A Comparative LCA of Aeroponic, Hydroponic, and Soil Cultivations of Bioactive Substance Producing Plants

Sustainable agriculture is currently trendy. It is supported not only for the urban environment but also as an innovation of conventional practices in order to increase the efficiency and quality of agricultural production. This study presents the results achieved within selected soil-less (hydroponic and aeroponic) systems. Then, it compares them, using the tool of comparative life cycle assessment (LCA), with the results of soil cultivation. The attention is directed towards biomass production and the content of bioactive substances, which can compensate for higher operating costs of soil-less cultivation systems. Coffea arabica has shown a significant increase of caffeine and theobromine contents, both in leaves and roots, as well as higher biomass yield during the aeroponic cultivation. On the contrary, Senecio bicolor evinced the results of a considerably increased growth in the hydroponic system, with no higher contents of alkaloid or flavonoids, except for the rutin concentration. The LCA results of the compared soil and soil-less systems showed that the consumption of fertilizers, diesel, and water in soil systems and of conventional electricity in aeroponics and hydroponics contributed mostly to their environmental burden. The major environmental impact categories are terrestrial ecotoxicity, human non-carcinogenic toxicity, and global warming. Therefore, in order to make the soil-less cultivation systems sustainable, these environmental aspects need to be considered deeply

Fenton Reaction–Unique but Still Mysterious

This study is devoted to the Fenton reaction, which, despite hundreds of reports in a number of scientific journals, provides opportunities for further investigation of its use as a method of advanced oxidation of organic macro- and micropollutants in its diverse variations and hybrid systems. It transpires that, for example, the choice of the concentrations and ratios of basic chemical substances, i.e., hydrogen peroxide and catalysts based on the Fe2+ ion or other transition metals in homogeneous and heterogeneous arrangements for reactions with various pollutants, is for now the result of the experimental determination of rather randomly selected quantities, requiring further optimizations. The research to date also shows the indispensability of the Fenton reaction related to environmental issues, as it represents the pillar of all advanced oxidation processes, regarding the idea of oxidative hydroxide radicals. This study tries to summarize not only the current knowledge of the Fenton process and identify its advantages, but also the problems that need to be solved. Based on these findings, we identified the necessary steps affecting its further development that need to be resolved and should be the focus of further research related to the Fenton process