MANAGEMENT OFPHOTOCHEMICAL WASTES

Source Reduction, SilverRecovery, Safe Substitutes

By Sue Allen

Maryland Dept. of the EnvironmentWater Management Administration

Underground Injection Control Program

MAJORPHOTOCHEMICALS

Photography is very dependent on chemicals.Wastewater from the photographic process

contains contaminants such as: hydroquinine,sodium sulfite, silver, mercuric chloride,cadmium, ferrocyanide, acids, andformaldehyde.

The types of wastes include: process bathwastes, color developer wastes, bleach, fixerand fixer wastes. All are toxic and highlyalkaline.

Laws affecting photoprocessing include the SafeWater Drinking Act and the Toxic SubstancesControl Act.

SILVER EXPOSURE INBIOSPHERE

Silver is a rare but naturallyoccurring metal deposited asmineral ore, extracted fromthe main ore, Argentite.

It is recovered as a by-product from smelting nickelor copper ores and fromplatinum & gold deposits.

Sources of silver includeemissions from smeltingoperations, manufacture &disposal of photographic/electrical supplies, coalcombustion & cloud seeding.

Sorption is the main processthat controls silver’s entryinto water & its movement insoils.

WASTE DISPOSALOPTIONS

About 100 million gallons ofsilver-bearing wastewatersare produced annually.

Materials that leach morethan 5 mg/L of silver areclassified hazardous waste.

Most POTW’s can tolerateand treat photo wastewaters- if the volumes andconcentrations ofcontaminants are not toohigh.

Local sewer authoritiesregulate concentrations &volumes per day ofchemicals released intosewer systems.

SILVER-BEARING WASTE

Silver in photoprocessingwaste is less toxic than“free” silver which can killaquatic organisms.

Silver thiosulfate is thedominant silvercompound inphotoprocessingeffluents.

High concentrations oforganic & sulfur-basedmaterials in municipalwastewater treatmentsystems ensure that anyactive silver materials arecombined into sludge.

SILVER-BEARING WASTE

After silver is discharged intonatural waters, it is foundtightly-bound in sediments,where it remains and notreleased into the water column.

Silver nitrate can cause skin,eye, and respiratory irritation.

Argyria, a conditioncharacterized by bluish-graypigmentation of the skin,mucous membranes and eyes,is a major effect resulting fromlong-term chronic exposure tosilver.

ONSITE SEWAGE DISPOSAL(SEPTIC SYSTEM)

Subsurface disposal systemsare designed to managedomestic wastes.

Septic systems do not havethe ability to properly treatphotographic effluents sinceseptic systems operate withanaerobic biologicaltreatment.

MDE does not recommenddischarging photoprocessingchemicals into septic systemsbecause these chemicalsupset the functioning of thesystems and adversely affectnearby underground drinkingwater sources.

CODE OF MANAGEMENTPRACTICE

The Code of Management Practice for Silver Dischargersis a voluntary set of recommendations on technology,equipment, & procedures for controlling silver dischargesand preventing pollution.

The purpose is to develop a consensus among localitiesand photo-processing silver dischargers to reduceregulatory burdens and costs for municipalities and smallbusinesses.

The Code involves the use of recovery and equipmentoptions best suited to a facility, to enhance silver recovery& track the monitoring processes for effectiveness.

Silver has a secondary drinking water standard of 0.1parts per million (ppm).

SILVER RECOVERY

Silver Recovery harvestssilver from photoprocessingsolutions.

There are several ways torecover silver, depending onthe operation size, theconcentration of silver in theeffluent, and the silverdischarge limits for the localPOTW.

Concentrations of silver inused fixer usually exceedsallowable limits for dischargeto municipal water systems.

The silver recovery processcontrols laboratory costsand maintains the lab’sregulatory compliance.

TYPES OF SILVERRECOVERY

Metallic Replacement involvesan active solid metal, suchas iron, contacting a solutioncontaining dissolved ions ofa less active metal.

Electrolytic Recovery appliesa direct current across 2electrodes in a silver-bearingsolution. Metallic silverdeposits on the cathode.

Chemical Precipitation mixesa precipitation agent withsilver-bearing wastewater ina batch reaction tank with pHcontrol. Solid particles areformed, settle beforefiltering, and are sent to asilver refiner.

