Ecotoxicological Evaluation and Treatment of a Denim-Laundry Wastewater

Méndez-Hernández, Jazmín Edith; Ramírez-Vives, Florina; Sobrino-Figueroa, Alma Socorro; Garza-López, Paul Misael; Loera, Octavio

Ecotoxicological Evaluation and Treatment of a Denim-Laundry Wastewater

2022

Méndez-Hernández, Jazmín Edith | Ramírez-Vives, Florina | Sobrino-Figueroa, Alma Socorro | Garza-López, Paul Misael | Loera, Octavio

Several laccase-based products have been launched on the market over the years. However, there is little information about their toxicity and/or the toxicity of their residues. We evaluated the toxicity of a simulated denim-laundry wastewater containing Biolite BSN, a laccase-based product used for denim bleaching. The evaluation included a viability test with Saccharomyces cerevisiae, a phytotoxicity test with Sorghum vulgare, and a toxicity test with Daphnia magna. The viability of S. cerevisiae was reduced to 40%. The radicle and plumule growth of S. vulgare was reduced to 62 and 66%, respectively. The CL₅₀ for D. magna was 29.7%, which classified this water as toxic (according to the percent rank method). Biolite BSN was identified as the main cause of the toxic effects; furthermore, the chemical oxygen demand (COD) of the wastewater was significantly high (3346.2 mg/L), and more than 90% of the COD corresponded to Biolite BSN. The anaerobic biodegradability tests showed that the denim-laundry wastewater could be treated anaerobically; therefore, it was treated in an upflow anaerobic sludge blanket (UASB) reactor. The treatment reduced the toxicity and COD in 50 and 77%, respectively, and a methane yield of 311.1 mL CH₄/g of CODᵣₑₘₒᵥₑd was obtained. Based on these results, we recommend to analyze the toxicity of all textile chemicals, regardless of whether they are enzyme-based products. A UASB reactor can be used as the first treatment stage for similar effluents in order to reduce the COD and the toxicity and recover methane as an added benefit.

Показать больше [+]