Water usage at textile mills can generate millions ofgallons of dye wastewater daily. The unnecessary usage of water addssubstantially to the cost of finished textile products through increasedcharges for fresh water and for sewer discharge. Additionally, wastewaters fromtextile dyeing processes impose substantial pollutant loads on downstreampublicly owned treatment works due to high levels of color, chemical oxygendemand (COD), biological oxygen demand (BOD) and suspended solids.


Various processes have been utilized to reduce pollutantloadings in textile mill wastewater discharge. These "end-of-pipe"treatment systems treat the mill discharge just prior to discharge to the localsewer system. End-of-pipe treatment systems include flocculation, membranefiltration, chemical oxidation and activated carbon adsorption. For example:


  • the use of cationic polymers to flocculate organic compounds in wastewater discharge from textile yarn and fabric manufacturing operations.
  • the use of a macroamine polymer as the sole flocculating agent for clarifying and decolorizing wastewater.
  • purifying wastewater effluent generated during the manufacture of dyestuffs. The process employs lime to remove heavy metals from the wastewater, followed by carbon adsorption and secondary biological treatment.
  • purifying/decolorizing dyeing wastewaters using a membrane separation process.
  • decolorizing dye wastewater which first acidifies the wastewater, then adds a cationic flocculating agent followed by a reducing agent.


Many of the afore-mentioned processes can effectively treatand recycle a portion of the wastewater effluent discharged from textile mills.However, the capital and operating costs of these systems are high. The use oflarge quantities of chemicals or the use of membranes, which foul easily, leadsto operating costs that in many cases exceed the savings in reduced water andsewer discharge costs.


In spite of environmental regulations the implementation ofwastewater treatment systems at many textile mills is solely an economicdecision. In many areas, the local textile mill can threaten to relocate to aregion with looser regulations resulting in a loss of jobs to the region.



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