Remoción de cromo (VI) de agua residual de curtiembre empleando biomasa orgánica vegetal en un reactor biológico secuencial aerobio

[Introduction]: In the removal of chromium (VI) from tannery wastewater, physicochemical methods are the most used. However, these require high operating costs, and worse still, generate secondary pollutants that again require complementary treatments for their elimination. Given this, the applicability of vegetable organic biomass (VOB) emerges as an environmental alternative based on: the simplicity of its obtaining, the reduction as waste, it does not generate secondary pollutants and, above all, it removes chromium (VI). [Objective]: Use VOB waste in an aerobic sequential biological reactor (SBR) for the removal of chromium (VI) in the treatment of tannery wastewater. [Methodology]: 3 aerobic SBR systems were implemented; 2 controls (SBR1 and SBR2) and 1 study subject (SBR+VOB). Each system was fed with tannery wastewater (18 L) and connected to an aeration mechanism (12.7 L/min). The bacterial inoculum, a fundamental part of an SBR system, was gained from the selective culture of chromium (VI) reducing bacteria (RBCrVI) taken from the wastewater under study, and integrated into SBR2 and SBR+VOB at 0.6 g/L. The VOB was obtained from Stenotaphrum secundatum residues, fragmented, sieved, sterilized and integrated into the SBR+VOB at 1.5 g/L. [Results]: The SBR+VOB system achieved the highest percentage of chromium (VI) removal (93 %), followed by SBR2 (80.1 %), and finally SBR1 (2.8 %). With respect to COD and TSS, the statistical test (Tukey) showed that there was no significant difference between the system under study and the controls, recording COD removal percentages ranging from 87.8 % to 88.4 %, and TSS ranging from 63.8 % to 69.2 %. [Conclusions]: The viability of using VOB waste to remove chromium (VI) in the treatment of tannery wastewater has been evidenced. The results of this research create a promising panorama to mitigate the effects derived from inadequate management of tannery wastewater and organic solid waste.