Dear Sir. Concerning your issue about the methods available for the complete recovery/reuse of chromium (Basic chromium sulphate) used in the chrome tanning process. The chromium (Cr) used in the manufacture of leather from hides has well-known adverse effects when inappropriately disposed in the environment. The tanneries use large quantities of water for processing hides. The recovery of Cr from the wastewater produced in the tanning step is an environmentally friendly and economically viable alternative avoiding the disposal of large amount of Cr-containing sludge in industrial hazardous waste landfills. This work aims at studying the removal of the Cr from the tanning wastewater through chemical precipitation (CP) and electrocoagulation (EC) techniques and its reuse in tanning process. In the CP experiments, efficient Cr removal from wastewater samples was achieved, with up to 99.74% removal efficiencies. In the EC experiments, three different electrode materials, Al, Cu, and Fe were tested. The highest removal efficiency of 97.76% was obtained with Al electrodes by conducting electrolysis at 3.0 V for 110 min. This was followed by Fe electrodes and Cu electrodes, which showed removal efficiencies of 90.27% (at 2.5 V) and 69.91% (at 2.0 V), respectively, for an electrolysis of 100 min. The recovered Cr was reused as a tanning agent in leather processing, where good crossing of Cr was reached in leathers tanned with the liquors prepared from the sludge, and the pH and ash content values were measured. While the hides tanned with the Cr-containing liquor recovered by CP and by EC with Cu electrodes showed good hydrothermal stability and Cr content above 2.5% Cr2O3, the hides tanned with Cr-containing liquors recovered by chemical precipitation and by EC conducted with Fe and Cu electrodes showed contents of Cr according to technical specifications. However, the Cr samples obtained with the iron electrode showed a dark coloration due to oxidation of the iron. It can be concluded that the tanning process with Cr recovered by CP and by EC with Cu electrodes showed the best results. I think the following below links may help you in your analysis:

http://www.psep.ichemejournals.com/article/S0957-5820(15)00055-5/fulltext

http://researchpub.org/journal/jais/number/vol3-no3/vol3-no3-2.pdf

https://www.researchgate.net/profile/Balaraman_Madhan2/publication/8904693_Bioaccumulation_of_Chromium_From_Tannery_Wastewater_An_Approach_for_Chrome_Recovery_and_Reuse/links/0deec523325224bc1b000000.pdf

http://www.clri.org/writereaddata/biodata/award_2005_files/recognitions/leather-biosorp.pdf

Thanks

Article Bioaccumulation of Chromium From Tannery Wastewater: An Appr...

 Dear Prof.Isam Eldin Hussein Elgailani,

Thanks a lot to spend your valuable time for me and your valuable suggestions.

Definitely your mentioned articles will be helpful for me.

Regards,

Maharaja.P

In Addition to Prof.Isam Eldin Hussein Elgailani suggetion, Phytoremideation is also another method to recover Cr from tannery waste water.

Dear Prof.Hayelom Dargo Beyene,

Thank you for your suggestions.But i think that how much extend the phytoremediation process  can be applicable for high concentrated Chrome wastewater.There will be the problem occurs when we going for scale up to large volume.

Regards,

Maharaja.P

Chrome leather waste scraps, preferably defibered, can be dechromed by first leaching with oxalic acid; being that followed by alkali (NaOH or KOH) and/or lime slurry treatment, with added H2O2 (approx. 3.5 wt%). Na2SO4 can also be added to this alkaline solution (or slurry). H2SO4 can partially (or totally) substitute for oxalic acid. The acid and the alkaline leaching stages should be intermediated by washing with water. The prior acid leaching treatment can take approx. 3 days at room temperature. The following alkaline oxidative treatment can take no more than around 30 min at approx. 50 ºC; or considerably more time if chiefly lime-based, and/or if taken at room temperature. Collagenous material is obtained. 

Dear Prof.Carlos Araujo Queiroz,

Thank you for your valuable suggestions.

Regards,

Maharaja.P