Responsible water management at Merebank and Syktyvkar mills
Syktyvkar’s STEP and Waste Water Treatment Plant
The STEP investment between 2008 and 2010 resulted in a reduction in water consumption for production and an increase in recycled water usage for energy production. As a consequence, the volume of water intake from the Vychegda River decreased by 16.7 million m³ or 14.9% in 2013, compared with 2008. In pulp production, the specific fresh water consumption decreased by a significant 32%.
To further meet our Group-wide commitment to reducing water consumption and minimising the volume of COD discharged to the aquatic environment, our Syktyvkar mill is upgrading its WWTP. This project, which is due for completion in 2016, will introduce improvements at four different stages of waste water treatment: mechanical treatment; biological treatment; treatment in lagoons; and finally the control of waste water treatment.
Sergey Tsyganov, Syktyvkar mill’s environmental manager, explains, “We have worked together with the local authorities for the project’s implementation. Mondi Syktyvkar accepts and treats storm and municipal waste waters as well as waste water from other industries in the Syktyvkar area where there are inadequate treatment facilities.”
Merebank mill and the use of 95% second-class water
In just over 10 years, second-class1 water has replaced 95% of the potable water formerly used at our Merebank mill. In a further development, the quality of our treated water has reached the high standard necessary for steam generation.
The major motivation was South Africa’s water scarcity. Previously, potable water was used for all process requirements at the mill as well as for domestic consumption. There is no associated negative impact on pulp and paper quality.
Gladys Naylor, environmental manager, Mondi South Africa Division, says, “Merebank’s objective is to continue to reduce the amount of water required to make each tonne of paper, thereby further improving its water use efficiency.”
In 1993, EWS (eThekwini Water Services), the local municipality waste water treatment plant in south Durban which treats domestic and industrial sewage before final disposal out to sea, developed a reclamation process for the production of high-quality reclaimed water and tested it on laboratory and pilot scales in 1994 and 1995. These results along with studies conducted by Mondi confirmed the mill could use second-class water or upgraded sewage.
Mondi engaged with eThekwini Water and Waste in the selection of the service provider, which led to the establishment of the first private water-recycling plant in South Africa, Durban Water Recycling (DWR). This plant is the culmination of a 20 year Build, Own, Operate and Transfer (BOOT) contract awarded to treat 10% of the city’s wastewater.
As a means of further reducing our reliance on potable water, Veolia Water Solutions and Technologies was commissioned to install a reverse osmosis (RO) plant at the mill in 2013. This RO plant treats the second-class water to a standard required for the production of steam. The RO water has now substituted potable water fed to Mondi boilers and hence further reduced potable water usage in the mill. The benefits of this venture will continue to deliver positive environmental outcomes.
Concludes Gladys, “The water recycling project shows that a combination of innovation, sound environmental principles and water treatment technology can deliver significant improvements in water resource management. The project further demonstrates the success which can be achieved through public private partnerships which harness the strengths of both sectors.”