What forms of silver are present in a sewage treatment plant discharge?
Silver that is present in POTW sludge and wastewater discharges is primarily silver sulfide and silver bound to particulate matter, with small amounts of metallic silver, silver chloride and silver organic complexes. The silver thiosulfate complex that is present in photographic processing solutions is biologically degraded to silver sulfide which is relatively non-toxic. Silver sulfide is one of the most stable and insoluble of the metal sulfides.
