Comparative Life Cycle Assessment of Direct and Indirect Solar Water Disinfection Processes in Developing Countries

In July 2010, the UN General Assembly recognized the universal human right to sufficient water for health and sanitation (UN…, 2010). The reliable disinfection of this water plays a critical role in public health (Carter and Miller, 2005), and this study investigates the use of four ultraviolet (UV) disinfection methods for use in international development and disaster relief. The study focuses on the life cycle impacts of four direct and indirect solar ultraviolet disinfection systems. Direct solar disinfection refers to exposure of water to solar radiation, while indirect solar disinfection collects solar energy and uses this to power a UV lamp disinfection reactor. These four systems were compared to chlorine disinfection and automobile distribution as baseline methods. Existing literature was used to define a life cycle functional unit for each system, which quantified the material use, infrastructure required, and life cycle of the components of each system. The impact of each system was then defined in the Life Cycle Analysis software SimaPro. Analyses compared the use of each technology at “community, school, small group, and family” scales. Due to the significant impact that end-of-use of a system can have on rural communities, an end-of-life analysis was conducted in addition to the quantitative life cycle analysis. Life cycle analysis shows that both direct and indirect UV disinfection methods vary dramatically over several categories of impact assessment. End of life analysis and this variation highlight the extremely complicated process of designing the appropriate disinfection system for use in developing countries

Water Supply in Developing Countries: Student Experiences in the Dominican Republic

In 2010, the United Nations established access to safe drinking water as a basic human right; however, many areas around the globe still lack access. The interdisciplinary service-learning course “Water Supply in Developing Countries” was established at Purdue in 2012 to address the complex issue of water insecurity around the world. Over the past five years, the course has produced teams involving students from nursing, engineering, agricultural economics, biology, and food science working together to develop sustainable, community-scale drinking water treatment systems. In partnership with Aqua Clara International, the student team in 2017 established a drinking water treatment system at the Ana Julia Diaz Luna primary school in the rural community of Las Cañas, Dominican Republic. In addition to the focus on a physical water system, they also collaborated with local educators to design a water, sanitation, and hygiene (WASH) education program. Students guided development of sustainable economic strategies to utilize the system for generation of revenue to reinvest in maintenance and improvements. The observations and lessons learned from the completed stages of this project have been applied to improve the effectiveness and efficiency of subsequent interventions

Zinc 1s valence-to-core X-ray emission spectroscopy of halozincate complexes

The Zn 1s valence-to-core (VtC) X-ray emission spectra of seven ionic liquids have been measured experimentally and simulated on the basis of time-dependent density-functional theory (TDDFT) calculations. Six of the ionic liquids were made by mixing [C8C1Im]X and Zn(II)X2 at three different ZnX2 mole fractions (0.33, 0.50, or 0.67) for X = Cl or Br, and a further ionic liquid was made by mixing [P6,6,6,14]Cl and a mole fraction of ZnCl2 of 0.33. Calculations were performed for the [ZnX4] 2−, [Zn2X6] 2−, and [Zn4X10] 2− ions to capture the expected metal complex speciation. The VtC emission spectra showed three bands arising from singleelectron processes that can be assigned to emission from ligand p-type orbitals, zinc d-orbitals, and ligand s-type orbitals. For all seven ionic liquids, the highest occupied molecular orbital arises from the ligand p orbitals, and the spectra for the different size metal complexes for the same X were found to be very similar, in terms of both relative peak intensities and peak energies. For both experiments and TDDFT calculations, there was an energy difference of 0.5 eV between the Cl-based and Br-based metal complexes for the ligand s and p orbitals, while the Zn 3d orbital energies were relatively unaffected by the identity of the ligand. The TDDFT calculations find that for the ions with symmetrically equivalent zinc atoms ([Zn2X6] 2− and [Zn4X10] 2−), the most appropriate core-ionized reference state has a core-hole that is localized on a single zinc atom. In this framework, the spectra for the larger ions can be viewed as a sum of spectra for the tetrahedral complex with a single zinc atom with small variations in the structure of the coordinating ligands. Because the spectra are relatively insensitive to small changes in the geometry of the ligands, this is consistent with the small variation in the spectra measured in the experiment

Applying the Food-Energy-Water Nexus approach to urban agriculture: from FEW to FEWP (Food-Energy-Water-People)

