Sustainable Industry

Steel giant ArcelorMittal has the largest seawater desalination plant in the country

ArcelorMittal spent BRL 50 million in a plant with initial capacity to generate 500 m³/hour of desalinated water

Water supply is a major challenge facing governments and society alike. Data from the National Water Agency (ANA) show that the demand for water in Brazil is expected to increase by 24% by 2030, i.e., more than 2.5 million liters per second. In order to avoid water crises in the near future, solutions must be sought for the sustainable use of this vital resource for human beings. Desalination of sea water is an option.

ArcelorMittal – one of the largest steel makers in the regular steel, long and flat steel, and coils segment in the world – stands out with initiatives involving the use of water. Their Tubarão site, located in the Metropolitan Region of Greater Vitória (ES), has started operations in the largest seawater desalination plant in the country. Its initial capacity to generate 500 m³/hour of desalinated water means greater water security for the company and for the State.

The system required an expenditure of BRL 50 million to materialize. “Several technological options for desalination, seawater quality analysis, technical discussions with suppliers from all over the world, laboratory testing, and even technical visits to plants in Argentina and the United States were part of the efforts,” says Jorge Oliveira, CEO of ArcelorMittal Aços Planos América do Sul.

The company’s initiatives are in line with the strategy of the National Confederation of Industry (CNI) towards a low-carbon economy in Brazil based on four pillars: energy transition, carbon market, circular economy, and forest conservation.

Recirculation – Approximately 96% of the water used by ArcelorMittal’s Tubarão site comes from the sea and is used to cool steel production equipment. The remaining 4% come from the Santa Maria da Vitória River. In order to mitigate the use of this 4%, ArcelorMittal runs projects to reduce this consumption. Currently, the site’s freshwater recirculation rate is above 97%.

For sea water capture, reverse osmosis technology is used, which is quite common in countries such as Israel, Spain, the United States, and others. A unique feature of this project is its modular layout. The first module has the capacity to desalinate 500 m³/hour of sea water (this is enough to supply around 80,000 people/day), and new modules can be added in the future.

Thanks to this technology, the company recovers 50% of the energy used to power high-pressure pumps in reverse osmosis membranes. The plant consumes around 3MW of electricity and accounts for less than 1% of the total energy generated by ArcelorMittal’s Tubarão site, which is self-sufficient.

The process does not generate significant environmental impacts either. The salt-in-water solution resulting from desalination, i.e. the brine, is returned to the sea through a return channel already in place at the plant.

Reuse – In addition to the desalination process, the site has other water management actions underway. The company recently signed Terms of Use to use reused water from the Effluent Treatment Plant of Companhia Espírito Santense de Saneamento (Cesan).

The agreement covers a monthly purchase of 540 m3/h (150 l/s) of sewage reuse water for industrial purposes. The water comes from effluents from Cesan’s Sewage Treatment and Reuse Station. The acquisition will be under a 25-year contract, which may be renewed, and will reduce the plant’s demand for water from the Santa Maria da Vitória River, thus sparing water for alternative uses.

The company has also been involved in a project for the recovery of springs in the Santa Maria da Vitória River Basin, together with several partners. All these actions are part of the company’s Water Master Plan, which includes initiatives aimed at strengthening water security.