Local regulation needed for best water use in steel industry, Worldsteel says
Steelmakers must adopt a more balanced approach to the use and recycling of water, according to report published by the World Steel Assn (Worldsteel) on Wednesday April 15.
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The report emphasised the need for a local approach and a tailor-made regulatory framework in each territory to achieve the best use of water in the steel industry.
The water-use challenges facing steelmakers around the world differ depending on local conditions – such as availability of the resource, water quality, plant configuration and legislation – so local or regional regulation would be the best way to achieve customised solutions, Worldsteel said.
The issue of industrial usage of water has been highlighted in Brazil, where unusually dry seasons have led to disputes over water use and its taxation.
The Worldsteel report also argued for increased recycling of water – for example, by introducing “zero discharge” policies in areas where fresh water is scarce.
“Around 90% of the water used in the steel industry is cleaned, cooled and returned to source. Most of the loss is due to evaporation. Water returned to rivers and other sources is often cleaner than when extracted,” Worldsteel director general Edwin Basson said.
Water recycling rates in blast furnace-based steelmaking were slightly lower than for electric arc furnaces (EAFs), according to a member survey published by Worldsteel in 2011.
The average water intake for an integrated plant was 28.6 cubic metres per tonne of steel produced, with an average discharge of 25.3 cu m. For an EAF, the average intake was 28.1 cu m per tonne of steel, with an average discharge of 26.5 cu m.
Additional processes for cleaning and cooling water required large amounts of energy, however, which often went against the objectives of reducing energy use and carbon emissions.
The effectiveness of water reuse must therefore be assessed taking into account all the relevant local environmental considerations, the report said.
“The steel industry takes its responsibility for water management seriously and is constantly evaluating how best to use water, finding improvements in both conversion and reuse,” Basson said.
As an example, Abu Dhabi-based Emirates Steel has outlined plans to pioneer green policies, including encouraging the reduction of water usage in its steelmaking process by recirculating it.