The co-processing of municipal waste in a cement kiln in Mexico. A life-cycle assessment approach

A growing population and a high level of consumption generate increasing municipal waste, which requires integral and environmentally efficient waste management systems. In contrast, the cement industry has an inherent need for fuel with a high heat of combustion. Thus, municipal solid wastes with high calorific value are desirable as Refuse-Derived Fuel for thermal processes in the cement industry, which is an opportunity for both the waste sector and cement industry. However, the environmental viability must be objectively, systematically and holistically evaluated. For the last trait, a comparative Life Cycle Assessment was developed to evaluate the environmental impact from clinker production for two fuel scenarios: one considering a 100% petroleum coke and the other a 20% Refuse-Derived Fuel and 80% petroleum coke co-process. This study considers real operating data from waste management systems and the cement industry in Mexico. Both scenarios considered the impact of the raw material extraction, manufacture and transport of fuels, electricity generation and use air emissions, discharge and wastewater generated during the life cycle of the analyzed fuels. The evaluated impact categories were the abiotic resource depletion, acidification, eutrophication, global warming, stratospheric ozone depletion, photochemical smog and terrestrial toxicity based on the CML IO Baseline V3.01. The results indicate the co-processing scenario exhibited a lower environmental impact than using only petroleum coke as a fuel for all categories. Therefore, using Refuse-Derived Fuel from municipal waste in Mexican cement plants mitigates environmental impacts and could be a strategic alternative for waste management.