scholarly journals Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here?

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 429 ◽  
Author(s):  
Charles Nanseu-Njiki ◽  
Willis Gwenzi ◽  
Martin Pengou ◽  
Mohammad Rahman ◽  
Chicgoua Noubactep

Inadequate access to safe drinking water is one of the most pervasive problems currently afflicting the developing world. Scientists and engineers are called to present affordable but efficient solutions, particularly applicable to small communities. Filtration systems based on metallic iron (Fe0) are discussed in the literature as one such viable solution, whether as a stand-alone system or as a complement to slow sand filters (SSFs). Fe0 filters can also be improved by incorporating biochar to form Fe0-biochar filtration systems with potentially higher contaminant removal efficiencies than those based on Fe0 or biochar alone. These three low-cost and chemical-free systems (Fe0, biochar, SSFs) have the potential to provide universal access to safe drinking water. However, a well-structured systematic research is needed to design robust and efficient water treatment systems based on these affordable filter materials. This communication highlights the technology being developed to use Fe0-based systems for decentralized safe drinking water provision. Future research directions for the design of the next generation Fe0-based systems are highlighted. It is shown that Fe0 enhances the efficiency of SSFs, while biochar has the potential to alleviate the loss of porosity and uncertainties arising from the non-linear kinetics of iron corrosion. Fe0-based systems are an affordable and applicable technology for small communities in low-income countries, which could contribute to attaining self-reliance in clean water supply and universal public health.

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1981
Author(s):  
Pedro Martínez-Santos ◽  
Miguel Martín-Loeches ◽  
Silvia Díaz-Alcaide ◽  
Kerstin Danert

Water access remains a challenge in rural areas of low-income countries. Manual drilling technologies have the potential to enhance water access by providing a low cost drinking water alternative for communities in low and middle income countries. This paper provides an overview of the main successes and challenges experienced by manual boreholes in the last two decades. A review of the existing methods is provided, discussing their advantages and disadvantages and comparing their potential against alternatives such as excavated wells and mechanized boreholes. Manual boreholes are found to be a competitive solution in relatively soft rocks, such as unconsolidated sediments and weathered materials, as well as and in hydrogeological settings characterized by moderately shallow water tables. Ensuring professional workmanship, the development of regulatory frameworks, protection against groundwater pollution and standards for quality assurance rank among the main challenges for the future.


2021 ◽  
Vol 13 (17) ◽  
pp. 9645
Author(s):  
Zhe Huang ◽  
Esther Laurentine Nya ◽  
Viet Cao ◽  
Willis Gwenzi ◽  
Mohammad Azizur Rahman ◽  
...  

This communication is motivated by recent publications discussing the affordability of appropriate decentralized solutions for safe drinking water provision in low-income communities. There is a huge contrast between the costs of presented technologies, which vary by a factor of up to 12. For example, for the production of 2000 L/d of treated drinking water, the costs vary between about 1500 and 12,000 Euro. A closer look at the technologies reveals that expensive technologies use imported manufactured components or devices that cannot yet be locally produced. In the battle to achieve the United Nations Sustainable Development Goal for safe drinking water (SDG 6.1), such technologies should be, at best, considered as bridging solutions. For a sustainable self-reliance in safe drinking water supply, do-it-yourself (DIY) systems should be popularized. These DIY technologies include biochar and metallic iron (Fe0) based systems. These relevant technologies should then be further improved through internal processes.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 491
Author(s):  
Sona Jain ◽  
Wanessa Santana ◽  
Silvio S. Dolabella ◽  
André L. S. Santos ◽  
Eliana B. Souto ◽  
...  

Leishmaniasis is one of the deadliest neglected tropical diseases affecting 12–15 million people worldwide, especially in middle- and low-income countries. Rapid and accurate diagnosis of the disease is important for its adequate management and treatment. Several techniques are available for the diagnosis of leishmaniasis. Among these, parasitological and immunological tests are most widely used. However, in most cases, the utilized diagnostic techniques are not good enough, showing cross-reactivity and reduced accuracy. In recent years, many new methods have been reported with potential for improved diagnosis. This review focuses on the diagnosis of Leishmania exploring the biosensors and nanotechnology-based options for their detection. New developments including the use of nanomaterials as fluorophores, fluorescence quenchers as reducing agents and as dendrimers for signal improvement and amplification, together with the use of aptamers to replace antibodies are described. Future research opportunities to overcome the current limitations on the available diagnostic approaches are also discussed.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Pavlos Topalidis ◽  
Cristina Florea ◽  
Esther-Sevil Eigl ◽  
Anton Kurapov ◽  
Carlos Alberto Beltran Leon ◽  
...  

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did display biases. In addition, the MB-derived wake-up and total-sleep-times showed high agreement with subjective reports, but partly deviated from GT3X predictions. Study 2 revealed similar MB step counts across countries, but significant later wake-up and bedtimes for Ukraine than the other countries. We hope that our studies will stimulate future large-scale sensor-based physical activity and sleep research studies, including various cultures.


Author(s):  
Giorgia Gon ◽  
Abdunoor M. Kabanywanyi ◽  
Petri Blinkhoff ◽  
Simon Cousens ◽  
Stephanie J. Dancer ◽  
...  

