Studies on treatment and reuse of tannery waste water by embedded system

Abstract

The day-to-day human activities, industrial revolution and use of the old and polluting technologies lead to increase the environmental pollution. Since the environmental protection has now become a global issue, a cleaner and greener technology is warranted for the abatement of present industrial crisis. Leather industry is one of the most polluting industries in newlineterms of the volume and complexity of the effluent discharge. Leather is a natural product like wool and is obtained from a variety of animals, like, cows, sheep, goats, etc. The transformation of the raw hide into leather product involves several processing steps consuming considerable amount of water in each processing step. Chemical processing is generally carried out using different chemicals; e.g., acids, alkalis, salts of sodium and chromium, dyes, etc. In India, the annual quantum of hides and skins processed is about 70,000 tonnes resulting in generation of nearly 75,000m3of the liquid effluent per day. The tanning industry is known to be very polluting especially through effluents high in organic and inorganic dissolved and suspended solids content accompanied by propensities of high oxygen demand and containing potentially toxic metal salt residues. Disagreeable odour emanating from the decomposition of protein solid waste, presence of hydrogen sulphide, ammonia and volatile organic compounds are normally associated with tanning activities. A significant part of the chemical used in the leather processing is not actually absorbed in the process but is discharged into the environment. Due to increased pollution, public awareness and consequent demand for protection of the world s water resources, industries are looking for a better treatment process which can treat the leather effluent effectively without generating any secondary effluent. Good amount of work has been reported on tannery effluent treatment using several techniques. Since the conventional methods are becoming inadequate, there have been increased economic, social, legal,