RO for Ultrapure Water

Production of ultrapure water (UPW) for the electronics industry is an established and growing application of RO. The usual feed is municipal drinking water, which often contains less than 200 ppm dissolved solids. However, the electronics industry requires water of extraordinarily high purity for wafer production, so extensive treatment like Ion exchange, carbon absorption along with sterilization (to combat bacterial growth) are also incorporated. The rejection rate for these systems is above 98% and since the feed water is already at potable grade, the recovery rate is also very high (above 90%). These processes will reduce the mentioned typical TDS down to roughly 0.1 or 0.2 ppm (or even lower – although the typical criterial for UPW is its EC – Electrolyte Conductivity in µS/cm unit).