Sappi Southern Africa
Sustainability Report

FOCUSING ON WATER USAGE AND EFFLUENT DISCHARGE

The primary input to our water resources is rainwater and South Africa’s rainfall, at 490 mm per year, is half the world average. Our rainfall is highly seasonal and variable, with greater variability in the dry interior. Against this backdrop, we focus on reducing water usage and minimising effluent discharge.

South Africa’s plantations use about 3% of the country’s available water resources—but this varies considerably from place to place and during different times of the year. To put this into context, irrigated agriculture uses approximately 60% of the country’s available water resources.

ZAR8.3 million

That’s how much we spent in 2018 on upgrading forestry villages, including water and sanitation projects.


TUGELA MILL

1,188 metres

That’s how many metres of piping are being used for the new highdensity polyethylene (HDPE) effluent pipeline at Tugela Mill which is replacing the existing steel pipeline at a cost of ZAR55 million. The advantage of HDPE is that the potential for corrosion, unlike a steel pipeline, is eliminated. The replacement of the pipeline and the subsequent lower risks of effluent leaks aligns with our focus on treading more lightly on the Planet.

Reducing COD demand and water abstraction

High demand for a high-performance fluting grade, UltraFlute produced at Tugela Mill, increased the internal requirements for high quality neutral sulphite semi-chemical (NSCC) pulp from the semi-chemical cooking process. With the assistance of the Sappi Technology Centre, the mill embarked on multiple projects to improve the washing in the pulp plant and ensure quality pulp transfer to the paper machine.

The results lead to modification to the washing stages and filtrate system which significantly improved pulp quality. Further improvements made in the pulp plant included the re-use of process water and the introduction of closed loop seal water systems. These initiatives not only reduced water consumption, but also yielded some energy savings.

The cleaner pulp to the paper machine had a direct impact on the mill’s final effluent chemical oxygen demand (COD), reducing the COD load by 40%. The increase in direct pulp feed to the paper machine also reduced the water demand from the repulpers. Additional water reduction projects in the mill included the control of process water balances, fixing water leaks together with inspections and repairs of open water storages, all of which resulted in further reduction in abstracted water of approximately 30%.

All the water improvements described above were made while the mill increased its pulp production by more than 23% and paper production 5% over the same period.

STANGER MILL

Striking a balance

In line with our focus on continuous improvement, we conducted an effluent characterisation study at Stanger Mill which highlighted that the wet-depithing plant is the main contributor to dissolved organic material and solids to the mill effluent. The wet-depithing plant functions like a woodyard, preparing the bagasse for pulping. The waste streams generated in the wet-depithing plant (liquid and solid waste) have a high organic content and the Sappi Technology Centre is currently developing a detailed water and fibre balance of the plant.

The balance will help to:

  • Reduce fresh water consumption.
  • Reduce effluent load.
  • Provide information for the evaluation of anaerobic treatment of the wet-depithing effluent. This has the potential to generate energy from the organic material in the effluent.
  • Allow optimisation of process units and improve removal of pith and sand which in turn, should lead to saving on chemicals (mainly caustic) in the pulping operation.