Recycle aluminum plates, negatives and any other silver-laden paper. Image Processing Silver compounds are classified as hazardous wastes under state and federal law if liquid wastes exceed five milligrams per liter of silver at a pH of 5.0. If process baths are discharghed into the sewer, a permit by the local sanitation department is usually required. Concentrations of silver-contaminated wastewater must be maintained below local limits established by each sewering agency. Ways to Manage Silver Eliminate by using silver-free films.
Some silverless products are vesicular, diazo and electrostatic films.
Photopolymer films contain carbon black as a substitute for silver. Recover silver from fixing baths and have a commercial recycler pick it up. Purchase a silver recovery unit and recycle fixer on premises. Add ammonium thiosulfate to silver-contaminated baths to extend the allowable buildup of silver. Process Baths Use an acid dtop bath prior to the fixing bath.