L.W. PACKARD & CO., INC
DYE RECOVERY PROJECT
FINAL REPORT
September 12, 1995
by
Todd D. Malcolm
(603) 868-6989
Chemical Engineering Department
P2I Program, University of NH
Copies to: Ms. Susan Francesco, V.P.
L.W. Packard & Co., Inc.
Mr. John Glidden, President
L.W. Packard & Co., Inc.
Dr. Ihab H. Farag, P.E.
Dept. of Chemical Engineering, UNH
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FACILITY AND CONTACT PERSON
L.W. Packard & Company, Inc.Ms. Susan Francesco, V.P.
Woolen ManufacturersEnvironmental Coordinator
P.O. Box 515(603) 968-3351 Ext. 314
6 Mill Street(603) 968-7649 fax
Ashland, NH 03217
EXECUTIVE SUMMARY
L.W. Packard & Co., Inc (LWP) requested an internship assignment because of difficulty with the town of Ashland’s POTW (Publicly Owned Treatment Works) in regard to the industrial wastewater coming from the facility. LWP also felt that an intern would be able to suggest some in-house process modifications that could effect savings, thus “killing two birds with one stone.”
The difficulty from the POTW arose because it was having difficulty processing LWP’s colored wastewater to its permitted discharge levels. Since the POTW was one of the first of its type built in the state, it really was designed for sanitary (domestic) wastewater, not the industrial effluent coming from the plant. Essentially it was having difficulty in removing all the color from the dyehouse wastewater, and therefore was discharging an objectionable amount of color into the receiving surface water. At the same time the operators were complaining of significant odor problems, arising from the chemical nature of the wastewater. It was therefore our duty to research possible solutions and test their “in-house” feasibility/ cost-effectiveness.
My specific project was to research the possibility of recovering the unused color remaining in the water after the dyeing operation, thereby effecting a raw-material savings while at the same time removing the color from the wastewater. While looking into this process I ended up conducting a general plant audit and looked into any other wet-process operations which were contributing to the waste stream.
My recommendations thus far have been to consider a filtration application and to begin to recycle process water within the mill. At this point the project is continuing since it has been targeted for a year-long period. I will continue to work with LWP, the UNH Chemical Engineering Dept., the NHIRC (New Hampshire Industrial Research Center), NH-DES, the Town of Ashland, and several vendors and universities to evaluate the results achieved thus far. The bench-scale tests seem to be promising and we need to proceed with pilot-scale studies at the mill.
INTRODUCTION
LWP is a vertically integrated woolen manufacture that produces a variety of unique fiber mixtures as well as custom colors. This means they start with raw fleece, scour (clean) it, spin the fiber into yarn, weave the yarn into fabric, and then dye the material to the customers specifications for color. This is a demanding market in terms of quality control, and large fluctuations seasonally and annually occur in terms of product demand (both in volume and composition). Therefore in order to remain competitive, LWP must be able to adjust their process quickly and accurately according to the desired product. This makes the analysis of the process flows difficult since they are extremely transient both in volume and makeup.
The two processes I attempted to analyze and chart were:
DYEHOUSE- This is where the large bolts of fabric are placed in large open vats and colored
through chemical addition to an aqueous phase.
FULLING- This process actually is situated directly before the dyehouse and is where the
woven pieces of fabric are scoured and shrunk(fulled) to their final dimensions.
These two processes were chosen because they consume most of the water and chemicals used at the mill. Therefore, they are responsible for the bulk of the water pollution created and by properly addressing them the situation with the POTW could be resolved.
GOALS AND OBJECTIVES
Upon arriving at the facility I was charged with the DYE RECOVERY PROJECT. (Although I also examined the fulling process and present some results pertaining to it, the nature of this report is discuss the former since a separate team was assigned the latter.)
Since the wastewater which is “dumped” from the vats in the dyehouse contains a noticeable amount of color (thus the current situation with the POTW) the management feels that if this color was to be removed from the waste stream and collected, it might be reused (substituted) in later dye solutions. Therefore it was my responsibility to:
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.Characterize the nature of the dye solution and the mechanism by which it interacts with the cloth.
.Determine the usual process flow volumes and their makeup.
.Determine what technology might be applied to achieve the reuse/removal option.
.Contact vendors that deal with the required equipment and determine feasibility and costs.
.Choose a vendor to work with and have preliminary bench-scale tests conducted.
.Evaluate the results of the bench-scale tests to determine if our objective can be achieved.
.Move to pilot-scale tests on-site and re-evaluate the feasibility in actual process conditions.
.Determine the cost of implementation of a full-scale system if pilot-scale tests are successful.
.Report the results to the management.
