Recycling Our Most Precious Resource
|By Jeff Gottesfeld|
"Buy land,” the old saw—attributed to both Will Rogers and Mark Twain—goes. “They’re not making any more of it.”
Whichever of the storied American humorists said it, he had a point. It took 100 years to get from a world population of one billion to 2.5 billion (in the year 1950).
It took 50 years to go from that number to six billion at the end of the 20th century. Now, we’re at seven billion and counting . . . all on the same terra firma. It’s not just land that they’re not making any more of, either. It’s also water.
Just like land, the long-term cost of water is rising. In Ohio, for example, the cost of water increased by 289 percent during a recent 20-year period, and that is not a misprint. Small wonder then that we in the landscape business are hyper-sensitive about water.
We’ve moved to drip and low-volume irrigation, low-precipitation sprinkler heads, and smart controllers with advanced technology, as well as using native plants, and landscape fabrics that help soil retain moisture, all in an effort to help our clients avoid “meter shock.”
One of the best methods to give our customers a helping hand is to use recycled water whenever we can. Recycled water begins as water that has already gone down the drain. It comes into water treatment and purification plants laden with soaps, detergents, grease, oils, feces, urine, deceased family goldfish—and whatever else we wish didn’t go down the drain, but inevitably does.
Then, through a combination of mechanical, bacteriological, and chemical treatment, the effluent water is purified to where it can at least be safely applied to lawns, landscapes, and used in industrial applications.
Can you imagine how much potable water can be saved when recycled water is used for landscaping?
According to the federal Environmental Protection Agency, just the cities of Chicago, Miami and Los Angeles combined use more than a trillion gallons of water a year.
That’s a lotta flushes. The gulf coast city of Clearwater, Florida, is a leader in the use of recycled water at the local level. With three treatment facilities in the city itself, Clearwater residences and businesses use upwards of 5.75 million gallons a day of recycled water, according to Jerry Wells, public utilities coordinator for the city.
“Last year, we had 3,400 customers tied into our recycled water system,” Wells says. “The cost savings to them is remarkable; 25,000 gallons of potable water cost the property owner $95. That same amount of recycled water costs only $25. With that difference in water rates, it makes so much sense to irrigate with recycled water when it’s available.” The problem is, there are only a few places where recycled effluent water is used.
Many water utility companies have not begun to build more facilities.
While many municipalities are using recycled water to irrigate highway median strips and land around public structures, Clearwater has made an exceptional effort to bring recycled water to the homeowner. “Since the mid-1990s,” Wells explains, “we’ve been working with the Southwest Florida Water Management District to run reclaimed water from our treatment facilities to where the water can be used by homeowners. We even have a master plan that we revise every five years as to where we want to run the pipes (purple pipes, that is) next.”
In projects jointly funded with the water district, the municipality accepts contractor bids to install mainline pipes dedicated to recycled water, plus service lines and separate meter boxes for property owners. There’s neighborhood education every step of the way.
After the water meter for recycled water is installed, thus giving the homeowner two meters, one for potable water and one for recycled water, the homeowner will receive a door hanger advising that cheaper recycled water is available to them.
At that point, Wells says, the process goes local. “The customer would engage a licensed irrigation or plumbing contractor to make the PVC pipe connection between the meter and the customer’s own irrigation lines. Then, the contractor would contact the city for an inspection. After a successful inspection for leaks and the like, the inspector will permit recycled water to flow through the meter.”
There are practical advantages, in addition to cost, for using recycled water for irrigation. When drought occurs and Clearwater orders irrigation restrictions, those restrictions do not apply to those using recycled water.
Even with these advantages, Wells admits that not everyone in Clearwater who can connect to the purple pipes wants to connect. Customers who have wells of their own have been slowest to move toward recycled water.
Nor is the shift to recycled water moving as quickly as the administrator would like. Clearwater was one of the early Florida adopters of recycled water technology. Now, other water utilities are making the same kinds of co-funding requests for pipe construction, and it’s slowing things down.
More communities will be making the move to recycled water if the innovative idea of smaller-scale facilities for wastewater treatment takes hold. Arizona’s Global Water Resources in Phoenix, Arizona, is a pioneer in this technology. Essentially, these facilities aim to supply recycled water to as little as a 36-square mile area.
According to Graham Symmonds, senior vice president of regulatory affairs and compliance and chief technology officer for Global Water, that company is working with two Arizona communities that expect new growth once the economy stabilizes.
“We’re not looking to put up the giant treatment facility that one city will need for the 22nd century. We want to do 10 to 12 million-gallon-per-day plants to handle current needs, and have those facilities close to the areas being served.”
With these smaller plants situated close to where the recycled water is actually used, infrastructure water line costs, and costs of water transport are significantly diminished.
What’s also good about small-scale plants, Symmonds explains, is that they have a smaller environmental footprint than their big brothers. “Here in Arizona, we have to think about odor, noise, and aesthetic controls. Smaller facilities are easier to manage on all three fronts.”
Another small-scale plant paradigm, Symmonds says, is the so-called small-scale “scalping” treatment plant. These plants function by “scalping” a designated amount of effluent water from one of the big lines that carry effluent water to conventional large treatment facilities. The scalped water is diverted to one of these local treatment plants, who deliver the recycled water locally.
Most wastewater recycling follows the same straightforward process.
John Mays is the city environmental engineer for the Tillman Water Reclamation Plant in the San Fernando Valley, a suburb of Los Angeles. He points out, “We’re at about 700 feet above sea level, and we’re the catchment area for gray water coming from higher elevations than ours. It’s gravity-fed to us, and consolidated into a main pipe that leads to our facility. We turn that effluent into usable recycled water—I’ve been in this business long enough to want to call it ‘reclaimed’ water.”
All that effluent—80 million gallons worth a day, when the plant operates at full capacity—goes through filters that remove plastic bags, Styrofoam cups, clothing, rags, and other less savory non-biologic solids that have been carried downstream through the sewer pipes. Once filtered, the effluent continues through a piping system to the next stage of cleaning.
That next stage is physical and bacteriological. From filtering, water is directed into a series of massive holding tanks, where greases and oils rise to the top, while solids settle at the bottom. After this separation has occurred, and as many solids as possible are removed, specially selected bacteria are introduced to do their thing on non-settling solids. As these bacteria eat away at the non-settling solids, oxygen gets piped into the tanks to further nourish the bacteria. It’s in these tanks that the majority of the specially selected bacteria go to work on the organic solids.
At the Tillman plant, these tanks are an awesome sight, laid out in long rows, each holding two million gallons of effluent water at a time. Yes, it smells, but the air is not as pungent as one might think. The bacteria do their job efficiently.
Following bacteriological treatment, the much-clarified water is moved to other tanks for further skimming of greases and filtering. The water is drawn through specially designed cloth filters by a mechanical process. Mays said the process is even self-cleaning. “As the filters fill with tiny debris, the water level in the tanks rises. Once they reach a high-water trigger point, the flow of water into the filtration tank reverses, automatically cleaning the filters.”
The last step in the treatment process is chemical, where the water is disinfected. This often means that the water gets chlorinated, though some facilities are now moving toward exposing the water to ultraviolet light as a method of killing any harmful bacteria that might have survived the earlier parts of the process. If chlorine is involved in the process, dechlorination with sulfur dioxide is desirable.
What comes out the other end, Mays says, is excellent water for irrigation. With a little more processing, it would easily be good enough to drink.
Whether the process happens in big plants or small plants, recycled water is here to stay. We’ll be using it until they start making more land . . . which will be the same time that they start making more water; which is to say, we’ll be using it for a long, long time.