The raw salt produced in the crystallisers is then transported to the Salt Upgradation Plant. At the Salt Upgradation Plant, raw salt containing calcium, magnesium, etc., is sent through a conveyor belt to a slurry preparation tank where it is washed with brine, to remove these impurities. The salt is then taken to an overhead thickener and passes through a centrifuge where solid salt is separated from liquid. This liquid, collected in a pit, is recycled to continue with the same process. When the impurity level increases, fresh brine is used. The salt thus formed is emptied directly into trucks supplying feedstock to the Mettur plant for the manufacture of caustic soda and chlorine.
The fully equipped laboratory at the Salt Upgradation Plant ensures that the product conforms to the required quality norms for industrial grade salt. The leftover stock is stored in closely packed heaps and covered by ‘cudgeon leaves’, to protect it from the rains during the monsoon season.
The bittern or mother liquor that remains after salt is separated from the sea brine is converted to alkaline bromine solution by treatment with acid in the ABSOL plant. The reddish colour of the bittern is attributed to the presence in it of the marine microalga dunaliella salina—which, in China, is used in the production of natural carotene, polysaccharides and Vitamin E.
During the rainy season, from September to December, the production of raw salt comes to a halt, while the Salt Upgradation Plant activity continues, using the raw salt from the storage heaps, and deliveries continue.
The rain water actually helps reduce the magnesium content in the storage ponds, but heavy, intermittent rain affects the production, diluting the brine concentration in the crystallisers.
Besides Chemplast Sanmar and Gujarat Heavy Chemicals Limited, there are several small salt manufacturers at Vedaranyam, mostly producing edible salt. Vedaranyam is the second largest salt producer in the state after Thoothukudi.
The finished product being loaded directly on to the trucks through the conveyor belts of the Salt Upgradation Plant.
The JCB machine forming salt heaps for storage.
The temple tank (Manikarna tirtham) at the Vedaranyeswarar temple.
The Ramar paadam or Rama’s feet at Vedaranyam. According to mythology, Lord Rama stood on this spot on a reconnaissance visit to locate Ravana’s fort in Sri Lanka.
The gopuram of the Vedaranyeswarar temple at Vedaranyam. This temple is dedicated to the Hindu god Siva and his consort Parvati.
As we enter Vedaranyam, the road bifurcates the Vedaranyam Wildlife Sanctuary of the Forest Department on one side and the swamp lands of the Chemplast Salt Works on the other. We were lucky to spot a number of spotted deer drinking at a watering hole adjacent to the road, filled daily with water by the company as one of its contributions to the preservation of the ecosystem of the region. The spotted deer is usually shy, and does not leave the more thickly wooded forest to come to the roadside, unlike the hundreds of blackbuck we saw cavorting, jumping and running in the open, towards the seashore, leaving the safety of the woods, drawn by the cool seabreeze. We also saw wild boar, foxes and a whole herd of wild horses, prominent in the landscape, apparently coexisting peacefully. The birdlife on view was however limited to storks, cranes, and smaller birds like the kuil, as this was not the season for the migratory birds.
The Vedaranyam swamp, situated along the Coromandel Coast of Tamil Nadu in Tanjore district, extends over an area of 2400 hectares. Interspersed with numerous small islets and ponds constructed for production of industrial and table salt, the swamp is bordered in the north by man-made dykes of mud, beyond which lie villages and arable land. Larvae, fungi, fishes and a large number of other organisms which form the staple diet of shore birds can be found in abundance in salt ponds. Vedaranyam is home to many rare species of birds. Around 47 species of migratory and non-migratory shore birds have been recorded here. The region is a birdwatchers’ delight and migratory birds from all over the world gather at Point Calimere during October-February. “Asian Wetland News” from Asian Wetland Bureau, Malaysia has reported that “the functioning of the salt industry with the formation and use of salt ponds favours shore birds and other aquatic birds in many ways.”
Clockwise: Feral horses, black buck, flamingoes,
black winged stilt, whitebreasted
kingfisher,
spoonbills and egrets.