Evaluating the performance and membrane fouling of an electro-membrane bioreactor treating textile industrial wastewater

This study evaluated for the first time the performance and the membrane fouling behavior of a laboratory-scale electro-membrane bioreactor (EMBR) for the treatment of real textile wastewater. The EMBR was operated initially with no electrocoagulation process (control period) during 30 days (run I), and thereafter, the electrocoagulation was started, using the electrical current density of 10 A m−2 (run II) and 15 A m−2 (run III). The reactor performance on color removal was significantly improved by electrocoagulation process, attaining average efficiency of 50 and 70% in the experimental runs II and III. Similarly, the nitrification performance also was enhanced during the period with electrocoagulation, enabling an average NH4+–N removal efficiencies above 90% in the runs II and III. Activity batch assays have shown that autotrophic biomass exhibited a higher oxygen uptake rate during the electrocoagulation experiments, indicating that nitrifying activity increased in the EMBR over this period. Despite the substantial variation in the influent COD values, the COD removal efficiencies were practically constant (75–77%) throughout experimental period. This behavior indicates that the reactor exhibited a great resistance to shock loading, an important feature for the treatment of industrial wastewaters. Better mixed liquor filterability conditions were found during the electric current application, resulting in a lower membrane fouling rate and demanding a lower frequency of the membrane chemical cleaning process.