Toilet to tap.

In the past few years, these three words have been powerful enough to make a consumer shudder, an engineer shiver. By itself this phrase, some say, has effectively killed proposed projects designed to add treated municipal wastewater to groundwater supplies used for drinking.

Like magic, the three little words can turn a rational discussion about a scientifically sound—and age old—water source into an emotionally charged debate about human health.

The debate, officials say, ignores the reality that water reuse is as old as time, that every time we take a drink, we're consuming water that has been used many times before.

The water cycle guarantees that nature uses the same supply of water over and over again. And people have been reusing water for centuries. (By some estimates, the water in the Mississippi River is used seven times before it reaches New Orleans).

Today, technology and personal choice is changing the way we reuse water. Reuse systems can be as basic as a homemaker using the leftover potato water to irrigate the petunias, newfangled as piping a new building with reused water for landscape irrigation, or sophisticated as the systems that keep astronauts hydrated in space.

No matter what their sophistication level, each manner of water reuse stretches a limited resource a bit further. And, as California struggles to reduce its dependence on Colorado River water, and environmental concerns continue to plague the San Francisco/San Joaquin Bay-Delta, water reuse will become more important — perhaps enough to make the thought of drinking recycled water more palatable.

"(Public reluctance to drink recycled water) will all blow over during the next drought," predicted Earle C. Hartling, water reuse coordinator for the Los Angeles County Sanitation District. "Right now we have all kinds of water, lots of places to put it and other options.

"But I'd say this will be an accepted option within the next 10 years, sooner if we have a drought," he said.

Andy Hui, a civil engineer specializing in water reuse for Metropolitan Water District of Southern California, agrees. "Our (water supply) situation is not dire but you want to explore ways to achieve long-term planning reliability," Hui said. "So we have to ask people 'Where's your next water supply going to come from?' There are restrictions on the Delta, there are restrictions on Colorado River, and at some point in time you're going to have to explore alternative sources."

Looking for alternatives

One way the Metropolitan Water District of Southern California is doing that is with its Local Resources Program, which helps local water agencies develop recycling, groundwater recovery and recharge programs that will, in turn, reduce their need for imported water.

The program provides a sliding-scale incentive, paying agencies up to $250 for every acre-foot of water that is recycled, recovered or returned to the groundwater supply. (An acre-foot is about 325,851 gallons of water—enough to serve the needs of two Southern California families for a year).

Groundwater recovery projects recover and treat brackish groundwater via reverse osmosis or carbon filters while recycling programs reuse highly treated municipal wastewater for irrigation purposes. Recharge programs take the treated water and lets it percolate into the ground, where it mixes with other sources and becomes part of the groundwater supply. Where recycled water is used for groundwater recharge, the process is highly regulated at each step including the treatment, recharge and well water production steps.

Many people are unfamiliar with groundwater recharge and other reuse processes, but indirect potable reuse is fairly common.

The water that flows into Southern California via the State Water Project and the Colorado River includes treated wastewater that has been used to recharge the groundwater. And locally, nearly all the water flowing into Orange County via the Santa Ana River is treated effluent from Riverside and San Bernardino Counties. This water has been used to replenish the groundwater supply in that area for more than 40 years.

In its six-county service area, Metropolitan has contracts for 75 reuse projects with a projected yield of about 315,000 acre-feet of water annually. Presently 47 of those projects—11 groundwater recovery and 36 recycled water—are operating.

The largest recycling project Metropolitan supports is the West Basin Water Reclamation Program, a 25-year project that will ultimately recycle 100,000 acre-feet of treated recycled water annually for landscape irrigation and industrial uses in the South Bay, stretching from Torrance to El Segundo. Some of the water recycled from this project is being injected into the ground to prevent seawater intrusion that threatens wells in the area.

Another project, the Santa Monica Dry Weather Runoff Reclamation Project, diverts up to 280 acre-feet per year of storm water headed for the Santa Monica Bay, treats it and distributes it for freeway and landscape irrigation.

Businesses face barriers

Many businesses, looking to further protect themselves from the effects of droughts, readily incorporate recycled water use in their landscaping. Using recycled water for industrial processes, such as cooling towers, provides water supply reliability during drought and is being accomplished on a large scale at West Basin refineries. However, such use requires individual pipelines to move the recycled water from the public wastewater treatment plant to the user. If the industrial plant is close to a recycled water main, then usage is more likely, officials said, but there are other barriers.

"When a plant decides to use recycled water, regulations open them up to (California Department of Health Services) inspections and expensive tests that are otherwise not required—even if the industrial plant is full of chemical feed pipelines that are far more hazardous than recycled water lines," said Andrew Sienkiewich, manager of Metropolitan's Resource Implementation Section.

One business that experienced this was San Diego-based Toppan Industries, an electronics circuit board manufacturing business that connected to recycled water main.

