MechChem Africa November-December 2021

The paper industry: the epitome of the circular economy The pulp and paper manufacturing and recycling sector has been adopting production innovations to reduce its environmental footprint, divert waste from landfill and stay ahead of the circular economy curve.

T he circular economy is a continuous closed loop that involves taking, making and re-using, as opposed to a linear process of taking, making and discarding. The problem with the linear model is clear. When we treat rawmaterials such as wood, water and energy as infinite, we end up with waste. Waste costs money, which in itself is waste, especially when you consider the costs of landfilling, the loss of reusable materials, and the livelihoods that could have been supported. There are also losses at the expense of the environment – greenhouse gas emissions when waste degrades, for example. The circular economy, however, is based on three core principles: reducing waste by design, retaining materials in circulation and restoring the systems fromwhich resources are extracted. Contrary to popular belief and opinion, the paper industry has formany years adopt- ed the circular approach. We all know that paper comes from the wood of trees – even the fibres in recycled paper came froma tree at some point in their lives. In South Africa’s case, these trees are sustainably farmed in plantations, with stringent management of their impact on water, soil, neighbouring indigenous landscapes and biodiversity.

The sustainable forest: Gone are the days of detrimental, wall-to-wall afforestation. Today, forestry companies work in tandem with wetlands, riparian zones and high conservation value areas to create a mosaic of planted trees and conservation spaces. Sustainable forest management balances economic, social and environmental needs. While forestry practices optimise the land’s ability to mitigate climate change through carbon sequestration, they also act as buf- fers for protected indigenous areas. Depending on the species – usually euca- lyptus or pine – trees for the paper industry take around seven to ten years to reach maturity. The reason we use exotic species is because they are fast-growing and we cannot – and will not – use indigenous trees for wood or paper products. Currently, South Africa has 850-million trees growing over 676 000 hectares re- served for pulp and papermaking. Of these, less than 10% of this total area (67 600 hectares) is harvested each year. The same area is replanted with new trees or saplings, often at a ratio of two trees for every one harvested. This is the first cycle: plant, grow, harvest, replant. The natural cycle: The circular economy in forestry extends to leaving forest residues

in-situ as a mulch for the next generation of trees. After harvesting, bark, limbs, leaves and small parts of the harvested trees are left on the forest floor, offering sustenance and refuge for creatures that aid in the decomposition of organic matter, which in turn attracts birds – and so we have another cycle. In addition, through photosynthesis, trees remove carbon dioxide from the atmo- sphere and convert it into food for growth. They also take up water, from the ground or fromrainfall. They keep the carbon locked up in their fibres and give us back the oxygen, and some water is returned to the atmo- sphere through transpiration. Circular production: Even pulp and paper mills operate in a closed loop process, by using natural resources efficiently – often more than once. Process water is reused and recycled, lost fibre is recovered and reused, and spent chemicals are recovered for energy production. Even bark and other biomass is used to power boilers, producing steam that generates electricity. This sees us being better at using more of the tree, ensuring little goes to waste. The paper cycle: Once pulp and paper are made into what we know – office paper, magazines, books, pizza boxes, cereal boxes,

Paper is sorted and baled into different types before being sent to the paper recycling mill.

34 ¦ MechChem Africa • November-December 2021