Annual Report 2010 - Outokumpu

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Smaller amounts of rainwater fall on landfill areas located on Group sites, and this water may come into contact with
alkaline wastes that could be contaminated with the hazardous compound hexavalent chromium. Such waters are
treated to reduce the already-small chromium content to its naturally-occurring level, either through direct treatment in
landfill areas, or by pumping the water to neutralisation plants.
Paying attention to water discharges
From an environmental perspective, the most significant components in water discharges from Outokumpu's stainless
steel production processes are metal compounds and nitrates resulting from the neutralisation of acidic wastes
generated in the Group's cold rolling units. Effluent discharges at all of Outokumpu's production units are controlled so as
to minimise their impact on the environment. At the Tornio Works in Finland, for example, external studies conducted in
the 2000s have shown that levels of metals in the primary discharges from the plant are much lower than the natural
loading of metals in local rivers flowing into the Gulf of Bothnia.
Developing discharge handling techniques
Nitrate loadings originate in the pickling acids used in descaling operations involving stainless steel. A number of
different techniques are employed by the Group to reduce nitrate loadings in effluent discharges from these operations,
including pickling-acid recycling technologies. Outokumpu continues to work on the development of discharge-handling
techniques to further reduce effluent loadings.
At the Group's Kemi Mine, the main source of nitrates is the explosives employed in blasting – a small proportion of the
explosive charges used is washed out into the facility's water-circulation system. Passage through three large ponds (a
total of almost 200 hectares) located upstream of the point at which discharges into the recipient water system take place
results in the nitrate content of the water being reduced by some 60%. As these water ponds are natural removal units
there are no associated negative impacts on the Iso-Ruonaoja, the recipient water system.
R&D to reduce discharges into water
Several research projects aimed at reducing nitrate discharges into the waterways
have been carried out at a number of Outokumpu's production sites in Sweden. At
Avesta, this resulted in the investment of EUR 28 million in a new acid-recycling
system that was installed during 2010. Process start-up is scheduled for early
2011 and this method of handling acids will result in drastic reductions in the
quantities of nitrates that are discharged in this location. As the new process also
generates a metal oxide that can be used as a raw material in the steel melting
process, the new system will also reduce the quantities of sludge sent to landfill.
At the Avesta site, the oil-separation station used for purifying cooling water and
rainwater has been converted into a modern lamella filter unit. Process control
ensures that oil is separated from water streams. At Tornio, to further reduce
concentrations of nitrogen and suspended solids, plans to use the large dredging
pond near the harbour as a post-treatment area for effluents from the Works have
moved forward. The basin is expected to be taken into use during the year 2011.
It has also been decided that the cleaning station for sanitary waters will be renewed.
Read more about the health of water ecosystems.
Outokumpu Annual Report 2010 – Business – Water