Abstract

Mineral tanning practices have become increasingly more common in recent years and there is increasing concern that chromium discharged in the effluent after chrome tanning may cause ecological problems. Keratin hydrolysate (KH) prepared from keratinous material like poultry feather and tannery hair is found to reduce the discharge of chrome in effluent to an appreciable extent. KH was employed both in chrome tanning and rechroming operations. In chrome tanning KH was added in the tanning bath after basification and in rechroming, KH was added in the same float either before or after rechroming. Control sets without KH were run simultaneously under identical conditions. All of the experiments were done on goat skins. Total chrome in the exhaust liquor and in the leather both before and after addition of KH was estimated for each set. Data on physical parameters of leather were also measured. It is also seen that the use of KH helps to reduce the percentage of syntans and fillers required for retanning. Using the data obtained from laboratory tests the process was scaled up in our tannery permitting us to assess the commercial aspects of the use of KH in leather processing.