Remediation of wastewater from the semi-artisanal tanning process using microalgal consortium

Abstract

Human, commercial and industrial activities are polluting the waters that are normally used for agricultural productivity. The Ministry of the Environment (MAE) regulates these activities by demanding, according to environmental legislation, that the water collected be returned upstream in equal or better conditions than the initial ones, and within the parameters of the unified text of environmental legislation when it is discharged into the sewage system. The poor disposal of liquid effluents with the presence of chromium by various industries, especially tanneries, is causing pollution of water bodies. The percentage removal efficiency was presented 10 days after the start of the experiment, showing the highest removal for the heavy metals cadmium, arsenic and lead at 100%, followed by a reduction in the amount of total coliforms (98), faecal coliforms (100), total solids (78) and nitrates (97%). The removal of total phosphorus corresponded to 72%, while for total phosphorus it was 72%.  It is also observed that the biological oxygen demand (BOD5) was reduced by 82% and the biochemical oxygen demand (COD) by 89% with respect to the initial values found reported in tannery wastewater before the experiment. Alternately these effluents could be used as alternative substrates for the growth of microalgae, which would generate a positive impact on the total costs of biomass production at large scales.