Legitimacy of source-separating wastewater systems with Swedish water utilities

Nutrient management is one of the critical challenges for developing sustainable circular economies in cities. Nutrients such as nitrogen and phosphorus from our food end up in our wastewater and pose an environmental threat when they are released in waterways. Yet, these nutrients are essential for crop production and food security. Hince human excreta contains the bulk of nutrients going through the urban ecosystem. Source separation of excreta from the rest of urban wastewater flows can enable safe and efficient nutrient recovery. Yet, source-separating wastewater systems are not yet common in urban areas. The aim of this study is to assess the legitimacy of source-separating wastewater systems from the perspective of wastewater professionals in Sweden. The study uses interviews and a survey to explore the pragmatic, normative, cognitive and regulatory dimensions of legitimacy and how these aspects can vary between different municipalities. Finally, it looks into possible knowledge-based activities to increase legitimacy. The results from this study show variations in legitimacy levels in urban areas in Sweden. Overall opinion appears to be neutral to the concept rather than negative. Although many see multiple barriers to implementation. Normative legitimacy (moral motivation) was relatively high, while cognitive legitimacy (knowledge & experiences) was lowest. Respondents from organizations where source-separation is being implemented, or they believe that it will be implemented within 10 years, generally saw more drivers and fewer barriers. These innovators were also more interested in knowledge-based activities. Overall recommendations to increase cognitive knowledge regarding source-separating systems among multiple stakeholders seems the most promising path forward to increase legitimacy in the Swedish wastewater sector

Urine recycling-Diffusion barriers and upscaling potential; case studies from Sweden and Switzerland

In this study, we explored why urine recycling systems have failed to gain wide-scale expansion despite their high potential for food and fertilizer security. Additionally, we examined the future perception of urine recycling in Sweden and Switzerland, as these two countries are at the forefront of technological advancement. Along with identifying barriers, we also proposed pathways for overcoming those barriers and achieving the upscale. The analysis was conducted using the technological innovation (TIS) approach, which is technology-focused, i.e., revolves around emerging technologies. Additionally, the study provides a methodological contribution to the innovation systems research by employing the Delphi method in conjunction with urine recycling experts to enforce transparency and prevent bias in the analysis. For urine recycling to overcome its current challenges, actors must work collectively. There needs to be a combination of top-down and bottom-up efforts to achieve the upscaling pathways. Lobbying and knowledge provision are necessary to adjust the current regulatory frame-work in a manner that provides public and private incentives. For urine recycling to diffuse and break into the mainstream market, we must move beyond enthusiasts, innovators, and niche markets into the mass market (ordinary people); dedicated service providers can facilitate this process. Pilot projects have been found integral to urine recycling upscaling. Future work could conduct life cycle assessments on existing pilot projects to un-derstand the environmental and economic performance of urine recycling systems when scaled up

Egestabase - An online evidence platform to discover and explore options to recover plant nutrients from human excreta and domestic wastewater for reuse in agriculture

Restoring nutrient circularity across scales is important for ecosystem integrity as well as nutrient and food security. As such, research and development of technologies to recover plant nutrients from various organic residues has intensified. Yet, this emerging field is diverse and difficult to navigate, especially for newcomers. As an increasing number of actors search for circular solutions to nutrient management, there is a need to simplify access to the latest knowledge. Since the majority of nutrients entering urban areas end up in human excreta, we have chosen to focus on human excreta and domestic wastewater. Through systematic mapping with stakeholder engagement, we compiled and consolidated available evidence from research and practice. In this paper, we present `Egestabase' - a carefully curated open-access online evidence platform that presents this evidence base in a systematic and accessible manner. We hope that this online evidence platform helps a variety of actors to navigate evidence on circular nutrient solutions for human excreta and domestic wastewater with ease and keep track of new findings

Poly(vinylidene fluoride-hexafluoropropylene) polymer electrolyte for paper-based and flexible battery applications

