Recycling water eases the demand on limited water sources and promotes an environmentally favorable, economically realistic option for multiple applications.
Water is a scarce commodity that must be conserved and managed. Due to population growth and environmental causes, this once-abundant natural resource is in increasingly short supply. Utility companies are raising water rates as they grapple with escalating treatment costs, replacement of aging infrastructure, accelerating power prices, regulatory mandates, and water scarcity. Water covers roughly 71% of the surface of this blue planet, but most of that is seawater. About 3% of the earth’s water supply is fresh water, and nearly 70% of that is confined in glaciers and polar ice caps. Only 1% of the water on this planet is suitable for drinking, and only 0.08% of the world’s drinkable water is accessible to humans.
With the world’s population now topping 7 billion, it’s no exaggeration when Guy Carpenter, vice president of water supply and reuse for Carollo Engineers in Phoenix, AZ, says, “We are running out of water.”
Established in 1933, Carollo is a group of civil engineers who plan, design, and construct management of water and wastewater plants.
“If you double the population on the same resource, you need a new resource, or you have to reduce usage by half,” says Carpenter. “Unfortunately, there are not many new resources to go get now. The Colorado River is over-allocated. Seven states rely on it; there’s simply not enough to go around.
“There’s talk of a smaller drinking water system, limiting the amount of water treated to drinking water standards because less than one-tenth of 1% is ingested,” he adds.
Carpenter also expects to see a rapid increase in pricing—as much as a 30% change in water rates—because it’s more expensive to find resources than to recycle.
Prices have already risen. The Salt River Project in Arizona delivers water for $11 per acre-foot, he estimates. And when the CAT canal was constructed in the 1980s, it was $150 per acre-foot.
“After we’re done using it in 25 years, we’ll have to import desalinated brackish water at $1,000 per acre-foot,” says Carpenter. “The next step is to build a pipeline to the Mississippi or Alaska or build a desalination plant in Mexico at $2,500 per acre-foot.”
Echoing Carpenter’s concerns, Trevor Hill, cofounder, president and CEO of Global Water, agrees it’s a very serious global issue that’s difficult to solve.
“There’s no substitute for water,” he says. “It’s a finite resource. We can make drinking water from seawater, but it’s power-intensive and creates brine. It’s not a panacea.”
Demand exceeds supply, reiterates Hill, who also warns that water rates are increasing due to scarcity, aging infrastructure, and the need for further treatment. “There’s a fixation on supply in this country; we consume until it’s gone. We must do much more on the demand side. We need to balance the needs of the people and the environment.”
Conserving Water to Preserve Water Sources
A two-pronged approach to ensure sufficient supplies of the precious liquid involves conservation and reuse. Reuse—collecting water, treating it to high standards, and redistributing it for non-potable applications—is driven by population growth. Because the water supply is diminishing, a major change has to take place.
“Graywater—water that runs out of the sink and shower—can be used in the garden, untreated,” says Hill.
In fact, graywater is suitable for most traditional uses of water because, in many cases, potable water quality is not required. As such, collecting potable wastewater and recycling it for non-potable uses is good management of resources.
|Photo: GLOBAL WATER
Public education can encourage public conservation.
“When you need additional water, do you buy more resources, develop new suppliers or use what you have?” asks Hill. “Where’s the next drop coming from? It’s simple economics: Use the water already here. All roads lead to recycling. The technology has been available for decades; it’s on the cusp of becoming mainstream. Recycling is cheaper than developing new sources—and there’s no need to get the water rights.”
To successfully conserve water requires a “shift in thinking, out of necessity,” says Carpenter.
Conservation is a strong driver for reuse, he believes. “Usually, reuse is an opportunity to save drinking water due to a scarcity issue; you conserve water for potable use,” he says. It’s a simple idea with complex approaches and a wide range of applications.
With suitably designed infrastructure, conservation efforts can include stormwater harvesting and internal recycling. Carpenter references a Calgary study for a new growth area. Although residents in the “prairie desert” depend on river water, Canadian city planners were determined to keep diversion from the river at 2003–05 levels, which would require 45% water use efficiency. Methods that helped them achieve their targeted numbers included containing stormwater, installing green roofs, and designing lawns that allow stormwater to soak in.
Several methods require a dual system, which necessitates new infrastructure. Aging infrastructure must be repaired anyway, Hill points out, so why not replace it with a dual-distribution system?
It’s time for the public to get re-energized in infrastructure, Carpenter maintains. That includes landfills, highways . . . and water.
