You flush the toilet, pull the plug in the tub, and throw the food in the disposal. But do you know where it all goes?

Well, if you live in the area between the western end of Santa Barbara and all the way to El Capitan, it all goes downhill — to the Goleta Sanitary District facilities, 1 William Moffett Place, right across from the Santa Barbara Airport.

“We are not the Goleta Water District,” said lab technical services supervisor Kathleen Werner, referring to a common misconception about her district. “We take care of what flows out of your home, not what flows in.”

What flows out of homes and businesses into the sanitary district’s plant is, on average, about 5.5 million gallons of raw sewage every day. That’s about 8.3 Olympic-sized swimming pools of raw sewage a day.

“It fluctuates depending on the time of year and who’s in town,” said Werner, whose district draws from Goleta, including the area served by Goleta West Sanitary District, as well as the airport, UCSB and Isla Vista.

If UCSB is not in session, for example, the amount of sewage to treat decreases. Otherwise, anything that goes down the drain and sent through the approximately 130 miles of pipeline winds up in this place, where it gets digested, filtered, treated and either sent out clean into the ocean or saved for reuse.

But First, a Little History

The Goleta Sanitary District was formed in 1942. At the time Goleta was still very much the rural community, popular for its lemons, avocados, walnuts and pampas grass. Only about 1,500 people lived in the valley, and sewage was collected in septic tanks and cesspools.

The Goleta Valley, however rural, was on the edge of modern development. World War II brought the military, and with it the construction of several bases and facilities. The district, through an agreement with the Navy Department, managed to connect to the sewage system at the Marine air base, which is now the airport. In 1951, the Sanitary District opened its first plant.

Fourteen years later, the district constructed its outfall pipe, which stretches out a little more than a mile into the ocean from a point at Goleta Beach.

The district upgraded its main facilities in 1987, after more than 35 years of operation. And, in response to the drought of the late 1980s and early ‘90s, the district partnered with the Goleta Water District to build reclamation facilities that recycle wastewater for landscaping purposes.

Process of Elimination

So what happens to the vegetable peelings, bathwater, toilet paper and human waste that winds up at the district’s facilities?

First, the sewage gets pumped up to the headworks from a collection area located at the plant’s lowest point.

“If you look at other wastewater treatment plants in other cities, you’ll find that they’re often located at the lowest place in the community,” Werner said.

The reason, she said, is because all sewage flows to the plant through gravity. However, if you live or work in El Sueno, a neighborhood in the unincorporated part of the Goleta Valley, or in the Aero Camino industrial section of Goleta, your wastewater gets pumped upward first by a lift station before feeding into the sewer lines because some structures in those areas can’t use gravity to feed the sewer lines.

The Sanitary District’s headworks is where sewage undergoes its first round of filtration, mechanically screening out large objects and dirt.

After processing at the headworks, the water undergoes further filtration at the primary settling tanks, where heavier material settles to the bottom and lighter solids, oil and grease float to the top and are removed. According to the district, 50 percent of solids are removed during this phase of treatment.

From the settling tanks, wastewater is then moved through a biofitration process, using microorganisms to consume the organic solids dissolved in the water. In fact, much of the work at the plants consists of maintaining an optimum environment for these tiny creatures — the right population, the right amount of oxygen and an abundance of food.

At the plant’s trickling filter, wastewater is passed out of a pipe that spins and streams water over a black plastic medium. Microorganisms — single-cell organisms, nematodes —  in that filter consume organic material in the water.

“This replicates water running down the creek over rocks,” said operator Paul Buckley, an almost 20-year employee of the plant. “That’s how Mother Nature cleans her water.”

After making a couple of rounds through the trickling filter, the water then flows to a rectangular concrete channel, where the less sludgy, but still black water churns and bubbles and foams. The microorganisms — the ones that were feasting in the trickling chamber — are here, too, but their function in the solids contact channel is to clump solids together into a heavier mass.

The water moves to the secondary settling tanks where the heavy clumps settle to the bottom, taking out more solids.

At this point there are two things that can happen to the wastewater: Recycling, or disinfection and discharge.

If there is a demand for reclaimed water, like in the summer months, Werner said, up to 3 million gallons a day can be reclaimed, through further clumping, filtration and disinfection. If you’ve ever been to the golf course, or seen large-scale landscaping like at UCSB, the water they use comes from this process.

“It’s probably safe to bathe with, but not safe enough to drink,” said Buckley.

Whatever can’t be reclaimed, he said, gets disinfected with chlorine to kill what bacteria and other organisms may be present. Then the chlorine is neutralized.

“Chlorine is really toxic to marine life,” Buckley said. The water then gets pumped out a mile or so into the ocean via the outfall pipe.

Testing, Testing

The district performs regular tests on a multitude of things, from what flows into the facility to what flows out. If operators find something unusual — like an abnormal pH reading, for instance — they are able to isolate and trace the source of the abnormality.

Out in the ocean, the district tests the water in the area of its outfall pipe, located almost 100 feet below the surface, checking for bacteria, water chemistry, sedimentation, effects on animals and the soundness of its pipe.

Wait, What Happens to the Sludge?

Whatever it was you flushed down the toilet or washed down your drain winds up in one of several huge cylindrical buildings, called digesters, after it has been removed from the wastewater.

“They’re like huge stomachs,” Buckley said.

The sludge is heated in those digesters, where it is acted on by bacteria and other decomposing agents for up to two months. In that time carbon dioxide is emitted, and also methane, which is recaptured and used to fuel the digesters.

From the digesters, the sludge moves to stabilization basins, three lagoons about 15 feet deep and about three to five acres in area, where the sludge further decomposes and settles. This part of the process can take years.

If you want some soil amendments for free, you may consider taking your shovel and bucket to the Goleta Sanitary District. Some of the biosolids from the lagoons are pressed to take out the water or dried on drying beds.

“It’s free,” Buckley said. “We just have to know how much they need. If they want a lot, we can get out the skiploader, or they can come out with a shovel and maybe fill up a garbage can or something.”

Bird Watching … Where?

The lagoons are an unlikely but very popular place for birdwatching, once you get used to the odor — and you do. According to Buckley, easily a hundred different species of waterfowl — from ducks to egrets to swans and geese — find a smorgasbord in these lagoons, as well as in the filters that process the water.

“The filter flies, that’s like gourmet food to the ducks,” Buckley said.

The district also has some resident chickens, which are tested regularly for diseases like West Nile or avian flu. Although they’re primarily for vector control, at least one person has warmed up to them.

“We used to have just the chickens,” Buckley noted. They’ve since branched out into exotic chickens and at least one rooster, taken care of by the facilities’ gardener.

Buckley is apparently unfazed by the “pets” at the district’s facilities.

“We’ve had some pot-bellied pigs but they’ve died since,” he said. “We used to have a llama some years ago.”

Looking Ahead

Grand things are in the works for the Goleta Sanitary District. Currently, the district, in anticipation of new housing in Goleta and on UCSB property, is planning a $30 million to $40 million upgrade, one that is expected to finish in 2014.

The Goleta Sanitary District is open to tours and birdwatching. Click here to contact the district or call 805.964.4519.

— Noozhawk staff writer Sonia Fernandez can be reached at sfernandez@noozhawk.com.