Comparison of alternative management methods for phosphogypsum waste using life cycle analysis

Abstract

The objective of this paper was to compare the following four alternative management methods of phosphogypsum (PG) waste using Life Cycle Analysis (LCA) and select the one with the lowest environmental footprint: (1) use of PG in brick production, (2) use of PG as soil amendment, (3) use of PG in road construction and (4) disposal of PG in a stack. The results showed that the use of PG waste as soil amendment has a lower environmental footprint than the respective use of conventional gypsum with commercial fertilizers. Similarly, PG waste has a lower environmental footprint when replacing conventional clay in road construction. In contrast, use of PG waste in brick production has a higher footprint than the respective use of clay and sand. Comparison of the four alternative management methods using LCA showed that the use of PG as a soil amendment had the lowest environmental footprint. Disposal of PG waste in stacks, which is currently the most common management method, was ranked as the least preferred one. As an example, using Ecoindicator 99 and the egalitarian perspective total scores were 12.807, −5.334, −0.064 and 15.484 Points (Pt) for brick production, soil amendment, road construction and stack disposal, respectively. Among indicative impact categories, carcinogen scores were 7.643, −0.228, 0.0001 and 0 Pt, respectively. Respiratory inorganics scores were −0.192, −4.540, −0.0383 and 0 Pt, respectively. The ranking based on cost is stack disposal<soil amendment≪road construction<brick production. For any alternative PG waste use, it is required that activity concentration of naturally occurring radionuclides is below the respective European Union standards. Using LCA is a useful approach for comparing PG waste valorization methods within the context of Circular Economy.