SILVER RECOVERY FROMRINSE WATER

Ion Exchange is the reversibleexchange of ions between asolid resin and a liquid. It canrecover up to 98% of silver.

Reverse Osmosis has thewastewater flow underpressure over the surface of aselectively permeablemembrane. Water moleculespass through the membrane,and other constituents are leftbehind, recovering 90 % of thesilver thiosulfate.

SILVER RECOVERYOPTIONS

Developer/fixer disposalcan be handled throughan off-site silverreclamation facility,licensed to accepthazmats.

Operate your own silverrecovery unit. This unitmust be operated undercertain regulations.Ensure that the silverconcentrations in yoursystem are acceptable tothe local sewer system.

BEST MANAGEMENTTECHNIQUES

Seal all floor drainsconnected to the sewer orstorm drains by productionarea.

Any solutions touched bydeveloper must be put inhazmat. receptacle for pick-up by licensed hauler.

Use squeegees to wipeexcess from films andpapers. This saves $$ &chemical quantities.

Install secondarycontainment around allmachines.

Keep waste fluid segregatedfor reuse, recycling or trt.

BEST MANAGEMENTTECHNIQUES

Floating lids onreplenisher tanks reduceoxidation, evaporation &contamination from dirt.

Replace highly toxicdevelopers, such ascatechol, chlorquinol, andpyrogallo with less toxicones, such as phenidone.

Donate unemulsified inksto school or publicagencies.

BEST MANAGEMENTTECHNIQUES

Clean up spills at once.Use absorbent materialsto confine any fluids.

Replace solvent-basedplate-making systemswith water-bases ones.

Reduce amount of wasterinse water by usingcountercurrent rinsetanks.

Install automatic inklevelers to keep inkfountains at optimal levelfor good print quality inlarge web presses.

PHOTOCHEMICALRECYCLING

Choose inks & cleaningsolutions that are non-toxic.

Avoid halogenatedcompounds, petroleum-based,or phenol cleaners.

Recycle spent fixer, solvents,waste ink.

Strip “goldenrod” fromnegatives and used metalplates & accumulate for pick-up by a licensed hauler.

Accumulate “chromoliths” forrecycling.

SAFE SUBSTITUTES

Use soybean, walnut, or vegetableoil-based inks for lithographyprinting. Water-base inks can beused for screen printing.

Reduce concentration of IsopropylAlcohol (IPA) with a fountainsolution with low IPA or switch tolow-VOC substitutes.

Use soap solutions when possible.Solvents should be used only forcleaning inks & oils.

Some specially made blanketwashes & acetic acid-basedsolvents, with less hazmats, arenow available.

Some small solvent recoverysystems are on market, able toaccommodate many medium-largeprinters.

PHOTORECYCLING NEWS

* Washless minilabs use a stabilizerinstead of washwater, recovering silvereffluent and discharging it only to amunicipal secondary treatment system.

* Digital cameras now rival conventionalphotography. They recycle by reducingsize & run on fewer batteries. Somecompanies remove lead from lenses,cadmium from sensors, & mercury fromdisplays.

* The disposable camera is the mostrecycled consumer product.Polystyrene covers & viewfinders aregrinded down into new cameracomponents and lens acrylic is madeinto toothbrushes.

* One company extracts 99% of the silverand other toxic heavy metals from usedphoto liquids to produce a liquidfertilizer.

REFERENCES

1. http://environment.aboutcom/library/weekly/bldearearthtalk12-15.htm, pp.1-7.

2. http://www.silvercouncil.org/html/faq.htm, pp. 1-4.3. Environmental Support, “Disposing of Minilab Effluent,”Kodak J-

98D, 1994.4. “Penny Stock Profile..Itronics Inc.”, pp.1-6, Jan. 2005,

www.allpennystocks.com.5. “Photographic Materials: Safety Issues and Disposal Procedures,”

University of Florida, Gainesville, FL, pp.1-12.6. POTW Guidance Manual, V./1, “What is the CMP and Why Use It?,

pp.1-2. “What are the Sources of Photographic Silver?”,pp. 3-47. RCRA in Focus, “Photo Processing,” EPA/530-K-99-002. 1991,

Center for Env. Research & Dev., USEPA, Cincinnati, Ohio, pp.1-17.

8. www.inchem.org/documents/cicads/cicads/cicad44.htm, pp1-18.9. www.kodak.comglobal/en/service/faqs/faq5023.shtml, pp. 1-7.