starch or modified starches and cellulose com- 

 pounds requires only small amounts of water for 

 making the 10-percent suspensions, but because 

 of the large number of mills and changes in size 

 suspensions needed, the total water used is about 

 2 percent of the process water for cotton (SIC's 

 2211, 2221, 2231). No recycling is practiced. 



The scouring of cotton and wool fibers and/or 

 fabrics is widely practiced. While water quantity 

 requirements are large, the quality requirements 

 for specialized textile or fiber products are quite 

 rigorous. Scouring is done at temperatures of 80 

 to 120 C and at pH 12 for cotton, but at much 

 lower temperatures of 30 to 50 C and at pH 2 to 

 4 for wool. The water is not recycled in the scour- 

 ing though large volumes of fabric may be scoured 

 in one batch. The rinsing operation may be de- 

 signed with counter current flow with use of the 

 discharge for makeup water in scouring operation. 

 The reuse of water in the textile industry is 

 limited to the newest mills, for any reuse or con- 

 servation is not common in the older mills. The 

 desizing of fabric is a cleaning operation that is 

 similar to scouring in its water requirements. These 

 operations involve 23 percent of the total process 

 water for the cotton textile industry. Mercerizing 

 of cotton is a specialized process which is becom- 

 ing much less significant with the introduction of 

 fiber blends and several cotton finishing plants 

 have discontinued its use. In 1963, when the cot- 

 ton textile industry figures were obtained, 13 per- 

 cent of the cotton was mercerized but this required 

 28 percent of the process water. 



The bleaching of textiles is done with either 

 chlorine or hydrogen peroxide. Chlorine is gen- 

 erally used with cotton while hydrogen peroxide 



TABLE V-6. Quality Characteristics of Surface 



Waters That Have Been Used by the Textile 



Industry (SIC 22) 



[Unless otherwise indicated, units are mg/l and values are 



maximum. No one water will have all the maximum values 



shown.] 



Characteristic 



Iron (Fe) 



Manganese 



(Mn) 



Copper (Cu) .._ 

 Dissolved 



solids 



1.0 

 0.5 



Suspended 



solids 1,000 



Hardness 



(CaCO,) 120 



pH, units 6.0-8.0 



Color, units C) 



1 Accepted as received (if meeting total solids or other limit- 

 ing values); has never been a problem at concentrations 

 encountered. 



NOTE. — Application of the above values should be based on 

 Part 23, ASTM book of standards (1). or APHA Standard 

 methods for the examination of water and wastewater, (5). 



is used with blends containing synthetic fibers and 

 with wool. When chlorine is used, the solution is 

 generally adjusted to pH 9, but when hydrogen 

 peroxide is used, the pH is adjusted in the range of 

 2.5 to 3.0. Rinsing of the bleached fibers or cloth 

 requires a high quality water. Recent academic 

 studies have suggested reuse of this water for 

 preparing chlorine bleach, but the reuse is not 

 now practiced (SIC 226). The bleaching opera- 

 tions in the cotton textile industry uses 20 percent 

 of the process water. 



Water for dyeing operations has very high qual- 

 ity criteria, but no higher than those needed in the 

 other processes. Cotton fibers (cloth) are dyed at 

 moderately high pH values while wool is generally 

 dyed at mildly acidic pH values. Synthetic fibers 

 are dyed at various pH values depending upon 

 the chemical character of the synthetic fiber. Water 

 from the dyeing operations cannot be reused. The 

 dyeing operations in the cotton textile industry use 

 approximately 32 percent of the process water. 



Significant indicators of water quality 



Table V-6 shows the quality characteristics of 

 raw waters that have been treated by existing proc- 

 esses to produce waters acceptable for the process 

 waters used by the textile industry. Table V-7 

 shows the water quality requirements at point of 

 use for the various processes within the textile in- 

 dustry. These processes are sizing, scouring, 

 bleaching, and dyeing. 



TABLE V-7. Quality Requirements of Water at 

 Point of Use by the Textile Industry (SIC 22) 



[Water quality prior to addition of substances used for internal 



conditioning. Unless otherwise indicated, units are mg/l and 



values that normally should not be exceeded.] 



Sizing 

 suspen- 

 Characteristic sion Scouring Bleaching Dyeing 



Iron (Fe) 0.3 0.1 0.1 0.1 



Manganese (Mn)_ 0.05 0.01 0.01 0.01 



Copper (Cu) 0.05 0.01 0.01 0.01 



Dissolved solids__ 100 100 100 100 



Suspended 



solids 5 5 5 5 



Hardness 



(CaCOc) 25 25 25 25 



pH, units: 



Cotton 6.5-10 9.0-10.5 2.5-10.5 7.5-10.0 



Synthetics 6.5-10 3.0-10.5 C) 6.5-7.5 



Wool 6.5-10 3.0-5.0 2.5-5.0 3.5-6.0 



Color, units 5 5 5 5 



^ Not applicable. 



NOTE. — Application of the above values should be based 

 upon analytical methods in Part 23 of the ASTM book of 

 standards (1), or APHA Standard methods for the examination 

 of water and wastewater (5). 



196 