“We must make infrastructure choices and change our use behavior,” he says. “We have to match supply to use.”
But Carpenter proposes an optional solution to the dual-distribution system.
“There used to be a separate purple pipe system [for recycled water]. Those pipes are made of PVC—an oil-based product. A separate system involves economic, environmental, and social aspects; it monetizes elements of reuse.”
Increasingly, he says, utilities consider separate systems as a way to deploy supply, which cause disruption of the environment and commerce.
“Why not put [recycled water] in the aquifer?” ponders Carpenter. “Wastewater is a more reliable source than river water, even in a drought.”
Acknowledging what he calls the “yuck factor,” Carpenter says using recycled wastewater is no different from breathing the same air molecules others have exhaled or using a fork in a restaurant that was previously used by other diners.
“We all live downstream from something; the pristine spring doesn’t exist anymore,” he says.
But the technology to treat water to whatever level is required to keep people safe does exist, and several communities have embraced it. Carpenter mentions a full potable reuse project in Big Springs, TX, that conveys wastewater to a water treatment plant where effluent is treated to drinking water standards.
JoJo Wouldn’t Leave His Home in Tucson Now
One community incorporating recycled wastewater in their program is the desert city of Tucson, AZ. As explained by John Kmiec, environmental and regulatory compliance supervisor for Tucson Water, the region’s water table was going down, due to agriculture and urban growth.
Tucson features one of the region’s largest groundwater utilities, drawing its available water from two aquifer basins because no surface water to pull from is available. In an area that sees only 10 inches of rain annually, concern about pumping groundwater led to the realization that a removable water supply was needed. The Central Arizona Project of 1968 diverted water from the Colorado River to the state, but it didn’t resolve the problem entirely.
“It doesn’t matter how much it rains in Tucson now,” says Kmiec. “It matters how much it snows in Colorado.”
In 1984, a reclaimed water program was launched. Raw wastewater was delivered to the Pima County treatment plant, then returned to Tucson Water for tertiary treatment—polishing, as Kmiec describes it—in one of two ways: pressure filtration or soil aquifer treatment.
The purpose of the reclamation system was to get users off the potable groundwater supply, Kmiec explains. Currently, Tucson Water diverts 16,000 acre-feet of water to 1,000 customers—primarily golf courses, parks and schools, although 700 single-family residences also use the system.
“We learned that traditional turf areas like parks and golf courses give the biggest bang for the buck,” he says.
Economic factors in neighborhoods already conserving make the addition of a dual system for reclaimed water impractical.
“People don’t want to tear up the streets for a second pipe and pay protection for backflow, especially in neighborhoods where the HOA has banned grass, so there’s no need to irrigate,” says Kmiec.
By diversifying their portfolio with guidance from Carollo Engineers, Tucson Water assures its customers of a reliable source of water.
“Recharge from the Colorado River is climate-dependent,” he explains. “Recharge from reuse is climate-independent.”
Managing Through Measurement
Tuscon’s solution is a system more cities will have to consider, Carpenter believes, in part due to the disparity between older and newer cities.
“Older cities have water rights,” he elaborates. “First in time, first in right. Many have a surplus of water; they have a robust water profile. But newer areas have one-tenth the resources, so they must be innovative.” He says newer settlements are quicker to employ reuse, but it “takes a long time to change older cities.”
Change starts with information, which is why Global Water has launched a pioneering effort to put hourly data into the hands of customers. Information is the first step.
“To get customers to focus on usage, they need better visibility to data and price signals,” explains Hill.
|Photo: GE POWER AND WATER
Water treatment for reuse involves a multi-step process.
|Photo: GE POWER AND WATER
By injecting “visibility into consumption” through automatic meter infrastructure that takes hourly readings, customers can receive usage data in real time, he says. “It’s like a smart grid for water. It’s a great tool for the customer and the utility.”
To prove its point, Global Water came to Phoenix, one of the largest per-capita users of water (200 gallons per person per day) where there is a shortage of water.
“The Global story is that we took chances,” says Hill. “This is not a small pilot—it’s on scale. We have 16 aggregated utilities. It can be done; it’s not complicated. It just takes a little cash, but there are a growing number of investors.
“It’s a 15% increase in capital investment for a 40% reduction in usage,” he estimates. “It’s not an austerity move. It’s more expensive by definition, but it’s sustainable.”
