It is the treatment to remove calcium by cationic resins which is called as a softner. Another treatment which is called as a D.M. Plant will remove all the minerals by cationic and anionic methods. Even though using this kind of water is good for circulation water but this treatment is not complete solution for solving the problems in circulating water. For example the softener removes only calcium other minerals such as silica, sulphite, and chloride cannot be removed as it also forms as a scale or corrosion. In this treatment you have to use lot of water for back washing and after regeneration. In soft water biological growth will be high and it chokes the system. Taking all in to this it is better to go for internal treatment programme.
As per the d.M. Plant it removes all the minerals and hence the water become acidic which will leads to corrosion. Operation cost for this treatment is very high and it is not advisable to use for circulating water
In any cooling process water takes heat from process and cools the system. By the way it gets heated up and in turn it need to be cooled to reuse the same. It gives up the heat through a process called evaporation.
There are three types of cooling systems which are in use in industry:
Once through systems normally present nearby a sea or river. In this system water is drawn from the source and pass it through the system once and discharge it back into the source.
In closed re-circulating system water is re-circulated continuously. The heat taken from the process is cooled in a heat exchanger which in turn cooled by cooling tower water.
Thus in other words it is called as a primery circuit.
In this system water is re-circulated continuously through the process where it is required to take heat.
The heated water gets cooled in a cooling tower through evaporation method. The loss of water through evaporation is compensated with fresh makeup water. The open re-circulating systems are prone to many external contaminations which calls for proper treatment control.