Pulp and paper

Wood chips and plant material make pulp that is used to produce paper products.

Wood chips and plant material make pulp that is used to produce paper products.

Pulp mills

A pulp mill is a manufacturing facility that converts wood chips or other plant fibre sources into a thick fibre board which can be used by a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical or fully chemical methods. The finished product may be either bleached or non-bleached, depending on the requirements. Mechanical wood pulp is "brightened" as opposed to bleached using less toxic chemicals than are needed for chemical pulps. Aotearoa’s mills use mechanical or chemical (e.g., the Kraft process) methods for making pulp.

Paper mills

A paper mill is a factory devoted to making paper from wood pulp and other ingredients. It is a common misconception that paper mills are sources of odors. Pulp mills, not paper mills can be a source of malodorous air emissions. Paper mills can be fully-integrated mills or non-integrated mills. Integrated mills consist of a pulp mill and a paper mill on the same site. Such mills receive logs or wood chips and produce paper. Chemicals used in the pulp and paper making process are contaminants that are extremely toxic to mahinga kai.

Find out more about chemical contamination 

Wastewater treatment

The major environmental impacts of producing wood pulp come from its impact on forest sources (see land use/forestry page) and from its waste products. Wastewater from a pulp mill contains a lot of organic material (tannins and lignin) from trees, and chemical contaminants such as chlorinated organic material from a bleach plant and other persistent organic pollutants (POPs). While properly treated effluent may be considered safe to discharge into water catchment areas, mills which discharge untreated or poorly treated effluent can potentially pollute waterways with chemical contaminants and high nutrients from decomposing organic material that will quickly deteriorate water quality.

Find out more about chemical contamination 

Find out more about discharges

Find out more about nutrient overloading 

Chlorine free bleaching?

Most Aotearoa mills are integrated operations producing both pulp and paper and have high grade technologies in their fibrelines, with modified cooking and elemental chlorine-free (ECF) bleaching. Elemental chlorine use was eliminated for environmental reasons and replaced with chlorine dioxide. A measure of adsorbable organohalogen compounds (AOX) quantifies the amount of chlorinated organic material that is discharged from a mill. AOX discharges have been reduced dramatically since the installation of oxygen delignification and washing improvements to the mills fibrelines and more recently the extended delignification in pulping. These improvements have reduced chlorine use in New Zealand mills.

More about the paper bleaching process

There are several types of paper bleaching processes. All use the word "chlorine free" but actually describe the different forms and varying degrees of chlorine used.

Elemental Chlorine Free (ECF) - refers to systems not using chlorine gas, but likely involve chlorine derivatives like chlorine dioxide. ECF may meet the standards for acceptable non-detection of dioxin depending on the scale of measurement, but the chemicals, such as chlorine dioxide, are actual compounds and derivatives of chlorine. There are also varying degrees of ECF, some better than others, such as Enhanced ECF (which involves peroxide, oxygen or ozone in conjunction with chlorine dioxide).

Process Chlorine Free (PCF) - are common for Kraft pulp mills in some countries that have mills that produce pulp from deinking, meaning the recycling of recovered paper. PCF uses peroxide, hydrosulphite, oxygen, or ozone with pulp that is likely recycled fibre or a mixture of recycled and virgin pulp.

Totally Chlorine Free (TCF) – are timber based Kraft pulp mills using non-chlorine, Totally Chlorine Free system. TCF resources are likely to have come from pulp or paper imported from Europe and refers to virgin paper.