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Design Options for a More Sustainable Urban Water Environment
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long-term capital planning, and must prioritize protecting public health and the environment. Halaburka et al. (DOI: 10.1021/es305011z) use a case study in a water-scarce region to show the benefits of streamflow augmentation using recycled water. Surprisingly no studies have addressed the merits of direct and intentional use of recycled water to benefit ecosystems, such as the creation or augmentation of wetlands and streams. This study explores the difficulty of decision making based on strict cost comparisons of the status quo versus less tangible long-term benefits associated with urban aesthetics, recreational improvements and habitat restoration. Better infrastructure can be incentivized by impact fees and property taxes as shown by Lu et al. (DOI: 10.1021/ es304924w, leading to more compact development and green space, which over time generates more tax revenue. The paper by Zhou et al. (DOI: 10.1021/es304816h) explores the water−energy nexus and the cobenefits of municipal water conservation and green house gas emissions. Decisions about centralized versus decentralized wastewater treatment and future resource recovery are the subject of a paper by Lee et al. (DOI: 10.1021/es401011k) The geographic scale of resource recovery requires consideration of many criteria and situational realities, such as for communities close to a centralized facility versus communities far away that may use a satellite resource recovery. The configuration of such hybrid systems needs accurate cost and design analysis for components of satellite systems. Stokes et al. (10.1021/es4006256) assess water loss savings and green house gas reduction by better pressure management in water distribution systems. Life cycle analysis shows that better pressure management is comparable to the water and energy savings of installing low-flow toilets. Papers by Jasper and Sedlak (DOI: 10.1021/es304334w), and Mohanty et al. (DOI: 10.1021/es305136b) explore how natural systems may be incorporated as part of our urban water infrastructure. Jasper and Sedlak investigate shallow, open-water cells in unit process wetlands that exploit sunlight photolysis to remove trace organic contaminants. Mohanty et al. describe geomedia-enhanced bioinfitration systems to remove fecal indicator bacteria. Their work shows the importance of fundamental studies to assess stormwater treatment for reuse. In total, the papers in this special issue illustrate that engineers will have to embrace unfamiliar systems that are not designed to be fully controlled, like decentralized systems and managed natural systems. For managers and politicians, the planning process will have to encompass measures of performance beyond initial costs and the finances of a single entity. For researchers, we see the importance of teaming to assess the impacts of new technologies on overall system
ater systems and technologies in industrialized nations evolved when energy and water resources were abundant, populations were smaller, and ecological impacts were of less concern. Nowadays, society is increasingly aware of the fragility of its urban water supply systems and the challenges associated with climate variability, increasing populations, and the need to protect ecosystems impacted by water infrastructure development. These issues are felt more acutely in regions experiencing chronic water shortages and vulnerabilities to cycles of very low precipitation like Australia and the American west and southeast. More broadly, urban water challenges in the developed world come at a time when the existing infrastructure systems are approaching the end of their design lifetimes, requiring massive investments for replacements and upgrades. These stresses call for a substantial change in urban water management by addressing both fundamental and systemslevel barriers to make sound decisions about future investments, overcoming barriers to adoption of existing but underutilized technologies, and developing technologies for managing natural systems to treat and store water while simultaneously improving habitats and urban aesthetics. This special issue of Environmental Science & Technology addresses the theme of designing urban water infrastructure in ways that save energy, money, and resources while meeting the needs of urban users and aquatic ecosystems. With representation from Europe, America, Asia, and Australia, the special issue speaks to policy, management, and technological approaches to secure a more sustainable urban water environment. The cover feature article by Hering et al. (DOI: 10.1021/ es4007096)on a new framework for urban water systems calls attention to sweeping changes needed in the way that engineers and managers of urban water systems approach planning, design, and operation. Only in this way can industrialized countries achieve greater efficiency and resiliency while serving as models for future water management in developing countries. A new framework for urban systems comprises four overarching themes: increasing water availability (e.g., reuse, stormwater harvesting, and improved system efficiency), broadening treatment options (e.g., incorporate managed natural systems into urban water infrastructure), considering wastewater as a resource (e.g., energy and nutrient recovery), and establishing an enabling environment (e.g., institutional change to account for nonmonetary benefits and managing trade-offs among alternatives). The article by Grant et al. (DOI: 10.1021/es400618z) focuses on the Australian decade-long Millennium Drought and Melbourne’s response through water supply augmentation schemes including interbasin transfer and building the largest desalination plant in the Southern Hemisphere. The Melbourne experience is a graphic illustration of the complexities and change in public concern that arise when the urgency to augment water supply holds sway during severe drought versus financial, equity, and environmental concerns that dominate during periods of water abundance. Several papers in this issue deal with policy and decision making in the water sector. This tends to be conservative, entail © 2013 American Chemical Society
Special Issue: Design Options for More Sustainable Urban Water Environment Published: October 1, 2013 10719
dx.doi.org/10.1021/es403728p | Environ. Sci. Technol. 2013, 47, 10719−10720
Environmental Science & Technology
Comment
performance and urban design, and the need for pilot- and full-scale trials to assess reliability and gain public trust for innovation in urban water systems.
Richard G. Luthy
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Engineering Research Center for Re-Inventing the Nation’s Urban Water Infrastructure (ReNUWIt), Stanford University, Stanford, California 94305, United States
AUTHOR INFORMATION
Corresponding Author
[email protected]. Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS. The authors declare no competing financial interest.
BIOGRAPHY Dick Luthy is the Silas H. Palmer Professor in the Department of Civil and Environmental Engineering at Stanford University. His area of
teaching and research is environmental engineering and water quality. He is the Director of the NSF Engineering Research Center for reinventing the nation’s urban water infrastructure, a collaboration among four universities that promotes new strategies for urban water systems to achieve more sustainable solutions to urban water challenges. He is a Water Environment Federation Fellow and a member of the National Academy of Engineering. (http://www.stanford.edu/group/luthygroup/ news_new.htm)
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ACKNOWLEDGMENTS I thank my coeditors for their valuable assistance: Yujie Feng, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, China; and Gatze Lettinga, Wageningen University and Lettinga Associates Foundation, The Netherlands.
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dx.doi.org/10.1021/es403728p | Environ. Sci. Technol. 2013, 47, 10719−10720
