Bleaching plant source

FIGURE 21.5 Typical bleach plant source. (Taken from U.S. EPA, Profile of the Pulp and Paper Industry, 2nd ed., report EPA/310-R-02-002, U.S. EPA, Washington, November 2002.)... 

The two main sources of air pollutants that may be emitted from basic wastewater treatment plant operations are pulping condensates and bleach plant effluent. The pulping condensates may include total reduced sulfur (TRS) compounds as well as volatile organic compounds (VOCs) such as methanol. The primary pollutants of concern for the bleach plant effluent are chloroform and methanol. Any volatile compounds that could be released as air emissions from basic wastewater treatment plant operations are relatively minor and are generally not subject to specific regulation.65-66... 

Sources 1 BC Research, CPAR Report 245-1, Identification of the Toxic Constituents in Kraft Mill Bleach Plant Effluents . May 1974, p. 22. 2 BC Research, CPAR Report 245-2, Identification of the Toxic Constituents in Kraft Mill Bleach Plant Effluents . May 1975, p. 31. 3 R.H. Voss, J.T. Wearing and A. Wong. Effect of Hardwood Chlorination Conditions on the Formation of Toxic Chlorinated Compounds , Tappi, 1981, 64, 3, pp. 167-170. 4 R.H. Voss, J.T. Wearing and A. Wong, Effect of Softwood Chlorination Conditions on the Formation of Toxic Chlorinated Compounds , 1979 CPPA/TS Environmental Conference, Victoria BC, Canada, November 1979. 

Lecithin, both natural and refined grades, occurs as a substance varying in consistency from plastic to fluid depending on free fatty acid and oil content and on the presence or absence of other diluents. Its color varies from light yellow to brown, depending on the source, on crop variations, and on whether it is bleached or unbleached. Lecithin is obtained from soybeans and other plant sources. 

A PLENTIFUL supply of Suitable water is essential for a dyeing and bleaching plant. Before modern methods of water purification were available, the textile industries tended to congregate in areas where the natural water supply was plentiful and sufficiently pure. Water with a high degree of purity is rarely obtainable from natural sources. A knowledge of the impurities which will probably be present and how to remove them is, therefore, desirable. Supplies of water may be classified as follows ... 

In WPC decking and railing, plastic is filled with natural fiber, such as wood flour, rice hulls and by-product residues from the papermaking industry. Again, there are countless types of natural fiber, obtainable from countless plant sources, however, either a scale is not there, or an availability is restricted, and/or price is too high. Rice hulls cost is about 30/lb, wood flour about 3-50/lb, bleached fiber by-product (as a blend with minerals) of paper mills between 3 and 9 0/lb... 

The most appropriate point to install a treatment system is a key issue when developing waste utilization technologies. Targeting individual sources of organic materials prior to biological treatment appears to be the most effective approach. A major source of this material in bleached kraft pulp mills is the bleach plant where lignin residues are oxidized and dissolved into the water. 

End-of pipe effluent source. Effluent samples were taken from the El (first extraction stage) sewer of the bleach plant while the mill was processing Pinus radiata. Samples were stored at 4 °C. Treatment trials were carried out on filtered wastewater samples (25 mL) which had been adjusted to pH 11. The Fe-TAML catalyst (0.5 - 10 pM) was added simultaneously with H2O2 (2 - 30 mM) and stirred at 50 °C for a prescribed amount of time 30 - 300 minutes 34),... 

Chlorine dioxide degrades rapidly in air (see Seetion 6.3.2.1) and should be measurable only near its source of production or use (e.g., pulp and paper mill plants, water treatment facilities). As part of an international study of workers in the pulp and paper industry, the concentration of chlorine dioxide was measured in the workplace air of pulp and paper mills from 19 countries. The concentration of chlorine dioxide was measured in the following work areas steam and power generation (range, <0.001-0.06 ppm) effluent water treatment (range, not detected to 0.003 ppm) and maintenance (range, <detection limit to 5.8 ppb) (Kauppinen et al. 1997 Teschke et al. 1999). In another study, the concentration of chlorine dioxide was measured in the workplace air at a pulp mill in British Columbia, Canada between May and June, 1988. The concentration of chlorine dioxide was <0.01 ppm in area samples and personal full-shift samples. The exception was in the bleach/chemical preparation area sample in which the concentration of chlorine dioxide ranged from <0.01 to 0.3 ppm (Kennedy et al. 1991). 

Another cheap and readily available source of cellulose is the straw of annual plants. This raw material usually contains exceptionally large quantities of mineral matter. In order to separate cellulose the chlorine process is often used. It consists in treating the cellulosic raw material (previously boiled in a 10% sodium hydroxide solution and then in water) with chlorine. The decomposition of lignin, pentosans and other substances takes place and at the same time the cellulose is bleached. Crude cellulose prepared in this way contained 80-92% of a-cellulose and about 1% of mineral matter. 

A number of combustion and chemical production processes contribute to environmental concentrations of PCDD/F. Sources that have traditionally caused the greatest concern include municipal waste incinerators, hospital waste incinerators, bleached chemical wood pulp and paper mills, motor vehicles and wood combustion. We have attempted to represent the most recent data available on PCDD/F emissions from these sources. It should be remembered that the list presented here is by no means exhaustive. Potential sources of TCDD not discussed in the following paragraphs include discharges from metal processing and treatment plants, copper smelting plants and pentachlorophenol production. 

There are many other plants for continuous bleaching either in rope form or open width, and for further information the following sources should be consulted J. K. Skelly, J.S.D.C., 1956, 72, 7, N. F. Crowder and W. A. S. White, J.S.D.C., 1955, 71, 764, and Textile Scouring and Bleaching, E. R. Trotman, Griffin, London. 

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