scholarly journals Comparative study of disinfectants for use in low-cost gravity driven household water purifiers

2013 ◽  
Vol 11 (3) ◽  
pp. 443-456 ◽  
Author(s):  
Rajshree A. Patil ◽  
Shankar B. Kausley ◽  
Pradeep L. Balkunde ◽  
Chetan P. Malhotra

Point-of-use (POU) gravity-driven household water purifiers have been proven to be a simple, low-cost and effective intervention for reducing the impact of waterborne diseases in developing countries. The goal of this study was to compare commonly used water disinfectants for their feasibility of adoption in low-cost POU water purifiers. The potency of each candidate disinfectant was evaluated by conducting a batch disinfection study for estimating the concentration of disinfectant needed to inactivate a given concentration of the bacterial strain Escherichia coli ATCC 11229. Based on the concentration of disinfectant required, the size, weight and cost of a model purifier employing that disinfectant were estimated. Model purifiers based on different disinfectants were compared and disinfectants which resulted in the most safe, compact and inexpensive purifiers were identified. Purifiers based on bromine, tincture iodine, calcium hypochlorite and sodium dichloroisocyanurate were found to be most efficient, cost effective and compact with replacement parts costing US$3.60–6.00 for every 3,000 L of water purified and are thus expected to present the most attractive value proposition to end users.

2014 ◽  
Vol 13 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Rajshree A. Patil ◽  
Dilshad Ahmad ◽  
Shankar B. Kausley ◽  
Pradeep L. Balkunde ◽  
Chetan P. Malhotra

Simple, low-cost household interventions are known to be effective in lowering the incidence of waterborne diseases in developing countries. However, high costs along with operational and maintenance issues have prevented the successful adoption of these interventions among the affected communities. To address these limitations, a cost-effective, gravity-driven water purification cartridge has been developed by employing the synergistic disinfection action of low concentrations of silver and chlorine on bacteria and viruses. The silver and chlorine treatment components within the cartridge have been developed using inexpensive materials and integrated with a life indicator and auto-shut-off-mechanism within a compact form factor. The antibacterial as well as antiviral performance of the cartridge was tested by using ground water spiked with Escherichia coli and MS2 bacteriophage. The results show that, although individually, the silver and chlorine treatment systems were unable to inactivate the test strains, the integrated cartridge inactivates both bacteria as well as viruses up to the log reduction requirement of the USEPA guide standard for microbiological water purifiers over its designated life of 2,000 liters.


2018 ◽  
Vol 32 (2) ◽  
pp. 103-119
Author(s):  
Colleen M. Boland ◽  
Chris E. Hogan ◽  
Marilyn F. Johnson

SYNOPSIS Mandatory existence disclosure rules require an organization to disclose a policy's existence, but not its content. We examine policy adoption frequencies in the year immediately after the IRS required mandatory existence disclosure by nonprofits of various governance policies. We also examine adoption frequencies in the year of the subsequent change from mandatory existence disclosure to a disclose-and-explain regime that required supplemental disclosures about the content and implementation of conflict of interest policies. Our results suggest that in areas where there is unclear regulatory authority, mandatory existence disclosure is an effective and low cost regulatory device for encouraging the adoption of policies desired by regulators, provided those policies are cost-effective for regulated firms to implement. In addition, we find that disclose-and-explain regulatory regimes provide stronger incentives for policy adoption than do mandatory existence disclosure regimes and also discourage “check the box” behavior. Future research should examine the impact of mandatory existence disclosure rules in the year that the regulation is implemented. Data Availability: Data are available from sources cited in the text.


2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Adam Teusner ◽  
Rhett Butler ◽  
Pierre Le Clech

Fluoride concentrations in drinking water in excess of 1.5 mg L-1 are unsafe for human consumption. To reduce excess fluoride intake, developing countries must use low-cost, point-of-use defluoridation techniques. Although previous work has extensively assessed defluoridation using bone char (BC), most of the advanced studies have been based on the use of fluoridated distilled water as a feed solution. In the present study, BC columns were challenged with a range of model solutions, mimicking various pretreatment options. As a result, the relative impact of dissolved organic carbon (DOC) and suspended solids (SS) on the performance of BC filters was assessed. In addition, the performance of a gravity-driven, hollow fibre ultrafiltration (UF) module was examined with regards to the potential for use as a pretreatment option. SS were observed to severely clog the columns and cause the complete cessation of flow. The subsequent removal of SS by UF improved the general filter performance as well as increasing the BC lifetime by 50 %. The UF module achieved a reduction in DOC of 34 ± 6 %, resulting in an additional 30 % increase in the lifetime of the BC column.


