Waterless urinals: a proposal to save water and recover urine nutrients in Africa

Waterless urinals have two important advantages compared to conventional water-flushed urinals: They save water and they allow the collection of undiluted urine, which – because of its nitrogen and phosphorus content is a valuable resource as fertiliser in agriculture. In the context of African developing countries, costs and maintenance requirements of waterless urinals need to be as low as possible. Despite the fact that hundreds of thousands of waterless (and odourless) urinals are now already in use worldwide, many municipalities are not yet aware of their existence or are reluctant to accept them as a viable option. This paper aims to reduce this knowledge gap by describing available models, odour control methods in waterless urinals (flat rubber tube, silicon curtain valve or sealant liquid), and the aspects to be considered regarding maintenance requirements and costs. Waterless urinals are a promising step towards achieving water saving, more sustainable sanitation and reduced dependency on costly artificial fertilisers, thus contributing to poverty reduction

Up-scaling lessons from the EU-Sida-GTZ Ecosan promotion project in Kenya

This paper analyses the requirements for up-scaling of sustainable sanitation systems based on the lessons learnt from the EU-Sida-GTZ EcoSan Promotion Project (EPP) in Kenya. The EPP reached 50,000 users with reuse oriented sanitation systems (ecosan). The project areas for urine diversion dehydration toilets (UDDTs) were villages in rural and peri-urban areas of Kenya where farming is practiced and cholera is common during the rainy season. The total number of installed UDDTs in households and schools was 984 with an estimated 20,000 users. The UDDTs were implemented either directly through Community Based Organisations (CBOs), or via the pro-poor basket fund called Water Services Trust Fund (WSTF) together with the regional Water Services Boards (WSBs) and CBOs. Future strategies for up-scaling must provide a comprehensive strategy to bundle resources and create synergies of the sanitation related sectors in Kenya with a focus on behaviour change and sanitation market development that can provide sustained demand and trigger community investment in sanitation

Tackling the urban waste and food crises simultaneously and sustainably - examples from the Philippines and Burkina Faso

The current urban population of 3.3 billion is expected to reach 5 billion by 2030. This urbanisation of the global population is equally an urbanisation of poverty. Cities concentrate people, huge volumes of excreta and nutrients from vast areas of farmland into a limited area. For the urban poor in particular, these accumulations result in major health problems and a low standard of living. In recent decades sanitation practitioners and researchers have been working on modern sanitation systems that address two related urban problems the waste and the food production problem. The approaches developed are usually considered under the term ecological sanitation (ecosan) and are based on recognising the value of nutrients as part of a sustainable wastewater management system. Two large-scale projects from the Philippines and Burkina Faso, are presented to illustrate the benefit to the urban poor offered by affordable ecosan alternatives in terms of sanitation and fertiliser production

Alternative solutions for challenging environments: a look at UNICEF-assisted ecosan projects worldwide

This paper summarises information from 20 UNICEF-assisted ecological sanitation projects in 12 countries. The projects varied widely in size from 95 users for a project with household urine diversion dehydration toilets (UDDTs) in Bangladesh up to 23,000 users under emergency conditions in Zimbabwe. They share characteristics of purpose, scope, challenges, opportunities and sanitation technologies, which were mainly UDDTs and composting toilets. Specific insights are given for the projects in Bangladesh and Rwanda where large-scale ecological sanitation „ecosan‟ programs are currently underway. We discuss the potential to scale-up initiatives by providing increased technical back-up support to users, greater linkages with community-led total sanitation and with income generation initiatives via higher agricultural yields. In the context of growing urbanisation and hydro-geological challenges, this paper highlights that “ecosan technologies” (such as UDDTs) can be a suitable technical solution where pit-based toilets are impossible to be implemented sustainably

On the width of the equatorial deep jets

The equatorial deep jets (EDJ) are a striking feature of the equatorial ocean circulation. In the Atlantic Ocean, the EDJ are associated with a vertical scale of between 300 and 700 m, a time scale of roughly 4.5 years and upward energy propagation to the surface. It has been found that the meridional width of the EDJ is roughly 1.5 times larger than expected based on their vertical scale. Here we use a shallow water model for a high order baroclinic vertical normal mode to argue that mixing of momentum along isopycnals can explain the enhanced width. A lateral eddy viscosity of 300 m2 s−1 10 is found to be sufficient to account for the width implied by observations

