Treatment and Recycling of Wastewater from Tannery

Tanneries are one of the most important industries of the world, but discharge toxic hexavalent chromium through their waste water into the environment beyond the permissible limit. Such waste water may cause significant damage to the agricultural lands and receiving water bodies due to its higher toxicity and high COD and BOD values and thus is a matter of global concern. To reduce the impact of discharged waste water on all living beings and the environment, several conventional physico-chemical treatment methods are developed to remediate metal polluted sites. However, these methods are costly due to use of non-regenerable materials, high operating cost and generate toxic sludge. Microbial bioremediation is a relatively cheaper and eco-friendly technique for the removal of heavy metals and chloroorganics from tannery waste water and thus has wider implications. Also, there is a chance to recover the economically valuable metal for reuse. Among various microbes, bacteria have proven to be very effective in removing Cr (VI) and pentachlorophenol from tannery waste water. The treated waste water can also be used for various non-potable purposes including agriculture and also during leather tanning. It will ultimately minimize water scarcity problem and will increase the productivity.