Water Efficiency May 2012 : Page 35
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 engi-neers 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, limit-ing 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 pric-ing—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 seri-ous 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 diminish-ing, 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. “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 re-cycling. 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 ef-forts can include stormwater harvesting and internal recy-cling. 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 effi ciency. Methods that helped them achieve their targeted numbers included containing storm-water, installing green roofs, and designing lawns that allow stormwater to soak in. Several methods require a dual system, which neces-sitates 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 infrastruc-ture, Carpenter maintains. Th at includes landfi lls, highways . . . and water. Arsenic Removal for Small Water Systems Isolux Technologies provides systems for removal of arsenic, boron, chromium, lead, and other contaminants from drinking water and wastewater s Packaged systems for all sizes from Point-Of-Use to 450 gpm s Unique cartridge design eliminates bulk media handling s No backwash required s NSF Std. 61 certified s Cartridge return program available 75-gpm Module Shown Isolux Technologies Division of MEL Chemicals, Inc. Phone: (800) 366-4850 E�d;MAILa;ISOLUX MEICHEM�e;COMsWWW�e;ZRPURE�e;COM MAY 2012 WATER EFFICIENCY 35