Abstract Background Healthcare associated infections (HAI) are estimated to affect up to 15% of hospital inpatients in low-income countries (LICs). A critical but often neglected aspect of HAI prevention is basic environmental hygiene, particularly surface cleaning and linen management. TEACH CLEAN is an educational intervention aimed at improving environmental hygiene. We evaluated the effectiveness of this intervention in a pilot study in three high-volume maternity and newborn units in Dar es Salaam, Tanzania. Methods This study design prospectively evaluated the intervention as a whole, and offered a before-and-after comparison of the impact of the main training. We measured changes in microbiological cleanliness [Aerobic Colony Counts (ACC) and presence of Staphylococcus aureus] using dipslides, and physical cleaning action using gel dots. These were analysed with descriptive statistics and logistic regression models. We used qualitative (focus group discussions, in-depth interviews, and semi-structured observation) and quantitative (observation checklist) tools to measure why and how the intervention worked. We describe these findings across the themes of adaptation, fidelity, dose, reach and context. Results Microbiological cleanliness improved during the study period (ACC pre-training: 19%; post-training: 41%). The odds of cleanliness increased on average by 1.33 weekly during the pre-training period (CI = 1.11–1.60), and by 1.08 (CI = 1.03–1.13) during the post-training period. Cleaning action improved only in the pre-training period. Detection of S. aureus on hospital surfaces did not change substantially. The intervention was well received and considered feasible in this context. The major pitfalls in the implementation were the limited number of training sessions at the hospital level and the lack of supportive supervision. A systems barrier to implementation was lack of regular cleaning supplies. Conclusions The evaluation suggests that improvements in microbiological cleanliness are possible using this intervention and can be sustained. Improved microbiological cleanliness is a key step on the pathway to infection prevention in hospitals. Future research should assess whether this bundle is cost-effective in reducing bacterial and viral transmission and infection using a rigorous study design.


Author(s):  
Alexandra E. Hill ◽  
Izaac Ornelas ◽  
J. Edward Taylor

The labor supply response to agricultural wages is critical to the viability of crop production in high-income countries, which hire a largely foreign farm work force, as well as in low-income countries, where domestic workers move off the farm as the agricultural transformation unfolds. Modeling agricultural labor supply is more challenging than modeling the supply of other agricultural inputs or of labor to other sectors of the economy owing to unique features of agricultural production and farm labor markets. Data and econometric challenges abound, and estimates of agricultural labor supply elasticities are sparse. This review explains the importance and challenges of modeling farm labor supply and describes researchers’ efforts to address these challenges. It summarizes estimates of agricultural labor supply elasticities over the last 80 years, provides insights into variation in these estimates, identifies priority areas for future research, and reviews the most influential empirical work related to this important topic. Expected final online publication date for the Annual Review of Resource Economics, Volume 13 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2018 ◽  
pp. 255-276
Author(s):  
Philip J. Landrigan

Children in today’s ever-smaller, more densely populated, tightly interconnected world are surrounded by a complex array of environmental threats to health.1 Because of their unique patterns of exposure and exquisite biological sensitivities, especially during windows of vulnerability in prenatal and early postnatal development, children are extremely vulnerable to environmental hazards.2,3 Even brief, low-level exposures during critical early periods can cause permanent alterations in organ function and result in acute and chronic disease and dysfunction in childhood and across the life span.4 The World Health Organization estimates that 24% of all deaths and 36% of deaths in children are attributable to environmental exposures,5 more deaths than are caused by HIV/AIDS, malaria, and tuberculosis combined.6–8 In the Americas, the Pan American Health Organization estimates that nearly 100,000 children younger than 5 years die annually from physical, chemical, and biological hazards in the environment.9 Children in all countries are exposed to environmental health threats, but the nature and severity of these hazards vary greatly across countries, depending on national income, income distribution, level of development, and national governance.10 More than 90% of the deaths caused by environmental exposures occur in the world’s poorest countries6–8—environmental injustice on a global scale.11 In low-income countries, the predominant environmental threats are household air pollution from burning biomass and contaminated drinking water. These hazards are strongly linked to pneumonia, diarrhea, and a wide range of parasitic infestations in children.9,10 In high-income countries that have switched to cleaner fuels and developed safe drinking water supplies, the major environmental threats are ambient air pollution from motor vehicles and factories, toxic chemicals, and pesticides.10,12,13 These exposures are linked to noncommunicable diseases—asthma, birth defects, cancer, and neurodevelopmental disorders.9,10 Toxic chemicals are increasingly important environmental health threats, especially in previously low-income countries now experiencing rapid economic growth and industrialization.10 A major driver is the relocation of chemical manufacturing, recycling, shipbreaking, and other heavy industries to so-called “pollution havens” in low-income countries that largely lack environmental controls and public health infrastructure. Environmental degradation and disease result. The 1984 Bhopal, India, disaster was an early example.14 Other examples include the export to low-income countries of 2 million tons per year of newly mined asbestos15; lead exposure from backyard battery recycling16; mercury contamination from artisanal gold mining17; the global trade in banned pesticides18; and shipment to the world’s lowest-income countries of vast quantities of hazardous and electronic waste (e-waste).19 Climate change is yet another global environmental threat.20 Its effects will magnify in the years ahead as the world becomes warmer, sea levels rise, insect vector ranges expand, and changing weather patterns cause increasingly severe storms, droughts, and malnutrition. Children are the most vulnerable. Diseases of environmental origin in children can be prevented. Pediatricians are trusted advisors, uniquely well qualified to address environmental threats to children’s health. Prevention requires a combination of research to discover the environmental causes of disease coupled with evidence-based advocacy that translates research findings to policies and programs of prevention. Past successful prevention efforts, many of them led by pediatricians, include the removal of lead from paint and gasoline, the banning of highly hazardous pesticides, and reductions in urban air pollution. Future, more effective prevention will require mandatory safety testing of all chemicals in children’s environments, continuing education of pediatricians and health professionals, and enhanced programs for chemical tracking and disease prevention.


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