VPE 511: Environment and Environmental Hygiene (2+1)

INTRODUCTION

Tannery, wool, bone and blood meal industry pollution and its control

• Tanning is a chemical process that is used to convert animal hides and skins into leather. The term hide used for the skin of large animals (e.g., cows or horses), while skin is used for that of small animals (e.g. sheep). In the tanning process, chemical reactions convert the semi-soluble protein “collagen”, present in the corium of animal skins and hides into tough, flexible and highly durable leather.
• The tanning process uses acids, alkalis, salts, enzymes and tanning agents to dissolve fats and non-fibrous proteins and chemically bind the collagen fibers together.

Chemical hazards

• The large variety of acids, alkalis, tannins, solvents, disinfectants and other chemicals in a tannery can be respiratory and skin irritants. Dust of vegetable tanning materials, lime and leather and chemical mists and vapours arising in the various processes may be responsible for causing chronic bronchitis.
• Several chemicals may cause contact dermatitis. Chrome ulceration may occur in chrome tanning, especially on the hands. Exposures in the beamhouse operations are mainly due to sulphur compounds such as sulphides and sulphates. Since these are alkaline substances, there is a potential to generate hydrogen sulphide gas, if these substances , there is a potential tog generate hydrogen sulphides gas, if these substances come into contact with acids.