INFLUENCE OF WASTEWATER TREATMENT IN THE LIFE CYCLE ASSESSMENT OF ALUMINIUM TRIFLUORIDE
Special Symposium - Environmental Protection & Sustainability
Environmental Protection & Sustainability - I
Keywords: Life Cycle Assessment, wastewater treatment, aluminium trifluoride, crystallization, fluidized bed reactor
Sustainable Development is a model of progress that links economic development, protection of the environment and social responsibility. This progress towards Sustainability is a key feature of the policy making in the European Union (EU). As a consequence, an Integrated Prevention and Pollution Control (IPPC) Policy and an Integrated Product Policy (IPP) have emerged. Related to IPP, the Life Cycle Assessment (LCA) has been pointed out by the EU as the best framework to evaluate the environmental impact related to products. This LCA approach is essential for an objective quantification, giving a vision of the relationship between human activities and environment, and identifying the main environmental impacts. The latest developments show LCA as a powerful decision making tool in order to identify more sustainable options in process engineering.
In this work, the environmental impacts of two technologies for fluoride removal from industrial wastewater in the AlF3 production have been considered: i) chemical precipitation for fluoride removal, leading to a water rich sludge, which has poor dewatering characteristics and therefore, it must be stored in waste landfills, and ii) the recovery of fluoride by a crystallization process as synthetic fluorite to be reused in the HF manufacture. Life Cycle Assessment (LCA) has been used for this purpose.
The LCA software SimaPro 7.0 (PRé Consultants®) makes possible the comparison in terms of different methodologies like Ecoindicator-99 and CML 2 Baseline 2000. In this work, the integration of the environmental metrics “IChemE Sustainable Development Progress Metrics” allows the comparison of the results using this metrics, obtaining results expressed in common engineering process terms. The functional unit used for the comparison between different data sources is the production of 1 tonne of AlF3. Data used in the Life Cycle Inventory (LCI) of wastewater options have been taken from reliable sources. The data used for the consumption of resources to complete the environmental impact life cycle assessment has been taken from the EcoInvent database v1.2.
Several data sources were considered to obtain the data for the LCI in order to avoid the influence of data source selection on the final results. In previous works, the crystallization process was developed as a more friendly alternative in relation to chemical precipitation from an environmental point of view in the aluminium trifluoride production. However, the wastewater treatment step in the AlF3 production has a minor environmental impact in the AlF3 life cycle, and the environmental benefits derived from crystallization become close to neglible under assumptions considered. Environmental burdens from raw materials consumption in the AlF3 production is the main step in the life cycle assessment.
Presented Monday 17, 11:15 to 11:35, in session Environmental Protection & Sustainability - I (S-7A).
