At certain times of the year, driving past the Sappi Ngodwana Mill in Mbombela, Mpumalanga, is like driving through a stink bomb. But its owners say there is nothing to worry about.
Sappi’s environmental manager Louise van Wyk said the company often does 24-hour monitoring at its ambient monitoring station and the 24-hourly average is then compared with national ambient air quality guidelines.
“We also monitor and capture continuous emission data for point sources in the mill and conduct annual stack monitoring by an external specialist,” she said.
“Climatic conditions can facilitate the odour such as the wind direction and speed, and moisture levels in the air. During the winter months, the Eland’s Valley can result in foggy, misty conditions along with temperature inversion that can possibly exacerbate the smell of the cooking process at the mill,” said Van Wyk.
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Linda Weech, who was travelling to the Kruger National Park, said “the pollution spreads for miles”.
“Is this legal,” she asked. “It’s not only the smell which is problematic. The clouds of dark smoke or fog which fill about 50km² irritate eyes and noses.”
Sappi spokesperson Zelda Schwalbach confirmed the climatic conditions and said the “fog” was not related to Sappi operations.
“Prevailing weather conditions can sometimes also exacerbate the smell of the cooking process at the mill.
“When Ngodwana Mill cooks wood chips to extract their fibres for the pulp-making process, organic sulphide compounds in the wood are released as total reduced sulphur (TRS) gases. Although Ngodwana Mill’s processes collect most of the TRS gases, a small amount unfortunately escapes, causing an unpleasant odour, similar to that of boiling cabbage,” she said.
“TRS gases are detectable by the human nose at extremely low concentrations (less than three parts per billion). Humans are sensitive to the smell…”
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Schwalbach said the odour was generally detected in an approximate 15km radius from the mill, “but this is wind direction and speed-dependent and especially early in the morning when there is a lot of moisture in the air, and when the aforementioned weather conditions are prevalent, the odour may extend further”.
“While the odour is unpleasant, the emissions pose neither a health nor an environmental risk. Our air emissions are regulated under an air emissions licence (AEL), which we report on to the authorities and we are required to report on the ambient concentrations annually.
“The mill also incinerates odour (TRS gases) in its lime kiln and results from this process show a significant reduction of the area that is affected and the concentration of detectable gases. As part of Sappi’s sustainability journey, we continuously aim to improve our technology and reduce our environmental footprint,” Schwalbach said.
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When asked about the air quality report for the area to understand the environmental evaluation by the government, the department of forestry, fisheries and the environment said local evaluations were done by the Ehlanzeni District Municipality – which could not produce the report.
Environmental activist Lerato Sedibe asked: “What is the reason for the respiratory issues if it’s not a crisis in the area?
“And if you are saying the government is not forthcoming with the report, it definitely raises eyebrows and we need to highlight these possible injustices.”