Hybrid MF and membrane bioreactor process applied towards water and indigo reuse from denim textile wastewater

ABSTRACT

This work investigates the application of a microfiltration (MF)–membrane bioreactor (MBR) hybrid process for textile dyeing process wastewater reclamation. The indigo blue dye was efficiently retained by the MF membrane (100%), which allows its recovery from the concentrate stream. MF promotes 100% of colour removal, and reduces the chemical oxygen demand (COD) and conductivity by about 65% and 25%, respectively, and improves the wastewater biodegradability. MF flux decline was mostly attributed to concentration polarization and the chemical cleaning was efficient enough to recover initial hydraulic resistance. The MBR provides to be a stable process maintaining its COD and ammonia removal efficiency (73% and 100%, respectively) mostly constant throughout and producing a permeate that meets the reuse criteria for some industry activities, such as washing-off and equipment washdown. The use of an MF or ultrafiltration (UF) membrane in the MBR does not impact the MBR performance in terms of COD removal. Although the membrane of MBR–UF shows permeability lower than MBR–MF membrane, the UF membrane contributes to a more stable operation in terms of permeability.

KEYWORDS:

• Microfiltration
• membrane bioreactor
• textile effluent
• indigo blue
• fouling

Acknowledgements

The authors would like to thank Tear Textil Ind. e Com. Ltda. for their support.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Wagner Guadagnin Moravia http://orcid.org/0000-0002-9851-7520

Additional information

Funding

This work was supported by the Coordination of Superior Level Staff Improvement (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) (CAPES); associated National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico) (CNPq); Foundation for Research Support of the State of Minas Gerais (Fundação de Amparo à Pesquisa do Estado de Minas Gerais) (FAPEMIG) and Federal University of Minas Gerais, Brazil (UFMG).