I'm not one of those writers who will tell you that I nervously sniffed the glass of former toilet water.

Not me. I put my nose to the surface of the water and inhaled with gusto, with vigor, with complete faith in the technology that scrubbed out all the bodily fluids suspended in it only hours before.

And I smelled nothing.

Around me, members of the US Society of Ecological Economists grinned. A few took pictures. And a man named Ed Clerico beamed -- as well he should. It is his company, after all, that designed, built, and operates the system that purified this water: the US's first onsite water reclamation system in a multi-family residential building, here in the basement of the Solaire.

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Buildings are like the people that inhabit them: they eat, they drink, they breathe, and they produce waste. In most buildings, the 1.6 gallons of pure drinking water you contaminate every time you use the toilet are excreted into the municipal sewage system. But in the Solaire, a 27-story, 293-unit building designed in 2000 and completed in 2003, that waste isn't wasted. Located in Battery Park City, the Solaire is the first green residential building in the country; and one of its most exciting features is that the showers, sinks, dishwashers, washing machines, and all 750 of the building's toilets flush up to 25,000 gallons of sewage each day down into a 1,500 square foot concrete room carved out of the parking garage. In a city where parking fetches up to $225,000 a spot, this valuable real estate houses a membrane bioreactor that turns sewage into clean water for non-potable uses throughout the building.

Ever since Poop Culture has come out, I've been meeting fascinating people who, like me, spend time thinking about what happens after you press the handle to flush. Ed Clerico, former president of Applied Water Management and current head of New Jersey's Alliance Environmental, is one of them. On a sunny day in June, Ed invited my wife and I to join the US Society of Ecological Economists on a tour of the Solaire, convening under the photovoltaic cells climbing up the Solaire's west-facing wall before proceeding directly to its basement -- a spotless, shining cacophony of tanks, pipes, and valves, roaring with machine noise, overwhelming in its complexity and yet sporting neat labels on each component for the benefit of what must be frequent tour groups.

Pressing a button, Clerico dulled the noise to a hum and explained exactly how a membrane bioreactor works.

Picture thousands of hollow spaghetti-like strands hanging down into a pulsating stew of sewage and bacteria. The Solaire's sewage, after settling in a tank to remove the largest solids, enters the membrane bioreactor, where bacteria digest the organic matter suspended in it. This kind of organic digestion takes place in most standard wastewater treatment facilities; what makes membrane treatment unique is that rather than separating the contaminants from the water, it separates the water from the contaminants -- sucking at the stew through billions of pores in the membranes so tiny that only water molecules can pass through.

Once through the membranes, the water is treated for color and odor by an ozone generator, further disinfected by UV light, and then pumped back into the building to help fill the cooling tower, irrigate the adjacent park, and, appropriately, refill each of the Solaire's 750 toilets.

Stepping to a faucet on the outflow side of the UV disinfection system, Clerico triumphantly filled a clear plastic glass. Early adapters though the Ecological Economists are, a few still gave the water distrusting looks as it passed from person to person on its way to me, now surely immortalized in some Flickr album as "the guy who smelled the toilet water."

It had no odor and no color. It was water, plain and simple. "Nearly potable," Clerico told me, "but a little too salty." Membrane pore size descends from microfiltration to ultrafiltration to nanofiltration to reverse osmosis; the Solaire uses ultrafiltration, which allows some salts to pass through. This is fine for non-potable uses; if the Solaire wanted drinking water, Clerico would rely on no less than reverse osmosis.

The tour took us up to the Solaire's 19th floor roof deck (a lovely view of Teardrop Park, made green by the Solaire's reclaimed water) and then down into a model apartment, where, standing on floors made from wood chips and coated with non-toxic varnish, talk turned from ecology to economics. The Solaire has reduced water consumption and discharge by 48% and 56% respectively while adding about 0.5% to the cost of the building. At current sewer and water rates, the Solaire's water reuse system will take up to twelve years to pay itself off. (Clerico says that a system would need to process 500,000 gallons a day -- a scope on par with the World Trade Center -- to make water reclamation profitable from day one.)

But that twelve-year estimate is based on 2003's municipal incentives, 2000's technology, and today's water and sewer rates. The New York City Water Board plans rate increases of at least 11% a year each year until 2010, instantly making water reclamation cost effective for a much wider range of projects. What's more, green technology has evolved in the seven years since the Solaire was designed, dropping costs and improving efficiency. And best yet, New York City is considering offering developers a reimbursement on every gallon of water they save above a yearly average of a thousand gallons a day -- which, Clerico believes, will drastically increase the attractiveness of water reuse by dropping the payback period to two or three years for a building the size of the Solaire.

Our tour of the Solaire ended in Teardrop Park. I'm not one of those writers who will tell you that I got all maudlin as I heard children laughing in the shade of trees irrigated by former toilet water. Not me. After the tour I just went home, where I shortly contaminated 1.6 gallons of pure drinking water and then hosed a few more gallons of pure drinking water on my tomato plants.

Note: I go much deeper into the economics of the city's proposed capital incentive over on The Poop Culture blog.