Treatment and recycling of textile wastewater — case study and development of a recycling concept

For a specific textile finishing company strategies for water recycling and recovery of valuable chemicals have been developed. A comprehensive study of the company’s resource consumption and emission profile was performed. On this basis selected end of the pipe and integrated recycling options were further examined in detail. When treating the mixed wastewater flow, a combination of a membrane bioreactor and subsequent nanofiltration has proved to meet all requirements for reuse. However, this approach is associated with considerable technological effort and potentially high costs. As an alternative, a relatively simple and straightforward process was tested to treat only the washing effluents by means of ultrafiltration. Based on results obtained from the ultrafiltration experiments, a process integrated recycling concept is proposed. By its implementation water consumption can be cut down by 87.5% within the washing process. Furthermore total COD emissions can be reduced by 80%, and as washing agents are partly recycled, consumption for the washing process can be lowered by 20%.

MBR treatment proved to be an efficient tool for the treatment of textile wastewater. Nevertheless, it was not possible to achieve the required standards for direct reuse. In order to accomplish this task, an additional post-treatment process has to be implemented. Of the post-treatment methods tested, NF was the best choice. With an MBR and subsequent NF, it is possible to meet all requirements for reuse. However, it has to be noted that this approach is associated with Fig. 4. Water and COD balance after the implementation of the proposed water recovery process by UF.