Paper-based batteries represent a new frontier in battery technology. However, low-flexibility and poor ionic conductivity of solid electrolytes have been major impediments in achieving practical mechanically flexible batteries. This work discuss new highly ionic conductive polymer gel electrolytes for paper-based battery applications. In this paper, we present a poly(vinylidene fluoride-hexafluoropropylene) (PVDH-HFP) porous membrane electrolyte enhanced with lithium bis(trifluoromethane sulphone)imide (LiTFSI) and lithium aluminum titanium phosphate (LATP), with an ionic conductivity of 2.1 × 10−3 S cm−1. Combining ceramic (LATP) with the gel structure of PVDF-HFP and LiTFSI ionic liquid harnesses benefits of ceramic and gel electrolytes in providing flexible electrolytes with a high ionic conductivity. In a flexibility test experiment, bending the polymer electrolyte at 90° for 20 times resulted in 14% decrease in ionic conductivity. Efforts to further improving the flexibility of the presented electrolyte are ongoing. Using this electrolyte, full-cell batteries with lithium titanium oxide (LTO) and lithium cobalt oxide (LCO) electrodes and (i) standard metallic current collectors and (ii) paper-based current collectors were fabricated and tested. The achieved specific capacities were (i) 123 mAh g−1 for standard metallic current collectors and (ii) 99.5 mAh g−1 for paper-based current collectors. Thus, the presented electrolyte has potential to become a viable candidate in paper-based and flexible battery applications. Fabrication methods, experimental procedures, and test results for the polymer gel electrolyte and batteries are presented and discussed

Electrospun Nanofibers for Label-Free Sensor Applications

Electrospinning is a simple, low-cost and versatile method for fabricating submicron and nano size fibers. Due to their large surface area, high aspect ratio and porous structure, electrospun nanofibers can be employed in wide range of applications. Biomedical, environmental, protective clothing and sensors are just few. The latter has attracted a great deal of attention, because for biosensor application, nanofibers have several advantages over traditional sensors, including a high surface-to-volume ratio and ease of functionalization. This review provides a short overview of several electrospun nanofibers applications, with an emphasis on biosensor applications. With respect to this area, focus is placed on label-free sensors, pertaining to both recent advances and fundamental research. Here, label-free sensor properties of sensitivity, selectivity, and detection are critically evaluated. Current challenges in this area and prospective future work is also discussed

V2O5/Graphene Hybrid Supported on Paper Current Collectors for Flexible Ultrahigh-Capacity Electrodes for Lithium-Ion Batteries

An ultrahigh-capacity, flexible electrode made with vanadium pentoxide/graphene (with a specific capacity of 396 mAh/g) supported on paper-based current collectors has been developed. The ultrahigh-capacity graphene-modified vanadium pentoxide is fabricated by incorporating graphene sheets (2 wt %) into the vanadium pentoxide nanorods to improve the specific capacity, cycle life, and rate capability. This active material is then incorporated with the paper-based current collectors [carbon nanotube (CNT)–microfiber paper] to provide flexible electrodes. The flexible current collector has been made by depositing single-wall CNTs over wood microfibers through a layer-by-layer self-assembly process. The CNT mass loading of the fabricated current collectors is limited to 10.1 μg/cm2. The developed electrodes can be used to construct the flexible battery cells, providing a high-capacity/energy and rechargeable energy storage unit for flexible electronic devices

Paper-Based Flexible Lithium-Ion Batteries

Paper-based flexible batteries have a wide range of applications in paper-based platforms, including in paper electronics, packaging, product displays, greeting cards, and sensors. This poster will present lithium-ion batteries using flexible paper-based current collectors. These current collectors were fabricated from wood microfibers that were coated with carbon nanotubes (CNT) through an electrostatic layer-by-layer nanoassembly process. The use of paper-based current collectors provides flexibility and improved electrode adhesion. Electrodes were fabricated by casting thin layers of lithium titanium oxide, lithium cobalt oxide or lithium magnesium oxide on the conductive paper. Half-cell and full-cell devices were fabricated and tested. The results show that the presented batteries use reduced mass loading of carbon nanotubes (10.1 μg/cm2) compared to CNT film based batteries. Experimental capacities of the half-cell devices were measured to be 150 mAh/g for lithium cobalt oxide, 158 mAh/g for lithium titanium oxide, and 130 mAh/g for lithium magnesium oxide. Device designs, fabrication processes of paper-based current collectors, electrodes, and batteries, and further experimental results, including solid electrolytes, will be presented

