The Application of Reverse Osmosis to Recover Photographic Processing Wastes

Donald C. Brandt

Reverse osmosis is a process in which dissolved salts are removed from aqueous solution by passing the solution across a semi-permeable membrance at elevated pressures. The membrane passes most of the water and rejects the dissolved salts as concentrated solutions. In the photographic processing industry, reverse osmosis can provide high quality make-up water (called product water) for film manufacture, chemical make-up solutions and film washing. It also provides a technique to concentrate wash waters to reclaim from them valuable salts. These concentrated streams may be recycled directly with proper chemical adjustment, or be further treated to reclaim valuable materials by other techniques such as electrolysis, precipitation, etc. Wash water reclamation can cost from $0.90 to $1.10 per 1000 gallons ($0.24–$0.29 per 1000 liters) of reused water for a 100,000 gal/day (378, 541 L/day) installation. These costs can most often be recovered by the value of the reclaimed chemicals. Chemical recovery costs can range up to $0.05 per pound ($0.11 per kilogram) of recovered chemicals. The use of reverse osmosis may be beneficial in areas short of water, or where there is difficulty in meeting local effluent standards.

Print ISSN
Published
1980-11
Content type
Original Research
DOI
10.5594/J01539