Digester operator

Digester operators, or cooks, cook wood chips with soda ash or acid to separate the wood pulp from unwanted constituents. They test the resulting solution.

The following job titles also refer to digester operator:

digester worker
pulp mill machine technician
digester cook
pulp mill specialist
pulp mill machine specialist
pulp mill operator
digester operative
pulp mill machine operator
pulp mill technician
digester technician
digester specialist

A high school diploma is generally required to work as a digester operator.

ISCO skill level is defined as a function of the complexity and range of tasks and duties to be performed in an occupation. It is measured on a scale from 1 to 4, with 1 the lowest level and 4 the highest, by considering:

• the nature of the work performed in an occupation in relation to the characteristic tasks and duties
• the level of formal education required for competent performance of the tasks and duties involved and
• the amount of informal on-the-job training and/or previous experience in a related occupation required for competent performance of these tasks and duties.

Digester operator is a Skill level 2 occupation.

These occupations, although different, require a lot of knowledge and skills similar to digester operator.

bleacher operator
froth flotation deinking operator
paper machine operator
wash deinking operator
pulp technician

These occupations require some skills and knowledge of digester operator. They also require other skills and knowledge, but at a higher ISCO skill level, meaning these occupations are accessible from a position of digester operator with a significant experience and/or extensive training.

pulp control operator
automated assembly line operator
paper mill supervisor
machine operator supervisor
industrial robot controller

This knowledge should be acquired through learning to fulfill the role of digester operator.

• Types of digesters: This includes the stationary and rotary steam digesters, which cook wood chips in an acid solution to make pulp for use in the manufacture of paper.
• Types of paper: The different criteria used to determine differences in paper types such as coarseness and thickness, and the different fabrication methods and wood types from which the types of paper stem.
• Quality standards: The national and international requirements, specifications and guidelines to ensure that products, services and processes are of good quality and fit for purpose.
• Types of wood: Types of wood, such as birch, pine, poplar, mahogany, maple and tulipwood.
• Types of pulp: Kinds of pulp are distinguished based on their fibre type and the specific chemical processes through which they were created.

These skills are necessary for the role of digester operator.

• Concentrate pulp slurry: Measure the weight and concentration of the pulp slurry for further processing and storage by using disk filters and calculating slurry density with specific formulas.
• Troubleshoot: Identify operating problems, decide what to do about it and report accordingly.
• Work safely with machines: Check and safely operate machines and equipment required for your work according to manuals and instructions.
• Wear appropriate protective gear: Wear relevant and necessary protective gear, such as protective goggles or other eye protection, hard hats, safety gloves.
• Monitor pulp quality: Avoid lesser quality and lower grades of recycled paper and pulp by keeping an eye open for stickies, plastics, colour, unbleached fibres, brightness, and dirt.
• Monitor automated machines: Continuously check up on the automated machine’s set-up and execution or make regular control rounds. If necessary, record and interpret data on the operating conditions of installations and equipment in order to identify abnormalities.
• Operate digester machine: Add cooking chemicals and steam to dissolve lignin and separate the plant fibres, breaking down wood chips to recover pulp after a bleaching and drying process.
• Wash fibres: Remove the chemical solution of the digesting process, making paper pulp soft and fibrous.
• Supply machine: Ensure the machine is fed the necessary and adequate materials and control the placement or automatic feed and retrieval of work pieces in the machines or machine tools on the production line.
• Set up the controller of a machine: Set up and give commands to a machine by dispatching the appropriate data and input into the (computer) controller corresponding with the desired processed product.

This knowledge is sometimes, but not always, required for the role of digester operator. However, mastering this knowledge allows you to have more opportunities for career development.

• Types of bleach: The range of bleach and others chemicals used to remove the colour from materials in a steam cooking process, adjusting the brightness and colour of the materials.
• Deinking processes: Various deinking processes such as flotation, bleaching, and washing. These are used to remove ink from the paper in preparation for producing new paper.

These skills and competences are sometimes, but not always, required for the role of digester operator. However, mastering these skills and competences allows you to have more opportunities for career development.

• Test paper production samples: Acquire test samples at various stages of the paper deinking and paper recycling process. Process the samples, e.g. by adding a measured amount of dye solution, and test them to determine values such as the pH level, the tear resistance or the degree of disintegration.
• Tend bleacher: Add the required amount of bleaching substances and additives and operate the bleaching part of the paper machine, which bleaches the pulp with liquid and solid chemicals, removing any remaining lignin and other impurities.
• Monitor gauge: Oversee the data presented by a gauge concerning the measurement of pressure, temperature, thickness of a material, and others.
• Record production data for quality control: Keep records of the machine’s faults, interventions and irregularities for quality control.
• Monitor chipper machine: Monitor in-feed and clear the chipper equipment of debris to avoid blockages and jams in order to secure a free flow of materials.
• Dispose of hazardous waste: Dispose of dangerous materials such as chemical or radioactive substances according to environmental and to health and safety regulations.
• Dispose of non-hazardous waste: Dispose of waste materials which pose no risk to health and safety in a manner which complies with recycling and waste management procedures.
• Carry out waste water treatment: Perform waste water treatment according to regulations checking for biological waste and chemical waste.
• Operate debarking machine: Set up and monitor the machine that strips remaining bark from timber or logs before they can be further processed, for example chipped for pulp production.
• Perform machine maintenance: Perform regular maintenance, possibly including corrections and alterations, on a machine or machine tool to ensure it remains in a proper productive state.
• Clean equipment: Perform cleaning routines after equipment use.
• Prepare production reports: Prepare a comprehensive and unbiased report on wood technology production and progressive development of wood based materials.
• Consult technical resources: Read and interpret such technical resources such as digital or paper drawings and adjustment data in order to properly set up a machine or working tool, or to assemble mechanical equipment.
• Report defective manufacturing materials: Maintain required company records and forms in order to report any defective materials or questionable conditions of manufacturing machinery and equipment.
• Check quality of raw materials: Check the quality of basic materials used for the production of semi-finished and finished goods by assessing some of its characteristics and, if needed, select samples to be analysed.
• Drive chipper truck: Drive chipper trucks or vans, from which the machine is often controlled and operated. Use the vehicle for pickups of processed wood materials in forest job sites.
• Keep records of work progress: Maintain records of the progress of the work including time, defects, malfunctions, etc.
• Operate wood chipper: Operate wood chipper machine by inserting long logs, poles, and pieces of timber, producing wood chips.
• Use deinking chemicals: Handle surfactants or deinking chemicals, which remove ink from fibres. Chemicals such as hydroxides, peroxides, and dispersants are used in processes such as bleaching, flotation, washing, and cleaning. Amongst these non-ionic and electrolyte surfactants are the most important.
• Monitor chemical process condition: Monitor the conformity of the chemical process, checking all indicators or warning signals provided by the instruments such as recording instruments, flowmeters and panel lights.

8171 – Pulp and papermaking plant operators

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References

1. Digester operator – ESCO