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Opportunity at U.S. Environmental Protection Agency (EPA)

Emergy Accounting System Modeling of Urban Water Systems


National Risk Management Research Laboratory, Sustainable Technology Div

RO# Location
22.03.02.B8340 Cincinnati, OH 45268


Name E-mail Phone
Ma, Cissy 513.569.7828


Finite water resources facing many communities, generally increasing demands and aging water infrastructure are some of the greatest challenges for our Nation and many other global regions. The Safe and Sustainable Water Resources (SSWR) research program in EPA is conducting research and analyses that strive for solutions to ensure future generations will have adequate water of sufficient quality. The research program will develop sustainable solutions by integrated transdisciplinary research addressing social, environmental, and economic outcomes. The complex water issues cannot be sustainably solved by the traditional “siloed" water management approach. In a water-connected world, sustainable solutions have to require a system-based approach, in which water services (traditionally within wastewater, stormwater, and drinking water) are integrated with the efforts of maximizing the recovery of resources (energy, nutrients, materials, and water). The SSWR research team intends to use holistic analyses of water resource and water infrastructure that provides the full life-time, water system assessments at the same time to avoid transferring issues from one problem area to another. Next-generation sustainable water systems should employ effective water management practices, which provide safe and sustainable water from source to drinking water tap to receiving water. Further, these water systems need to be adaptive so as to address changing societal aspirations, demographics, and climate.

One of the system-based methods is emergy synthesis. Emergy synthesis method has been used for various systems at multiple scales to incorporate environmental, social, and economic aspects into a common unit of nonmonetary measure (solar energy equivalents) and objectively assess the sustainability of the systems. It not only quantitatively assesses the direct and indirect energy required to produce goods and services but also provides managers a decision criterion to evaluate the efficacy of alternatives. For example, at the drinking water supply and distribution level, emergy will provide a unique holistic aspect of the system that capture the natural capitals in the background supporting any economic system, such as the “free” contribution of rain to the economy. Emergy can be used to evaluate the impacts of the following in terms of overall system efficiency: dual water quality, nutrient and energy recovery, natural green infrastructure, aquifer storage recovery, and regional water allocation. This method has the potential to integrate sustainability principles to water system management at different scales and levels. Another issue needed to be explored further is to build a bridge between emergy measure and economic terms. This effort intends to identify possible policy steps to facilitate the evolution from existing water management schemes to future alternatives. This method is often compliment to and integrated with other system metrics such as life cycle assessment (LCA).

The products of this research will include the development of decision support aids that will guide decision-makers towards sustainable water system management. The Associate will interact with other team members with a range of skills advancing other sustainability metrics and indicators of water systems. The participant will have latitude in exercising independent initiative, creativity, and judgment in the research commensurate with the level of training. EPA will review completed papers for adherence to EPA principles and policies, quality, and soundness of scientific conclusions.

Applicants must have received a Doctoral Degree in system ecology, ecological engineering, environmental engineering, environmental science, natural resources economics or a related discipline within five years of the desired starting date or completion of all requirements for the Degree should be expected, prior to the starting date. The successful candidate must have extensive research experience on emergy theory and emergy synthesis in different systems and strong knowledge about different components and unit processes in a complex integrated urban water system. Demonstration of research scholarship and productivity, as well as good scientific writing and writing for the general public are a must. Preferred knowledge of life cycle assessment and characterization methods of life cycle impact categories and the ability to relate these to water systems is also important. The successful candidate is expected to be a highly motivated individual with critical thinking skills, independence, and creativity.



Ma X; et al: Sustainable Water Systems for the City of Tomorrow—A Conceptual Framework. Sustainability 7(9): 12071, 2015

Xue X; et al: Critical insights for a sustainability framework to address integrated community water services: Technical metrics and approaches. Water Research 77(0): 155-169, 2015


Emergy; LCA; System analysis; Sustainability metrics; Water reuse; Green infrastructure; Energy recovery; Nutrient recovery; Urban water;


Citizenship:  Open to U.S. citizens, permanent residents and non-U.S. citizens
Level:  Open to Postdoctoral and Senior applicants
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