Detoxification of chromium slag by chromate resistant bacteria.

This paper presented direct detoxification of chromium slag by using microorganisms. Our work showed that a bacterial consortium isolated from chromium slag can efficiently accelerate Cr(VI) leaching rate and remove it. The chromate resistant bacterial consortium consists of three strains. The detoxification efficiencies of the three respective strains follow the sequence: strain I > strain III > strain II. The detoxification capability of the bacterial consortium is far stronger than that of the respective strain, showing an excellent synergistic effect. The specific growth rates in pure and chromium-containing medium are 0.1475 and 0.1573 h(-1), respectively. The presence of Cr(VI) has little effect on growth rate of the bacterial consortium. Cr(VI) removal takes place in exponential growth period of the bacterial consortium; the detoxification time should be controlled in this phase for every run. The kinetics of detoxification process was studied and can be described as eta = 0.0615e(0.1573t), which can be used to predict Cr(VI) removal efficiency.