2018 ◽  
Vol 52 (25) ◽  
pp. 3429-3444 ◽  
Author(s):  
Ezequiel Buenrostro ◽  
Daniel Whisler

Three-dimensional fiber-reinforced foam cores may have improved mechanical properties under specific strain rates and fiber volumes. But its performance as a core in a composite sandwich structure has not been fully investigated. This study explored different manufacturing techniques for the three-dimensional fiber-reinforced foam core using existing literature as a guideline to provide a proof of concept for a low-cost and easily repeatable method comprised of readily available materials. The mechanical properties of the fiber-reinforced foam were determined using a three-point bend test and compared to unreinforced polyurethane foam. The foam was then used in a sandwich panel and subjected to dynamic loading by means of a gas gun (103 s−1). High-strain impact tests validated previously published studies by showing, qualitatively and quantitatively, an 18–20% reduction in the maximum force experienced by the fiber-reinforced core and its ability to dissipate the impact force in the foam core sandwich panel. The results show potential for this cost-effective manufacturing method to produce an improved composite foam core sandwich panel for applications where high-velocity impacts are probable. This has the potential to reduce manufacturing and operating costs while improving performance.


Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 872
Author(s):  
Resoketswe Charlotte Moropeng ◽  
Maggy Ndombo Benteke Momba

The current study investigated the acceptance rate and long-term effectiveness of cost-effective household water treatment systems deployed in Makwane Village. A structured questionnaire was used prior to implementation to collect information such as level of education, level of employment, and knowledge about point-of-use water treatment systems in the target area. The long-term effectiveness was determined by factors such as the Escherichia coli removal efficiency, turbidity reduction, silver leached, and flow rate of the household water treatment devices. The results of the survey prior to deployment revealed that only 4.3% of the community had a tertiary qualification. Moreover, 54.3% of the community were unemployed. The results further revealed that 65.9% of the community were knowledgeable about other point-of-use water treatment methods. The acceptance rate, which was found to be initially higher (100%), reduced after three months of implantation (biosand filter with zeolite-silver clay granular—82.9%; silver-impregnated porous pot filters—97.1%). Moreover, the long-term effectiveness was determined, taking into consideration the adoption rate, and it was found that silver-impregnated porous pot filters have a long life compared to biosand filter with zeolite-silver clay granular. Although household water treatment systems can effectively reduce the burden of waterborne diseases in impoverished communities, the success of adoption is dependent on the targeted group. This study highlights the significance of involving community members when making the decision to scale up household water treatment devices in rural areas for successful adoption.


2008 ◽  
Vol 136 (11) ◽  
pp. 1463-1471 ◽  
Author(s):  
V. GARRETT ◽  
P. OGUTU ◽  
P. MABONGA ◽  
S. OMBEKI ◽  
A. MWAKI ◽  
...  

SUMMARYLack of access to safe water and sanitation contributes to diarrhoea moribidity and mortality in developing countries. We evaluated the impact of household water treatment, latrines, shallow wells, and rainwater harvesting on diarrhoea incidence in rural Kenyan children. We compared diarrhoea rates in 960 children aged <5 years in 556 households in 12 randomly selected intervention villages and six randomly selected comparison villages during weekly home visits over an 8-week period. On multivariate analysis, chlorinating stored water [relative risk (RR) 0·44, 95% confidence interval (CI) 0·28–0·69], latrine presence (RR 0·71, 95% CI 0·54–0·92), rainwater use (RR 0·70, 95% CI 0·52–0·95), and living in an intervention village (RR 0·31, 95% CI 0·23–0·41), were independently associated with lower diarrhoea risk. Diarrhoea risk was higher among shallow well users (RR 1·78, 95% CI 1·12–2·83). Chlorinating stored water, latrines, and rainwater use all decreased diarrhoea risk; combined interventions may have increased health impact.


