Recycled water is still a priority at Padre Dam
Despite the deluge of rain in recent weeks, officials at the Padre Dam Municipal Water District continue working on a regional water reclamation program that converts sewage discharge into drinkable water.
The still-controversial “toilet to tap” process has yet to be officially implemented, but it’s not that far off. An advanced water purification demonstration program, now in its second year, has a scheduled completion target of 2021. By then, reclaimed and purified sewage could be providing up to 30 percent of the district’s water demands.
At a recent tour organized by the district, a dozen East County residents got a close look at utility’s systems including the purification program and the science behind it.
Although the idea of treated sewage discharge is certainly a psychological hurdle, the fact is that recycled, purified water is being distributed in water districts throughout the nation, including one in Orange County.
“In fact, if you’ve been to Disneyland, you drank retreated water,” says Melissa McChesney, Padre Dam’s spokeswoman. Orange County’s customers have been drinking reclaimed and purified sewage water since 2008.
The rationale for the reclamation system is clear. The cost of water in California continues to rise, and the cost for treating sewage is also increasing. All of the water used by Padre Dam customers must be imported, with most coming from the Colorado River.
Padre Dam customers now pay about $1,700 per acre-foot for water, among the highest rates of 25 water districts in the county. By 2021, the cost will be about $2,000 an acre foot, officials said. An acre-foot equals the volume covering one foot over one acre, or about 326,000 gallons.
The cost for treating sewage is certainly going to rise because of planned upgrades to the Point Loma Sewage Treatment Plant, which handles about 60 percent of the district’s discharge. The remainder, about 2 million gallons daily, is treated here.
By implementing a water reclamation program, the district could augment its imported water with a reliable, drought-proof supply and would reduce the amount of sewage it now delivers to Pt. Loma, the district says.
“Padre Dam is now 100 percent importing its water,” McChesney said. “This (reclamation program) gives a us a lot more local control and the ability to provide some of the water supply to our customers.”
Reclaiming water is nothing new to Padre Dam, which has been recycling its water since the late 1950s. The district’s then-cutting edge water treatment plant later became Santee Lakes. In 1997, the Ray Stoyer Water Recycling Facility was expanded to treat some 2 million gallons daily, providing so-called grey water for non-potable uses such as landscaping.
The current water purification program takes that recycled water and puts it through an additional four steps of treatment involving chlorine disinfection, membrane filtration, reverse osmosis, and finally, ultra-violet oxidation.
About 100,000 gallons of purified water is produced at the facility daily, but not yet distributed into the system. The purpose behind the demonstration treatment program is to show the community and state regulators the district is capable of operating the system on a much larger scale, McChesney said.
Joining Padre Dam in the advanced purification program is the Helix Water District, San Diego County, and the city of El Cajon. These entities operate a complex web of pipes, reservoirs, holding tanks, and pumping stations, all of which rely on electrical power to move the water.
Not all of the local residents taking the tour were totally on-board with the program, with some voicing suspicion about the level of purity, and why the district isn’t pursuing using more desalinated water.
Water officials said the water produced at the plant is probably cleaner than what is now delivered to their taps, and that desalinated water costs about twice as much to process. The $1 billion Carlsbad desalination plant that opened in December 2015 produces up to 50 million gallons daily, or about 8-10 percent of the county’s supply.
Like other water districts, Padre Dam maintains back-up power systems in the event of massive electric power failure. At the Lakeside station, residents saw one 2 million watt-turbine generator that the district got at a deep discount in the early 2000s, said Paul Clark, the district’s director of operations.
The Caterpillar generator was sold off at an auction from a failed dot com business in San Diego, Clark said. “We paid about $200,000 for a generator that was almost brand new and cost about $600,000, and maybe had only nine hours of running time on it,” he said.
The Lakeside pumping station is one of 16 in the district, and part of a system that lifts water to about 2,600 feet at its highest point in the Viejas Mountain area. In all, the district covers 72 square miles and includes all of Santee, parts of El Cajon and Lakeside, Blossom Valley, Crest, Harbison Canyon and Alpine.
That coverage combined with a limited customer base translates to higher average bills for the district’s 24,000 plus customers. An average customer pays $86 per month compared to $62 for San Diego County users, according to the district.
Because of the higher densities of users, other water districts enjoy lower water rates, said General Manager Allen Carlisle.
In any event, costs for everything including replacing pipes and maintaining the extensive systems isn’t getting any cheaper, Carlisle said. “We are investing in your system, and we are investing in reliability...and it comes at a cost.”
The district said it would conduct another tour of its facilities March 18, and likely add another one in April. For more information go to www.padredam.org.