HBI-94-004-01
Pub. 10/31/94
The amount of pollutants and waste generated by industrial facilities has become an increasingly costly problem for manufacturers and a significant stress on the environment. Companies, therefore, are looking for ways to reduce pollution at the source as a way of avoiding costly treatment and reducing environmental liability and compliance costs.
The United States Agency for International Development (USAID) is sponsoring the Environmental Pollution Prevention Project (EP3) to establish sustainable programs in developing countries, transfer urban and industrial pollution prevention expertise and information, and support efforts to improve environmental quality. These objectives are achieved through technical assistance to industry and urban institutions, development and delivery of training and outreach programs, and operation of an information clearinghouse.
EP3 pollution prevention diagnostic assessments consist of three phases: pre-assessment, assessment, and post-assessment. During pre-assessment, EP3 in-country representatives determine a facility's suitability for a pollution prevention assessment, sign memoranda of agreement with each facility selected, and collect preliminary data. During assessment, a team comprised of U.S. and in-country experts in both pollution prevention and the facility's industrial processes gathers more detailed information on the sources of pollution, and identifies and analyzes opportunities for reducing this pollution. Finally, the team prepares a report for the facility's management detailing its findings and recommendations (including cost savings, implementation costs, and payback times). During post-assessment, the EP3 in-country representative works with the facility to implement the actions recommended in the report.
This assessment evaluated a dye house serving a variety of fabric manufacturers. The objective of the assessment was to identify actions that would:
Overall, the assessment identified 37 pollution prevention pollution opportunities -- classified as first, second, and third priority opportunities -- that could reduce energy use at this facility and avoid the release of over 14 metric tons of air emissions each year, in addition to unquantified reductions in the release of global warming gases and heavy metals. Water use could be reduced by 125,000 cubic meters per year, and chemical releases to surface waters could also be reduced. Finally, it may be possible to avoid the disposal of 330 cubic meters of solid waste per year.
This facility is a dye house serving fabric manufacturers. The facility operates two eight-hour shifts, six days per week, employing seventy shift workers and twenty technical and administrative employees. In 1992, the facility processed 350,000 kg of cotton and 360,000 kg of wool fabric.
In general, cotton dyeing involves two procedures, desizing and bleaching, and dyeing. Each procedure involves a number of steps that must be carried out in proper sequence and under optimal conditions. For detailed depictions of these procedures, see Figure 1 [provided in source document]. Wool dyeing also involves several procedures:
EP3 is sponsored by the U.S. Agency for International Development.
White fabric is desized and bleached in becks, with nominal capacities of 500 liters, 1,000 liters, and 1,500 liters of water. Fabrics to be dyed are desized and then dyed in jets.
At the time of the assessment, there were a number of pollution problems at the facility, including:
| Unit Operation | Pollution Prevention Action and Environmental/Product Quality Benefit | Cost | Financial Benefit/Payback Period |
|---|---|---|---|
| First Priority Opportunities | |||
| Steam Traps | Repair leaking traps - reduces air emissions and fuel costs. | $700 to replace traps. | $47,000 per year: 1 week |
| Steam System | Evaluate steam system components and layout and add at least two steam traps - reduces energy use prolongs life of components and reduces bath and boiler water contamination. | $120 for insulation; $500 for traps. | To be determined: To be determined |
| Steam Traps | Improve knowledge of steam trap selection - reduces energy use and avoids purchase and repair of traps. | None | To be determined: Immediate |
| Steam Traps | Purchase and use steam leak detector - reduces fuel consumption. | $1100 for instrument | To be determined: To be determined |
| Dyeing Becks | Modify rinsing procedures and becks - reduces water costs. | $400 for 16 valves flow restrictors and siphon piping. | $45,000 per year: Less than 1 week |
| Dye Baths | Replace sodium sulfate with sodium chloride - reduces sulfate emissions below effluent standards and reduces chemical costs. | None | $7,500 per year: Immediate |
| Wool Laundries | Repair leaks - reduces water and energy use. | $50 for screens and valve. | $3,700 per year: Less than 1 week |
