Our focus is on minimising end-of-life waste through waste beneficiation. This not only helps to mitigate environmental impact, but also, as with reducing purchased energy usage, it brings down costs and can generate additional revenue. Sending waste to landfill adds costs, while valorising waste brings in revenue.
The least desirable method of solid waste disposal from an environmental perspective is landfill. Organic waste emits methane, a greenhouse gas with 28 times the global warming potential of CO2. Inorganic waste can leach, resulting in surface and/or groundwater pollution.
As can be seen from the pie chart below, globally most of Sappi’s solid waste generated is in the form of bark. In all regions, this is used as a fuel for onsite energy generation. In South Africa, bark is also used for composting and landfill stabilisation. As can be seen from the graph below Disposal methods of solid waste (%), the amount of solid waste combusted has increased over time, as has the quantity of waste sold.
How we valorise waste
- Used oil is dewatered, chemically treated, refined and filtered for reuse in various grades of base oils.
- At Alfeld and Ehingen Mills in SEU, coarse pigments from repulping internal broke are recovered from paper machine effluent and reprocessed to substitute virgin material. In another process, coating colour is also recovered from effluent and reprocessed. These partly Sappi-patented processes help to increase material efficiency.
- Sludges, bark and wood are combusted for energy production in each region, while in SEU, dried sludge is also used for animal bedding by farmers.
- At some mills, tall oil (a byproduct of the kraft pulping process) is sold to convertors as a renewable chemical raw material and used to make detergents, lubricants and paint additives.
- In SNA, lime and boiler ash is provided to farmers as a soil enhancer through a partnership with the University of Minnesota Extension Service, Carlton County By-Products Programme, while in SSA, lime mud is sold.
- In SNA, inorganic ‘grit’ removed from the chemical recovery process is used for roadbed underlayment.
- Bagasse supplied to Stanger Mil in South Africa is depithed, and the pith given to farmers as a soil enhancer.
- Lignosulphonate, a byproduct of the pulping process, is a sound revenue stream (see Key material issues – Extracting maximum value from woodfibre in adjacent markets).
We generate very little hazardous waste, 0.13% of the total generated. This is closely controlled and carefully managed, both at our operations and the receiving facilities.
Disposal methods of solid waste (%)
Disposal methods of solid waste (%)
Specific landfilled waste (t/adt)
Across the group, there was a decrease. However, in SEU there was an increase generated by operations standstill at Stockstadt Mill which led to higher use of insulation wool due to lagging replacements. There was an increase in specific landfilled waste at all three mills in SNA. Cloquet Mill increased lime/dregs landfilling due to extra kiln cleaning and to manage the size of the land application piles. The increase at Somerset Mill was due to 9% less production driven by the PM1 rebuild. In addition, paper mill losses were high during the start-up of PM1 following the rebuild. These were offset to some extent by a reduction in boiler ash due to less biomass firing at Somerset Mill. The landfilling rate at Westbrook Mill also increased due to an increase in coal- and biomass-firing for economic reasons. In SSA, there was a decrease at all mills, with boiler ash used for capping at Ngodwana and Tugela Mills and increased beneficiation at Saiccor Mill (ash, gypsum and building rubble) and Tugela Mill (timber fines).