Color in Textile Wastewater: How Much Comes from Dyeing Auxiliary Chemicals?
Project Title: Color in Textile Wastewater: How Much Comes from Dyeing Auxiliary Chemicals?
Continuation Project? No
Research Team Leader George L. Baughman and Warren S. Perkins
Phone: 706-542-4883
Team Leader's e-mail gbaughma@fcs.uga.edu
Team Leader's Institution University of Georgia
Industry Partner Contact Gene Roberts/Eddie Lanier
Phone: 706-645-4645/706-645-4515
Industry Partner's Organization WestPoint Stevens
Proposed Research Team:
Researcher Name and Institution Phone
George Baughman University of Georgia Phone 706-542-4883
Warren Perkins University of Georgia Phone 706-542-4885
Mary Sue Brewer University of Georgia Phone 706-542-3758
Requested Funds:
College or University $$ Requested
University of Georgia $135,000
Total TIP-PFFP Funds Requested for FY2003 $135,000
Executive Summary
Color in wastewater often creates regulatory or public relations problems for textile manufacturers in Georgia. Textile companies typically remove excess color from wastewater by adding chemical treatments. The cost of this treatment usually amounts to several hundred thousand dollars per year for a single plant.
Traditionally, industry has assumed that the color in wastewater from textile manufacturing plants came mostly from dyes not fixed to materials in the dyeing process. However, in our TIP-PFFP research work concerning the wetlands wastewater treatment system at Coats American in Toccoa, Georgia, we were surprised to find that the wastewater contained almost no dye. Rather, the color in the wastewater came from sources other than unused dye. After extensive investigations, we discovered that auxiliary chemicals such as dispersing agents used in the dyeing process may be the major source of color in the wastewater. These substances contribute to color in two ways. First, the dispersing agents themselves are dark brown and add some color to the wastewater. But more importantly, the two dispersing agents most commonly used in dyebaths both undergo photochemical reactions that generate intense color. These agents may transform to intensely colored substances when exposed to light during wastewater treatment. For example, a solution of a commercial dispersing agent used in large quantities at the Coats plant changes from virtually colorless to intense yellow when exposed to sunlight for just two hours. Interestingly, these same types of dispersing agents are used widely as additives in dyestuffs themselves. The amount of dispersing agent in a dye product can be as great as the amount of dye. Although, dispersing agents used in dyeing may be the greatest source of color in wastewater from the Coats American plant, we do not know that the same is true for other textile plants discharging water from dyeing processes. Furthermore, there may be other photochemically active auxiliary chemicals being used in dyeing and finishing that we have not identified.
The study proposed in this project will determine the contribution of auxiliary chemicals to the color level in wastewater from various types of textile manufacturing plants. If auxiliary chemicals are found to be a major contributor to color in textile wastewater, then the plants can look for substitute dispersing agents that do not contribute to the color problem in textile wastewater. This project has the potential to save textile manufacturers in Georgia several million dollars per year in wastewater treatment costs without any capital investment by eliminating the need for chemicals currently used for color removal.
The goals are:
1. to identify and quantify sources (auxiliary chemicals, unused dyes, dye decomposition products) of color in textile wastewater from the industrial partners' plants.
2. to identify possible alternatives to the chemicals that cause excessive coloration of wastewater.
We plan to work with 3 or 4 companies that discharge wastewater from dyeing processes to determine the contribution of auxiliary chemicals to color level in wastewater. The companies that participate will represent the major types of dye houses in Georgia including exhaust dyeing of yarn, continuous dyeing of flat fabrics, and indigo dyeing.
Explanation of Work Proposed
Description of the Critical Industry Problem
Color in wastewater often creates regulatory or public relations problems for textile manufacturers in Georgia. In the past, lawsuits brought by Georgia citizens against textile manufacturers resulted in consent orders that severely limited the amount of color that industry could discharge in wastewater. In these cases, the color removal measures that industry used to meet the requirements of the consent orders cost industry up to several million dollars in capital investment and hundreds of thousands of dollars in annual operating costs. Textile companies typically remove excess color from wastewater by adding coagulants to precipitate the color. The cost of chemicals for this treatment usually amounts to several hundred thousand dollars per year for a single plant. Furthermore, the removal and disposal costs of the resultant sludge are great and the sludge can generate additional environmental problems.
Traditionally, industry has assumed that the color in wastewater from textile manufacturing plants came mostly from dyes not fixed to materials in the dyeing process. However, in our TIP-PFFP research work concerning the wetlands wastewater treatment system at Coats American in Toccoa, Georgia, we were surprised to find that the wastewater contained almost no dye. Rather, the color in the wastewater came from sources other than unused dye. After extensive investigations, we discovered that auxiliary chemicals such as dispersing agents used in the dyeing process may be the major source of color in the wastewater. These substances contribute to color in two ways. First, the dispersing agents themselves are dark brown and add some color to the wastewater. But more importantly, the two dispersing agents most commonly used in dyebaths both undergo photochemical reactions that generate intense color. These agents may transform to intensely colored substances when exposed to light during wastewater treatment. For example, a solution of a commercial dispersing agent used in large quantities at the Coats plant changes from virtually colorless to intense yellow when exposed to sunlight for just two hours. Although, dispersing agents used in dyeing is probably the greatest source of color in wastewater from the Coats American plant, we do not know whether or not the same is true for other textile plants discharging water from dyeing processes. Furthermore, other photochemically active auxiliary chemicals that we have not identified may be in use in dyeing and finishing processes.
Industry and government have spent many millions of dollars in the past few years on funded research projects having the objective of decolorizing textile wastewater. Technologies studied have included oxidative methods using ozone, hydrogen peroxide, chlorine, chlorine dioxide, and other advanced oxidation technologies. Reductive technologies, adsorption technologies, precipitation technologies, and more recently, biological processes such as fungal, bacterial, and enzymatic processes have been studied for color removal. Interestingly, most of these projects assumed that the color in textile wastewater comes from unused water soluble dyes such as reactive, direct, and acid dyes. Consequently, the studies were conducted mostly with "synthesized" wastewater where known quantities of dye were added to water to make "wastewater" for experiments of the various technologies. Therefore, while these studies may have determined whether or not a given technology was effective in decolorizing dyes, the results may not reveal much about color removal from textile wastewater.
The study proposed in this project will determine the relative contributions of auxiliary chemicals and dyes to the color level in wastewater from various types of textile manufacturing plants. If auxiliary chemicals are found to be a major contributor to color in textile wastewater, then auxiliary chemicals that do not contribute to the color problem in textile wastewater can be sought and used. This project has the potential to save textile manufacturers in Georgia several million dollars per year in wastewater treatment costs without any capital investment by eliminating the need for the chemicals (or other technologies) currently used for removal of color from wastewater.
Objectives/goals for FY2003
The goals are:
1. to identify and quantify sources (auxiliary chemicals, unused dyes, dye decomposition products) of color in textile wastewater from the industrial partners' plants.
2. to identify possible alternatives to the chemicals that cause excessive coloration of wastewater.
Brief description of findings in current year
This proposal is for a new TIP-PFFP project. Some findings related to this proposed project were made in the course of our research on the TIP-PFFP project, "Evaluation of Wetlands forTreatment of Textile Wastewater." What we know based on limited studies done thus far is that dispersing agents based on naphthalene sulfonate condensates and lignin sulfonates generate a large amount of color when exposed to sunlight. Furthermore, these two types of dispersing agents are used in large quantitites in most dyehouses and are also widely used as diluents and dispersing agents in the formulation of commercial dyestuffs. As much as one- half of a dyestuff product may consist of these agents (sulfonates). We believe, but have not proved so far, that these agents are responsible for most of the color in wastewater from the Coats American plant in Toccoa which serves as our industrial partner in the Wetlands project. We suspect that these (or other photochemically active) chemicals are responsible for muchof the color in wastewater from many textile manufacturing plants .
