Using combined membrane processes for textile dyeing wastewater reclamation

In this study, the performance of sequencing batch reactor (SBR), aerobic membrane bioreactor (AMBR), anaerobic-oxic membrane bioreactor (AOMBR) and AOMBR/RO processes treating the synthetic textile dyeing wastewater (Reactive Black 5) was investigated and compared. After more than 2 year process operation, the average SS concentration for SBR, AMBR, AOMBR, and AOMBR/RO process effluent were 96, 0, 0, and 0 mg L−1, respectively. Furthermore, the COD of the above effluent were 133, 95, 37, and 38 mg L−1, respectively. It was found that the anaerobic tank of AOMBR and AOMBR/RO can lower the COD concentration. In addition, the BOD of the above effluent were 68, 3, 3, and 0 mg L−1, respectively. For this parameter, the membrane unit also showed an excellent performance. Finally, the true color of the above effluent were 548, 513, 196 and 32 ADMI, respectively, revealed that the anaerobic tank and RO unit could achieve higher color removal performance. This revealed that the processes containing membrane unit performed excellent efficiencies on SS and BOD removal. Additionally, the anaerobic tank can enhance the COD and true color removal, while the RO unit can further remove the true color. According the experiment result, all the processes containing membrane unit meet the Taiwan EPA effluent criteria, but only the AOMBR/RO process meets the water reclamation criteria for toilet flushing, landscaping, irrigation, sprinkling, and cooling water usage. This study also isolated higher decolorized performance microorganisms by using TGE, PDA and TGC mediums. Only 3 isolates performed more than 90% Reactive Black 5 degrading efficiencies by using both TGE and aerobic PDA mediums. On the contrary, no isolate was obtained by using anaerobic PDA mediums, implied that there is no strictly anaerobic fungi in the anaerobic tank. Furthermore, 18 isolates cultured from anaerobic TGC medium showed more than 90% Reactive Black 5 removal efficiency, revealed that the anaerobic tank did enhance the growth of the high decolorizedmicroorganisms, especially anaerobic bacteria.