Advanced Water Treatment Technology is Proven Safe
The California Department of Health Services, Monterey County Environmental Health, and the Regional Water Quality Control Board strictly monitor and regulate agricultural irrigation, landscape irrigation and groundwater replenishment. The regulations and monitoring requirements fully protect the public’s health and safety as well as the environment. In addition, a special advisory panel of experts is independently reviewing the Project. Groundwater replenishment is used in many places around the world.
U.S. locations where advanced water treatment is being used safely are shown in the map (right), courtesty of PUB, Singapore’s national water agency.
The graphics below, courtesy of the City of San Diego (Water Purification Demonstration Project Report, March 2013) provide details for various potable water reuse projects (click for larger views).
Orange County, California — Orange County Water District’s Groundwater Replenishment System
World's Largest Water Purification System for Potable Reuse: The Groundwater Replenishment System (GWRS) takes highly treated wastewater that would have previously been discharged into the Pacific Ocean and purifies it using a three-step advanced treatment process consisting of microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. The process produces high-quality water that exceeds all state and federal drinking water standards. Near-distilled quality water is injected into the groundwater to act as a seawater barrier and to recharge the basin.
Orange County Water District has operated a groundwater replenishment project since 1971 in partnership with the Orange County Sanitation District. Orange County expanded its groundwater project in 2008 to 70 million gallons per day and by 2015 will further expand capacity to 100 million gallons per day, or an additional 31,000 acre-fee per year (for a total of 103,000 AFY). This is enough new water to supply 850,000 residents.
Northern Virginia’s Upper Occoquan Service Authority (UOSA)
In 1978, the UOSA Regional Water Reclamation Plant, located on 470 acres in western Fairfax County and serving four jurisdictions (Fairfax County, Prince William County, City of Manassas, and City of Manassas Park), commenced operations and replaced eleven small secondary treatment plants in the region. Since that time, water quality in the Occoquan Reservoir has steadily improved and the reliable, high-quality effluent produced by UOSA has increased the safe yield of the Reservoir.
UOSA has consistently met strict effluent limits into the reservoir and, as a result, eliminated wastewater as a source of pollution in the Occoquan Watershed. After 30 years of highly successful operations, UOSA’s reclaimed water is an increasingly important component of the drinking water supply strategy for the Washington metropolitan area.
Singapore’s NEWater Facilities
The Public Utilities Board of Singapore operates five NEWater factories, producing 50 million US gallons per day (mgd). Some of the NEWater is used at micro-chip fabrication plants and for other non-potable industrial applications. The rest is fed into nearby reservoirs where it mixes with other waters before being pumped, and treated for potable uses.
The first NEWater plants were opened in Bedok and Kranji in 2003. The latest and largest NEWater plant at Changi, with a capacity of 50 mgd, was opened in May 2010. Currently, NEWater meets 30% of the nation’s water needs. By 2060, they plan to triple the current NEWater capacity so that NEWater can meet 50% of their future water demand.
The NEWater factories utilize the latest ultrafiltration/microfiltration and reverse osmosis membrane technologies, followed by ultraviolet disinfection, to treat used water to standards higher than the drinking water standards of the World Health Organization and the U.S. Environmental Protection Agency. The project has been fully operational since 2003.
Scottsdale, Arizona’s Water Campus
The Scottsdale Water Campus is a state-of-the-art water and wastewater treatment facility encompasses three treatment facilities: a 70 mgd surface water treatment plant for potable use, a 20 mgd water reclamation plant (WRP) for open access irrigation, and a 20 mgd advanced water treatment (AWT) plant for indirect potable reuse. The AWT plant treats tertiary effluent from the WRP prior to distribution into the reclaimed water system or its extensive recharge system using vadose zone wells. The AWT consists of pressurized ultrafiltration followed by reverse osmosis, capable of treating 20 mgd. Together, these facilities achieve aquifer sustainability and make sure that water levels in the aquifer stay stable even during water shortages and during peak demands.
The Scottsdale Water Campus has undergone several upgrades and expansion over the years and has experienced successful and continuous operation since October of 1998, recharging in excess of 35,000 acre feet of highly treated effluent and providing 100% of the irrigation needs for over 20 golf courses.
For history of the project read the paper entited “THE WATER CAMPUS: From a Dream to Reality” by Mr. Leonard Dueker.
Other Planned Advanced Water Treatment Facilities
San Diego, California’s Water Purification Demonstration Project
In 2009, the City of San Diego embarked on a 1 mgd demonstration project to examine the use of advanced water purification technology to provide safe and reliable water for San Diego's future. The Water Purification Demonstration Project (PDF) has evaluated the feasibility of a full-scale reservoir augmentation project, which would diversify San Diego's water supply, reduce its dependence on imported water and provide a reliable, local drinking water supply for residents.
The project’s operational testing and monitoring verified the water purification process consistently produces water that meets all regulatory requirements and is similar in quality to distilled water. The California Department of Public Health and the San Diego Regional Water Quality Control Board granted conceptual approval of the reservoir augmentation plan. The energy requirements were determined to be comparable to importing water, and the cost for full-scale, 15-mgd facility would be $2,000 per AF. In addition, public support increased dramatically to 73% in 2012.
Santa Clara Valley Water District’s Silicon Valley Advanced Water Purification Center
The state-of-the-art facility will take treated wastewater and purify it by using three processes: microfiltration, reverse osmosis and ultraviolet light. The result will be 8 million gallons a day of highly purified water that is expected to meet California State primary drinking water standards.
The highly purified water produced at the new purification center will be blended with the existing recycled water supply produced at the neighboring San Jose-Santa Clara Regional Wastewater Facility to enhance its quality and expand its usage.
The center will demonstrate proven technologies to produce highly purified water that can be used for a variety of purposes, including potentially expanding Silicon Valley’s future drinking water supplies.