Provision of sustainable sanitation in emergency situations: role of ecosan

This paper describes the potential of ecological sanitation (ecosan), and in particular of urine-diversion dehydrating (UDD) toilets, to provide sustainable excreta disposal in emergency situations in low-income countries. Three case studies of emergency sanitation were analysed: El Salvador (hurricane), Afghanistan (civil war) and Pakistan (earthquake). The analysis of these case studies has shown that the systems implemented in the long-term phase of the emergency were sometimes more sustainable than what was in place before the emergency occurred. For UDD toilets to be viable during emergency situations, specific criteria have to be in place. The essential criteria include awareness and expertise among aid agencies, ease of transportation and quick installation of standardised UDD units, stage and duration of emergency and the role of government in sanitation provision. For emergency situations in low-income countries, we propose the use of UDD toilets (e.g. with pre-fabricated urine-diversion squatting pans) as a suitable excreta management option, particularly in those instances where pit latrines are not sustainable in the longer term

Identification of LRRC8 heteromers as an essential component of the volume-regulated anion channel VRAC

Regulation of cell volume is critical for many cellular and organismal functions, yet the molecular identity of a key player, the volume-regulated anion channel VRAC, has remained unknown. A genome-wide siRNA screen in mammalian cells identified LRRC8A as a VRAC component. LRRC8A formed heteromers with other LRRC8 multispan membrane proteins. Genomic disruption of LRRC8A ablated VRAC currents. Cells with disruption of all five LRRC8 genes required LRRC8A co-transfection with other LRRC8 isoforms to reconstitute VRAC currents. The isoform combination determined VRAC inactivation kinetics. Taurine flux and regulatory volume decrease also depended on LRRC8 proteins. Our work shows that VRAC defines a class of anion channels, suggests that VRAC is identical to the volume-sensitive organic osmolyte/anion channel VSOAC, and explains the heterogeneity of native VRAC currents

Games of timing with detection uncertainty and numerical estimates

Mobility and terrain are two sides of the same coin. We cannot speak to our mobility unless we describe the terrain's ability to thwart our maneuver. Game theory describes the interactions of rational players who behave strategically. In previous work1 we described the interactions between a mobility player, who is trying to maximize the chances that he makes it from point A to point B with one chance to refuel, and a terrain player who is trying to minimize that probability by placing an obstacle somewhere along the path from A to B. This relates to the literature of games of incomplete information, and can be thought of as a more realistic model of this interaction. In this paper, we generalize the game of timing studied in the previous paper to include the possibility that both players have imperfect ability to detect his adversary

Epidemiological and genetic characteristics of vancomycin-resistant Enterococcus faecium isolates in a University Children's Hospital in Germany: 2019 to 2020

Background: Vancomycin-resistant Enterococcus faecium (VREfm) strains are one of the most important pathogens causing nosocomial infections in Germany. Due to limited treatment options and an increased risk for acquisition in immunocompromised children, surveillance to monitor occurrence of VREfm in paediatric clinical facilities is of critical importance. Following an unusual accumulation of VREfm positive patients between April 2019 and August 2020 at Dr. von Hauner Children’s Hospital in Munich, Germany, our study aimed to identify dynamics and routes of transmission, and analyse the affected population in view of previously described host risk factors for VREfm colonisation or infection. Methods: The hospital database was used to collect epidemiological and clinical data of VREfm cases. Descriptive statistical analyses were conducted to outline patient characteristics and depict possible differences between VREfm-colonised and -infected children. An outbreak investigation determining genetic relatedness among VREfm isolates was performed by core genome multilocus sequence typing (cgMLST). To examine potential transmission pathways, results of genome analysis were compared with epidemiological and clinical data of VREfm positive patients. Results: VREfm acquisition was documented in a total of 33 children (< 18 years). Seven VREfm-colonised patients (21.2%), especially those with a haemato-oncological disease (4/7; p = 0.011), showed signs of clinical infection. cgMLST analysis revealed seven distinct clusters, demonstrating a possible connection within each clonal lineage. Additional eight singletons were identified. Comparison with epidemiological and clinical data provided strong evidence for a link between several VREfm positive patients within the hospital. Conclusions: A nosocomial spread—at least in part—was the most likely reason for the unusual accumulation of VREfm cases. The study highlights that there is a constant need to increase efforts in hygiene measures, infection control and antibiotic stewardship to combat VREfm transmission events within German paediatric hospitals. Continuous monitoring of adherence to respective policies might reduce the occurrence of clustered cases and prevent future outbreaks.Peer Reviewe

Plane torsion waves in quadratic gravitational theories

The definition of the Riemann-Cartan space of the plane wave type is given. The condition under which the torsion plane waves exist is found. It is expressed in the form of the restriction imposed on the coupling constants of the 10-parametric quadratic gravitational Lagrangian. In the mathematical appendix the formula for commutator of the variation operator and Hodge operator is proved. This formula is applied for the variational procedure when the gravitational field equations are obtained in terms of the exterior differential forms.Comment: 3 May 1998. - 11