Assessment of AOPs as a polishing step in the decolourisation of bio-treated textile wastewater: Technical and economic considerations

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Petrick A. Soares (Author) FEUP; Tânia F. C. V. Silva (Author) FEUP; Adriana Ramos Arcy (Author) Other; Selene M. A. Guelli U. Souza (Author) Other; Rui A. R. Boaventura (Author) FEUP; Vítor J. P. Vilar (Author) FEUP

Journal

Title: Journal of Photochemistry and Photobiology A: Chemistry

Vol. 317

Pages: 26-38

ISSN: 1010-6030

Publisher: Elsevier

Indexing

ISI Proceedings

ISI Web of Knowledge - 12 Citations

Scopus - 25 Citations

Scientific classification

CORDIS: Technological sciences > Technology > Environmental technology

FOS: Engineering and technology > Environmental engineering

Associated Projects

LSRE/LCM LA - RL1_P3 - Environmental Technologies

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

Other information

Authenticus ID: P-00K-0X6

DOI: 10.1016/j.jphotochem.2015.10.017

Abstract (EN): Biological oxidation processes have shown good results for the mineralisation of the non-recalcitrant fraction of textile wastewater. However, they do not always represent a feasible technique for colour removal, requiring a polishing step for decolourisation before the wastewater can be discharged into a receiving water body. In this study, UVC/H2O2 and photo-Fenton (PF) oxidation processes were used as a polishing step in the decolourisation of a bio-treated real textile wastewater. The photolysis of hydrogen peroxide using UVC radiation showed decolourisation efficiencies of 86% (Pt-Co method) and 96% (DFZ(436 nm)), consuming 1.6 mM H2O2 after 0.9 KJ(UV) L-1 (time = 35 min; UVC lamp power = 6 W; natural pH 7.8; T = 30 degrees C). The PF reaction was promoted by different radiation sources (UVC, UVA or UVA-vis), showing best results under UVC light. The efficiency of the UVC/Fe2+/H2O2 system was also studied for different iron concentrations, H2O2 availability and pH values. Decolourisation efficiencies of 78% (Pt-Co method) and 93% (DFZ(436 nm)) were achieved applying the UVC/Fe/H2O2 system at pH 2.8 and T = 30 degrees C, consuming 3.6 mM H2O2 after 0.6 KJ(UV) L-1 (time = 25 min; UV lamp power = 6 W). To further investigate the use of solar energy, additional PF assays mediated by ferric-organic ligands under UVA-vis radiation were also performed, considering the effect of the type of ferric-organic ligand as well as the iron/ferric-organic ligand molar ratio, iron concentration and pH. Maximum values for the decolourisation with UVA-vis/Fe3+/H2O2/oxalic acid were 84% (Pt-Co method) and 94% (DFZ(436 nm)), consuming 1.9 mM H2O2 after 2.9 KJ(UV) L-1 (pH 2.8). In addition, the costs associated with the processes studied were estimated. For the optimal conditions, aiming at achieving the legal wastewater discharge requirements, the total unit costs were: (a) 0.25 (sic)m(-3) (UVC/H2O2 at pH 2.8); (b) 0.16 (sic)m(-3) (UVC/H2O2 at natural pH); (c) 0.24 (sic)m(-3) (UVC/Fe2+/H2O2 at pH 2.8); (d) 0.61 (sic)m(-3) (UVA-vis/Fe2+/H2O2 at pH 2.8); (e) 0.79 (sic)m(-3) (UVA-vis/Fe3+/H2O2/oxalic acid at pH 2.8) and; (f) 0.83 (sic)m(-3) (UVA-vis/Fe3+/H2O2/oxalic acid at pH 5.0).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13