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Water World

What's so special about a wastewater-treatment plant? Just ask the birds of Petaluma.

By David Templeton

After years of delays and escalating expenses, construction has finally begun on Petaluma's new $110 million wastewater-treatment plant, an event that has triggered twitters of delight among birdwatchers across Northern California. While that may sound like a non sequitur, the truth is that the opening of the Ellis Creek water-recycling facility in the fall of 2008 is expected to do at least as much for visiting egrets and buffleheads, herons and bitterns as it will for the actual human beings of Petaluma. Unless, of course, the city runs out of money before the final stages--the bird-friendly ones--are complete.

While most Petaluma residents have a vague idea that a new treatment plant is being built, only a small number of folks, many of them wildlife advocates, understand how it will work in relation to the man-made wetlands that will be built as a major part of the project.

"Apparently, most people are not wastewater-treatment designers," laughs Mike Ban, Petaluma's director of Water Resources and Conservation. "If you're an engineer like me, you'll think it's all fascinating, but most people don't even want to think about wastewater. In the end, though, I think everyone will agree that the new system is truly unique and pretty special."

Generally speaking, there are three stages to wastewater treatment. Initially, large items (bottles and branches and things) are screened out of the wastewater, which then flows into a grit chamber where coffee grounds and eggshells and sand are pulled out. From there the wastewater flows into a pair of oxidation ditches, where air is introduced to the water with a mechanical aerator before it is sent into a large round tank, where secondary clarifiers remove much of the additional waste. After all of that, the water is sent into a series of 10 oxidation ponds, where it sits in the open air for 30 to 40 days.

Most wastewater now receives only the first two stages of treatment before being sent out to the river, where it eventually makes its way to the sea. In the new system, secondary water will be introduced to a man-made, 30-acre expanse of "polishing wetlands" for the final tertiary stage. The resulting water will be used for landscaping and agricultural purposes. (Recycled water, though not legally drinkable, is perfect for agricultural and landscaping uses.) This kind of recycling program is expected to save Petaluma over 2 billion gallons of drinkable water a year.

When Ellis Creek is completed, water will eventually be introduced into small, densely vegetated wetlands ponds, which create enough shade to kill any algae, while the ebb and flow of the water through the vegetation will filter away the residue, along with harmful metals and nutrients. The water will then be sent into the larger polishing wetlands, a combination of open water and vegetated areas, where additional metals and nutrient removal can occur. Because the polishing wetlands include plenty of native greenery--perfect for birds and animals--the whole system would ultimately end up treating the city's wastewater while it simultaneously provides habitat for marsh-dwelling life forms.

"There were other ways of treating water that are fully mechanical," says Ban, "but the city chose to do it this way. This system is far less energy-intensive, it requires very little equipment and we've certainly got the land to do it, so that's what were building."

There are similar facilities throughout the United States and several in California, including one in Marin County. "There are a couple of hundred of these all over the country and they can be pretty spectacular," says Gerald Moore, a dedicated wildlife photographer and current chairman of the Petaluma Wetlands Alliance (PWA). As with many of these newer and more innovative treatment facilities, the Ellis Creek plant will be decked out with a series of water-level nature trails and deep-marsh walkways. Though Moore makes the point that wastewater ponds are not a park per se, the area could eventually include such amenities as a small amphitheater, permanent sculpture displays and an education center built from a farmhouse that currently stands on the property.

"I've visited several of these kinds of places, from Arcata to Florida," Moore says. "They can become incredible wildlife refuges filled with birds and animals--if the city or county in question actually takes the steps, and spends the money, to do it right.

"What we want," he continues, "is to have suitable plant material to make the site look very natural to wildlife and to people, and then to give some partial screening to ponds, so when they are filled with birds, and people walk by, they don't scare off all the birds. PWA's big issue now is making sure we get good habitat in there for wildlife."

Ban confirms that the money isn't there to install all of the aesthetic vegetation and plant life that were originally planned for the polishing wetlands. "There was some interest in doing more aesthetic and bird-friendly things in terms of creating blinds and comfort areas for the birds," he explains. "Right now, we won't be able to afford that. This is a $110 million project after all, and we're working to make that money stretch as far as possible. But if money comes available in the future, we'd be interested in doing more of those kinds of habitat things.

"But even without those little things we can't afford," he adds, "it's going to be unlike any other wastewater plant around. Just wait and see."

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From the February 15-21, 2006 issue of the North Bay Bohemian.

Copyright © 2006 Metro Publishing Inc. Maintained by Boulevards New Media.