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Wastewater from textile manufacturing introduces recalcitrant organic compounds, such as dyes and toxic by-products into the environment, where advanced oxidation processes are used to treat toxic and non-biodegradable organic pollutants which cannot be removed by traditional methods. H 2 O 2 /UV, photo-Fenton and heterogeneous photocatalysis (TiO 2 /H 2 O 2 /UV) processes were used, and the effect of the hydraulic retention time on total organic carbon (TOC) removal was evaluated by fitting the analytical data for the three processes to different kinetic models. The high correlation between empirical and modelled data was accomplished with a pseudo-first-order model for the three processes (R 2 = 0.9823 ± 0.017). Mineralisation, decolourisation and disinfection of textile wastewater were investigated with laboratory-scale experiments for each process. Data showed that when 5 g/L H 2 O 2 was used, heterogeneous photocatalysis was the most effective method for the removal of TOC (94.55 %). With respect to colour, all three processes achieved nearly 100 % removal (99.6, 99.3 and 99.9 % at 120 min for the H 2 O 2 /UV, photo-Fenton and TiO 2 /H 2 O 2 /UV processes, respectively).

BACKGROUND: This study analyzed the effects of carbamazepine, ciprofloxacin and ibuprofen on the behavior of a membrane bioreactor (MBR) system treating urban wastewater that was doped continuously with three different concentrations of this mix of pharmaceuticals under a hydraulic retention time of 6 h. RESULTS: The degradation capacity of these chemicals and the heterotrophic kinetics regarding the organic matter removal were evaluated in the control and doping cycles.CONCLUSIONS: Although the MLSS decreased drastically, these differences were not observed in the organic matter removal as the increase of cell growth rate cancelled out the increase in cell decay rate due to the chemical stress caused by the addition of pharmaceuticals, as shown by the increased organic matter degradation rate from 86.27 mgO 2 L −1 h −1 in the control cycle to values within the limits 183.97 mgO 2 L −1 h −1 and 192.88 mgO 2 L −1 h −1 in doping cycles. The degradation rates were 0.0154, 0.0152 and 0.0160 gS/(( gS in /L)*h*mgMLSS) for carbamazepine, ciprofloxacin and ibuprofen, respectively, involving removal yields higher than 71.9, 88.7 and 94.7% for carbamazepine, ciprofloxacin and ibuprofen, respectively, at the three different concentrations tested. Therefore, MBR technology can be used as a reliable process to significantly reduce this mix of pharmaceuticals without reducing its organic matter removal capacity.

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