This presentation deals with the problems faced in the paper and pulp industry regarding pitch accumulation and its biological control.

1. Solving Pitch Problem in Paper and Pulp
Industry
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Suby Mon Benny
MSc Microbiology
20LS601032

2. An Introduction to Paper
& Pulp Industry
 The pulp and paper industry converts wood or recycled
fibre into pulp and primary forms of paper.
 In the 1800s, there was a shift away from using cotton
rags for paper production. Wood became the most
important source of fiber.
 First mechanical and then chemical methods have
been developed to produce pulp from wood.
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3. Production process
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Simplified flow diagram of integrated mill
The production process can be
divided into 7 sub processes:
 raw materials processes;
 wood-yard;
 fibre line;
 chemical recovery;
 bleaching;
 paper production;
 products and recycling.

4. Pulping processes
Pulping aims to separate cellulose fibers from
the wood structure.
Possible types of pulp production are:
Kraft (68%)
mechanical (22%)
semi-chemical (4%)
sulphite (4%)
dissolving (2%).
www.handprint.com
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5. Kraft Pulping
Sulfate or Kraft pulping
was invented in Germany
in 1884 and remains the
dominating technology
today.
It is a process for conversion
of wood into wood pulp,
which consists of almost
pure cellulose fibers, the
main component of paper.
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6. Environmental problems
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Regulated wastes and
emissions from the pulp and
paper industry include liquid
and solid wastes, air
emissions, and wastewater.
 Air emissions
 Wastewater releases
 Solid waste
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7. Raw water use
 Pulp mills are big water
users.
 Consumption of fresh
water can seriously
harm habitats near
mills, reduce water
levels necessary for
fish, and change water
temperature, a critical
environmental factor for
fish.
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8. What is Pitch Problem ?
• Pitch are lipophilic extractives from wood and other
lignocellulosic materials.
• Pitch deposits along the pulp and paper
manufacturing processes.
• It is responsible for
• reduced production levels
• higher equipment maintenance costs,
• higher operating costs,
• an increased incidence of defects in the finished products, which
reduces quality and benefits
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9. Pitch deposition in pulp
processing
• Mechanical pulping only affects slightly the
composition of extractives.
• Chemical pulping saponifies triglycerides.
• Sterol and tri-terpenol esters are much less
affected.
• The wood extractives remaining in the
unbleached pulp are carried over to the bleach
plant.
• The use of totally chlorine free (TCF) bleaching
in place of elementary chlorine free (ECF)
bleaching is increasing the severity of pitch
problems
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10. Solving the Problem
• Traditional methods:
• Natural “seasoning”
• Adsorption or dispersion of the pitch particles with
chemicals
• Fungal pitch control:
Wood decaying fungi, including
1. white-rot (Funalia trogii,
Bjerkandera, Pleurotus
pulmonarius),
2. brown-rot,
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11. • Enzymatic pitch control:
• Hydrolytic enzymes- Lipases
• Oxidative enzymes- Oxidoreductases
(laccases- 2,2′-azinobis(3-
ethylbenzothiazoline- 6-sulphonic acid
[ABTS], 1-hydroxybenzotriazole [HBT] ),
lipoxygenases.
3. soft-rot, and
4. sap stain (Ophiostoma, Ceratocystis,
Leptographium) species
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12. Source: Microbial Enzymes and Their Application
in Pulp and Paper Industry
Abdulhadi Yakubu, Upasana Saikia, and Ashish Vyas

13. Ideal paper mill
• From cleaner production point of view is a chlorine-free and zero-
discharge one, with minimized quantity and toxicity of air pollution and
solid wastes.
• It is seen that closed loops represent the most effective approach to save
both energy and resource consumption and at the same way to decrease
all kind of wastes production.
• Such an approach is developed in the form of paper recycling, different
types of substances re-use during production processes, coproduction and
chemicals recovery.
• Future research can develop more sustainable reuse options for Kraft
pulping solid wastes, as well as pulping methods that result in purified by-
products that can serve as feedstock for other manufacturing processes.
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14. Conclusion
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• Lipophilic extractives are responsible for pitch
problems.
• Pulp mills are almost always located near large bodies
of water due to their substantial demand for water.
• Delignification of chemical pulps releases considerable
amounts of organic material into the environment,
particularly into rivers or lakes.
• The process effluents can be treated in a
biological effluent treatment plant, which can
substantially reduce their toxicity.
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