Research on treatment of printing and dyeing wastewater by hybrid anaerobic baffled reactor

The printing and dyeing wastewater was treated by a pilot-scale hybrid anaerobic baffled reactor (HABR) which was modified from general anaerobic baffled reactor by adding combined packing in the upper part of each compartment and inert carrier at the bottom of the reactor. The start-up of the reactor, the performance of HABR in treating printing and dyeing wastewater, and the transformation of sulfate and removal of bivalent sulfur in the treatment were investigated. The results showed that less time was taken during the start-up in comparison with the general one, and higher COD removal efficiency and sufficient color removal rate were also obtained in the HABR. When the hydraulic retention time was 12-13 h and the sludge return ratio was 0.3, the average COD and color removal rates were 47% and 56%, respectively. The anaerobic bacteria community in each compartment developed well because of available substrates and specific environmental conditions. The results also showed that high reduction rate of [GRAPHICS] was reached in the HABR, and the S2- transformed from [GRAPHICS] could be removed by adding Fe2+ into the wastewater in order to reduce the inhibitory effect on the anaerobic bacteria and the odor.