||Combined reverse osmosis and freeze concentration of bleach plant effluents /
Wiley, Averill J. ;
Dambruch, Lyle I. ;
Parker, Peter E. ;
Dugal., Hardev S.
||Institute of Paper Chemistry, Appleton, WI.;Industrial Environmental Research Lab.-Cincinnati, OH.
|| Environmental Protection Agency, Office of Research and Development, Industrial Environmental Research Laboratory ; For sale by the National Information Service,
Sewage--Purification--Reverse osmosis process. ;
Paper mills ;
Pulp mills ;
Water pollution control ;
Water reclamation ;
Performance evaluation ;
Industrial water ;
Cost estimates ;
Reverse osmosis ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||xi, 144 pages : illustrations ; 28 cm.
Reverse osmosis (RO) and freeze concentration (FC) were evaluated at three different pulp and paper mills as tools for concentrating bleach plant effluents. By these concentration processes, the feed effluent was divided into two streams. The clean water stream approached drinking water purity in some instances, and could potentially be recycled to the mill with minimal problems. The concentrate stream retained virtually all the dissolved material originally present in the feed. Typically, reverse osmosis removed 90% of the water from a stream containing 5 g/l of total solids to give a concentrated stream with 50 g/l solids. Freeze concentration further concentrated the reverse osmosis concentrate to about 200 g/l. Thus, each 100 liters of feed resulted in about 98 liters of clean water and 2 liters of concentrate. Schemes for the ultimate disposal of this final concentrate were not tested. Based on data collected at the three mills, estimates of the process economics were made. Reverse osmosis alone, or combined with freeze concentration, is quite expensive. At current levels of water usage for bleaching, costs ranged from $18 to $27 per metric ton of bleached pulp (approximately $3.50/1000 gallons (M gal) of bleach plant and increased membrane life could significantly lower these costs.
Prepared by the Institute of Paper Chemistry, Environmental Sciences Division, Appleton, Wisconsin, under grant no. R 803525-01. Issued June 1978. Includes bibliographical references. Microfiche.