Clean Water Advocacy - Newsroom - AMSA in the News
Silver Recovery 2003
8/11/2003 Focus on Imaging
Code of Management Practices Guide for Photo Processors (CMP) Helps Stabilize
Silver Recovery Technology
No one involved in photofinishing will argue that there have been tremendous
changes in photo-processing over the last several years. According to the Photo
Marketing Association International (PMA) Photo Industry 2003: Review and
Forecast, film and camera sales peaked in 2000. Since then, they’ve been on the
decline. The report attributes this to the aftermath of the 2001 recession,
combined with consumers’ shifting preference towards digital products.
The Eco Still from Cal-Glass uses a distillation technique to produce distilled
water and solid silver-bearing waste from photo chemicals.
By the end of 2002, 21 percent of U.S. households owned a digital. That’s one of
the main reasons that film processing volume fell by two percent for that year.
The one bright spot in the picture for traditional photographic products is the
continued growth of one-time-use cameras.
There’s one area, though, where there haven’t been such revolutionary changes,
and that’s silver recovery in film processing. Of several factors contributing
to this stability, the most important is the development and promotion of the
Code of Management Practices Guide for Photo Processors (CMP) by the PMA, which
came about as a result of increasingly stringent, and increasingly difficult to
meet, out-fall regulations.
In the mid-1980s, regulators identified photo processors as one of the primary
sources of silver pollution in sewer systems and set out to regulate them. While
regulations for labs were increasing, the other sources of silver pollution were
being ignored. Regulators didn’t put the same effort in trying to control
out-fall from medical facilities that generated X-rays, printers and pre-press
operations, microfilm firms, and the various other types of businesses that
produced waste water with silver-halide in it. Photo labs were targeted to take
the brunt of the regulatory pressures.
The Big MO metallic replacement cartridge is filled with CPAC’s own brand of
iron that recovers more silver, pound for pound, than other types.
Regulatory pressures often resulted in concentration limits that were so
stringent that they could not be met, even with the best available technology,
at least not in a way that was economically achievable. So the PMA developed the
CMP, which suggests performance-based limits rather than concentration-based
limits. Performance-based limits are spelled out as a percentage of silver that
must be recovered from silver-rich solutions. “The Code of Practice is designed
to have all sources of silver included, so that all (types of) photo processors
do their fair share,” Ron Willson, who serves as a consultant to PMA, explained.
For best results with cartridge systems like CPAC’s Big MO, a constant flow rate
such as that provided by the METS A101 is recommended.
Under the CMP, photo processors are grouped by size into four categories. Small
specialty labs, such as those found in dental offices, must recover silver to at
least 90 percent efficiency; medium-sized labs, such as small mini-labs and
quick print facilities, must recover silver to at least 95 percent efficiency.
Large labs, such as commercial facilities, must recover silver to 99 percent
efficiency. And significant industrial users that discharge more than 25,000
gallons of effluent into the sewer system per day must apply for individual
permits from the city. The CMP provides a level playing field, with compliance
based on the type of silver recovery system each silver-generating facility has
in place. Between 35 and 40 cities, including such diverse, and different sized
cities as New York, NY, San Diego, CA and Laramie, WY, have adopted the CMP.
Willson points out other factors contributing to the stability in the silver
recovery area are the de-emphasis on silver as a major source of pollution. “The
efforts of PMA in educating groups like the Association of Metropolitan Sewerage
Agencies has resulted in current compliance efforts targeting areas where there
are real effluent problems, like grease from restaurants. And in times of
budgetary cutbacks in government, municipalities are more likely to adopt the
CMP that is working in other cities, and is designed to be fair to producers of
silver waste while significantly lowering silver discharge in sewage.” To ease
this process further, PMA, in coordination with the Silver Council, has
developed a CMP Self-Implementation Kit that is made available to cities without
charge.
Photo labs, municipalities and manufacturers welcome the calm that the CMP has
brought to the field. “Silver recovery is a mature market at this point, with
well defined requirements and a wide range of products to meet them,” according
to Ernie Thompson, Vice President of CPAC, one of the major suppliers of silver
recovery equipment.