Other research in this area
We found one published paper that discusses photochemical generation of color in water containing naphthalene sulfonates. That paper dealt with the effect of these agents on generation of color in a river and was not related to the use of these agents as dispersing agents by the textile industry.
Industry Partner's Involvement
This project requires close cooperation between the industry partners and university researchers. Industry partners provide information on consumption levels of chemicals used in the plant and potentially discharged in the plant's wastewater. The industry partners will also assist in collecting wastewater samples, analyzing for color level in wastewater, and performing other tests on the wastewater as appropriate.
Technical Approach
We plan to work with three or four companies that discharge wastewater from dyeing processes to determine the contribution of auxiliary chemicals to color level in wastewater. The companies that participate will represent the major types of dye houses in Georgia including exhaust dyeing of yarn, continuous dyeing, and indigo dyeing.
Westpoint Stevens will be the lead industrial partner for this project. Coats American, Milliken Co., and Mount Vernon Mills have all agreed to assist us by providing samples of wastewater and information about processing chemicals used in their plants. Fruit of the Loom at Rabun Gap also expressed interest in the project. The test sites will be selected from these or possibly other industrial partners. We have also had discussions with a major dyestuff supplier and a major supplier of dyeing auxiliary chemicals since the findings of this project could impact dye and chemical suppliers. Both have expressed interest in the project. Finally, we have discussed the project with the Georgia Environmental Protection Division (EPD). An expression of interest from the EDP is attached.
The main thrust of the project will be to identify those substances that generate color in textile wastewater so that actions can be taken to remedy the color problem. The university researchers will use chemical inventories and chemical consumption data provided by the industry partners to identify potentially photochemically active chemicals that may generate color in wastewater and other auxiliary chemicals that contribute to color in wastewater.
We will collect the data required to understand the photochemistry involved in the generation of color by selected chemicals. These studies will be done under controlled conditions in the laboratory so that we can understand the kinetics and quantitative aspects of the color generation phenomenon. We plan to use UGA's Atlas Weather-o-meter equipped with a xenon arc source to expose water samples. Exposure of samples in actual sunlight will likely also be done in some cases. Color will be measured using UV-visible spectrophotometry. High performance liquid chromatography (HPLC) and capillary electrophoresis (CE) procedures that we developed during the Wetlands project will provide data to help the research team understand the chemical phenomena involved in photochemical generation of color in wastewater.
We will monitor the color level in wastewater from each of the plants chosen for this study over a period of several months. Comparison of color levels in the influent and effluent will show whether color is generated during wastewater treatment. Chemical analysis of these samples may also be done in some cases to identify the source of color.
Findings from the research will be conveyed to the industrial partners in bi-monthly meetings of the project team members. We will also present findings at regional and national meetings of the AATCC and publish results in trade and scientific journals.
Project Team
Warren Perkins (Georgia Power Company Professor of Textile Sciences at the University of Georgia) has over 30 years experience in textile wet processing. Much of his research relates directly to water pollution abatement.
George Baughman (Senior Research Textile Chemist at the University of Georgia) has over 30 years experience in analytical and environmental chemistry. His previous employers include NASA and the U. S. EPA. He has worked for many years on textile-related projects, mainly concerned with water pollution abatement.
Schedule
Months Activity/Milestone
1-2 Obtain chemical usage data from each test site
2-6 Obtain and do color analysis on wastewater from each test site
3-10 Monitor color level in wastewater treatment systems of all of the plants included in the study
3-11 Test propensity of various chemicals to form color by photochemical mechanisms. Determine the effect of variables such as pH, temperature, inhibitory effects of other chemicals, etc.
12 Prepare final report
SUMMARY (for website)
Color in wastewater discharged from textile dyeing facilities is objectionable to the public. This project seeks to identify chemicals that contribute to color in textile wastewater enabling dyeing facilities to utilize alternative chemicals that do not contribute to color in wastewater.
