Dodangoda, K. D. G. P. <br/><br/>
Recovery of chromium & protein from leather shavings 

 - Bangkok :  Asian Institute of Technology,  1992 
 - 58, A-16 p. 
 - Thesis ;  no. EV-92-25 .
 - Asian Institute of Technology.  Thesis ;  no. EV-92-25 .
<br/><br/> A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering 
<br/><br/>Thesis (M.Eng.) - Asian Institute of Technology, 1992 
<br/><br/> Leather shavings generated, when the thiclrn ess of the pre tanned hides and  sl<ins is corrected either manually with a double handled lrnife or by machines in  the chrome-tanned leather processing, are toxic wastes, high in chromium content  (about 3%). Generation of solid wastes in the tanning industry is estimated to be  1 million tons per year throughout the world. The bigger pieces of trimmings are  utilized for the production of artificial l eather. However, most of them are just  disposed of in environmentally unsound manner in spite of the growing  environmental awareness.  Chromium can be extracted from the leather shavings and recycl ed in the  tanning process, leaving two kinds of byproducts; protein and protein residue. The  former can be used as industrial glue or animal feed, while the latter can be  utilized as organic fertilizer for non-edible crops.  The experiments utilizing calcium oxide as the all<ali and the leather  shavings from the Kwang Hah Lee Tannery was carried out in order to demonstrate  the viability of recovery of chromium and protein from leather shavings in small scale tanneries. For this purpose, pilot-scale digeste r was designed based on the  bench scale experimental data, and fabricated in the workshop of the AIT Physical  Plant.  From four pilot-scale experimental runs of which two were made in AIT and  the rest performed in the tannery, it was verified that prolonged digestion does  not increase the concentration of protein obtained while enhancing the  concentration of chromium in t he protein recovered. Further these revealed that  the particle size of l eather shavings has a profound effect on digestion of leather  shavings.  Results of the pilot-scale experiments indicate that the recovery of chromium  and protein from leather shavings is technically feasible and viable on small scale  applications provided the separation of chromium from protein is controlled  carefully. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Tanning--Waste disposal<br/>Sewage--Purification--Chromium removal