Innovative Environmental Technologies Including Water Recovery for Reuse from Tannery and Industrial Wastewater – Indian and Asian Scenario

Wastewater discharge from world tannery sector is about 600 million m3/annum. The tanneries in Asia discharge more than 350 million m3 of wastewater per annum from the process of 8 to 10 million tons of hides and skins. The ground and surface water resources in many locations in and around tannery cluster contain high Total Dissolved Solids (TDS) and not fit for domestic and industrial use. The conventional treatment systems implemented all over the world reduce Biochemical Oxygen Demand, Chemical Oxygen Demand, Suspended Solids, Heavy Metals etc. and not TDS and salinity which are mainly contributed by chlorides, hardness and sulphates. The treatment plants are unable to meet the standards in terms of TDS, chlorides and salinity which are being enforced in India and many other countries. The pollution control authorities also insist on water recovery integrated with Zero Liquid Discharge (ZLD) system. Naval treatment systems such as special Micro Filter, Ultra Filtration, Membrane Bio-Reactor, Nano Filtration, Reverse Osmosis, etc. have been developed for recovery of water from domestic and tannery wastewater. The achievement of ZLD concept has got many technical challenges. Management of the concentrated saline stream treatment by adopting energy intensive evaporation system is one of the major sustainable issues. The innovative treatment technologies developed and adopted for water recovery, saline stream management, etc. are dealt in this paper.