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Silver Recovery Policy and Procedures

POLICY:  All image/photo processing equipment utilizing “wet chemistry” methods (e.g., fixer and developer) must be outfitted with equipment to recover silver halide from the wastewater effluent prior to discharge into the New York City Public Sewer System, as required by the New York City Department of Environmental Protection’s Best Management Practices Plans (BMPPs) for Persons Discharging Total Silver Halide Process Wastewater to the Public Sewer System.   In addition, scrap film and negatives may contain high silver concentrations and require proper handling and disposal through the University’s Hazardous Waste Management Program.

PURPOSE:  To reduce the potential for silver, a toxic, heavy metal regulated by the USEPA, NYSDEC and NYCDEP, from entering the environment in wastewater (e.g., equipment effluent) or as a solid waste (e.g., film media) by-product of image/photo developing activities.   Since waste generated in the processing of images/photos contains silver, all waste from these activities must be collected and/or filtered in accordance with this Policy and procedure.

RESPONSIBILITY:  All principal investigators, administrators, laboratory, facilities operations and EH&S personnel involved in using, managing, constructing and/or maintaining  dark room facilities and photo processors in Columbia University spaces.

APPLICABILITY:   All dark rooms and image/photo processing installations using “wet chemistry” methods. 


  1. Columbia University utilizes silver recovery units in processing the wastewater effluent generated in the processing of films and use “scrap film” collection containers for capturing silver-containing solid waste.  All dark rooms and image/photo processing installations using “wet chemistry” methods must be equipped with silver recovery equipment prior to use. 
  1. If a silver recovery unit appears to be damaged or leaking or if the laboratory or image/photo processing area is not equipped with a silver recovery unit, please contact a Hazardous Materials Officer in the EH&S office at the respective campus.  For the Medical Center office please call 212-305-6780.  For the Morningside, Lamont Doherty-Earth Observatory and Nevis campuses please call 212-854-8749.
  1. EH&S is the sole authorized department responsible for silver recovery equipment installation and maintenance and must be contacted to schedule installation of silver recovery equipment prior to use of image/photo processing equipment.
  1. Silver recovery units are not to be removed or altered with in any way. If your image/photo processing equipment supplier or service provider removes the silver recovery unit to repair or replace your image/photo processing equipment, the silver recovery unit must be re-installed by the service provider prior to use.  Contact EH&S prior to use so proper connection can be verified. 
  1. All silver recovery units are inspected quarterly by EH&S personnel in conjunction with the University’s contracted vendor to ensure the effluent silver concentration is not beyond the acceptable threshold and the all parts of the unit are functioning properly. 
  1. Silver contaminated fixer is fed into the top of silver recovery unit allowing gravity to pull the product through the filters collecting silver as the product moves toward the effluent at the bottom of the unit.  The silver recovery equipment is an “end of pipe” process and does not interfere with or otherwise impact the function of the processing equipment. 
  1. Scrap film must be kept in a labeled scrap film collection container provided by EH&S. These containers must be kept closed or sealed when not in active use.  If a scrap film container is needed please contact the Hazardous Materials Officer as indicated in Item 2.
  1. The silver recovery units and the associated work areas must be maintained free of debris, sharps and gels.
  1. A darkroom log must be kept inside or posted on the entrance to the dark rooms. All personnel using x-ray/photo processor must maintain the dark room log.  A copy of the log is available at the EH&S website at ROOM LOG SHEET.pdf  The information provided by the log is utilized for silver recovery unit maintenance performed by a Columbia University approved vendor.
  1. If the dark room also contains applications for ethidium bromide (agarose gels) usage, the resulting waste must be managed in accordance with Columbia University’s Hazardous Waste guidelines available for the Morningside campus at or for the Medical Center campus at  In summary, all containers must be kept closed when not in use, properly labeled, checked periodically for leaks and stored for disposal in the darkroom where the gels are used.
  1. If razor blades and other sharp items are used within the dark room a sharps container must be used.  If a sharps container is needed please contact the Medical Center’s Facilities Operations office at 212-305-7367.  At the Morningside campus please submit an online waste pickup request by completing the comment section and requesting a container(s).
  1. Housekeeping must be performed on a regular basis. Housekeeping helps prevent slips, trips and falls. Floors must be kept free of debris such as film, sharps, gels and paper. General housekeeping is the responsibility of the laboratory personnel. If extensive housekeeping is needed such as floors swept &/or mopped and trash removal contact Facilities Operations.  At the Medical Center campus call 212-305-7367 and at the Morningside campus call 212-854-2222. 

FAQs (under construction).

Columbia University Morningside Campus
Environmental Health & Safety
(212) 854-8749

Columbia University Medical Center
Environmental Health & Safety
(212) 305-6780

6 NYCRR Parts 370 through 374 and 376 – Hazardous Waste disposal:

6 NYCRR 371.1(c)(7) – prior notification for scrap metal exemption available at:

Further information is available in the U.S. EPA’s guidance document “RCRA in Focus: Photo Processing.”  Available at: