Characterization of dissolved organic matter in treated textile wastewater from membrane bioreactor

Abstract

This research aims to investigate the DOM removal efficiency in textile wastewater by MBR at different sludge retention time. In addition, the characteristics of DOM was investigated by using resin fractionation and fluorescent excitation-emission matrix techniques. Textile wastewater was synthesized by using commercial dyes and used in all experiment. The characteristics of synthesis textile wastewater showed that the COD concentration was high as 2,000 mg/L. In addition, the DOC concentration in synthesis textile wastewater was also high at 466.1 mg/L. MBR was conducted under HRT 2.5 days and SRT was varied at 15 days, 30 days and infinite, respectively. MBR was operated continuous until it reaches steady state (60 days). The effluent of MBR were collected and measuring various parameters including COD, colour and DOC concentration. From the result, it was found that MBR at all SRT conditions can provided the high percent COD reduction (>95%). However, MBR cannot reduced colour to meet the standard of discharge wastewater; nevertheless, the high percent colour reduction was obtained (>80%). Trends of colour value was not significantly different for non-adjusted pH and adjusted pH to 7. Furthermore, MBR has provided high percent DOC reduction more than 80% for all SRT conditions. MBR has very high efficiency for retained suspended solid (SS) and volatile suspended solids (VSS) in the reactor with 99%. In term of trihalomethane formation potential, MBR can reduced the formation potential of THMs by reduced the organic matter. The formation of THMs was increased with the increasing of SRT conditions. The obtained results of DOM characteristics confirmed that the formation of THMs not only depend on the organic matter concentration but also the characteristics of organic matter. The specific THMFP revealed that the organic matter that removed by MBR was low ability to form THMs. However, the THMFP was decreased due to the amount of organic matter was removed.