.Move to installation of full-scale system if deemed cost-effective.
At this point in time I am still awaiting the laboratory analysis of the results obtained from bench-scale and will proceed to pilot-scale testing if appropriate.
METHOD OF APPROACH
After meeting all the key players at the facility and the operators of the POTW I conducted a literature search, contacted universities known for their textile departments, interviewed consultants who specialize in wastewater and textile operations, discussed chemical and process specifics with vendors, and gathered as much general information about the process by auditing the facility and questioning the operators.
It was determined that a filtration application was necessary to remove the color, either by first precipitating through chemical addition (no reuse), or by using a membrane capable of removing the dye molecules without removing them from their “active” (dissolved) state. Four methods of filtration were examined:
Microfiltration- removes suspended solids but not dissolved solids
Ultrafiltration- molecular weight selective 10,000-100,000 MW removed
Nanofiltration- finer than ultrafiltration (roughly 100-10,000 MW)
Hyperfiltration-(Reverse Osmosis) all the way down to MW of 18 (water) originally
designed for the desalination of drinking water since salt (Na) is
hardest to remove, MW23, very close to same molecular size as H2O
After determining that these were the appropriate methods to consider, I contacted several vendors and made a final selection of whom to work with by examining their references and past experience with similar projects. (Their names are given in the appendices.) Basically, I provided them with flow information from our process and sent them several volumes of solution that would normally be “dumped” into the waste stream, as well as a volume of fresh water (before chemical addition) used in our process. (A solution from the fulling process was also sent for evaluation.) They then processed this liquid through a system and sent the individual samples created out to an independent laboratory to be tested. The following is a list of the parameters to be tested:
ANALYTICAL TESTING
COST / TEST / RAWWATER / DYE
DUMP / DYE UF
PERM / DYE NF
PERM / FULLING
DUMP / FULLING
UF PERM / TOTAL
COST
$12 / pH / X / X / X / X / X / X / 72
$40 / SDI / X / 40
$24 / Ca / X / 24
$24 / Mg / X / 24
$24 / Na / X / X / X / X / 96
$24 / K / X / 24
$30 / NH4 / X / 30
$30 / HCO3 / X / 30
$24 / NO3 / X / 24
$24 / Cl / X / 24
$24 / F / X / 24
$24 / SO4 / X / X / X / X / 96
$24 / SiO2 / X / 24
$36 / COD / X / X / X / X / X / 180
$40 / O&G / X / X / 80
$24 / TSS / X / X / X / X / X / 120
$24 / TDS / X / X / X / X / X / X / 144
As mentioned earlier, this is the information I’m waiting for at this point. This information will be used to evaluate water recycle possibilities, dye re-constitution/re-use, fulling process chemical reuse, as well as the reduction of pollution in the effluent by application of the given technology.
CHEMICAL USAGE AND EQUIPMENT NEEDS
The actual dyehouse procedure followed for a piece-dyeing was given in detail in my second progress report (See PROGRESS REPORT II or go to pack2A.doc on disk), but in general the chemicals used in bulk in this process are:
.Aqueous Ammonia
.Polydyol EV-M (textile agent)
.Aqautex NBL (textile agent)
.Sodium Sulfate
.Citric or Sulfuric Acid
.Eccoscour LP-1 (textile surfactant)
Equipment hasn’t been installed yet for the filtration process, but the schematic of the dyekettles used is included in the appendices. For more specific information on either the process or the chemicals used please consult PROGRESS REPORT II. (The fulling process has been described in detail by the other team, but generally the chemicals used are: a solvent for removing the tar-like contaminants, water, and a surfactant used to form an emulsion with the solvent. The specifics of these chemicals can be found in earlier documentation.
RELEASES AND WASTES GENERATED
LWP has eliminated most air emission sources (or is working on reducing any remaining source), but continues to discharge the various chemicals mentioned earlier to the POTW by way of their effluent (aqueous). Concurrently the town is working to upgrade the treatment efficiency of their POTW with a consultant. It is felt that through their work and our source reduction efforts “in-house,” a solution will be reached to the issue of the discharge to the surface water of unacceptable pollutants. The issue of solid waste generation is also being researched by consultants hired by LWP since the town’s solid waste disposal facility is in the process of closing.
WORK ACCOMPLISHED / PROJECT RESULTS
During the summer portion of the project a technology was found to partly remove the color from the wastewater generated, namely, ultrafiltration followed by nanofiltration. Likewise it was found to reduce the pollutants in the fulling wastewater significantly.
