San Diego's Recycling Water Project

The Pure Water program, Estimated to Cost up to $3.5 Billion, Would Generate 83 Million Gallons of Ultra-clean Water Per Day by 2035, Helping to Significantly Lessen the Region's Reliance on Imported Water

San Diego could be on the way to producing a third of its drinking water from sewage flows if the City Council votes for a landmark water purification project Tuesday.

The Pure Water program, estimated to cost up to $3.5 billion, would generate 83 million gallons of ultra-clean water per day by 2035, helping to significantly lessen the region's reliance on imported water. At completion, it would be one of the nation's two largest water purification systems.

If the city moves forward with this water recycling proposal, it also might be able to avert costly upgrades to the Point Loma Wastewater Treatment Plant by reducing the amount of effluent piped to sea. That plant is the last, big sewage-processing facility in the country that hasn't met the federal standard of secondary treatment, a cleaning procedure that increases the quality of water discharged.

The retrofit would cost nearly $2 billion. City officials said that money should instead be invested in the Pure Water project because it would not only help San Diego meet state and federal wastewater requirements, but also create a new and more reliable water source.

"When we start producing this water, it will be the cleanest and purest source of raw water we have in the region," said Halla Razak, director of the city's Public Utilities department. "When we start to deposit it in reservoirs, it will improve the quality of water in the reservoirs."

Community leaders agree that a stable supply of water is critical for the county's still-growing population and major business sectors such as the biotech industry, agriculture and tourism.

With the addition of the Poseidon desalination plant now under construction in Carlsbad, along with another such facility that could be built on Camp Pendleton in the future, the Pure Water program could dramatically alter the region's water dynamics.

In 1991, San Diego County imported 95 percent of its potable water. The figure has dropped, but remains high at 75 percent today.

San Diego officials said Pure Water is the prime component of their blueprint for having locally sourced water making up 40 percent of the city's total water supply by the mid-2030s.

"My priority is to protect the interests of San Diegans and ratepayers and to create solutions for a reliable, drought-proof water supply," Mayor Kevin Faulconer said in a statement Friday. "Pure Water is a cost-effective and innovative project, and we're going to seek funding from state and federal sources to minimize the local cost. The cost of doing nothing is even higher because without Pure Water, we would have to continue to rely almost entirely on costly imported water sold to us at rates we don't control."

BROAD SUPPORT

On Tuesday, the City Council is set to vote on whether to approve Faulconer's proposal to request a waiver of a discharge permit for the Point Loma Wastewater Treatment Plant. The request for exemption also would spell out how the city plans to meet federal wastewater standards through the water purification project.

The plan has the blessings of the San Diego County Taxpayers Association as well as the region's leading environmental organizations, including San Diego Coastkeeper, the local chapter of the Surfrider Foundation, the Coastal Environmental Rights Foundation and the San Diego Audubon Society.

"We believe this program will benefit not only our marine environment by beginning to reduce discharges into the ocean, but that it will also set up our region to address current and future water supply needs in an environmentally responsible manner," Matt O'Malley, waterkeeper for San Diego Coastkeeper, said in a statement.

The Pure Water concept is being demonstrated with a 1 million-gallon-per-day pilot project at the North City facility, where engineers have fine-tuned the purification process in recent years. They have verified through about 9,000 tests that the end product meets or exceeds the government's water quality standards, Razak said.

The system starts with micro-filtration: rows of plastic tubes containing bundles of tiny straws that allow water molecules in and then filter out microbes and other contaminants.

From there, the water flows to reverse-osmosis units that force the water through filters at high pressure to screen out organic material, salts and other solids. By the time the water runs through reverse osmosis, there are almost no impurities left in it.

During the final step, workers use a combination of ultraviolet light and hydrogen peroxide to obliterate any potential contaminants.

City officials want to replicate that process through a system of three plants in different parts of the city. In the first phase, San Diego plans to build one of those facilities at the North City Reclamation Plant near Miramar Road. It would produce 15 million gallons of water per day by 2023.

A subsequent phase would add 15 million gallons per day from a facility at the South Bay Reclamation Plant, plus a separate injection of 53 million gallons per day from a facility on the former Naval Training Center grounds on Harbor Drive. That milestone is projected to be reached by 2035, Razak said.

Current thinking calls for the purified water to be mixed with supplies in San Vicente Reservoir and then piped from there to customers. An alternate strategy would allow the city to route the water directly into water distribution systems and ship it directly to users.

Both of those procedures would require changes to state regulations, which city leaders said they're discussing with officials in Sacramento.

FUNDING OPTIONS

San Diego officials said the Pure Water program would cost $1.5 billion to $2.5 billion to build out. That price tag would rise to as much as $3.5 billion when interest is included.

City leaders believe they can cover between a quarter and a third of that cost with state and federal grants. They plan to apply for funding from the recently passed $7.5 billion state water bond and earlier California water measures. They also intend to seek grants from the federal Environmental Protection Agency.

The remaining expense would be paid through rate increases of about 1 to 3 percent per year for most of the project's construction period, Razak said.

The investment will pay dividends in the long run, as the city reduces reliance on increasingly costly imported water and avoids the expense of upgrades to the Point Loma water facility, said Sean Karafin, an economic policy analyst for the San Diego County Taxpayers Association.

"There's going to be a savings for ratepayers down the road," Karafin said. "It's good for our economy, it's good for the environment, it's good for ratepayers. It's a win-win."

Although the public originally took a dim view of water recycling, that opinion has turned around in recent years. A decade ago, a survey showed that three-quarters of San Diegans snubbed the water purification idea, which some derisively called "toilet to tap" at the time.

But the ongoing drought — and growing recognition that all potable water has been recycled and purified in some way — has reversed the figures. In a 2012 poll, almost three-quarters of respondents in the city voiced support for water recycling.

"Potable reuse is actually used in quite a few areas in the country," said Patricia Tennyson, executive vice president of Katz & Associates and a board member of the trade organization WaterReuse California. "Potable reuse occurs everywhere. Everybody who is downstream from another community is drinking water that is used by the people upstream."

Source: UTSanDiego

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Taxonomy

• Water Reuse & Recycling
• Water Supply
• Water Management