Removal of Silver from
Wastewater
Silver is most commonly found in plating shop wastewater, in photographic processing wastewater and X-ray processing wastewater. In plating shop wastewater the concentrations are usually less then 1 mg/l and the silver is complexed with cyanide. In photography wastewater the concentrations may be higher. Photography wastewater is usually treated with point of use ion exchange or plate out systems.
Silver cannot be precipitated by normal pH adjustment to discharge concentrations. Also carbonate precipitation of silver is ineffective. Phosphate precipitation can bring the silver to less than 0.1 mg/l, but to go lower sulfide precipitation will be necessary. Silver can be reduced to metallic silver with weak reducing agents.