"Their walls inside are covered with pipelines. One (carries) recycled water, there are others with sulfuric acid and other chemicals" Sienkiewich said of Toppan. "Prior to them doing the hook-up (to the recycled water main) they never had a health inspector come inside."

But regulations require that health inspectors test the lines to make sure there was no cross connection between the recycled water and the potable water. That meant shutting down the plant—which cost the $250,000 in profit, he said.

"That would be a show-stopper for most businesses," Sienkiewich said. "They'd never even consider it.

"Introducing highly-treated recycled water is such a non-issue compared to all the other type of fluids they are handling in the plant," he said. "It was absurd. As long as that impediment (for businesses) exists, it will be a burden."

Using recycled water in a building for toilet flushing also requires dual plumbing to keep the recycled and potable water separate. Currently, Health Department and building code requirements prevent the retrofitting of buildings, so the use of recycled water is often limited to new construction or irrigation. Irrigation is the easiest because the only thing changing is the source of supply, Hui said.

Expanding the uses for recycled water beyond non-potable use gets even more difficult, officials say.

"The public has generally accepted traditional uses such as landscape irrigation for industrial and commercial applications and also would accept some agricultural reuse, but in the last couple of years there's been opposition to go beyond that," Hui said.

Yet there are those—like Hartling—who believe strongly that public acceptance is a matter of time.

Hartling oversees the Montebello Forebay groundwater recharge project and is assisting in the development of the Upper San Gabriel Valley Water Reclamation Project, which will annually recharge 10,000 acre-feet of treated municipal wastewater into settling grounds near the Santa Fe Dam. From there, the water seeps into an underground aquifer and sits for six months to a year, blending with other groundwater. Most scientists agree that the many layers of sand and silt in the ground act as a natural filter, but before the water even comes close to a tap, the water is treated again to meet California Department of Health Services standards for drinking water.

"I'm not going to drink sewage and we're not asking you to drink sewage; we're asking you to drink water," Hartling said. "We take what Mother Nature has been doing for 3 billion years and just speed it up."

A three-step treatment process

Recycled wastewater goes through a three-step or "tertiary" treatment process that leaves it clear, odorless and indistinguishable from tap water. As it leaves the treatment plant the recycled water must meet state and federal drinking water standards for heavy metals, pesticides, trace organics, radionuclides and minerals. The tertiary treated water is then allowed to percolate into the ground and mix with existing groundwater—at that point, it also meets the remaining drinking water standards for nitrogen and bacteria.

The first step of the tertiary treatment gets all the large stuff out. Coffee grounds, egg shells and other heavy organic and inorganic matter settle to the bottom and lighter stuff like cigarette butts or oil floats to the top and is removed. The second step puts the water through a biological process during which bacteria eats the organic matter left from the first step. During the third step the water is filtered through sand and coal to trap any suspended solids. In nature, sunlight disinfects the water, but treatment plants use chlorine to kill bacteria and virus.

Once that treated water percolates through the soil and mingles with other water, it meets all state and federal drinking water standards. In essence, officials said, the tertiary treatment process recreates what happens in natural waterbodies, only faster.

The Los Angeles County Sanitation Districts and the Water Replenishment District of Southern California—the Central Basin groundwater manager—commissioned three epidemiological studies, done in 1984, 1996 and 1998 by the UCLA School of Public Health and the Rand Corporation. The studies examined the health of people ingesting water containing up to 35 percent reclaimed water, versus similar populations receiving no reclaimed water. There were no statistically significant increases in cancers, gastrointestinal disease or adverse birth outcomes in those areas where the people were drinking the reclaimed water.

Nevertheless, these studies and tests and public information campaigns have failed to convince some that treated water is safe enough to be added to the groundwater supplies—even though it already is being added, and has been for decades.

The most recent debate landed at the feet of the city of Los Angeles.

For years Los Angeles has used recycled water for irrigation purposes at Griffith Park, and at a project on the West Side near Los Angeles International Airport, as well as for a wildlife lake at the Sepulveda Basin.

Last year, the city's plan to use recycled water to recharge the San Fernando Valley groundwater basin came to an abrupt halt. The plan was to take treated water, let it soak into the ground, sit for five years—far longer than other recharge projects, mingle with the groundwater and eventually be pumped up to be treated and delivered to customers. Although the plan was no different than what's already being done in nature—and in Whittier and water districts throughout the country—public outcry temporarily stalled the plan.

The toilet-to-tap label struck it down, said Steve Ott, manager of the water-recycling group at the Los Angeles Department of Water and Power. So the city is now left with expanding its non-potable sources.

"We'll keep looking for whatever opportunities we have—especially with landscape irrigation and institutional uses," Ott said. "We won't be able to use as large a quantity and it will cost us a lot more to put the water to use this way, but the public seems to be very happy to back those types of efforts."

For more information about water reuse contact:
Andy Sienkiewich at Metropolitan Water District, (213) 217-6230; the Water ReUse Association at www.watereuse.org; www.ca-nv-awwa.org.

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