In the study, the researchers simulated water storage, pumping and treatment scenarios, considering different levels of alumina production and precipitation using internationally recognized modeling and simulation platforms. The Federal University of Campina Grande (UFCG) is widely recognized as a specialist in the field of chemical engineering in Brazil. The research team, composed of 14 people, was coordinated by Dr. Romildo Pereira Brito and Dr. Gilmar Trindade de Araújo, both professors at UFCG. The study was published on November 26th.

Main conclusions of the study:

• Computer simulations show that Alunorte's waste disposal areas, DRS1 and DRS2, did not overflow in February 2018
• The release of excess rainwater to the Pará River through the “Canal Velho” was the most appropriate decision in the face of the extreme rainy circumstances of February 2018
• Alunorte can, from the water management point of view, safely produce within its nominal capacity of 6.3 million tons of alumina per year.
• With the improvement projects that are being implemented at Alunorte, the alumina refinery is prepared for possible future climate changes that could lead to more frequent extreme rains.

“It is encouraging that we now have an independent study that states that Alunorte can safely produce at full capacity and that our continuous improvement projects will make us well prepared for even heavier rains than those we experienced in February. Together with the reports and confirmations from the Brazilian authorities that we did not have any overflow of waste deposits, this study is an important confirmation that Alunorte is capable of producing safely ”, says John Thuestad, Executive Vice President of the business area of Bauxite and Alumina from Hydro in Brazil.

Strengthening Alunorte's water treatment capacity

Hydro has projects underway to strengthen Alunorte's water management capacity, which will take the alumina refinery to a new environmental standard. The water storage capacity is expected to be increased by 350% (completion scheduled for the end of 2018) and the capacity of the water treatment infrastructure will be increased by 50% (scheduled for the second quarter of 2019).

The independent report attests that the improvements made on the three fronts mentioned (storage, pumping and treatment), are correctly designed and guarantee the safety of Alunorte's operations. The improvements have been tested for extreme rains that can occur only once in 5,000 or 10,000 years. The study concludes that Alunorte would operate safely in the face of these rains. With the improvement in storage and pumping capacity, completed in December 2018, the study confirms that there would be no need to use the Old Canal to release excess rainwater, which was done as an emergency measure during heavy rains in February this year.