Alright, so maintenance of a Reverse Osmosis machine on an annual basis for domestic consumption will need -

• Change of main RO membrane once in a year along with other membranes - like Activated Carbon filter, if used.
• Change of ball sensor once in a year. Ball sensors typically last only one year.
• Any minor part changes, cleaning of pump, cleaning water flow lines (pipes) to prevent clogging, cleaning the filter from inside, check for leakage, etc.

Industrial water and Boiler feed water treatment plant. Many industrial applications require Demineralised water. In addition to the water being free of suspended impurities, colloidal impurities and biological contaminants need to be free of any dissolved salts as these salts form a a hard scales in the boiler which causes corrosion to the boiler walls and could cause premature failure of boilers ans also reduce the main conductivity of boiler wall thus reducing the efficiency of the boiler. These use Ion Exchange plants to convert the dissolved salts and remove them in a chemical exchange form both to remove cations and anions. These are particularly critical for use in Boilers, Process Plants, Paper mills, textile dyeing plants. Digesters.

Are you interested in setting up a RO plant to sell purified water...., there are following steps to it

• Legal aspects- you would need permission to dig a bore well , you also need BIS certification (it is mandatory )
• you need identify a place, where ground water is available
• Plant and machinery- a plant for a capacity of 5000 litres per day
• Marketing - setting up distributor network, marketing