Pulp and Paper

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Pulp and Paper

• Canada is Worlds largest exporter of forest
  products.
• Large areas of forest are affected
• More than 100 pulp mills
• Plus lumber mills
• High volumes of water used and discharged, 100
  tons per ton of pulp
• High volumes of gases emitted

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Environmental issues

• Biodiversity and habitat loss
• Water Pollution
• High volume issues in effluents
• Suspended solids
• Biochemical Oxygen Demand (BOD)
• Minor constituents with significant impact
• Dioxins, furans
• Air Pollution
• Odor

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Wastewater Treatment for Pulp Mills

• Suspended solids settling by gravity
• BOD activated sludge process

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Paper

• Fibres of cellulose pressed together
• Source of fibre
• Papyrus, Egypt 3600 B.C
• Hemp, flax, cotton, linen
• Wood (dominates the scene today)
• Pulping separation of fibre cells in wood so
  that they can be formed into paper
• Mechanical
• Chemical
• CMP, TMP, CTMP

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Chemical Pulping

• Separates the two main components of wood
• Fibre (cellulose) is turned into pulp
• Lignin (the binder of cellulose fibers), burned
  for energy recovery
• The chemicals (cooking liquour) are contacted
  with wood chips at 110-160 C, 100-135 psig in a
  digester.
• Lignin dissolves, cellulose does not
• Cellulose is separated from liquour, washed and
  sent to bleaching and paper making.

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