Colour removal from textile wastewater using a pilot-scale dual-stage MBR and subsequent RO system

• Treatment of industrial textile wastewater using a pilot-scale dual-stage MBR.
• Consistent colour reduction of the industrial textile wastewater was observed.
• Subsequent treatment with RO removed both the residual colour and salts.
• The treated textile wastewater met the required discharge and re-use standards.

A necessity exists to find an effective treatment method capable of removing both the strong colour and the toxic organic compounds from textile wastewater. A pilot-scale dual-stage membrane bioreactor (dsMBR) incorporating two ultrafiltration (UF) sidestream membrane modules was designed, constructed, operated and evaluated on-site for treating high strength textile wastewater. The wastewater stream was characterised by a colour range of 195–2070 ADMI units and a chemical oxygen demand (COD) of between 728 and 1033 mg/L. A consistent reduction in the colour of the incoming wastewater was evident in the treatment stages. The residual colour and remaining salt in the UF permeate was treated with reverse osmosis (RO). The colour in the wastewater was reduced from an average of 660 ADMI units to ∼12 ADMI units in the RO permeate, a lower ADMI compared to the potable water (∼17 ADMI units) used on-site by this textile company.