Abstract

GILPAVAS, Edison; ARBELAEZ-CASTANO, Paula Eliana; MEDINA-ARROYAVE, José David  and  GOMEZ-ATEHORTUA, Carlos Mario. TREATMENT OF INDUSTRIAL TEXTILE WASTEWATER BY CHEMICAL COAGULATION COUPLED WITH FENTON PROCESSES INTENSIFIED BY LOW FREQUENCY ULTRASOUND. Rev. Int. Contam. Ambient [online]. 2018, vol.34, n.1, pp.157-167. ISSN 0188-4999.  https://doi.org/10.20937/rica.2018.34.01.14.

The present study evaluates the sequential treatment of chemical coagulation (CC) followed by the advanced oxidation process (AOP) of Fenton (H2O2/Fe2+) or photo-Fenton (UV/H2O2/Fe2+) intensified by low frequency ultrasound. Optimization of the pretreatment step through CC by jar test showed that an optimal coagulant (Al2[SO4]3) dose of 800 mg/L removed 99 % of turbidity and 53 % of the chemical oxygen demand (COD). The resulting supernatant is used for the AOP evaluation. The statistical analysis of a Box-Behnken response surface design showed that optimal conditions to carry out the US/H2O2/Fe2+ process are: 1 mM de Fe2+, 14 mM de H2O2 and pH 3. Under these conditions the CC coupled to the US/H2O2/Fe2+process removes 82 % of the COD of the supernatant while the US/UV/H2O2/Fe2+ process eliminates 95 % after 90 min of reaction. The use of ultrasound waves inducing an increase of 10 % in the process efficiency. The mineralization of pollutants during treatment as well as the H2O2 consumption were monitored.

Keywords : avanced oxidation process; sonochemistry; ultrasound; Box-Behnken; optimization.