Pretreated water is sent through a reverse osmosis system with a design flow rate of 20 GPM prior to deionization.	Water is maintained in its purified state as it passes through the complete manufacturing process.

At Ebara's Pennsylvania plant, city water is initially passed through a mixed bed multimedia filter and stored in a 1500- gallon tank which feeds the reverse osmosis (RO) system. At this point in the system, used process water (reclaim) from the factory's wet benches is mixed with city water in the same 1500- gallon tank.

A booster pump sends the pretreated water to an RO system with a design flow rate of 20 GPM. The RO-treated water then passes through a 254 nm ultraviolet-light sterilizer, also maintaining a 20-GPM flow, and into two 2,200-gallon RO storage tanks. Process water is returned from the distribution loop to the RO tanks after passing through a 0.2-micron filter at this location. "Any deionized water that's not consumed in the process returns to the RO storage tanks, moving through another 0.2 micron filter first," says Rosinski.

From here a re-pressure pump sends the RO water at a flow rate of 40 GPM through deionization tanks. The deionized (DI) water system consists of four mixed bed service tanks and two polishers. The DI water is passed through a 0.2-micron final filter and then through an additional UV light sterilizer (185nm) as the last step before entering the distribution loop.