Before “green” became cool, “sustainable” was the guiding phrase for shaping environmental solutions with economic prosperity. Like most trends, the focus on sustainability brought valuable changes and discussions, but at some point the term became overused and lost its meaning. Terminology aside, the concept remains very useful and important, as illustrated by Tracy Mehan’s recent testimony on “Sustainable Wastewater Management” before the U.S. House of Representative’s Transportation and Infrastructure Committee, Subcommittee on Water Resources and Environment.
Tracy was formerly Assistant Administrator for Water at the US EPA and Director of the Michigan Office of the Great Lakes. I usually find his insights and opinions to be right on, in part because he focuses on practical problems and solutions over scare tactics and ideology. His testimony offers a nice framework for “Sustainable Wastewater Management” as addressing, “in a comprehensive way, point and nonpoint source pollution; surface and groundwater protection; the nexus between water, energy and Greenhouse Gas (GHG) emissions; and cost-effectively restor[ing] the chemical, physical and biological integrity of the nation’s waters.”
A great example of this is the source water protection program under the Safe Drinking Water Act. Source water protection recognizes that preventing contamination of drinking water through watershed management can often be cheaper than treating drinking water at the plant. As Tracy notes in his testimony, a study of 27 water suppliers conducted by the Trust for Public Land and the American Water Works Association found that for every 10 percent increase in forest cover in the source area, treatment and chemical costs decreased approximately 20 percent. Thus, “the natural infrastructure … is a least-cost approach to protecting water quality which can generate multiple benefits such as habitat, carbon sequestration and aesthetics.”
These same concepts apply in urban settings, where impervious surfaces and the hardening of the landscape with roads, sidewalks, parking lots, roofs and tightly compacted building sites cause runoff pollution, elevated stream temperatures, and increased the velocity of stream flow. The resulting condition is sometimes called “urban stream syndrome.” There is no single silver bullet solution, but some cities have found success using “low-impact development” practices, which include green roofs, rain barrels, rain gardens, vegetated curb extensions, porous pavement, urban reforestation, and constructed or restored wetlands. The result of these practices is that rain water stays site, allowing for infiltration and evapotranspiration, reducing runoff and filtering unwanted pollutants.
Tracy recommended to the House subcommittee that State Clean Water Revolving Loan Funds be used for these practices and other new approaches that more comprehensively protect watersheds. He further recommended using new energy efficiency and methane capture technologies to improve the energy balance of wastewater treatment. He closed with this statement to the House Subcommittee:
This is not your parents’ water or wastewater sector! Green infrastructure now supplements gray infrastructure. The land and water interface requires that it be managed on a watershed scale. Finally, the nexus between energy, water and carbon necessitates new approaches which recognize the importance of this interrelationship.
