Efecto inhibitorio de cromo, cloruro y sulfuro en bacterias aeróbicas degradadoras de glucosa

The tanning process produces waste water which contains various highly toxic components that may interfere with the biological treatment. Wastewater from a tannery was pre-treated using a controlled mixing of acid and basic effluents, and a physical-chemical treatment of whitewash, was evaluated to determine if it could be submitted to a biological treatment. The inhibitory effect of chromium, chloride and sulfur in the metabolic activity of the degrading glucose bacteria was studied under batch type bioassay to determine the feasibility to apply an aerobic biological treatment to the pre-treated effluent of the tannery industry. Three types of sludge from different waste water treatment plants in the Metropolitan District of Quito were analyzed to determine the best microbial inoculum and obtain an aerobic enrichment culture for microbial toxicity. A concentration of 10% (v/v) of enriched aerobic culture was used, as demonstrated in an earlier study to be the most efficient biomass concentration under specific conditions [1]. As a result from the substances studied, trivalent chromium caused higher microbial toxicity. The chromium concentration that produced 50% of metabolic inhibition (IC50) was 82,59 mg L-1. An increase in salt caused IC50 = 8219,72 mg L-1, while sulfides registered IC20 = 0,22 mg L-1. In conclusion, according to the concentrations of chromium (1,95 mg L-1), chloride (7726,23 mg L-1) and sulfur (0,634 mg L-1) found in pre-treated waste water from tanning process, biological treatment of those effluents can be developed if salt and sulfur levels are controlled. ; Durante el proceso de curtido de pieles se genera agua residual que contiene varios componentes que pueden ser altamente tóxicos y pueden interferir con el tratamiento biológico de la misma. El agua residual proveniente de una curtiembre pre-tratada con un sistema de mezcla controlada y lechada de cal fue evaluada para determinar si puede ser sometida a un proceso de tratamiento biológico. El efecto inhibitorio de cromo, cloruro y ...