The most common methods of silver recovery from fixer and bleach fix processing
solutions are metallic replacement, electrolytic recovery and chemical
precipitation.
The stationary cathode design of CPAC’s new ML-27 fully automatic electrolytic
system requires fewer moving parts, so maintenance is reduced.
Metallic replacement units are the simplest. In silver recovery units, the
dissolved silver, which is present in the form of a thiosulfite complex, reacts
with and replaces a solid metal (usually iron in the form of steel wool), chosen
for its economy and convenience. Metallic replacement units are known by a
number of names, including cartridge, canister, CRC (chemical replacement
cartridge), MRC (metallic replacement cartridge) and SRC (silver recovery
cartridge). The EPA requires that two cartridges be placed in a series so that
the second will collect silver that the first could potentially let pass, if it
were to fail. When properly designed and operated according to manufacturers’
instructions, these types of systems are capable of recovering more than 95
percent of the silver.
In electrolytic recovery, a direct current is applied across two electrodes in
the silver-bearing solution. Silver is deposited onto the cathode from which it
is later recovered as high-purity silver flake. Electrolytic units can be used
as either primary or tailing units and are available for either batch or
continuous operations. Efficiencies of more than 95 percent can be achieved for
black-and-white fixer recovery. Efficiencies approaching 90 percent can be
achieved from bleach-fix and fix solutions from color processors.
Chemical precipitation is the oldest and most efficient method for silver
recovery. It, however, is somewhat more expensive than other silver recovery
technologies because of the precipitation chemical and filtration costs. Until
recently, it was used primarily by film manufacturers rather than by photo
processors. Under license from Kodak, Hallmark Refining and Academy Corporation
offer units for photo labs. Both companies use TMT (Trimercaptos-triazine,
trisodium salt) as the chemical precipitate to remove silver. The Academy
SR-1000 reduces photo solution effluent to less than 1 ppm. The resulting sludge
is easily refined and usually assays at 20 to 38 percent silver.
David Nycz, Vice President of Photo Business at Academy Corporation, sees a move
away from TMT-based precipitation equipment. “More reasonable and realistic
regulations, many resulting from cities adopting the CMP, have resulted in the
replacement of TMT systems with canisters [metal replacement systems]. They are
easier to deal with than TMT and require a less skilled operator.”
The Hallmark Corporation Mark 7WXi has been updated with quick disconnect
couplings to simplify cartridge removal.
Ease of use is becoming increasingly important. That’s particularly the case
with mini-lab equipment operated in mass merchandising stores, which are
frequently operated by minimally trained employees. One easy-to-operate unit,
the Eco Still from Cal-Glass, Inc., utilizes a patented distillation system. The
process reduces photochemical effluent to distilled water and a silver-bearing,
essentially solid mass. These non-volatile solids and silver are collected in
dry form within a plastic bag for disposal or shipment for silver reclamation.
The unit requires less than five square feet of floor space, operates on 110V
power, and processes five gallons of effluent in 20 hours.
USI International, Inc. also manufactures low-volume, easy-to-operate silver
recovery units, but of the more conventional electrolytic type. The Silver Eagle
Challenger ECO-SST line features no moving parts, virtually no maintenance, and
a five-gallon per day processing rate. The Silver Magnet Terminal line utilizes
a pump to agitate the solution around a stationary, patented, disposable
collection cathode. Costs of these systems are among the lowest in the industry,
beginning at $295 for an ECO-SST-1 and $1195 for a Silver Magnet Terminal manual
system.
CPAC also offer electrolytic recovery systems with a patented stationary cathode
design in its wide range of electrolytic and cartridge systems from $800 units
for small graphics shops to $30,000 for a single large unit for a motion picture
lab. These can recover from one-half a troy ounce to 32 troy ounces per hour.
Academy Corporation’s EPS-8 is a compact, affordable automatic silver recovery
system with disposable canisters.
