Towers Are Tapped Out by Updated Technology

Two mammoth water-treatment plants that have towered over the Santa Ana River for nearly three decades will be demolished this fall, made relics by advancing technology and the area’s rapidly disappearing farms.

The six-story structures--the tallest buildings in Fountain Valley--contain a maze-like network of pipes and fans that daily removed ammonia from 10 million gallons of water bound for the county’s ground water basin.

But the plants have remained idle for a decade.

The complicated process of removing ammonia by letting the water cascade 60 feet like a waterfall is now considered obsolete.

“It reminds me of a decommissioned ship. It’s kind of eerie being inside there,” said Ron Wildermuth, spokesman for the Orange County Water District. “It’s like being in an empty hotel. You know there was once tremendous activity in there. But now, there’s nothing.”

The water district now uses a reverse osmosis filter system that accomplishes the job much more efficiently and takes up a tiny fraction of the space.

At the same time, ammonia levels in the waste water have declined since the closure in the late 1970s of a nearby fertilizer plant that served the county’s agricultural industry.

“We really don’t have a reason to keep these buildings standing,” said Steven Conklin, director of engineering for the water district. “The process is very interesting--we were really doing the same thing that nature does with a waterfall. But it’s no longer the latest technology.”

The artificial “waterfalls” are located inside two nondescript industrial buildings off Ellis Avenue near the San Diego Freeway. They were built in the early 1970s to treat waste water from local sewers. After treatment, the water was injected into the ground.

The injections are designed to create barriers blocking seawater from entering the coastal aquifers and contaminating the fresh-water storage areas. They also help replenish the ground water basin, which is the primary source of drinking water for homes and businesses in the north, west and central county.

But before the waste water can be injected, it must be treated to remove pollutants such as ammonia, which contains nitrates, a toxic substance created by human and animal waste. In large enough doses, nitrates can cause a potentially fatal oxygen deprivation in infants known as “blue baby” syndrome.

In its raw form, the waste water contains nitrate levels that exceeded federal drinking water standards. But treatment by both the water district and the Orange County Sanitation District brings the water to top drinking quality, officials said.

Under the old ammonia-stripping process, waste water from the sanitation district was shot up 60-foot pipes and gradually released down a series of steps. The water would cascade down in sheets. At the same time, powerful fans would blow air at the water.

The process leached--or “stripped”--all the ammonia out of the water. Conklin said the process worked fine, but that the modern reverse osmosis system is superior because it removes ammonia as well as a variety of other minerals and pollutants.

“It really takes everything out of there,” he said of the new process, which runs the water through a series of membranes. The filters contain holes small enough for only water molecules to pass through.

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Out With the Old

The Orange County Water District this fall will tear down two massive “ammonia stripping” plants that treated waste water. The six-story towers are considered obsolete. The district now uses a smaller, more efficient reverse osmosis system.

The old “ammonia stripping” system:

1) Water enters at the top of the tower.

2) The water cascades down a series of steps.

3) The water is hit by air coming from the bottom of the tower; the air is generated by a fan at the top.

4) When the water hits the air, the ammonia gas (waste product) is naturally separated and floats up and out of the tower.

5) The water, now free of ammonia, exits at the bottom of tower and goes to the next step in the treatment process.

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The new reverse osmosis system:

1) Waste water is sent through a membrane filter.

2) Molecules of ammonia and other pollutants and minerals are too large to fit through the filter and are held back (the holes in the membrane are small enough that only water molecules can pass).

3) The pollutant-free water flows past the filter.

Source: Orange County Water District