Treatment and color removal of cotton textile industry wastewater with membrane bioreactor (MBR)

In this work, treatability and color removal of the wastewaters with dye and high amount of salt resulting from the different production processes of the textile industry by lab scale Membrane Bioreactor (MBR) has been investigated. Wastewater samples were obtained weekly from a treatment plant (Plant A) that treats 7 different textile company?s wastewater in Denizli region. Lab scale MBR system was used in treatment studies. MBR system is connected automatically to Supervisory Control and Data Acquisition (SCADA) system. The operation of the lab scale MBR system was performed by aiming aerobic oxidation and nitrification. Operation period (approximately 9,5 minutes) and bakwashing at regular intervals(0,5 minutes for every 9,5 minutes) was provided by SCADA software. Chemical cleaning was applied for the foulants which cannot be removed by regular backwashing . 3 types of MBR modules were operated at infinite and 25 days of sludge age ZeeWeed 1 (ZW-1) ultrafiltration, Polypropylene (PP) microfiltration and flat sheet microfiltration MBR modules (membranes) were used for 11, 5 and 6 weeks, respectively. Pollutants and dyestuff removals were evaluated.In treatability and dyestuff (color parameter) removal studies, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total nitrogen (TN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), other pollution parameters and color removal efficiency was evaluated. During the treatability experiments the color parameters of ZW-1, PP and flat sheet membrane modules decreased up to 90 Pt-Co, 105 Pt-Co, 162 Pt-Co, respectively. COD parameter values of ZW-1, PP and flat sheet membrane modules decreased to 60 mg/L, 39 mg/L, 55 mg/L, respectively. Although concentration of salinity in wastewater was high, permanent and consistent nitrification was provided. In addition, over 75 % of TN removal was achieved despite it wasn?t aimed with all three membrane modules. The minimum TN values measured were 4,7 mg/L, 6,1 mg/L, 3,46 mg/L for ZW-1, PP, flat sheet, respectively. Similarly, the lowest turbidity parameter values obtained were 0,65 NTU, 0,29 NTU and 0,16 NTU for ZW-1, PP and flat sheet membrane modules, respectively. Suspended solids (SS) parameter obtained was below 2 mg/L for all membranes used. The data obtained has shown that, textile wastewaters containing high graded and complex pollution can be treated much better with MBR systems than conventional active sludge systems, especially color parameter which can?t be removed enough with conventional treatment systems, can be decreased to very low levels with MBR systems.