Global Water serves 17,000 customers in the Phoenix area: common grounds, golf courses and green spaces are all fed by recycled water. In addition to owning utilities, Global provides a platform to help other utilities manage processes such as meter reading, customer service, and billing.
“Interactivity is the critical next step,” indicates Hill. “People respond to benchmarks. We’re conditioned to have push messages. Everyone thinks they’re trying but the data is eye-opening.”
In 2004, Global opened eyes in Maricopa (population 40,000). After reducing water consumption by 40% without sacrificing amenities, “we achieved another 10 to 15% extra with Fathom,” says Hill.
Location, Location, Location
Sometimes where water is recycled can be as important as recycling it. In areas where water is scarce—like southern California and the desert Southwest—it’s expensive to pump water from the Colorado River; no more can be taken out of the delta, and permitting for desalination is costly.
“Reuse is locally controllable and available,” says Carpenter. “It makes more sense than importing water.”
Hill suggests changing wastewater plants to water reclamation facilities. “A water factory is sexy—you can put it downtown. It’s better than deeper wells and longer pipes.”
He believes satellite facilities and decentralized systems are the wave of the future.
“Reclamation plants don’t need to be near a discharge point because they deliver through pipes,” adds Hill. “Pumping to a treatment plant is 20 to 40% of a budget. This is smaller and less expensive, and with electronic controls, it can be operated remotely, so there’s less staff to pay as well as less energy required.”
There is a desire to be environmentally responsible and economically viable, but, according to Derek Gnauck, CEO of WJP Solutions, the two key market drivers are either a shortage of clean water in a particular location, and/or the need to clean up wastewater in order to dispose of it in an environmentally acceptable manner.
“Both are driving demand in remote or regional locations ahead of the inner city building market,” he says.
While most of WJP’s recent contracts involve mining, oil, and gas production facilities or prisons that are built in areas with insufficient or non-existent infrastructure to cope with increased demand for clean water and disposal of waste water, Gnauck says they’re also starting to see need by regional water authorities for upgrading existing municipal water treatment plants in order to produce higher quality treated effluent to facilitate easier disposal to the environment or potential use for irrigation.
Membrane bioreactor technology is becoming more widely accepted as a practicable method of treating wastewater in a decentralized plant. It’s also becoming the most economical solution in many cases, Gnauck adds. WJP Solutions uses the most up-to-date MBR technology developed in conjunction with Siemens/Memcor in their treatment process, as well as the full range of pre- and post-MBR treatment processes, including coarse and fine pre-screening, ultraviolet, chlorine, chemical dosing, water balance adjustments, and odor control. This is all controlled by state-of-the-art PLC/SCADA systems to provide real-time monitoring and feedback.
Despite a higher initial capital outlay, advantages include smaller, compact plants, very high-quality treated water, automated operation, and the ability to remotely monitor and control plants. Gnauck points out that the level of acceptance of decentralized plants is still low, perhaps because they are not as simple to maintain as competing technologies and they consume a considerable amount of power. In addition, each plant has to pass a significant testing and validation process before being licensed to supply treated water, adding to the cost.
“Taking into account capital expense, power use, chemical costs, and on-going maintenance costs, a plant needs to achieve a certain process capacity before it begins to show any sort of financial return,” says Gnauck.
One of WJP’s clients spent several months negotiating with the relevant authorities before getting approval for a water reclamation plant. The Curlewis Golf Club is a private golf course situated on the Bellarine Peninsula in Victoria.
“Like most of the state, the area had suffered many years of drought, which had resulted in the government imposing strict restrictions on the use of town water for households and industry,” explains Gnauck. “As a result, the golf course could no longer be watered using town water. The greens and fairways quickly deteriorated, and the club’s membership began to reduce.”
The club hired consultants to consider methods of overcoming the problem. When they realized the club had a large municipal sewer rising main approximated 20 meters from its boundary, they recommended extracting the sewer from the municipal main to treat water onsite and use the treated water for irrigating the golf course.
Implementation involved engineering, design, and construction of a standalone decentralized wastewater treatment plant, including integration with the authority assets and supply mechanism for the treated water. In addition to the sewer extraction pipework, the plant consists of a 75,000-liter in-ground concrete balance tank, pre-screening, precast concrete biological process tanks and Siemens membrane, fully automated PLC/SCADA system, a steel shed to house equipment and controls, and fencing and landscaping. Plant capacity is 250,000 liters per day, but it can be detuned in winter to approximately one-third of that capacity.
The water is specified as Class “B”, which is suitable for controlled irrigation. “Use is purely for irrigation,” reiterates Gnauck.
