Performance of Halomonas sp. to reduce hexavalent chromium in batch and continuous fixed film reactor

The performance of fixed film bioreactor on bioreduction of Cr(VI) was evaluated. The reactor was operated under batch and continuous mode. Influent contained glucose as the single carbon source. The maximum specific growth rate obtained was 7.16 mg L-1. The half saturation constant for COD was 475 mg L-1. The yield coefficient was found to be 0.209. A maximum biomass of 457 h(-1) was obtained for Cr(VI) free cells. Both the reactor performed better under an hydraulic retention time of 24 h. Near complete reduction of Cr(VI) was reported for an initial Cr(VI) concentration of 10 and 20 mg L-1. The maximum number of suspended cells reported was 4.3x10(14) at an Cr(VI) loading rate of 240 mg L(-1)day(-1). The maximum amount of attached and suspended cells reported was 2013 and 238 mg. A maximum COD reduction of 84.1% was reported. The lag period for growth of cells under a Cr(VI) load ranging up to 40 mg L-1 was 3 h.