Many studies examine the correlation between the use of resources such as water, energy and land, and the production of food. These nexus studies focus predominantly on large scale systems, often considering the social dimensions only in terms of access to resources and participation in the decision-making process, rather than individual attitudes and behaviours with respect to resource use. Such a concept of the nexus is relevant to urban agriculture (UA), but it requires customisation to the particular characteristics of growing food in cities, which is practiced mainly at a small scale and produces not only food but also considerable social, economic, and environmental co-benefits. To this end, this paper proposes a new concept for a UA Nexus, together with a methodology for its assessment, that explicitly includes social dimensions in addition to food, energy and water. The paper develops a new conceptual basis, introducing People, together with Food, Energy and Water, as factors of the UA Nexus. A methodological approach for its assessment is presented, aimed at measuring not only resource efficiency and food production but also motivations and health benefits, as well as the ecological awareness of urban farmers. The methodology is based on a combination of methods such as diaries of everyday UA practices, a database of UA activities, life cycle assessment (LCA), and material flow analysis to connect investigations developed at a garden scale to the city scale

Differences in motivations and social impacts across urban agriculture types: Case studies in Europe and the US

Urban agriculture is an increasingly popular approach to addressing negative social and health effects of cities. Social benefits of urban agriculture include improved health and wellbeing, economic opportunities, social cohesion, and education. However, the extent to which urban agriculture participants are motivated by or experience these impacts has rarely been measured quantitatively, especially across the many different types of urban agriculture. We analysed survey data from 74 urban agriculture sites in France, Germany, Poland, the United Kingdom, and the United States to quantitatively assess the relationships between urban agriculture types, farmers and gardeners’ motivations, and the social impacts of urban agriculture. Through factor analysis, we established valid and reliable measurements of participants’ motivations and impacts. We identified four scales: general wellbeing impacts, nutritional health impacts, economic interests, and socialization motivations. Through multivariate analysis of variance, we document significant differences in motivations and reported impacts across types of urban agriculture. Finally, we conducted a multilevel multivariate analysis to explore the predictors of general wellbeing impacts. Participants with stronger economic interests, stronger socialization motivations, and who are owners or primary operators of their plots would be predicted to report greater general wellbeing impacts of urban agriculture. These results provide data about the impacts of urban agriculture projects that enable urban planners and policymakers to maximize the desired social benefits of urban agriculture

The role of urban agriculture in food-energy-water nexus policies: Insights from Europe and the U.S

The growth of urban agriculture (UA) has raised the awareness of city officials and civil society organizations of its potential effects on food systems. This has led to various policies to regulate and support UA. This research characterizes existing food, energy and water (FEW nexus) policies based on policy data from five case study cities in Europe and the U.S. (Dortmund, Gorz´ow Wielkopolski, London, Nantes, and New York City) to analyze their relationships to UA, and to identify policy types that support resource-efficient UA. The paper presents the results of an analysis of 78 policy documents related to UA and the FEW nexus, and the results of a Q-sort ranking by UA policy experts on the effectiveness of 16 generalized UA policies in promoting resource-efficient UA. The number, type, and degree of support for nexus policies vary among the five case studies. The results show that the majority of policies (36) are implemented at the local scale, that few policies (19) incorporate all elements of the nexus, yet many nexus policies include UA indirectly. Regulations are more prevalent and are considered more effective at ensuring resource-efficient UA than incentives or awareness-raising policies. The study offers guidance to policy makers who want to improve resource use in future UA pointing at the increasing importance of local food policies

Comparing the carbon footprints of urban and conventional agriculture

Urban agriculture (UA) is a widely proposed strategy to make cities and urban food systems more sustainable. Until now, we have lacked a comprehensive assessment of the environmental performance of UA relative to conventional agriculture, and results from earlier studies have been mixed. This is the first large-scale study to resolve this uncertainty across cities and types of UA, employing citizen science at 73 UA sites in Europe and the United States to compare UA products to food from conventional farms. Results reveal that the carbon footprint of food from UA is six times greater than conventional agriculture (420 gCO2e versus 70 gCO2e per serving). However, some UA crops (for example, tomatoes) and sites (for example, 25% of individually managed gardens) outperform conventional agriculture. These exceptions suggest that UA practitioners can reduce their climate impacts by cultivating crops that are typically greenhouse-grown or air-freighted, maintaining UA sites for many years, and leveraging circularity (waste as inputs)