Paper Production Is Dependent On Water, Yet Relatively Little Is Consumed

The pulp and paper industry depends on water in three crucial areas. Firstly, there is rain water that is essential for trees to grow and, through photosynthesis, transform carbon dioxide to oxygen and cellulose, which provides the industry’s primary raw material, wood fibre. Then there is water that is actually used to make pulp and paper, and finally there is the suitably treated effluent.

As water is a crucial resource for the industry, most pulp and paper mills are located near abundant supplies. In Europe, most mills utilise surface water, such as rivers and lakes (89% of intake), with some taken from their own supplies of groundwater (10%) and the rest from public water supplies (4%). Since the 1990s, the average water intake per tonne of paper has decreased by 47%.[1]

It is also important to recognise that intake does not equal consumption because most of the water will be returned to the environment. 93% of the water used in the European paper industry is returned in good quality (having been reused within the mill before being suitably treated), with the remainder either evaporated, staying within the product, or bound up in solid waste.[2]

Water is circulated within pulp and paper mills several times before it is returned to the environment. Before it is, it needs to be treated because it contains nutrients and organic matter. Various techniques are used, such as filtration, sedimentation, flotation and biological treatment.

Improvements in paper-making techniques and water treatment have had a dramatic effect on the cleanliness of effluent leaving the mill.

Since 1991, there has been a 95% reduction in AOX levels (a measure of the toxicity due to chlorine compounds) and a 78% reduction in COD (Chemical Oxygen Demand – how much oxygen is consumed by the decomposition of organic matter).[1]

Rainwater is essential for forests and tree plantations to grow. Water security depends on forests. Forests help regulate the water cycle, sustain water supply and maintain water quality. Forested watersheds supply approximately 75% of accessible freshwater and provide water to 90% of the world’s 100 largest cities.
FAO, Forests and Water, 2019

Sources

1. Cepi, Key Statistics, 2020
2. Cepi, Key Statistics, 2021