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Pollution Prevention (P2) for Printed Circuit Board Manufacturing 3672
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Sheets
Opportunities may exist to save a significant amount of money for your
business and simultaneously protect the environment through P2.
What is P2? P2 is the use of materials, processes, or practices that
eliminate or reduce the creation of pollutants or waste at the source. P2
consists of a variety of strategies and techniques that strive to avoid the
production of waste and the subsequent costly and sometimes dangerous waste
management activities. Waste avoidance or reduction may result in increased
facility efficiencies as well as significant savings from lowered waste
management costs, raw materials costs, reduced insurance and worker safety
costs. There is, therefore, the opportunity to simultaneously improve your
bottom line - and protect the environment.
Where can I obtain information? The Business & Environmental Service
Centers have compiled a library of P2 reference materials that may help you
identify and adopt P2 measures appropriate to your business. For local P2
information, call 1-800-GOV-1-STOP. The following publications may be requested
online:
What are the benefits of P2?
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Business Cost Savings: You may realize -
reduced energy costs, operational costs, production costs,
raw materials costs, transportation costs, treatment and
disposal costs, compliance permits, monitoring and
enforcement costs.
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Environmental Protection: Your employees and
patrons will appreciate your leadership in the
implementation of business practices that are economically
viable, sustain natural resources and diversity, and
enhance the quality of life for present and future
generations.
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Regulatory Relief: It is easier to achieve and
maintain compliance once P2 measures have been
implemented.
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Reduced Liability, Exposure, and Health Risk:
Less waste means less liability for environmental problems
at both on-site and off-site treatment, storage and
disposal facilities. Reducing waste also means less
potential risk to human health and safety and reduced
worker exposure to toxic chemicals.
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Reduced Energy Consumption: Energy conservation
and energy use efficiency will reduce costs and the risk
of power outages.
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What new technologies reduce costs and promote P2?
- Drag-out Reduction:1 minimizes the operation’s wastewater treatment. Loss of process chemical
due to drag-out is the most significant source of chemicals entering the
wastewater. Drag-out reduction techniques are available to reduce the
amount of chemicals that enter the wastewater. Withdraw work pieces from
tanks slowly to allow maximum drainage back into the process tank. Use air
knives or spray rinses above process tanks to rinse excess solution off
the work pieces back into the process bath. Install drainage boards
between process tanks and rinse tanks to direct drag-out back into the
process tank. Use dedicated drag-out tanks after process baths to capture
drag-out.
- Extend Process Bath Life:2 to reduce the
periodic replacement of the bath due to impurity build-up from drag-in,
decomposition, or the loss of solution constituents by drag-out. Corrosion
and salt buildup deposits on the rack elements contaminate solutions if
they chip away or fall into the solution. Proper design and regular
cleaning will minimize this form of contamination. Efficient rinsing of
the work pieces between different process baths reduces the drag-in of
other chemicals into the next process bath. Use deionized or distilled
water instead of tap water, since tap water may have a high mineral or
solids content, which can lead to impurity buildup.
- Material Substitution:2 reduces health
hazards to personnel and waste treatment costs. Use non-chelated rather
than chelated chemical baths to reduce hazardous waste generation. Once
the chelating compounds enter the waste stream, they inhibit the
precipitation of metals, and additional treatment chemicals must be used.
These treatment chemicals end up in the sludge and contribute to the
volume of hazardous waste sludge. Use mild chelators, where chelators are
required, which are less difficult to break down. Therefore, metals can be
precipitated out of the solution during treatment without using the volume
of treatment chemicals that is often necessary with strong chelators.
What are some methods to reduce waste in the
Printed Circuit Board Industry
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Waste
Source |
Waste
Stream
Description |
Waste
Stream Composition |
Waste
Minimization
Method |
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Cleaning/ Surface preparation |
Airborne particulates Acid fumes/ organic vapors Spent
acid/ alkaline solution Spent halogenated solvents Waste rinse water |
Board materials, sanding materials, metals, fluoride, acids,
halogenated solvents, alkali. |
Use abrasives, non-chelated cleaners, or recycle/reuse cleaners
and rinses. |
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Catalyst application/ Electroless plating |
Spent electroless copper bath Spent catalyst solution Spent acid
solution Waste rinse water |
Acids, stannic oxide, palladium, complexed metals, chelating
agents. |
Use non-cyanide baths, segregate streams, recover metal values,
or extend bath life. |
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Pattern printing/ masking |
Spent developing solution Spent resist removal solution Spent
acid solution Waste rinse water |
Vinyl polymers, chlorinated hydrocarbons, organic solvents,
alkali. |
Dry photoresist removal or recycle/reuse photoresist stripper. |
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Electroplating |
Spent plating bath Waste rinse water |
Copper, nickel, tin, tin/lead, gold, fluoride, cyanide, sulfate. |
Extend bath life, segregate streams, or recover metal values. |
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Etching |
Spent etchant Waste rinse water |
Ammonia, chromium, copper, iron, acids. |
Reuse/ recycle etchants, electrolytic recovery, or use
non-chelated etchants |
Source: DTSC, 1989
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