By Mike Allen
Photo, left: shot of early stage treatment of reclaimed water at PD water recycling plant just north of Santee Lakes.
February 27, 2017 (Santee) -- While the recent rainy weather has improved what was a critical drought situation for much of California, officials at the Padre Dam Municipal Water District continue work on a regional water reclamation program to convert 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, is planned to be finished by 2021. By then, the reclaimed and purified sewage could provide up to 30 percent of the district’s water demands.
Photo, right: Ryan Hughes, PD employee, explaining part of the process at the advanced water purification system at the plant.
Padre Dam isn’t alone in pursuing the costly water reclamation program. Similar systems have been operating in the state and around the nation for years.
“In fact, if you’ve been to Disneyland, you drank retreated water,” says Melissa McChesney, Padre Dam’s spokeswoman. Orange County has been delivering reclaimed and purified sewage water to its customers since 2008, and now produces some 100 million gallons daily.
During a recent tour by the district, officials said the rationale for setting up a reclamation system is clear. The costs of water, nearly entirely sourced from the Colorado River, continues to rise, and the cost for treating sewage is also increasing.
Padre Dam customers now pay about $1,700 per acre foot for water, among the highest rates of 25 water districts in the county. But by 2021, the estimated cost will be about $2,000 an acre foot, officials said. An acre foot is the standard water measure and 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, regional users would have a reliable, drought proof supply and one that would reduce the costs for transporting sewage down to Pt. Loma, the district says.
“Padre Dam is now 100 percent importing its water,” McChesney said. “This (reclamation program) gives us a lot more local control and the ability to provide some of the water supply to our customers.”
Photo, left: Paul Clark, director of operations, shows how pumps work at the El Monte Pumping Station in Lakeside.
An early leader in water conservation, Padre Dam has been recycling its water since the late 1950s when late General Manager Ray Stoyer had the district build an extensive water treatment system that became Santee Lakes. That system, since expanded and moved north, has become a world-renowned model for producing 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.
While impressive, and well-tested, some Santee residents taking the tour weren’t all on-board with the concept, with one asking why not pursue desalination as an alternative supply.
The answer is desalination costs about twice as much. The $1 billion Carlsbad desalination plant that opened in December 2015 has the ability to supply about 50 million gallons of water daily to the county, or about 8-10 percent of the county’s supply.
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 sewage collection systems that rely on reservoirs, holding tanks, and pumping stations, all of which run on electrical power.
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 pumping station, which is at about 500 feet above sea level, pushes water to a point above 1,000 feet. Eventually water is pumped more than 2,600 feet above sea level to Viejas Mountain at the district’s eastern boundary. In all, the Padre Dam district covers 72 square miles and includes all of Santee, parts of El Cajon and Lakeside, Blossom Valley, Crest, Harbison Canyon and Alpine.
The far-flung area combined with a limited customer base translates to higher average bills for the district’s 24,000 plus customers. The average Padre Dam customer pays $86 per month compared to $62 for San Diego County users.
Other water districts have fewer acres to cover, and more customers, meaning expenses are shared by more and so bills are lower, said General Manager Allen Carlisle.
There may be more water agencies than the county deserves to have, Carlisle said. “Do I think some districts should be consolidated? Yes.”
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.”