Stephanie K.L. Ishii

Behavior of reoccurring PARAFAC components in fluorescent dissolved organic matter in natural and engineered systems: a critical review.

Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) has been widely used to characterize dissolved organic matter (DOM). Characterization is based on the intensity and location of independent fluorescent components identified in models constructed from excitation-emission matrices (EEMs). Similar fluorescent components have been identified in PARAFAC studies across a wide range of systems; however, there is a lack of discussion regarding the consistency with which these similar components behave. The overall goal of this critical review is to compare results for PARAFAC studies published since the year 2000 which include one or more of three reoccurring humic-like components. Components are compared and characterized based on EEM location, characteristic ecosystems, and behavior in natural and engineered systems. This synthesis allows PARAFAC users to more confidently infer DOM characteristics based on identified components. Additionally, behavioral inconsistencies between similar components help elucidate DOM properties for which fluorescence spectroscopy with PARAFAC may be a weak predictive tool.

Life cycle comparison of centralized wastewater treatment and urine source separation with struvite precipitation: Focus on urine nutrient management.

Alternative approaches to wastewater management including urine source separation have the potential to simultaneously improve multiple aspects of wastewater treatment, including reduced use of potable water for waste conveyance and improved contaminant removal, especially nutrients. In order to pursue such radical changes, system-level evaluations of urine source separation in community contexts are required. The focus of this life cycle assessment (LCA) is managing nutrients from urine produced in a residential setting with urine source separation and struvite precipitation, as compared with a centralized wastewater treatment approach. The life cycle impacts evaluated in this study pertain to construction of the urine source separation system and operation of drinking water treatment, decentralized urine treatment, and centralized wastewater treatment. System boundaries include fertilizer offsets resulting from the production of urine based struvite fertilizer. As calculated by the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI), urine source separation with MgO addition for subsequent struvite precipitation with high P recovery (Scenario B) has the smallest environmental cost relative to existing centralized wastewater treatment (Scenario A) and urine source separation with MgO and Na3PO4 addition for subsequent struvite precipitation with concurrent high P and N recovery (Scenario C). Preliminary economic evaluations show that the three urine management scenarios are relatively equal on a monetary basis (<13% difference). The impacts of each urine management scenario are most sensitive to the assumed urine composition, the selected urine storage time, and the assumed electricity required to treat influent urine and toilet water used to convey urine at the centralized wastewater treatment plant. The importance of full nutrient recovery from urine in combination with the substantial chemical inputs required for N recovery via struvite precipitation indicate the need for alternative methods of N recovery.

Student support and perceptions of urine source separation in a university community

Urine source separation, i.e., the collection and treatment of human urine as a separate waste stream, has the potential to improve many aspects of water resource management and wastewater treatment. However, social considerations must be taken into consideration for successful implementation of this alternative wastewater system. This work evaluated the perceptions of urine source separation held by students living on-campus at a major university in the Southeastern region of the United States. Perceptions were evaluated in the context of the Theory of Planned Behavior. The survey population represents one group within a community type (universities) that is expected to be an excellent testbed for urine source separation. Overall, respondents reported high levels of support for urine source separation after watching a video on expected benefits and risks, e.g., 84% indicated that they would vote in favor of urine source separation in residence halls. Support was less apparent when measured by willingness to pay, as 33% of respondents were unwilling to pay for the implementation of urine source separation and 40% were only willing to pay

Expert stakeholder attitudes and support for alternative water sources in a groundwater depleted region

1 to

Evaluating the secondary effects of magnetic ion exchange: Focus on corrosion potential in the distribution system

10 per semester. Water conservation was largely identified as the most important benefit of urine source separation and there was little concern reported about the use of urine-based fertilizers. Statistical analyses showed that ones environmental attitude, environmental behavior, perceptions of support within the university community, and belief that student opinions have an impact on university decision makers were significantly correlated with ones support for urine source separation. This work helps identify community characteristics that lend themselves to acceptance of urine source separation, such as those related to environmental attitudes/behaviors and perceptions of behavioral control and subjective norm. Critical aspects of these alternative wastewater systems that require attention in order to foster public acceptance after implementation are also highlighted, such as convenient and aesthetically pleasing methods for waterless toilet paper disposal.

Case Study and Life Cycle Assessment of a Coastal Utility Facing Saltwater Intrusion (PDF)

The main objectives of this research were to quantify the risks/benefits and impacts of alternative water sources (AWSs) as perceived by expert stakeholders and to evaluate the overall support for multiple AWSs by expert stakeholders. The St. Johns River (SJR) basin, FL, USA was chosen as a case study for AWSs because it is a fresh groundwater depleted region and there are ongoing activities related to water supply planning. Expert stakeholders included federal, state, and local governments, public utilities, consulting engineering and industry, and environmental and social non-governmental organizations. AWSs under consideration in the SJR basin include surface water, desalination, water reclamation, and water conservation. A two-phase research approach was followed that focused on expert stakeholders. First, an elicitation study was used to identify salient beliefs about AWSs. Open-ended questions were asked about the risks/benefits of AWSs in terms of the three pillars of sustainability: ecological, economic, and human health impacts. Second, an online survey was constructed using beliefs identified during the elicitation study. The online survey was used to quantify attitudes toward and overall support for AWSs. The salient beliefs of expert stakeholders were dominated by the ecological pillar of sustainability. The support of expert stakeholders for AWSs, from least favorable to most favorable, was surface water withdrawals<desalination<water reclamation<water conservation, and was shaped by attitudes. The results of this research provide an improved understanding of the beliefs and attitudes that influence decision-makers involved in water supply planning.