Sustainable By Design: Water: Put It Aside For A Non-Rainy Day
By Anne Vazquez, TFM Managing Editor
Published in the September 2007 issue of Today’s Facility Manager
Inits 2005 “Report Card For America’s Infrastructure,” the AmericanSociety of Civil Engineers (ASCE) gave an overall grade of “D” to thecondition of 14 categories, which included bridges, drinking water,rail, and wastewater. It stated that $1.6 trillion would be needed overa five year period to bring infrastructure in all of the categories upto good condition.
Two years later, the tenuous state ofpublic infrastructure in the United States was brought to the forefrontthis past summer when a steam pipe burst in New York City, disruptingmany surrounding businesses. Then, in August, the tragic collapse of abridge in Minneapolis resulted in the deaths of 13 people. As officialsat all levels address these issues in their respective locations,facility managers concerned with the safety and security of theirbuildings and grounds may want to look into ways to become moreself-sufficient.
Water is one area that should garner attention. The ASCE2005 Report Card gave both the drinking water and wastewater categoriesa “D-” for the condition of infrastructure systems throughout thecountry. One way facility managers may be able to reduce pressure onthis infrastructure is to install a rainwater harvesting system. Justas facilities professionals have the option of on-site energygeneration (e.g. solar power), collecting rainwater on its roof enablesa facility to provide itself with at least a portion of its watersupply.
When facility managers reduce the amount of water usedfrom municipal sources, they help to lessen the need for newinfrastructure. Additionally, they save money with decreased waterbills. Though water is relatively inexpensive in many areas, this maychange in the near future, due to infrastructure improvements and atightening supply. (A recent federal government survey showed at least36 states are anticipating local, regional, or statewide watershortages by 2013.)
Another benefit of rainwater harvesting isthe mitigation of stormwater runoff from the facility. Rain that wouldotherwise drain off roofs down to the ground is directed through theharvesting system to a storage tank. Heather Kinkade-Levario, Arizonadirector of planning for Denver, CO-based ARCADIS, points out in herrecently published book, Design For Water: “The aim of rainwaterharvesting is to concentrate runoff and collect it in a basin orcistern to be stored for future use.”
The complexity and costof a system generally depends on the intended use for the collectedwater. For instance, if a facility wants to harvest rainwater fordrinking water, relatively complex and expensive equipment will berequired.
However, there are simpler systems capable ofcleaning rainwater so it is suitable for landscape watering, toiletflushing, and laundry cleaning. Approximately 40% of water used incommercial and institutional buildings is used for those threepurposes, so even a simple system can ease the pressure on naturalresources and infrastructure.
Typical systems consist of fiveor six primary components (see illustration), depending on whether ornot potable water is a goal. These components are: catchment;conveyance; roof washer (filtration); storage; distribution; andpurification (for potable water). While there are multiple factors, theamount of water that can be collected depends heavily on the amount ofrainfall and area and type of roof surface.
New constructionprojects are usually viewed as the best candidates for rainwaterharvesting, since the system can be incorporated during the designstage. However, Kinkade-Levario, who has served as the 2005-2007president of the American Rainwater Catchment Systems Association,notes there is opportunity for those in existing facilities.
“Foran existing building, the biggest issue is to have somewhere to storethe water,” she explains. “With rooftop rainwater collection, it’srelatively easy to put several storage tanks next to the building anddirect it from the roof into the tanks. All drainpipes and downspoutsneed to be connected to transport the water to the tank. If thebuilding has internal drains, it will be more difficult, because wateris coming out at the base of the building.”
In terms ofmaintenance, most facilities teams are able to care for rainwaterharvesting systems without calling in a service provider. “The systemsare simple enough that in-house staff members can be trained tomaintain them,” says Kinkade-Levario. “But, they do need to maintainthem. This includes checking for clogs throughout the system andensuring the water is being treated properly for the intended purposes.”
Byusing water efficiently, facility managers can help to preserve watersupply, save money, and protect the environment. Harvesting the raincan be one part of the solution to this myriad of challenges.
Informationfor this article was based, in part, on information fromKinkade-Levario. For more information, visit the American RainwaterCatchment Systems Association at www.arcsa-usa.org.
Doyou have a rainwater harvesting system at your facility? If not, wouldyou consider installing one? Share your thoughts by sending an e-mailto [email protected].
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