Water reuse paper industry

Disposal of the waste sellite soln, known as red water , is a serious problem. At TNT plants near paper factories, it has been possible to ship the red water to them for process use. For several reasons, this practice is being discontinued. Calcination of the red water gives crude Na sulfate, which has no commercial use. However, it can be reconverted to Na sulfite for reuse in the process by fusion with coal, a procedure in use in the Finnish paper industry. This involves the following reactions ... 

In general, the effluent volumes in the pulp and paper industry are huge, even cubic meters per second, and if aU the mixed effluent has to be treated by membranes, high fluxes and large membrane areas are needed. By keeping some water streams unmixed the membrane processes could be focussed on the most relevant streams and then only smaller volumes would need to be treated. Obviously, the membrane purification needed differs depending on the demands of the treated waters in the reuse application. 

Silva CM, Reeve DW, Woodhouse KA, Husain H, and Behmann H. Water reuse in the pulp and paper industry Evaluation of four microfiltration apphcations. Can. Pulp Pap. 1999 100(5) 38 3. 

Brady FJ. Industrial wastewater UF and RO treatment for water reclamation and reuse. A survey of commercial membrane system installations. 9th Annual Industrial Wastes Technical and Regulatory Conference, San Antonio, TX, April 13-16, 2003, 443-451. Lien L and Simonis D. Case histories of two large nanoflltration systems reclaiming effluent from pulp and paper mills for reuse. International Environmental Conference, Atlanta, GA, May 7-10, 1995, 1023-1027. 

Casani, S., Rouhany, M., and Knpchel, S., A discussion paper on challenges and limitations to water reuse and hygiene in the food industry, Water Research, 39(4) 1134-1146, 2005. 

The three major manufacturing consumers of water are chemicals and allied products, paper and allied products, and primary metals. These industries use water for cooling, processing, and boilers. Their potential for water reuse is high and then-total consumption of water is projected to drop in future years as recycling becomes more common. 

There are a number of papers and patents on recycling dye and textile industry wastewater for reuse of dye, textile auxiUaries, and water (99,102,120,306—311). Recycling is considered a part of pollution prevention. 

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