Biogas can be used in place of natural gas and coal in iron and steel mills, significantly reducing polluting emissions and wastes, thanks to a technique developed by professors at the Federal University of Minas Gerais and the Federal University of Ouro Preto. "Biogas is produced naturally, through the breakdown of organic matter by anaerobic bacteria. The most commonly used raw materials are urban household waste and animal manure," researcher Paulo Assis told Tierramérica.

"We propose that biogas be used for the production of sponge iron and pig iron, which are used in the steelmaking process, in place of natural gas, coal and charcoal, which are non-renewable sources of energy," he said.

"In the case of natural gas, it can be 100 percent replaced by biogas, while coal can be 40 percent replaced," he added. The technology is in the process of being patented.