| Startup Year | 1997
| Process | WW: NF/RO | Capacity (MGD) | 2.3 | Recovery Rate (%) | 88 | Pretreatment | NF | Post-Treatment | pH adjustment, disinfection | Feed Water Composition | TDS 3200mg/L | Product Water Composition | TDS=600mg/L | Concentrate Disposal | discharge to solar evaporation ponds | |
(from http://news.pollutiononline.com/case-studies/cs060597.html):
Chandler, a city in the Sonoran desert averages seven inches of annual rainfall and relies on groundwater for more than 50 percent of its potable water. The state of its water resources almost cost it the opportunity to attract the Intel Fab 12 microelectronics manufacturing plant, one of the largest microchip-processing facilities in the world. Chandler's predicament was that Microchip manufacturing is a water-intensive process and the city couldn't overdraft precious groundwater.
Also problematic was the overburden the plant would put on the wastewater-treatment infrastructure. Chandler's only option for attracting and serving Intel Fab 12 was to build the IPWTF, a 2.3-MGD, city-operated centerpiece. The IPWTF purifies wastewater from Fab 12, then injects it into the groundwater supply, recharging up to 90 percent of Fab 12's usage.
The IPWTF is one of the first facilities in the U.S. to use reverse osmosis (RO) to reclaim industrial process water, treating it to potable standards. (RO has been successfully used for treating drinking water but has not been widely used in industrial reclamation, particularly on a large scale.) Fab 12's wastewater is segregated in two process streams with different membrane types used for each. The first process stream,"RO100," is high in fluoride and uses conventional, high-pressure thin-film composite membranes. The membranes reduce the wastewater feed fluoride concentration from in excess of 15 mg/L to much less than the 4.0 mg/L required by SDWA regulations. The second system, "RO200," is equipped with nanofiltration membranes and uses significantly lower operating pressures, keeping energy costs low.
Anticipating water quality from each identified waste stream was difficult. Using RO to treat industrial effluent is not routine; so historical data was virtually nonexistent. Disposal of reject water from the treatment facility presented yet another challenge. Because Arizona is not coastal, discharge to seawater was not an option. The solution: Convey RO-processing reject to solar evaporation ponds and take advantage of Arizona's 60 inches-per-year evaporation rate.
The treatment facility was completed on-schedule for Fab 12's opening and under-budget. The IPWTF reduced Fab 12's net water demands from 5 MGD TO 1 MGD-eliminating the need for capital and O&M costs associated with a larger water system infrastructure. The facilities themselves are very environmentally-friendly. A thorough hydrogeological study identified appropriate location for the injection wells, protecting the land. RO is self-contained, eliminating odor/air pollution.
The facility, designed by Black & Veatch, earned the engineer/constructor firm the American Academy of Environmental Engineers Superior Achievement Award -- the academy's highest honor .
Source: Pollution Online, June 5, 1997, "RO Applied to Industrial Application," edited by Paul Hersch