2020 ◽  
Vol 10 (4) ◽  
pp. 1012-1018
Author(s):  
T. M. Ngasala ◽  
S. J. Masten ◽  
C. Cohen ◽  
D. Ravitz ◽  
E. J. Mwita

Abstract This study was conducted in an agro-pastoral community in Northern Tanzania, where water sources are contaminated, and point-of-use water treatment is rarely used. The objectives of the study were to determine the quality of drinking water at the household level and to assess the perception and attitude towards the treatment methods that were introduced to community members. The three treatment methods evaluated were chlorine tablets, silver-infused ceramic tablets, and solar water disinfection (SODIS). These methods were selected due to their availability, ease of use, cost, and effectiveness in water with high levels of coliform bacteria. Each home within the study area was provided with one of three treatment methods. The use, performance, and acceptability of the new water treatment methods were assessed over a three-week period. Prior to the introduction of the methods, 40% of households reported that they treated water regularly. However, 80% of the household water samples tested positive for Escherichia coli. After introducing the new methods, 60% of households increased their water consumption, and all water samples tested negative for E. coli during the final week of testing. The work demonstrates the need to provide access to cost-effective household water treatment methods, especially in rural communities that lack access to potable water.


2021 ◽  
Author(s):  
Jane Mellor ◽  
Phillip Lorenz ◽  
Anna Lamstaes ◽  
Harry J Fischl ◽  
Shidong Xi ◽  
...  

Genomes are pervasively transcribed leading to stable and unstable transcripts that define functional regions of genomes and contribute to cellular phenotypes. Defining comprehensive nascent transcriptomes is pivotal to understand gene regulation, disease processes, and the impact of extracellular signals on cells. However, currently employed methods are laborious, technically challenging and costly. We developed single-nucleotide resolution 4sU-sequencing (SNU-Seq), involving pulse labelling, biotinylation and direct isolation of nascent transcripts. Artificial poly-(A)-tailing of the 3' most nucleotide of nascent transcripts ensures oligo-d(T) primer-based library preparation and sequencing using commercial 3' RNA-Seq kits. We show that SNU-Seq is a cost-effective new method generating even read profiles across transcription units. We used SNU-Seq to identify transcription elongation parameters, to map usage of polyadenylation (PAS) sites and novel enhancers. Remarkably, 4sU labelled nascent RNA accumulates short ~100nt transcripts that map to the 5' end of genes. We show that isolation of these short nascent RNA and sequencing the 5' and 3' ends using size-selected SNU-Seq (ssSNU-Seq) provides highly sensitive annotations of mapped and novel TSSs, promoter-proximal pause/termination sites. Thus, SNU-seq and ssSNU-seq combined yield comprehensive transcriptomics data at low cost with high spatial and temporal resolution.


2005 ◽  
Vol 26 (2_suppl2) ◽  
pp. S186-S192 ◽  
Author(s):  
Donald Bundy

This paper argues that there is now reliable evidence that ill health and malnutrition affect education access, participation, completion, and achievement, and that school-based health and nutrition programs can provide a cost-effective and low-cost solution. International coordination around this issue has been helped by a consensus framework to “Focus Resources on Effective School Health (FRESH),” developed jointly by UNESCO, WHO, UNICEF, Education International, and the World Bank, and launched at the World Education Forum in Dakar in April 2000 as part of the global effort to achieve the goal of Education for All (EFA). The need for school health and nutrition programs as part of EFA actions is now recognized by both countries and development partners, and examples of successful practical sector programs that have gone to scale are presented for both low- and middle-income countries. This paper argues that, despite this progress, there are two key unresolved issues related to the targeting of nutrition interventions toward school-age children. The first concerns the role of food as an incentive for participation in education, and the second concerns the appropriate target age group for nutrition interventions. It is suggested that finding clear answers to these key policy questions in nutrition could profoundly influence the impact of future school health and nutrition programs.


Author(s):  
Richard Cookson ◽  
Susan Griffin ◽  
Ole F. Norheim ◽  
Anthony J. Culyer

This chapter is a guide to designing a distributional cost-effective analysis (DCEA) for research commissioners and producers. It describes the main components of DCEA and how they can be combined in different ways to inform decision-making in various contexts. The appropriate design of a DCEA will depend on the objectives of the relevant decision-making authorities; the political, economic, and institutional environment, and the prevailing social norms in the population being served; as well as the resources available for the analysis. We start by reviewing key questions about the decision-making context and illustrate how the answers to those questions can shape the study design, using our training example of nicotine replacement therapy in England. We then present the equity-efficiency impact plane, a visual tool for illustrating the relationship between the impact of a decision on efficiency (e.g. net health benefit) and equity (e.g. reduction in unfair health inequality). We then go through the main components of DCEA, including simple, low-cost forms of equity analysis that may be useful when detailed bespoke modelling of distributional consequences is not a practical option.


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