Hydro Annual Report 2011b

Water management
Enough clean water is a challenge in some of the areas where
Hydro operates. Local initiatives show that with simple measures,
substantial water savings are achievable. The systematic
mapping of our water situation in 2011 showed that about 3
percent of our overall water input came from water-stressed
areas, with regard to annual renewable water supply (according
to the definition used by WBCSD).
Although the Amazon is recognized for its abundance of water,
we have observed over the last decades that parts of the area
have had repeated droughts. We will therefore carefully address
water as an issue also for our sites in Brazil. Qatalum gets water
from public water works, produced by desalination. Sea water
is used for wet cooling towers at the power plant.
We regularly follow up the impact on aquatic life in rivers near
our hydropower plants. In addition, we are following up a
rehabilitation project of the Måna River in Rjukan, Norway.
In 2011, this included improvement of fish habitats. We will
in 2012 start similar projects in the Årdal river and fortun
river. All projects also include increased accessibility to the riversides
for the local communities.
According to requirements in our hydropower concessions, we
finance operation of two fish nurseries in Sogn in Norway.
Trout are bred every year, and approximately 100,000 fish fries
are stocked in the small lakes in the concession area. This mitigates
the impacts from the regulation of the water going to the
power plants. In the fortun River we also stock salmon fries
every year in order to maintain the population.
Minimizing waste
Our goal is to minimize the amount of waste produced and
then reuse or recycle it. This is beneficial, both environmentally
and economically.
Tailings and bauxite residue
Tailings from bauxite extraction consist of mineral rejects from
the extraction process mixed with water. No chemicals are
added. The tailings at Paragominas are stored in dedicated tailing
ponds, where the particles settle. Separated water is transferred
to a clarification dam before it is reused in the process.
There is a minor run-off to the river downstream of the tailings,
which is required to maintain an ecological flow. The
run-off is monitored, and the water quality meets the requirements
set by the authorities.
The current tailing ponds are reckoned to be full by 2015-
2020. The area will then be reforested. The total production of
tailings in 2011 was 5.9 million metric tons (mt). The Paragominas’
mine produced 8.2 million mt bauxite in 2011.
Bauxite residue, also known as red mud, is a by-product of the
alumina refining process. Alunorte uses the Bayer process,
vIABIlItY perForMAnCe
Resource management
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which includes the use of caustic soda. The residue is washed
with water to lower the alkalinity and recover caustic soda to
be reused in the process. The residue is dry-stacked, which
means it is transformed into a clay-like solid with a low moisture
content. Alunorte is in the process of reducing the moisture
further through conversion to pressure filtration.
The bauxite residue deposit at Alunorte was extended in 2011.
In total, 6.4 million mt were disposed in 2011. When the
deposits are full, we have a plan for replanting of the area.
Bauxite residue from Alunorte is being tested as a raw material
for bricks and paving stones, but even with an optimistic market
estimate, this production will only use a small fraction of
the total residue. The remaining residue is disposed and
replanted.
After a spillage in 2009 of storm water from the bauxite residue
deposits at Alunorte, corrective actions have been taken,
including strengthening the drainage system and improving
the surveillance of the water treatment facility. A need for better
emergency handling, including information to the local
community, was also identified. There are still legal issues
pending following the incident, such as individual lawsuits
filed by local residents who claim compensation for damages
caused by the spillage. So far all of the claims have been dismissed.
There is also a negotiation in place with the public
prosecutor, who claims compensation for the environmental
damages caused by the spillage. If an agreement is not reached
with the public prosecutor, a class action lawsuit can be filed
against Alunorte in this regard.
Other waste
Spent potlining (SPL) from the reduction cells used in primary
aluminium production is defined as hazardous waste. In
2011, we generated 24,804 metric tons of SPL, which was 29
percent below the amount from 2010. The production of SPL
varies with the relining of smelter cells which is normally done
every 4-7 years for established smelters. New plants will get a
relining peak at the same interval after start-up. We expect an
increase in the SPL production from consolidated smelters in
a couple of years and from part-owned Qatalum some years
later.
Qatalum is aiming at “no-SPL-to-landfill”, together with other
aluminium plants in the Arabian Gulf, with a view to using
SPL in the cement industry.
In 2009, we formalized a cooperation with an external partner
to help identify applications for production waste from our
aluminium plants in Norway. The planned recycling plant at
Karmøy, Norway will also be able to handle dross. The building
of this plant was postponed in 2011, however, due to the
market situation. See also page 59.