REMOÇÃO DE AZO CORANTE EM ELETROBIORREATOR A MEMBRANA OPERADO SOB DIFERENTES IDADES DE LODO E TEMPOS DE EXPOSIÇÃO À CORRENTE ELÉTRICA

Abstract

The performance of an anoxic-oxic electro-membrane bioreactor (A/O-EMBR) on the treatment of an azo-dye containing wastewater was investigated. The A/O-EMBR was operated under three experimental conditions, in which different solids retention time (SRT) (45 and 20 d) and exposure mode to electric current (6´ON/30´OFF and 6´ON/12´OFF) were assessed. The reactor exhibited excellent performance on the decolorization process for all experimental conditions, with average dye removal efficiency ranging from 94.3 to 98.2%. Activity batch tests revealed that the dye removal rate (DRR) decreased from 16.8 to 10.2 mg L-1h -1 when the SRT was reduced from 45 to 20 d. When the exposure mode was 6´ON/12´OFF, a more substantial decrease of DRR to 1.5 mg L -1h -1 was noticed. By reducing the SRT to 20 d, a worse mixed liquor filterability condition was observed, with a membrane fouling rate (MFR) of 0.979 kPa d-1, while using the exposure mode of 6´ON/12´OFF the MFR obtained was 0.333 kPa d-1. A more attractive cost-benefit ratio in terms of dye removal was obtained by using the exposure mode of 6´ON/30´OFF, for which the energy demand was 92 – 99% lower than that observed for the mode of 6´ON/12´OFF.