A-Tec
(Wattwil, Switzerland) to treat heavily polluted part water flows, is
being tested on a full-scale textile production facility in Switzerland.
This technology is being tested as a method to handle wastewater with
high concentrations of sewage elements (COD 5,000 to 20,000 mg O2/L),
which cannot be disposed of using conventional methods.  Waste disposal
features of the system include:

*	oxidation of organic products to CO2 and water (e.g., dispersing
and emulsifying agents, natural and synthetic dyestuffs, oils and
greases, natural and synthetic polymers);
*	COD and BOD reduction up to 90 percent, with the remaining
organic parts biocompatible;
*	an autotherm reaction that requires very low power consumption;
*	sludge-free operation.
Oxidation reactors have been used with success in other industries, but
have never been tested for application to textile wastewater.  After
analyses of results from the field tests in Switzerland, which are
expected to be completed early this year, the technology will be
considered for commercialization in the U.S.  For more information, call
Richard Gibson (Sclavos USA, Charlotte, N.C.) at 704-522-6330, or Felix
Frey (V.P. Sales, Tex-A-Tec) at 41-71-845-2128.  (Source: America's
Textiles International, November 1996; Conversation with Richard Gibson,
January, 1997).

>From the third issue:
The Center for Applied Energy Research at the University of Kentucky in
Lexington has developed a new process for simultaneous removal of colors
and heavy-metal pollutants from textile dyeing wastewater.  Bench-scale
tests with dyeing wastewater from a textile dyeing plant in Kentucky
show that the process can efficiently remove 90-99% of colors/dyes from
the wastewater.  Color content was reduced from untreated effluent
contents of 1200-8000 color units (c.u.; American Dye Manufacturers
Institute, ADMI) to below 100 c.u. (ADMI) at a cost of less than 50
cents per 1000 gallons.  Conventional chlorination methods cost 40-90
cents to reduce color to around 300 c.u.  The results also show a linear
relationship between reduction of color and removal of toxic metals.
Other benefits of the process include shorter retention times (entire
treatments can be completed in 5-10 minutes), effective operation even
at high temperatures (enabling recycling of hot treated water, reducing
energy consumption), no sludge disposal problems, and high quality
water, which can be reused in the dyeing application.  The developers
are looking for textile companies to participate in further developing
and field testing the technology.  They propose doing a basic study over
a 12 month period at an expenditure of $200,000 (e.g., 10 companies
could invest $20,000 each) and performing further field tests at about
$50,000 per company.  This proposal will be presented on March 4, 1997
in Lexington at the Center for Applied Energy Center.  If you are
interested in participating in this project or would like more
information on the technology, call Dr. B.K Parekh at 606-257-0239 or
Email at parekh@alpha.caer.uky.edu.

> > From: 	Centre for Cleaner Production
> > Inicitiatives[SMTP:prodneta@cipn.es]
> > Sent: 	Tuesday, July 01, 1997 1:54 PM
> > To: 	p2tech
> > Subject: 	Ozone treatment
> > 
> > Dear sirs,
> > 
> > I would appreciate if you could give me any information about
> > Treatment
> > of textile, leather and dye effluents by means of ozone. I would
> > appreciate any other information about color and COD reduction.
> > 
> > Thanks in advance for your help,
> > 
> > best regards
> > 
> > Esther Monfa
> > Centre for Cleaner Production Initiatives
> > Travessera de Gracia, 56, 4
> > 08006 Barcelona
> > Spain
> > 
> > e-mail: prodneta@cipn.es
> > fax: +34 3 414 45 82
> > 
> > 

Jesse Baskir
Manager, Pollution Prevention Program
Research Triangle Institute
P.O. Box 12194
RTP, NC 27709-2194
Phone:  (919)541-5882
FAX:  (919)541-7155