Flows were established for both the fulling process and the dyehouse and a good deal of analysis was done for the two in terms of chemical oxygen demand (COD) through the cooperation of the POTW operators. The general flows are:
PRODUCTION VOLUMES IN FULLING
.Approximately 1350 gallons “dumped” per set
.Sets per day varies greatly due to different requirements for different fabric styles but a rough estimate is six per day per mill (if three shifts) times 6 mills
.Total = 50,000 GPD±
PRODUCTION VOLUMES IN DYEHOUSE
Assumptions:
.7 full size open dyekettles (1089 gallons w/o beam)
1 sample open dyekettle (135 gallon)
1 pressurized dyekettle (roughly same fill volumes as open full size)
.Cloth absorbs 2lbs. H2O for every lb. of fabric dyed therefore the full size kettles actually have 583 gallons of water that isn’t absorbed and is “dumped”
maximum production if LWP was running at full capacity
50% of dyeings at LWP are Black
4 kettles x 583 gallons H2O = 2332 gal H2O (contains residual chemicals) fill
3 to4 rinses x (583 x 4 kettles) =9328 gal H2O (contains residual chemicals)
remaining colors dyed at LWP
3 kettles x 583 gallons H2O =1749 gal H2O (contains residual chemicals) fill
2 to 3 rinses (583 x 3 kettles) =5247 gal H2O (contains residual chemicals)
sample kettle-assume 1 piece at 92 lb. absorbs 22 gallons of water
1 kettle x (135 - 22) =113 gal H2O (contains residual chemicals) fill
3 rinses x 113 =339 gal H2O (contains residual chemicals)
pressure kettle has continuous rinse mode
1 kettle x 583 gallons H2O =583 gal H2O (contains residual chemicals) fill
continuous rinse =? gal H2O (contains residual chemicals)
Total19,691 gal x 6 set/day = 118,146+ gal/day
actual production at LWP is about 80 % of this under normal conditions
FEED POSSIBILITIES FOR NANOFILTER SYSTEM
SCENARIO A
.treat only initial dyekettle dump from black dyeings (50% of total)
13,992 gal/daymaximum11,194 GPDcurrent operation
SCENARIO B
.treat initial dyekettle dump from all dyeings
24,486 GPDmaximum19,589 GPDcurrent
SCENARIO C
.treat initial dyekettle dump and first rinse from black dyeings
27,984 GPDmaximum22,387 GPDcurrent
SCENARIO D
.treat initial dyekettle dump and first rinse from all dyeings
32,874 GPDmaximum26,300 GPDcurrent
The size of the system chosen will depend on our ability to show savings from -reuse of dyestuffs captured as concentrate
-reuse of treated process water (permeate)
-capture of thermal value of treated process water
-savings in surcharges from the POTW through reduction of COD,BOD,TSS, color,etc.
Please refer to the appendices for COD analysis of fulling and dyebath solutions.
Basically at this point KOCH Membrane Systems, Inc. has visited LWP and feels that filtration will be cost effective for recovery of soaps used in the fulling mills (savings in the neighborhood of $70,000/yr. materials). Mr. David Van Ham, their representative, presented his system to LWP on September 11,1995 and has indicated that he will work towards providing some concrete figures/results to backup this claim. In regards to dye recovery, he said “anything is possible” but did not indicate any specifics.
It is my intent to determine LWP’s wishes as to the direction of this project at our September 15th meeting, and to aquire the results of the Dynatec Systems, Inc. laboratory study in the next few weeks to aid them in this decision. I feel that the project should continue and that membrane application is the application to use for both the fulling mills and the dyekettles. I also wish to continue work with Aqua-Aerobics Systems, Inc. in regard to color removal by chemical precipitation and cloth filtration as an alternative solution. The next step is to determine how much solid waste (sludge) will be created by each option and the costs associated with disposal.
POLLUTION PREVENTION BENEFITS
By removing the pollutants in LWP’s wastewater the following benefits could be realized:
.Savings on soaps used in the fulling mills by recovery and reuse.
.Savings on dyestuffs and chemicals used in the dye process by recovery and reuse.