Although “there is no traditional measure of ROI on this plant,” he says the club expects to benefit from increased membership due to lush fairways and greens. In addition, because the plant produces treated water high in nutrients, the club will see substantial savings in fertilizer costs each year. Offsetting the initial expense, financial assistance from the Victorian State Government was obtained, as well as a financial contribution from Barwon Water, the authority responsible for the rising main.
Service With a Smile
While maintenance personnel at the Curlewis Golf Club in Australia handle the day-to-day management of their water treatment system, not every client is equipped—or wants—to.
“Most cities pay for garbage collection,” says Louis LeBrun, vice president of marketing for APT Water in Pleasant Hill, CA. “There’s no reason water treatment shouldn’t be a service, too.”
Water that would have gone to a central wastewater treatment plant is treated at small-scale decentralized location to offset demand.
“It’s the same process,” explains Andrew Simon, sales and marketing analyst, “for lower cost and less infrastructure.” Centralized reuse operations at large treatment plants typically means expensive pipe installation and higher energy costs.
There are multiple steps prior to APT’s biological process, which provides disinfection and removes persistent organics, using oxidation technology. Rather than create another waste stream, LeBrun says APT eliminates most compounds by destroying them. The goal is complete destruction of these compounds and other minerals that could cause problems, including biologically toxic or non-degradable materials such as pesticides, petroleum constituents, and volatile organic compounds. The advanced oxidation process leaves no harmful by-products or process residuals. Water is refreshed for irrigation, toilets and even potable use.
APT’s process is the only ozone-based treatment accepted under the Title 22 standard, Simon adds. It qualifies for unrestricted water reuse by the California Board of Health. It’s designed to provide a level of treatment that meets or exceeds drinking quality; no other treatment process is needed.
“Discharge limits are more stringent on wastewater than drinking water,” states LeBrun. “Treating it to an extra level doesn’t cost a lot more; the incremental cost is lower than having to replenish water. Reuse makes economic sense, is sustainable, and is our future.”
|Photo: THE LIVING MACHINE
The low-energy Living Machine
Anaheim, CA, city leaders recognize that. They incorporated APT’s HiPOx pre-engineered and fully-automated water treatment system to remove the last level of compounds from 107,000 gallons wastewater per day, which is used to make ice for the Anaheim Ducks hockey rink.
“It was part of the waste treatment stream,” says LeBrun. “Now, the community benefits from it.”
The biggest ozone-based AOP project in the US is APT’s flagship—a 30 million-gallons-per-day Aquifer Storage Recover Project for the City of Wichita, KS. It involves seasonal operation of a water treatment plant to treat storm water from the Little Arkansas River. Clean water is injected into the Equus Beds Aquifer for recharge and to be used for the drinking water supply.
Due to its location in the heart of Kansas farmland, the water contained levels of atrazine, an herbicide that passes through typical treatment processes. Testing in 2009 indicated that the process met the established water quality goals for atrazine reduction and achieved all Primary Drinking Water Standards required by the Kansas Department of Health and Environment.
Currently, it processes 30 million gallons per day, but LeBrun indicates that capacity could be increased without the need to add another plant.
“The benefit of our technology is it’s scalable,” he says. “We can add capacity and quality or modify the process for higher levels at a later date.”
Decentralized treatment plants are an economically practical option.
“Cities could do big infrastructure projects, but money is difficult to come by,” postulates LeBrun. “The cost of infrastructure is not going down. The service model is a better fix. The return on investment is 12 to 18 months, depending on the level of treatment and size.”
Once cities embark on reuse, they find more uses than expected, Simon says, making the investment even more favorable.
Due to rising costs and decreasing availability of water, LeBrun believes the future is “regionally driven”.
“The driving principle is water reuse,” he says, “but it’s not just a technology-driven business any more. The service model provides convenience beyond the hardware.”
Perhaps the most aesthetically pleasing technology is the Living Machine system. The low-energy, totally green ecological wastewater treatment and reuse technology for black and grey water mimics a tidal wetland, accelerating its plant and microbial activity with advanced environmental engineering.
“It’s a turbocharged wetlands,” explains Will Kirksey, P.E., global development officer at Living Machine Systems. “There are no chemicals in the process.”
The patented tidal flow wetland process fills and drains cells like a tide, but at an accelerated rate, with 12–16 tides per day. When the cells drain, oxygen comes in by gravity. More surface area allows diversity of organisms.