The Effect of Resource Quality and Species Interactions on Dermestes maculatus

Forensic entomology is the use and application of insect information in legal matters, particularly in death investigations as insects utilize decomposing remains as a food source to complete their life cycle. Dermestes maculatus (DeGeer), larder beetles belonging to the family Dermestidae, are of considerable forensic importance since their larvae are typically found on human corpses during the later stages of decomposition – the advanced and dry/skeletal stages. Dermestes maculatus can be useful in estimating the post-mortem interval (PMI) of a cadaver with advanced decomposition. The purpose of this study was to investigate the colonization (egg-laying) behavior of D. maculatus; specifically, the study examined whether D. maculatus colonize during the later decomposition stages due to a resource preference for dry, aged tissue or due to competitive effects resulting from the presence of Lucilia sericata (Meigen) blow flies. Results from the olfactory trials support previous findings that D. maculatus have a significant preference for aged resources, and that the presence of blow fly eggs are a deterrent. Microcosm experiments were conducted to examine oviposition behavior in the presence of blow fly eggs and it was observed that there was no significant preference of colonization for either treatment option given (with blow fly eggs vs. without blow fly eggs). Results from this assay suggest that D. maculatus may delay colonization of carrion primarily due to their preference for aged resources. The findings from this study aim to provide greater insight into their recruitment and colonization behavior to increase their utility as forensic tools

Novel methods in retinal vessel calibre feature extraction for systemic disease assessment

Retina and its vascular network have unique branching characteristics morphology of which will change as a result of some systemic diseases, including hypertension, stroke and diabetes. Therefore, retinal image has been used as non-invasive screening window for risk assessment and prediction of such disease condition especially at the baseline. The assessment is based on a number of features among which vessel diameter (both individual and summary) and fractal dimension (FD) are the ones mostly associated with risk of diabetes and stroke. The association is linked to the higher risk of diabetes and stroke in people with narrower retinal arteriole diameter or change in overall fractal dimension independent of any risk factor (i.e. blood pressure, cardiovascular risk factors). Diameter measurement requires vessel edges to be located and tracked however; accurate edge perception is subject to image contrast, shadows, lighting condition and even presence of retinopathy legions close to vessel boundaries. This will lead to imprecision and inconsistencies between different automatic measurement techniques and may affect the significance of its association with disease condition in risk-assessment studies. As accuracy and success of diameter measurement is subject to large variations due to image artifacts it may not be suitable for fully automatic applications. In order to compensate for such error, at first two novel automatic vessel diameter measurement techniques were proposed and validated which were more robust in the presence of such image artifacts compared to similar methods. However, sometimes the exact edge location and actual diameter value is not of interest. In most case-control studies, it is of importance to comparatively evaluate the variations in retinal vessel diameter as a sign of retinopathy such as arteriolar nicking as an example of hypertensive retinopathy. Vessel diameter is often required to be compared with a reference value in many analytical assessments for diagnostic purpose. This includes monitoring the diameter variations of a specific vessel segment within single subject overtime or across multiple subjects. This helps ophthalmologists to understand whether it has undergone any significant change and perhaps associate it with a disease abnormality. A technique that can effectively quantify that change without being impaired by image artifacts is of more importance and one of the rationales of this study. This research hypothesized an edge independent solution for quantifying diameter variations when the actual diameter value is not required and proposed a new feature based on fractal analysis of vessel cross-section profile as a time series signal. This feature provides a link between FD as a global measure of the complexity and diameter variation as local property of a specific vessel segment. The clinical application of this feature has been validated on two population studies which showed promising result for assessment of mild non-proliferative diabetic retinopathy and 10-year stroke. This research work has also investigated whether the FD of retinal microvasculature would be affected by cyclic pulsations of retinal vessels and whether ECG synchronization is required prior to taking fundus images to compensate for this potential source of variations

Knowledge evolution within human urine recycling technological innovation system (TIS): Focus on technologies for recovering plant-essential nutrients

Adopting urine-recycling technologies can support a transition to circular nutrient management systems. Although these technologies have been developed since the 1990s, their large-scale implementation remains limited. From a technological innovation system (TIS) perspective, "knowledge development and diffusion" is a critical function in the development phase. Yet, available methods in the literature to evaluate this function are not standardized. Hence, this study aims to fill this literature gap by developing a novel multi-criteria framework for evaluating knowledge functions. Several characteristics of emerging technologies are reflected in the criteria, including the rate of growth, novelty, diffusion, and relationship to incumbent systems. The knowledge base was measured by bibliometric analysis of publications obtained from comprehensive mapping. Results showed that the rate of publications and knowledge diffusion increased sharply in 2011-2021 compared to 1990-2010. However, the function still has insufficiency in some criteria. The lack of innovation in scientific research and the diversification of technologies were found to be impediments. The analysis also identified the lock-in of con-ventional technologies and centralized infrastructures in terms of publication dominance as another impediment. For the TIS to be legitimate and to grow, more pilot-scale implementations at a higher level are recommended to demonstrate that the technology works in practice