Tijuana Finding the Beauty in Waste Water

TIJUANA —  Visitors are greeted by a soothing canopy of green. Rubber trees. Torrey pines. Acacias. Lemons, limes, oranges.

Colorful bursts of bougainvillea and bottlebrush edge the lush, 30-acre oasis, set on an otherwise arid hillside near Tijuana’s industrial zone.

Bring the children. Commune with nature. But don’t cringe at why this park is so abundantly fruitful.

It’s the sewage.

While all eyes have been turned to a massive new plant built north of the border to process chronic overflows of Tijuana sewage, researchers and activists here offer an unconventional alternative to long-standing waste woes: a low-tech treatment system and park in one.

Ecoparque, a demonstration project managed by the College of the Northern Border, takes waste water from a neighborhood and, using gravity flow and organic filtering processes, cleans it well enough to safely irrigate park grounds and more.

The facility, inaugurated in 1993, is but one humble response to runaway sewage that is among Tijuana’s least-becoming trademarks and a persistent source of pollution spilling north across the border into San Diego County. Backers would like to replicate the facility at dozens of sites around Tijuana and elsewhere along Mexico’s border with the United States.

“Tijuana has a deficit of green areas or parks. This would be a way to lower pollution . . . and demonstrate sewage can be a resource instead of something to be gotten rid of,” said Ecoparque Director Martin Medina.

So far, the city has signed up to have several similar parks designed, and plans are underway to build more in the cities of San Luis Rio Colorado, Nogales and Matamoros in northern Mexico.

“In 20 years, I hope to see many Ecoparques throughout Tijuana,” said former Director Oscar Romo, a senior advisor who also counsels top-level Mexican environmental officials.

Observers say Ecoparque is a fine place for studying alternative technologies, but far too small to serve as a model for overall change in the city--a third of which lacks sewers. State sewer officials plan to build four conventional waste treatment plants in the next five years and expand a plant north of Rosarito Beach that receives the bulk of Tijuana’s sewage.

A separate plant and ocean discharge system recently built in San Diego, funded largely by the U.S. government with some Mexican help, is set to treat as much as 25 million gallons of Tijuana sewage each day. Full start-up of the plant was delayed by glitches in recent days, at the same time a broken sewer pipe on the Mexican side spilled millions of gallons of Tijuana sewage across the border.

But boosters of Ecoparque see more in less. Tiny treatment parks could be sprinkled throughout Tijuana’s hilly topography, greening a parched landscape in the process. Better still, the decentralized system would mean closer resident control as each neighborhood took to running its own plant. It might sound like pie in the sky, but they are talking about a kind of waste water democracy movement, delivered one quirky park at a time.

By relying on gravity, the scheme also takes advantage of steep terrain that is more often a municipal enemy. Heavy winter rains and a leaky system send sewage down shanty-covered hillsides and, often, into the Tijuana River as it meanders north through an environmentally sensitive estuary and onto beaches in the United States. The problem is complicated by Tijuana’s rapid and chaotic growth.

“We don’t need a prime location. We just need a canyon, some piece of land where people can’t build,” Romo said. “They’re all over the place in Tijuana, already filled with trash and waste water.”

Romo, who also runs an environmental consulting business in Chula Vista, has scouted three dozen spots he considers suitable for such treatment parks. He figures it would cost about $150,000 to get each up and running. To succeed, the plants would pay their own way by providing irrigation water for city median strips or by doubling as nurseries.

Inspiration for the facility came in the mid-1980s from San Diego environmentalists looking for treatment alternatives. They experimented with a test plant just north of the border and later, with the help of the State Coastal Conservancy and the Environmental Defense Fund, moved to a site acquired by the Mexican think tank.

The facility gets raw sewage from a mainly residential neighborhood of 1,000 homes south of Tijuana’s Rodriguez Airport. The untreated water flows through a crude filter that catches branches and plastic bags and then through a finer sieve that screens out organic material. The material is mixed with grass cuttings and tree trimmings to make a fertilizing compost.

Water is piped down the slope into a 20-foot-tall bio-filter, where it tumbles through plastic filters while bacteria feed on remaining nutrients. The water emerges, cloudy gray, and flows to a clarifying tank. Sludge settles to the bottom and the water is pumped uphill--the only time electricity is used in the treatment process--to a storage tank. The water is distributed by gravity throughout the park by a network of pipes and sprinklers.

The result is a verdant swath that feels far removed from the whoosh of traffic on the busy highway below and from the city’s congested core a few miles beyond. The placid perch houses rabbits and squirrels, sage plants and succulents. A string of four pits waits to be converted into ponds.

As for the odor, there are a few spots where you need no reminding of the park’s functional side. But just a few.

Ecoparque staffers have built walking trails and notched a cozy amphitheater into the slope. Romo envisions poetry readings and concerts, plus an instructive vista of the barren hilltops on the far side of the city basin.

“It will be a window to the crude reality, from a place that is being sustained from the waste of the city,” he said.

Treating water this way is slow. Capacity is about one gallon a second, meaning it would take nearly 200 Ecoparques to equal the capacity of Tijuana’s existing treatment plant. And that, officials say, is a chief shortcoming.

“We need more small plants, but not that small,” said Leonardo Caloca, projects coordinator for the state commission that provides water and sewer services in Tijuana.

Even Ecoparque’s staunchest fans agree it’s no cure-all. But they say it has graduated from mere fancy and sits on the verge of a grander use.

“I’ve been here long enough to know now is the time,” said Romo. “Now we’re ready.”