Pollution Prevention

1
Pollution Prevention

• Lecture 8
• KKA 4106

2
Pollution Prevention

• To examine practices that reduce or eliminate
  hazardous waste at the source

3
General Considerations

• Methods and EPA hierarchy. (F7-1)
• - Source reduction
• - Recycling
• - Treatment
• - Disposal
• Waste Minimization. Any management technique or
  process modification that ultimately reduces the
  mass or toxicity sent on to treatment, storage
  and disposal facilities.
• Economic Incentives.

4
General Considerations

• Legal and Regulatory Incentives.
• Generators must certify that a waste minimization
  is in place.
• In 1991, the EPA instituted a voluntary 33/50
  program which had an overall national goal of 50
  reduction in the generation of 17 high-priority
  toxic chemicals by 1995. (T7-1).
• Public Incentives. No public will no longer
  tolerate hazardous wastes.

5
Management Strategies

• Planning
• Characterization of waste
• Options
• Feasibility
• Implementation
• Monitoring and optimization

6
Life Cycle Analysis ( LCA )

• LCA considers the impact of all phases of
  industrial activity, from raw materials,
  acquisition and RD to the final disposition of a
  product and its packaging.
• LCA provides an analytical framework for
  investigating the entire range of environmental
  impacts air emissions, wastewater, solid and
  hazardous waste, renewable resources and energy
  utilization.
• BMW introduced a car line in which the plastic
  (typical car 180 lbs) parts are stamped by type
  during fabrication. The cars are designed for
  disassembly.

7
Volume Reduction

• Reducing volume without reducing toxicity are
  sometimes explicitly excluded from the definition
  of source reduction.
• Consists of 3 steps
• Process modification
• Segregation
• Re-use

8
Process Modifications

• Raw Materials.
• Replace solvent based cleaners with water based
  cleaners.
• Equipment.
• Operating Procedures
• Materials Storage
• End Products

9
Process Modifications

• A special and pervasive case, reducing dragout in
  the electroplating industry.
• - Increase drain time
• - Low pressure air, air knife
• - Spray rinsing over process tank
• - Minimize concentration of metal in plating
  bath
• - Rack bars to maximize drainage
• - Drip bars to hold racked parts over plating
  baths
• - Maximize hole size on barrels
• - Rotate barrels above plating tank

10
Segregation

• A primary tenet of source reduction is to avoid
  mixing wastes. A small amount of hazardous waste
  mixed with a large amount of non-hazardous waste
  creates a large amount of hazardous waste.
  Segregation permits treating smaller quantities
  of waste.
• Keep non-contact cooling water and domestic waste
  away from hazardous waste streams.

11
Re-use

• Reclaiming a hazardous waste for use in another
  application.
• Toluene used for cleaning one ink is used to thin
  an ink of another color.

12
Toxicity Reduction

• It is often possible to lessen the toxic
  characteristics sufficiently so that the
  remaining waste is no longer considered a
  hazardous waste.
• Process Modification. Dry powder painting instead
  of using solvent based paints.
• Equipment Modification. Alarms to avoid bumps.
• Housekeeping. (T7-7)
• Simplest and most inexpensive method of reducing
  hazardous waste. Includes training, using
  pallets to discern leaks.
• Material Substitution. Non-cyanide baths in metal
  plating.

13
Recycling

• Water.
• Combine acid and alkalis.
• Use water for a less sensitive use. Non-contact
  cooling water.
• Solvents. (T7-8)
• Azeotropic distillation. An azeotrope is a
  mixture of liquids that behave as a single
  substance when boiled i.e. the vapor and the
  liquid have the same composition. Azeotropic
  distillation consists of adding a substance,
  typically steam, to a solvent that is to be
  recycled. The azeotrope has a lower boiling point
  than the original mixture thus facilitating the
  recovery of the solvent. Small package
  distillation plants are readily available.

14
Recycling

• Oil.
• Refined and reused.
• Use for heat value.
• Solids
• Paper, metal, plastics.
• Waste Exchanges.
• A regional clearing house to facilitate waste
  exchange.
• The first take is to exchange at the same
  location to avoid transportation liabilities.