New Technology Gives Us Designer Drinkable Wastewater
Through use of a new cellulose acetate reverse osmosis membrane, wastewater can be economically turned into "extra-pure" tapwater that, acording to San Diego's manager of Metropolitan Wastewater, Paul Gagliardo, "...is not only safe, but significantly better quality tha drinking water we have now."

The disinfection efficacy rate exceeds 99.99% and is continually monitored by a total organic carbon analyzer and uses an on-line flow method to remove both organic carbon and viruses from the water.

The system has been dubbed "re-purification." It is a term coined for the treatment of reclaimed water to a drinking-water quality level and appropriate introduction of re-purified water into the drinking water system.

In addition to meeting drinking water standards, a water re-purification project must use a raw water supply reservoir for blending and retention of the re-purified water prior to final treatment of the blended water at a water treatment plant.

The San Diego facility includes a 20-mgd advanced water re-purification treatment plant that will employ technologies never before combined, including low-pressure membrane filtration (microfiltration or ultrafiltration), reverse osmosis, advanced oxidation (ozone and hydrogen peroxide), and ion exchange.
Redundant features, called "multiple barriers," will also be used to provide extra safety assurance to the regulatory community. Individually, these processes have been used in previous full-scale operations, however the SDWRP will, for the first time, combine these technologies, along with operational and monitoring concepts, to treat wastewater to a level that meets the public health officials' drinking water goals of safety and reliability.

San Diego plans to go on-line in the year 2001 with this system to add 10% processed water to the City's drinking supply.

Although the city has no plans to follow Houston's lead in bottling it's tap water, it certainly would give a whole new meaning to the term “Eau de Toilet.”