RESUMO
In this research, a combined photocatalytic and biological treatment is proposed for the elimination of pollutants present in textile wastewater using a natural erionite zeolite (PE) and aluminum oxide (PA) synthesized by the sol-gel method as photocatalysts, and solar radiation. Both catalysts were characterized by XRD, SEM, and EDS. For biological treatment two bacterial consortium were used: BC1 (Escherichia coli N16, Serratia k120, Pseudomonas putida B03 and Enterobacter hormaechei), and consortium BC2 (Escherichia coli N16, Serratia Mc107, Enterobacter N9, Enterobacter hormaechei Mc9). The photocatalytic and microbiological treatments were carried out initially separately and subsequently in a sequential manner, first the photocatalytic followed by the microbiological to determine if a synergistic effect was achieved. Comparing the photocatalytic performance, erionite showed higher performance of dyes degradation (54.75%) than alumina (28.62%). While in the biological process, BC1 decreased the dye concentration to 56.93% and BC2 to 53.56%. Finally, the best combined process was PA+BC1 reaching pollutants degradation 64.62%, showing that the application of both processes promotes a decolorization in textile wastewater. The water resulting from the combined photocatalysis-microbiological degradation processes was tested for toxicity using Daphnia magna, obtaining that none of the effluents shows toxicity.
RESUMO
Mine tailings represent a serious environmental pollution problem and techniques such as phytoremediation using plant growth-promoting bacteria become an important solution due to their environmentally friendly nature. The study performed using Brassica juncea L. (Indian mustard) and plant growth-promoting bacteria such as Serratia K120, Enterobacter K125, Serratia MC107, Serratia MC119 and Enterobacter MC156 showed that plant roots colonization favored the transfer of metals to the plant, mainly Al and Pb from the 8 analyzed metals with bioaccumulation factors >1 for Al, Pb, Cd and Fe obtained with Serratia K120, Enterobacter K125, Serratia MC107, Serratia MC119 and Enterobacter MC156. Based on these results, this system could be used in phytoextraction processes whereas Enterobacter MC156 reduced the bioaccumulation of metals, indicating the possible phytostabilization of metals present in mine tailings.