Combined Removal of Hardness and Chromium by Pellet Reactor
Nowadays, the volume and levels of water pollution have been increased according to the developments in the industrial and human societies. On the other hand, the new processes have been emphasized on raising efficiency in the combined removal of pollutants, both in terms of process units and types of impurities.
In this paper, an advanced water treatment process with fluidized bed crystallization known as Pellet Reactor has been studied in order to remove heavy metals such as chromium (VI) combined with hardness factors. In fact, when crystalline calcium and magnesium deposits are formed on the fluidized bed, the chromium (VI) and its necessity for reduction to chromium (III) takes place by adding sodium bisulfate. The trivalent chromium is removed at PH above 9 as tiny crystals of Cr(OH)3 with low solubility on fluidized bed, while traces of chromium (VI) are absorbed on the crystalline forms too.
For this, the information has been gained from the available resources and some implemented worldwide projects, specially the gained experiences of Birjand project in Khorasan province at east of Iran. This project has been designed by MSV Co. experts at capacity 420 lit/s after extensive research on similar types and making its bench-scale model. In this paper, the high ability of fluidized bed crystallization systems and the possibility of their utilization have been emphasized.