Advanced treatment of textile wastewater for reuse using electrochemical oxidation and membrane filtration

The treatment of textile wastewater for reuse using an electrochemical oxidation step combined with a membrane filtration step is reported in this paper. The electrolytical process is a traditional one, which is easy to scale up and to apply in practice. This paper proposes a modification of the transfer-flow membrane (TFM) module with fibres welded in an arc-shape to enhance the mechanical properties of the fibres and to increase the specific membrane surface of TFM modules. The goal of this research was to study the performance of the arc-shaped TFM module to demonstrate these sequences of electrochemical oxidation coupled with membrane filtration processes and to develop a potential dyehouse wastewater treatment system for reuse. Two testing sequences of electrochemical oxidation and membrane filtration were studied in a sequential batch order. The results show clearly that fibres welded in an arc-shape can enhance the mechanical properties of the fibres effectively and that electrochemical oxidation and membrane filtration as sequential processes are feasible. Electrochemical oxidation has a high removal (89.8% efficiency) of the chemical oxygen demand (COD) of the wastewater while the membrane filter can almost totally remove the total suspended solids (TSS) (nearly 100% reduction) and turbidity (98.3% elimination) in it. Coincidentally, their advantages make up for their disadvantages. After these two steps, all the wastewater indices decrease to low levels; in particular, COD levels are reduced to 18.2 mg•l-1. The treated water can be reused in many production areas of the textile dyehouse factory. To take best advantage of this disposal system, the two processes should run in a rational sequence, with membrane filtration following the electrochemical oxidation process. With widely studied electrodes, this research offers a promising way for recycling textile wastewater. Key words: electrolysis, oxidation, membrane, dye, wastewater treatment Water SA Vol.31(1) 2005: 127-13