| Zonco Washer | Repair leaks and maintain drain valves - reduces water and energy use. | None | $2,200 per year: Immediate |
| Sulfuric Acid Decarbonizing | Filter acid continuously - reduces release of sulfuric acid to sewer system. | $700 for in-tank filter. | $300 per year: 2.5 years |
| Floor Drains | Install and maintain screens to prevent lint from entering drains - reduces suspended solids sedimentable solids and sulfide in effluent. | $10 for screens. | To be determined: To be determined |
| Beck Number 10 | Relocate steam coil to prevent boil-over - reduces loss of chemicals and energy to drains. | None | To be determined: Immediate |
| All Becks | Repair and maintain steam coils - reduces fuel consumption and prevents contamination of dye baths and boiler water. | None | To be determined: Immediate |
| Boiler | Purchase and install combustion controls - reduces emissions and fuel use. | Unquantified | To be determined: Immediate |
| Jet Dryers | Monitor dye bath temperature to detect out-of-control condition - avoids chemical loss to sewer and reduces energy use. | $25 for thermometers. | To be determined: To be determined |
| Dyeing Process | Use Datacolor instrument to control process - reduces chemical use. | None | To be determined: Immediate |
| EMOS Water Supply | Test plant water distribution system for leaks - reduces water use. | None | To be determined: Immediate |
| Green Dryer | Re-balance internal air flow - reduces emissions of H2SO4 mist and energy use. | None | To be determined: Immediate |
| Green Dryer | Install exhaust fan after re-balancing dryer - avoids worker exposure to sulfuric acid mist and future medical costs. | $700 (est.) | To be determined: To be determined |
| Sewer Effluent | Determine nitrogen and hydrocarbon concentrations - assures compliance with effluent standards and helps set reduction priorities. | $200 for testing. | To be determined: To be determined |
| TOTALS: | $4,500 | At least $105,700 per year. | |
The assessment identified almost 40 pollution prevention opportunities that could address the problems identified, with significant environmental and economic benefits to the facility. The assessment team prioritized these opportunities based on pollution prevented and implemented cost. Table 1 lists the high priority opportunities recommended for the facility and implementation costs, and estimated payback period for each (a completed list of recommendations is available from the EP3 Clearinghouse). Many of the recommendations can be implemented with no capital investment. Further, many can be implemented almost immediately, and most are not dependent upon other projects for their initiation.
Of the 19 high priority opportunities recommended, the savings possible from implementing six have been quantified. These six recommendations will reduce operating costs by almost $106,000 per year for an initial investment of $1,900. The simple payback period for these changes is one week. Another $2,600 in investments is required to implement other changes whose savings potential cannot be quantified without further research.
Implementation of the recommended actions will produce positive environmental impacts in three areas:
Many of the proposed changes will reduce steam consumption and lower fuel use, thereby reducing air emissions. Repairing all traps should reduce fuel consumption by 36 percent, or 454 metric tons of number 6 residual oil per year. The expected reductions in air emissions from this change total over 14 metric tons per year. In addition, this change will result in reduced carbon dioxide and heavy metal emissions.
When all rinsing changes have been implemented, the facility should consume half the water it currently does. The yearly reduction in water use will be about 125,000 cubic meters. Chemical use will decline due to a number of changes. Sulfate in the effluent will be reduced by more than 70,000 kg/year by changing to sodium chloride and filtering the decarbonizing acid bath.
Releases to the sewer of other chemicals such as dye, dye stabilizers, de-foamers, detergents, sodium hydrosulfite, bleach, optical brighteners, acetic acid, equalizers, and boiler treatment chemicals will be reduced as a result of the recommended changes. Among the changes that will affect chemical releases are:
Solid waste discarded by the facility consists mainly of sulfate chemical bags and shavings and combings from fabric, finishing. Assuming that the eight sulfate bags generated per day fill one large (0.1 cubic meter) garbage bag and that the combings fill ten bags per day, the yearly un-compressed volume of these solid wastes is 330 cubic meters. If both wastes are recycled, this volume of waste can be reused at least once before bing discarded.
For further information on this assessment or other activities sponsored by EP3, call the EP3 Clearinghouse at (703) 351-4004, send a fax to (703) 351-6166, or on Internet apendergathabaco.com.