Laboratory life tests were conducted with B-9 and NS-100 reverse osmosis (RO) membranes treating zinc cyanide plating solution at 10% of bath strength. The B-9 membrane was degraded by the high pH of the solution which was beyond the upper pH limit (pH 11) recommended for this membrane. The NS-100 membrane showed little deterioration in performance over the first 500 hours of operation. A reduction in permeate flux and rejection after 500 hours appeared to be due to precipitation of salts which resulted from operation in the closed loop test system and would not be expected in actual field operation. Field tests were conducted at New England Plating Company treating rinsewater from the zinc cyanide plating operation with a module of seven tubular NS-100 reverse osmosis membranes. A number of attempts were made to fabricate an NS-100 spiral-wound module, but all were unsuccessful. Further development will be required before the NS-100 can be commercially offered in an economically attractive configuration.

Includes bibliographical references (page 27). Prepared for U.S. Environmental Protection Agency, Office of Research and Development, Industrial Environmental Research Laboratory, Cincinnati, Ohio, submitted by Walden Division of Abcor, Inc. for American Electroplaters' Society, Inc., under Grant no. Contract Number: R803753.