.An easing of tensions with the town’s POTW through a reduction in BOD/COD loading due to the removal of chemicals from effluent of facility
.A possibility of water recycle by reuse of process water that has been cleaned by filtration (perfection of this at current location will make move to New Hampton easier)
.An easing of tensions with the town’s POTW through reduced hydraulic loading due to water recycle
.Increased worker productivity through health benefits gained by the reduction of hazardous chemical usage which can also be equated with a more environmentally conscious image projected to consumers of product
APPENDICES
REFERENCES
Porter, John J., and Grant A. Goodman, Recovery of Hot Water, Dyes and Auxiliary Chemicals from Textile Wastestreams, Desalination, 49 (1984) 185-192
Porter, J.J., and Eric H. Snider, Ozone Destruction of Selected Dyes in Wastewater, American Dyestuff Reporter, December 1979 pgs. 43-64
Porter, J.J., and C.A. Brandon, J.S. Johnson, R.E. Minturn, Complete Reuse of Textile Dyeing Wastes Processed with Dynamic Membrane Hyperfiltration, Textile Chemist and Colorist, vol. 5, #7, July 1973 pgs. 35-38
Porter, J.J., and C.A. Brandon, Ali El-Nashar, Reuse of Wasewater Renovated by Reverse Osmosis in Textile Dyeing, Membranes, pgs. 983-991
Porter, J.J., Application of Membrane Systems to the Recovery of Chemicals from Textile Wastestreams, School of Textiles, Fiber and Polymer Science; Clemson University; Clemson, South Carolina 29634
11 pages
Schiller, Mikhail, and Matthew E. Hackman, Water Re-use Systems for Zero Discharge, Environmental PROTECTION, September 1993 pgs. 72-75
Bergenthal, Jon F., and Anthony J. Tawa, Investigation of Textile Dyebath Reconstitution and Reuse, Industrial Environmental Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 July 1984
McClung, Suzanne M., and Ann T. Lemley, Department of Textiles and Apparel, Cornell University, Ithaca, NY, Electrochemical Treatment and HPLC Analysis of Wastewater Containing Acid Dyes, Textile Chemist and Colorist, vol. 26, #8, August 1994 pgs. 17-22
Wilcock, A.E., and S.P. Hay, Department of Consumer Studies, University of Guelph, Recycling of Electrochemically Treated Disperse Dye Effluent, Canadian Textile Journal, May 1991 pgs. 37-44
Demmin, Timothy R., and Kevin D. Uhrich, Andco Environmental Processes, Inc. Amherst NY,Improving Carpet Wastewater Treatment, American Dyestuff Reporter, June 1988 pgs.13-32
Spectrophotometric Analysis of Electrochemically Treated, Simulated, Disperse Dyebath Effluent, Textile Chemist and Colorist, November 1992 pgs. 29-37
LaGrega, Michael D., and Phillip L. Buckingham, Jefferey C. Evans, Hazardous Waste Management, McGraw-Hill,Inc.,NY, 1994
Calfa, Lyle, and Jean Holbrook, Cheryl Keenan, Tim Reilly, Dr. Robert Pojasek, A Guide to Pollution Prevention in Woolen Mills, prepared for the Northern Textile Association, July 1993
Byers, Bill, CH2MHill, Zero Discharge: A Systematic Approach to Water Reuse, Chemical Engineering, vol. 102, #7, July 1995 pgs. 96-100
Cappos, Steve, Fluid Systems Corp., Membranes Minimize Liquid Discharge, Chemical Engineering, vol. 102, #7, July 1995 pgs. 102-104
Metcalf & Eddy, Wastewater Engineering TREATMENT DISPOSAL REUSE, McGraw-Hill,Inc.,NY, 1991
UNH SAMPLING AND ANALYSIS
COD
Date of Sampling:7/26/95using HACH 0-15,000 ppm vials
Location:Dyekettle
Set #:12429
Original Formulation:
FORMULASHADESTYLEKETTLEFABRIC WEIGHT
BLK5035BLKBLK5035BLK4P824 lbs.
FLANNELPIECESPO#
5034BLK819950725
CHEMICALQUANTITY (LBS.)
SANDOCLEAN PC-RUN 10 MIN.16.480
AQUA AMMONIA 26 DEGREE16.480
AQUATEX NBL (NEW)16.480
GLAUBER SALT,SODIUM SULFATE82.400
POLYDYOL EV-M16.480
CITRIC ACID (imported)8.240
ECCO SCOUR LP-1
DYESTUFFS
BLACK SAS#5 200% ORCOAC25.673
ORANGE 2GL, LIGHT3.031
YELLOW 2G LIGHT3.462
ORANGE RO0.378
BLACK 10 BR BERKACID 125%1.081
BLACK NCS-F ORCOCIL3.139
Sample size:2 ml
multiplierCOD (mg/L)AVERAGE COD
reading 1:11*2002,2002,340mg/L
reading 2:11*2002,200
reading 3:262*102,600
UNH SAMPLING AND ANALYSIS
COD
Date of Sampling:7/26/95using HACH 0-15,000 ppm vials
Location:Fulling
Set #:12480
Original Formulation:
CHEMICALQUANTITY (GAL.)
SOAP90.0
TAR REMOVER (ORIGINAL)8.0
Sample size:2 ml
multiplierCOD (mg/L)AVERAGE COD
reading 1:101*20020,20019,734mg/L