Pollution Prevention Case Study

Artistic Plating Company

Reduce toxicity of wastewater sludge and effluent
Standard Industrial Classification (SIC) Electroplating/3471
Type of Waste Wastewater and sludge (F006-solid) from electroplating operations.
Strategy Product substitution and process modification
Company Background Artistic Plating Company (APC) has been located in the inner city of Milwaukee for over 40 years. The company is locally owned and employs 65 people. APC is a growing company that has built a broad base of customers in the United States and abroad.
Original Process As a job shop electroplater, wastewater pretreatment was instituted to comply with federal, state and local regulations in 1983. At that time, a traditional pretreatment system of alkaline chlorination and metal hydroxide precipitation was installed.
Motivation The purpose was to reduce the quantity of toxins in the wastewater stream discharged to the POTW in an effort to provide a wide margin between actual discharge and regulated limits and enhance the resulting sludge for recycling.
Pollution Prevention Process The goals of this project were:
  1. Reduction in the total metals emitted to the environment.
  2. Recovery of these metals in a reusable form.
  3. Reuse of the treated water.

In 1991, APC commissioned the design and installation of an ion-exchange system for tertiary polishing pretreatment of its wastewater effluent prior to discharge to the POTW. The system selectively removes heavy metals (nickel, zinc, copper, silver, cadmium, lead, chromium) by an order of magnitude below the categorical limits established under the Clean Water Act. Another ion exchange system was developed to remove silver-cyanide complexes prior to traditional wastewater treatment.

First, all cyanide-based metal strips were totally eliminated and replaced with acid-based formulations. Second, cyanide-based process baths were replaced with non-cyanide alkaline plating solutions. This resulted in a reduction of the toxicity and easier chemical treatment of the effluent. Silver metal cyanide complexes were selectively removed prior to traditional wastewater treatment with an innovative system that combines electrowinning and ionic exchange techniques. This process provides for near complete recovery of silver.
Stage of Development The pollution prevention techniques are in full use at this time.
Level of Commercialization These processes (e.g., equipment) are readily available, but typically have not been applied as they have at this facility. All incorporated processes are available for use today.
Material/Energy Balance Original Process
Feedstock
  1. cyanide based strips
  2. cyanide based process baths
  3. silver cyanide contaminated rinse water treated by alkaline chlorination followed by metal hydroxide precipitation and discharge to local POTW
  4. wastewater from secondary pre-treatment system discharged to local POTW

Waste

  1. spent cyanide contaminated/complexed metal strip solutions
  2. cyanide contaminated wastewater sludge
  3. silver and cyanide contaminated wastewater sludge
  4. metals-bearing wastewater discharged below allowable permit levels to the local POTW (based on an average daily system flow of 11,300 gallons per day prior to process installation the annual estimated metals discharged to the local POTW was 39.4 pounds/year)

Disposal

  1. off-site shipment for incineration
  2. off-site shipment for incineration, followed by landfill
  3. permitted discharge to local POTW
  4. permitted discharge to local POTW

Pollution Prevention Process
Feedstock

  1. non-cyanide based, acid strips
  2. alkaline-based non-cyanide plating bath solution
  3. silver cyanide contaminated rinse waters primary pre-treated first by electrowinning and ion exchange, followed by secondary pre-treatment using cyanide oxidation and chemical precipitation
  4. water from secondary pre-treatment system discharged to POTW after treatment with ion exchange prior to discharge

Waste

  1. spent non-cyanide/un-complexed metal strip solutions
  2. spent alkaline-based non-cyanide plating bath solution
  3. discharge to local POTW
  4. after installation of the tertiary wastewater (ion exchange system) the discharge is estimated to be 7.09 pounds. This is an 82% reduction in metals released to the environment on an annual basis via the discharge to the local POTW

Disposal

  1. off-site shipment of sludge (after in-house treatment for metals reclaim/recycle)
  2. off-site shipment of sludge after in-house treatment for metals reclamation/recycling.
  3. silver metal sent off-site for reclamation/recycling
  4. discharge to local POTW
Economics Capital Costs
  • $134,000 Purchase and installation of an ion exchange system designed to remove metal ions from the wastewater discharged to the local POTW facility.
  • $5000 Purchase of an electrolytic metal recovery machine for silver (electrowinning).
  • $15,000 Purchase of a ion exchange system designed to remove complexed silver cyanide metal ions from the wastewater.

Operation/Maintenance Costs

  • $15,400/year for additional labor and replacement parts.
  • $9,000/year is required for annual operating costs for replacement of ion exchange resin and upkeep labor.

Payback Period
Not calculated.
Benefits Effluent discharge values were significantly reduced below permitted levels and this ensures against the possibility of noncompliant discharge. There is now near complete capture of silver for recycling. Electroplating sludge toxicity has been reduced through the elimination of cyanide complexed metal hydroxides and this assures that the waste is consistently acceptable for recycling; eliminating landfill liability. This program sets the stage for a future in-house water reuse program.
Obstacles Wastewater treatment operators of traditional systems require a good deal of intensive training. The addition of the tertiary and silver ion exchange systems increases the complexity of operation, and the operator training requirements. In addition, increased systematic routine analysis must be maintained to determine the status of the columns.
Technology Transfer The use of alternative raw material formulations and metal recovery is quite transferable to similar applications in other industries. The focus must be to eliminate a chemical which inhibits the treatability of the waste. Substitution of alternative materials to obtain beneficial reuse serves both waste minimization and pollution prevention.
Company Address Artistic Plating Company
405 West Cherry Street
Milwaukee, Wisconsin 53212
Contact Person John S. Lindstedt, President
414/271-8138

William A. Campbell, Environmental Manager
414/271-8138
Pollution Prevention Resources

 

 

 

 Free, On-site Technical Assistance
University of Wisconsin Extension
Solid and Hazardous Waste Education Center
Milwaukee area: 414/475-2845
Remainder of state: 608/262-0385

Waste Reduction and Cooperative Environmental Assistance Publication Order Form
Wisconsin Department of Natural Resources
Bureau of Cooperative Environmental Assistance
608/267-9700
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Bureau of Cooperative Environmental Assistance
Wisconsin Department of Natural Resources
P.O. Box 7921
Madison, WI   53707
608/267-9700

PUBL TS-045 96