Life cycle assessment and water footprint evaluation of crude steel production: A case study in China

Abstract

China, as the world's largest crude steel producer, is suffering from water scarcity and pollution. However, only a few systematic analyses on the environmental burdens and improvements of China's crude steel production have been conducted. Therefore, it is important for research to be done how China's steel industry can be improved in environment management. To help decision-makers understand this, a life cycle water footprint analysis including gray and blue water was performed based on the methodology prescribed in the ISO 14046 standard. A life cycle assessment was also conducted to improve the environmental performance of the steel industry. Results of these assessments revealed that gray water footprint, which is mainly derived from aquatic eutrophication, carcinogens, and non-carcinogens, is higher than blue water footprint. Optimizing indirect processes, including iron ore mining, magnesium oxide production, transportation, and electricity generation, played dominant roles in the reduction of gray water footprint. Furthermore, COD, Cr (VI), phosphate, BOD5, Hg, As, nitrogen oxides, particulates, and sulfur dioxide were the key substances for environmental improvements. The underestimation of direct water footprint showed the importance and urgency of implementing scientific and adequate monitoring indicators. Meanwhile, the environmental burden can be reduced by adopting a reasonable location of the steel industry on the basis of regional water resources and actual transportation status, improving the efficiency of raw material consumption, and optimizing the power structure.