The Spatial Limits of Environmental Benefit of Industrial Symbiosis – life cycle assessment study
Industrial ecosystems are supposed to improve environmental performance. However, despite proven financial profitability, environmental justification of particular symbiotic initiatives is not obvious and demands verification. The authors of previous studies have recommended application of life cycle assessment method for environmental impact estimation in case of industrial symbiosis. However, few studies presenting life cycle assessment results of industrial symbiosis have been published so far. Among the factors which contribute to the success of symbiotic exchange, the close location of collaborating companies has been often mentioned in the literature. Most researches have focused on single industrial ecosystem where cooperating companies were located relatively close to each other. The positive environmental impact of particular symbiotic initiatives has been verified, however the results have not provided more general conclusion for other industrial ecosystems, including virtual eco-industrial parks. The main aim of this work was to determine the maximum distance of symbiotic transmission at which the environmental impact remains positive. Life cycle assessment results concerning the environmental impact of symbiotic fly ash exchange were presented. Concepts of relative distance and critical distance for the case of industrial symbiosis were proposed and defined. Considerable differences between critical distance obtained for particular endpoints were observed. The mixing triangle method was applied to estimate the critical distance taking into account individual impact categories. The final results pointed out that the critical distance of symbiotic fly ash exchange was much longer than in case of gypsum transmission. A sensitivity analysis indicated the relationship between critical distance and the means of transport which reflected the effect of scale. The effect of the fly ash pre-processing on the results was examined, and turned out to be insignificant.