Solid paper mills

The pulp and paper industry is the largest industrial process water user in the U.S.5 In 2000, a typical pulp and paper mill used between 15,140 and 45,420 L (4000 to 12,000 gal) of water per ton of pulp produced. 1 2 3 4 General water pollution concerns for pulp and paper mills are effluent solids, biochemical oxygen demand (BOD), and color. Toxicity concerns historically occurred from the potential presence of chlorinated organic compounds such as dioxins, furans, and others (collectively referred to as adsorbable organic halides, or AOX) in wastewaters after the chlorination/ extraction sequence. With the substitution of chlorine dioxide for chlorine, discharges of the chlorinated compounds have decreased dramatically. 

Willhoft A proposed process for making aluminum chloride from the solid waste from paper mills. The waste is mainly a mixture of clay with cellulose. It is dried and calcined in an inert atmosphere, giving a mixture of clay and caibon which chlorinates readily. Conceived by E. M. A. Willhoft and briefly examined by the Research Association for the Paper and Board, Printing and Packaging Industries (PIRA) in England in 1977, but not piloted. 

Solid waste discharges from chemical plants can represent very large problems, especially from paper mills, plastics plants, and food processing plants. Some materials do not decompose in the environment, and can become burdens when they accumulate. Some polymers have backbones that degrade in nature, such as aliphatic polyesters and polyvinyl alcohols others do not, such as polyethylene and polystyrene. 

The vendor claims that Ensol is applicable for the treatment of wastewaters including sewage after primary treatment, metal plating and finishing waters, and paper mill white water. The claim also extends to the treatment of solid wastes and soils, provided that they contain sufficient free water. 

The Food and Drug Administration permits the use of diethanolamine as a component of adhesives in food packaging, as an indirect food additive, as a component of the uncoated or coated food contact surface of paper and paperboard for use with dry solid foods with no free fat or oil on the surface, and for use only as an adjuvant to control pulp absorbance and pitch content in the manufacture of paper and paperboard or for use only in paper mill boilers in the United States (Food and Drug Administration, 1999). 

Oxidized Starches. Alkaline hypochlorite treatment introduces carboxyl and carbonyl groups, effects some depolymerization, and produces whiter (bleached) products that produce softer, clearer gels. Ammonium persulfate is used in some paper mills with continuous thermal cookers to prepare in situ bigb solids, low viscosity dispersions. Most of the hypochlorite-oxidized starch and all the ammonium persulfate-oxidized starch is used in the paper industry. The low solution viscosity and good binding and adhesive properties of these products make them especially effective in high solids, pigmented... 

Paper mill waste liquor" (40% solids) 20 ft ID at lop 1350 F 31 X 103 lb/hr Sulfur added to produce 90-95% Na2S04 and some NajC03... 

Fig. 3 shows a condensate purification system used in a paper-mill boiler cycle. The resin beds not only remove dissolved impurities by ion exchange but also serve as filters to remove suspended solids. It is necessary to backwash and regenerate these resin beds periodically. Several types of condensate purification systems are available from various vendors. Some of these are capable of operation at temperatures as high as 300°F (149°C). 

In recent years, environmental concerns over water quality have led to installation of waste water treatment plants at pulp and paper mills. The underflow from the primary clarifier has generated another solid waste disposal problem. To solve this problem, some mills are feeding clarifier sludge to hog fuel boilers. The high moisture content of the sludge in conjunction with its low Btu content creates more difficult operating conditions for the furnace. Comparative composition of TDF, coal, wood waste,... 

The mill effluents need to be treated to remove the suspended solids. Sedimentation and/or dissolved air flotation, as discussed in Section 9.4, are commonly used for solids removal from pulp and paper-mill effluents [551],... 

Paper mill waste liquor (40% solids) 20 ft I.D. at top 1350° F 31 x 103 lb/h Sulfur added to produce 90—95% Na2S04 and some Na2C03... 

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