One of the few new units to be introduced, the ML-27 from CPAC, features a
stationary cathode design in a small footprint, low maintenance package for labs
processing between 100 and 300 rolls per day. It treats all combinations of RA-4
and EP-2 bleach-fix, C-41 and E-6 fixers and washless stabilizers. CPAC’s Big MO
is a leak-proof, low-maintenance metallic replacement unit designed for small to
medium volume labs. It is universally compatible with every minilab using
easy-connect adapter kits.
Although there is little need for the introduction of new units, improvements in
existing lines are being constantly made, according to Mark Osborne, Director of
Sales for Hallmark Refining. “We are constantly striving to make our equipment
more user-friendly and its operation more fool-proof. Quick-disconnects have
been added to lines, replacing hose clamps and the need to use a screwdriver to
change cartridges. We are putting more ‘brains’ in the controllers to aid less
experienced operators in using the equipment properly.”
Hallmark has added alarms to some silver recovery equipment to warn users that
it is time to change cartridges. Some of its pumping stations will shut down if
an overflow situation is imminent. Hallmark sends replacement cartridges to
users on a scheduled based on their usage and follows up with reminders if the
spent cartridge isn’t promptly returned.
Having a regular replacement schedule is increasingly important according to
Osborne. “Film chemistry is becoming more and more concentrated to speed
processing and minimize replenishment rates. This is causing silver
concentrations in spent chemistry to be higher, requiring more frequent
collector changes, but also giving higher yields.”
Academy Corporation has also modified its units to fine-tune them for newer
processors according to Nycz. “Many processors are now trimming paper
internally, requiring filters in the lines before the silver recovery equipment
that must be periodically cleaned. We have also developed new ways of pumping
canisters to flush them.”
There are a number of other firms involved in silver recovery, some as equipment
manufacturers, some as refiners and some offering both services. Siltech
Corporation offers a full line of modular electrolytic and metallic replacement
systems that can be expanded as the need for increased capacity arises.
Commodity Resources and Environmental (CRE), on the other hand, is primarily a
refiner of silver. However, the company also works closely with photo labs,
providing silver recovery equipment, environmental services and refining as
needed.
Academy’s CMX-8C is designed for storage of silver-bearing solutions generated
during the day and metering them through the cartridges over a 24-hour period to
maximize silver recovery.
Environmental Control Systems (E.C.S. Technologies) is a Canadian firm that both
manufactures silver recovery equipment and process silver flake. Other silver
flake refiners can be found in the Display Classified listings.
Silver recovery equipment is also available from traditional photo processing
equipment providers. Noritsu sells the CMX-6 metallic replacement unit
manufactured by Academy Corporation. Also available from Noritsu is the ECS-2000
that concentrates photographic waste solutions by reducing liquid volume by 85
percent. This type of unit reduces waste volume where sewer codes are stringent
or off-site chemical disposal is required, thus reducing the volume of effluent
to haul away.
Metallic replacement silver recovery units that exceed the requirements of the
CMP are available through Kreonite from Canadian based Metafix, Inc. These
e-Control units are filled with MetaWool, a combination of inert, porous fibers
mixed with iron that are said to prevent channeling, the most common cause of
inadequate recovery in these systems.
While changes in the imaging business over the last few years could easily be
termed revolutionary, the silver recovery area is evolving more slowly, mainly
in response to new processing equipment and the need to provide simpler, more
user-friendly recovery units. With a stabilization of regulations thanks to the
CMP and other factors, imaging labs of all sizes have a wide variety of silver
recovery equipment available to them.
Websites:
Academy Corporation: www.academycorp.com
Cal-Glass: www.calglass.com
CPAC: www.cpacequipment.com
E.C.S. Technologies: www.ecsrefining.com
Hallmark: www.hallmarkrefining.com
Kreonite: www.kreonite.com
Metafix: www.metafix.com
Noritsu: www.noritsu.com
Siltech: www.siltech.com
USI International: www.silverprofit.com
Stan Sholik is a contributing writer for NewsWatch Feature Service. He is also a
commercial photographer with 30 years of large format studio and location
experience.