Focusing on water stewardship
How this issue links to other aspects of our business
|OUR 2025 TARGET|
REDUCE SPECIFIC WATER USE IN WATER STRESSED LOCATIONS
Water is vital to all life, and especially to our business. Water not only nourishes trees but is used to make pulp and paper, generate steam power and so much more in our mills. That’s why we take our role as responsible water stewards in the regions where we live and work so seriously. Our water reduction target focuses especially on our mills in South Africa where we have some of our largest operations.
Pulp and paper operations are highly dependent on the use and responsible management of water resources, with pulp production involving a higher level of specific water use than the production of paper. All our mills use and treat water in accordance with comprehensive environmental permits. Water management is included in our operational environmental management plans, which are reviewed and updated annually. We focus on identifying opportunities to save water throughout our pulp- and papermaking production process, recycling extensively within these processes and improving the quality of the wastewater (effluent) we discharge.
Most of the water used in our operations is drawn from surface water in the form of lakes and rivers, with small amounts of groundwater and municipal water used. Withdrawal from surface sources (mostly rivers) accounts for the largest percentage of water use. This withdrawal is subject to licence conditions in each area where we operate.
Water is used in all major process stages, including raw materials preparation (woodchip washing), pulp cooking, washing and screening, and paper machines (pulp slurry dilution and fabric showers). Water is also used for process cooling, materials transport, equipment cleaning, general facilities operations, and to generate steam for use in processes and on-site power generation as well as various other purposes.
Water is recycled and re-used several times throughout the mill and requires different levels of treatment depending on its use. For example, water used in the steam systems (boiler feedwater) must be purified to minimise corrosion. Once steam is condensed, it is recaptured and re-used in the steam system By contrast, raw water can be used without any treatment for non-contact cooling systems and can be returned directly to water sources as long as it is not too warm.
Throughout the process, especially on the paper machines and cooling towers, water is converted to water vapour and emitted from the process. These vaporised sources re-enter the atmosphere and will ultimately end up as precipitation.
Our closed loop cooking processes essentially serve as the first stage of effluent treatment, as they reduce chemical loading into the environment. At some mills, solid materials collected in the various treatment stages are dewatered and used as a fuel for energy production. Converting waste to energy also reduces the volume of organic materials sent to land. At our mills, once the water is used, reused and treated, it is returned to surface water sources.
Both freshwater and wastewater are routinely tested, either at mill sites or in laboratories to ensure that impacts on the environment are minimised. We use various metrics to ensure that we comply with all relevant environmental regulations.
According to the World Health Organisation, more people die from unsafe water than from all forms of violence, including war.
Key developments in 2020
Water is a significant input for Sappi. In 2020, globally we extracted 277 million m3 litres of water for all purposes. The impact of Covid-19 on our specific water consumption was significant, with production curtailment and downtime taking their toll. Read more. At half year (the end of March 2020) specific water consumption was 33,36 m3/adt (FY2019: 34.17 m3/adt, while at year end (30 September), it was 41.51 m3/adt – an increase of 24.4%, giving a total average of 36.82m3/adt.
Throughout our operations, we continue to focus on the responsible use of water. For example, in addition to the other environmental benefits our Vulindlela expansion project at Saiccor Mill will result in water consumption being reduced by around 5% and water use efficiency increasing by approximately 17%.
In South Africa, which is classified as a water-scarce country in terms of the World Resources Institute criteria, climate change has meant we are increasingly focusing on water availability and cost. As discussed under Helping to mitigate climate change, we have engaged a third party service provider to run water-related scenarios on Saiccor Mill. We have also established a Water Stewardship Working Group that is currently assessing the water risk and mitigation actions related to all our mills and forestry operations, as well as to our neighbouring communities. In addition, we are partnering with WWF South Africa on a water stewardship project in the uMkhomazi catchment area.
Specific process water returned to extracted (m3/adt)
Globally there was an increase in specific water consumption. In SEU, due to reduced production, all mills increased consumption with the exception of Carmignano and Alfeld Mills. In SNA, the increase was driven by curtailed production at Cloquet Mill. In SSA, consumption was stable, with increases at Stanger and Saiccor Mills offset by a decrease at Tugela Mill.
Total water withdrawal by source (m3/annum)
Total water withdrawal decreased globally and regionally due to reduced production.
Total water discharge by destination (m3/annum)
Specific TSS (kg/adt)
Globally, there was a decrease. In SEU, all mills except for Maastricht decreased TSS emissions or kept them stable, with Lanaken Mill returning to former values after finalising the pm 8 rebuild. As described above, as with COD, projects at Alfeld and Gratkorn Mills will have a positive impact on TSS levels. In SNA the increase was driven by curtailment at Cloquet Mill as well as primary clarifier rake failure in Q1. There increase at Somerset Mill was to carryover from the polishing pond, as dredging was delayed due to Covid-19. Matane and Westbrook Mills both showed improvements that only partially offset the increase. Nonetheless, both mills maintained compliance with the environmental regulations during these episodes. In SSA, there was overall decrease, attributable at Saiccor Mill to calcium line downtime and at Stanger decrease to successful chemical trials on the effluent system. The decrease at Tugela Mill was the result of improved clarifier and belt press efficiency, reduced fibre loss on the paper machine and reduced operation of the screw press.
Flattening the sodium curve at Ngodwana Mill
Irrigation effluent is pumped from Ngodwana Mill daily into two dams that are used as buffer capacity to manage both effluent temperature and any settling of fibre before being pumped to the irrigation fields.
Gypsum is used to treat effluent for soil remediation. The capacity of the previous gypsum dosing system did not address instantaneous and spike demand for additional gypsum.
Infiltration rate is defined as the rate at which soil can absorb rainfall or irrigation water and it varies with the water quality. There are two common water quality factors influencing infiltration rate, one of which is the sodium absorption rate (SAR), representing the concentration of sodium relative to calcium and magnesium. In general, the higher the SAR, the less suitable the water is for irrigation and the infiltration rate generally decreases.
The objective of a recently completed project at the mill was to ‘flatten the curve’. When there are excursions in the mill that influence the sodium in the effluent, the sodium concentration in the SAR equation increases. The mill countered this by adding more gypsum (CaSO4). However, by the time by the time the gypsum was added, much of effluent had passed the control point and was already being used for irrigation purposes.
To deal with this issue, the mill recently concluded a two-phase project. The first phase involved the installation of electronic equipment to divert and control the high and low conductivities to the dams. The second phase was the installation of an automated gypsum dosing system.
The project enabled the mill to catch the high sodium excursions and then bleed then in slowly with the rest of the irrigated effluent. This has reduced the effect of the high sodium on the SAR and by ‘flattening the curve’, has reduced SAR spikes.