Brackish Water Reverse Osmosis ( BWRO )

BWRO process means filtration by the source of well water by the reverse osmosis membrane. The RO water treatment plant has one stream producing ( capacity 1725 m3/day ) of permeate water. Raw water tank is the source of supply. Raw water is feed to system by filter feed backwash pumps. raw water is passed through manual sand filters where fine solids and silt are removed. Sand filters are provided with manual backwash system, the filter feed pumps are used to backwash as per requirement. Back washing should be done at least one or twice a day based on head loss of filters. Before sand filtration raw watr is dosed with sodium hypochlorite solution in order to disinfect raw water. Before feeding to cartridge filters feed water is employed by pretreatment. In preteatment system antiscalant and acid are dosed. Antiscalent is dosed to avoid scaling of membrane elements which hapers membrane filtration process. Dechloration is also done to avoid degradation of RO membrane.

Cartridge filters are used to remove fine particles of about 1 micron size. size 40″ cartridge filters 15 number of candles are used to filter raw feed. The high pressure pumps are used to generate required pressure for membrane filtration process. The RO unit consist of two stages. First stage comprises of 10 pressure vessels each with 5 element while second stage consist of 5 pressure vessels with 5 elements. The RO system is designed with recovery of 75%. RO permeate is then collected in permeate tank.

Before permeate storage tank RO permeate water is employed by post treatment. It is dosed with caustic soda in order to maintain pH to neutral and chlorination is useful for storage purpose. Addition of chlorine to permeate water avoids biological growth in permeate flows indicators indicate the flow of permeate and reject.