The Living Machine requires less energy than any other water reuse technology, yet meets the highest quality standards, including California Title 22 reuse standards. Capable of being scaled to almost any level, from several thousand gallons to a million gallons per day, it can be a standalone unit or operate as part of a larger water treatment network. Because it has a smaller footprint and shorter treatment time than other wetland treatment systems, it’s versatile, and because it is aesthetically pleasing, it can be located in building lobbies, housing developments, or the countryside.
The Port of Portland features a Living Machine in its 205,000-square-foot headquarters to treat 100% of the building’s wastewater for reuse in the toilets and cooling tower. The system, which looks like a lush tropical planter in the lobby, was credited with contributing to the Port’s Leadership in Energy and Environmental Design (LEED) Platinum certification, the highest LEED rating.
Bamboo, switch grass, and flowers can be grown in the wetland. The treated water can be used on food crops. Kirksey mentions one used in an agricultural field in Hawaii.
“The treated wastewater is used to grow Bird of Paradise flowers, and the treated water is used to water sugar cane,” he says.
Another project will treat sewer water to irrigate the landscaping at the Marine Corps Recruit Depot (MCRD) in San Diego. “Sewer mining,” extracting wastewater from an existing sewer line, and recycling the black water for sub-surface irrigation and equipment washing, will minimize water usage on the base in drought-prone San Diego. The onsite system will recycle 10,000 gallons of sewer-mined wastewater per day, treating it to water reuse standards in California.
Similarly, a showcase project is under construction at the San Francisco Public Utilities Commission. The regulatory body incorporated a Living Machine to demonstrate its viability in the hopes of encouraging others to decentralize.
“They wanted to be cutting-edge with technology that has the potential for immediate penetration,” explains Kirksey. “This is an opportunity to showcase innovation in water and energy technology.”
The system is in Commission headquarters and on the sidewalk in front of its downtown office. Complete in January, it will be used for the workers in the building until June, treating 5,000 gallons per day—enough for 500 people.
“It makes economic sense to recycle nutrients close to where they’re generated,” believes Kirksey. “Unless you have a point source, you must spend money to bring the water—often pumping on ground that isn’t flat.”
With no underground piping, the Living Machine is more economical than traditional systems because there’s no need to rebuild deteriorating infrastructure. Kirksey points out that Sacramento recently spent $2.5 billion to rebuild its aging underground piping. In regions that are susceptible to earthquakes or in drought-prone areas where water use is restricted, this system can save money and provide a reliable source of water.
“The ROI varies, depending on the site,” he explains, “but the Guildford School saved $4 million over sewer. It’s cost-competitive with other decentralized systems.”
Still, one of the challenges is to make people comfortable with the idea. To help open up the market, San Francisco is offering incentives for wastewater treatment.
“Many California building codes require dual plumbing for new construction and rebuilds,” he says. “It’s advanced technology, but it’s an old idea. We’re using the best 21st Century technology and science to enhance nature.”
Water in the Forecast
The intention of reuse is to ensure water is treated to a quality appropriate to use, Hill summarizes. Two federal acts are in place to regulate that: the Clean Water Act of 1972 ensures that water is discharged safely back into the environment and the Safe Drinking Water Act of 1974 sets standards for drinking water quality to protect public health.
However, adds Hill, “There’s no law governing reuse. Every state comes up with their own way to deal with it.”
Since 1981, Title 22 in California has set the benchmark for water reuse, but recycled water continues to face many challenges. It’s taken for granted because of its reliability.
“How many services are available 24/7?” asks Carpenter. “Water is a public thing. We can regulate it to a certain extent—until it infringes on rights. Until there’s a crisis, the politicians are unwilling to go farther.” If there’s a crisis, water might be more valued.
It starts with value, Hill agrees. “People undervalue water. It’s considered a right,” he adds.
People are willing to pay for cable, cell phones, and other luxuries, but balk at increases in water rates.
“First, we need to heighten awareness of its scarceness and tie it to a value proposition,” says Hill. “We have to move toward reduction [of use] through pricing. Then education begins: how to lower our bills through conservation.”
The problem, as Carpenter sees it, is that water is a confounding, spiritual issue.
“It’s visceral,” he says. “It’s a strange paradox that requires an evolution of thought. The first step is to decide how to use treated water. I hope we pay attention and learn. We don’t want to be like pond algae, which sucks up nutrients until it dies off. Are we not smarter than that?”
Writer Lori Lovely focuses on topics related to transportation and technology.