A Comprehensive Review on Treatment Technologies forTannery Wastewater Containing Chromium

Leather tannery industry is one of the main economic sectors in many countries and release of various recalcitrant pollutants by that is considered to be an environmental concern.To treat these wastewaters, various physical, chemical & biological methods can be used, each of which depending on the conditions, can be consideredas a suitable solution for the purification & removal of chromium from these hazardous streams. Obviously, the cost-effectivenes of each method depends on several factors.In this paper, a comprehensive approach to different used technologies in the world is performed using literature review. Results are indicative of assurance and reliability of combinedprocesses for reduction of contamination degree of tannery wastewaters. However, the ion exchange technology to recover chromium from waste streams is the most effective solution. Furthermore, electrocoagulation technology has attracted significant attention for pre-treatment of tannery wastewater due to its operational simplicity.