Our wastewater infrastructure is largely invisible and little understood. Most of us never question the wisdom of polluting pristine drinking water, losing valuable nitrogen and irreplaceable phosphorus in the process, just so we can make our poop disappear. Our own waste is a classic SEP—Somebody Else’s Problem.
The result? “Aging pipes and inadequate capacity lead .... to the discharge of an estimated 900 billion gallons of untreated sewage each year,” warns the American Society of Civil Engineers in its report Failure to Act. “Water infrastructure in the United States is clearly aging, and investment is not able to keep up with the need.” (For more, see “Failing Water Infrastructure Drains Economy, Report Warns,” EBN Feb. 2012.) Though most rest areas still use one-way water cycling (onsite septic fields or long-distance connections with centralized systems), a few throughout the U.S. are incorporating constructed wetlands and other natural filtration systems that close the loop, permitting safe and sustainable wastewater treatment and reuse right on the site.
We’re seeing more wastewater reclamation in building types that aren’t devoted primarily to human waste disposal too, even in cities: commercial offices, multifamily buildings, and even hospitals have been experimenting with these systems for more than a decade, producing not only clean water but also important lessons that can be applied in the buildings we’re designing today.
Whether onsite wastewater treatment is a good choice for your next project will depend on a lot of different factors, from local codes to annual rainfall to the age of municipal infrastructure. If your project team does choose to treat and reuse wastewater on the site, different types of systems can have broad implications for energy consumption and other aspects of the project—but decentralized treatment and reuse can also contribute to improvements in centralized infrastructure, sometimes in more ways than one.