Solar disinfection of wastewater to reduce contamination of lettuce crops by Escherichia coli

September 18, 2012 · 0 comments

Water Res. 2012 Aug 30.

Solar disinfection of wastewater to reduce contamination of lettuce crops by Escherichia coli in reclaimed water irrigation.

Bichai F, Polo-López MI, Fernández Ibañez P. Plataforma Solar de Almería-CIEMAT, Carretera Senés km 4, 04200 Tabernas (Almería), Spain. Electronic address: fbichai@seas.harvard.edu.

Low-cost disinfection methods to allow safe use of recycled wastewater for irrigation can have important beneficial implications in the developing world. This study aims to assess the efficiency of solar disinfection to reduce microbial contamination of lettuce crops when solar-treated wastewater effluents are used for irrigation. The irrigation study was designed as a complete experimental loop, including (i) the production of irrigation water through solar disinfection of real municipal wastewater treatment plant effluents (WWTPE), (ii) the watering of cultivated lettuce crops at the end of solar treatment, and (iii) the detection of microbial contamination on the irrigated crops 24 h after irrigation.

Solar disinfection was performed using two types of reactors: (i) 20-L batch borosilicate glass reactors equipped with CPC to optimize solar irradiation, and (ii) 1.5-L PET bottles, i.e. the traditional SODIS recipients commonly used for disinfection of drinking water in developing communities. Both solar and H(2)O(2)-aided solar disinfection processes were tested during ≤5 h exposure of WWTPE, and Escherichiacoli inactivation was analysed. A presence/absence detection method was developed to analyse lettuce leaves sampled 24 h after watering for the detection of E. coli.

Results of inactivation assays show that solar disinfection processes can bring down bacterial concentrations of >10(3)-10(4)E. coli CFU mL(-1) in real WWTPE to <2 CFU/mL (detection limit). The absence of E. coli on most lettuce samples after irrigation with solar-disinfected effluents (26 negative samples/28) confirmed an improved safety of irrigation practices due to solar treatment, while crops irrigated with raw WWTPE showed contamination.

Steve Luby – Household Water Treatment: A failed public health strategy?

September 14, 2012 · 5 comments

Below is a link to a presentation by Steve Luby and he welcomes comments about the presentation. Comments can be made at the end of this post.

Household Water Treatment: A failed public health strategy? Steve Luby, MD presentation at University of California, Berkeley Environmental Engineering Seminar September 7, 2012.

Excerpts from the presentation:

Barriers to Household Water Treatment

  • Very low demand for improved water quality, especially among the poor
  • The children who suffer most from waterborne disease are the poor
  • The poor are those who are least able to afford to purchase products to treat their water.

Hard Questions

  • Is household water treatment a failed strategy?
  • Is it a fundamentally bad idea to expect the poorest people in the world to set up a personal water treatment facility in their home?

Key Points

Water will continue to be contaminated with sewage in low income countries

  • Water demand is increasing
  • Water supply is reducing
  • Intermittent supply ==> contaminated supply

Point of use water treatment

  • Technically effective
  • Controversy over health impact
  • Low uptake in populations at greatest risk of death

Way forward?

  • Radical improvement of POU
  • With early consideration of uptake
  • Focus on system interventions

WASHplus Weekly – Focus on Household Water Treatment & Safe Storage

September 14, 2012 · 0 comments

Issue 71 September 14, 2012 | Focus on Household Water Treatment & Safe Storage

This issue contains some of the key HWTS literature published so far in 2012 and updates two previous WASHplus weeklies on HWTS. The studies listed below discuss health, behavioral, and economic aspects of HWTS and recent studies on SODIS, BioSand filters, boiling, and other household water treatment methods. Also included is a link to the International Network on Household Water Treatment and Safe Storage communications website.

Congressional Research Service – Global Access to Clean Drinking Water and Sanitation: U.S. and International Programs

September 14, 2012 · 0 comments

Global Access to Clean Drinking Water and Sanitation: U.S. and International Programs, Sept 2012.

Tiaji Salaam-Blyther. Congressional Research Service. 

Several agencies contribute to U.S. efforts to improve global access to clean drinking water and sanitation, of which programs implemented by the Millennium Challenge Corporation (MCC) and USAID make up roughly 90%. In FY2010, for example, the United States invested $953 million on water and sanitation programs worldwide, including $898 million provided by USAID and MCC. Appropriations for water projects are provided to USAID annually, while MCC receives multi-year funding for its country compacts that include support for water projects. As such, spending by MCC on water projects may vary significantly from year to year and may not
be requested annually.

The President requested $302 million for USAID’s water activities for FY2012 and Congress appropriated not less than $315 million for international water and sanitation programs through the FY2012 Consolidated Appropriations. The FY2013 request for USAID’s water and sanitation efforts was slightly lower at $299.1 million. This report addresses congressional efforts to address limited access to clean drinking water and sanitation, outlines related programs implemented by USAID and MCC, and analyzes issues related to U.S. and international drinking water and sanitation programs that the 112th Congress might consider.

CONTENTS

  • Introduction
  • Background
  • Global Access Rates to Clean Water and Sanitation
  • Clean Water
  • Sanitation
  • International Spending on Water and Sanitation
  • Water and Sanitation Funding Needs
  • Congressional Actions
  • U.S. Foreign Assistance for Water and Sanitation
  • U.S. Progress in Meeting Clean Drinking Water Targets
  • Water for the Poor Act, Implementing Agencies
  • U.S. Department of State
  • U.S. Agency for International Development
  • Distribution of USAID WASH Resources, FY2006-FY2010
  • Millennium Challenge Corporation
  • U.S. Global Water and Sanitation Efforts: Issues
  • Clarifying Roles and Responsibilities and Authorizing Funding
  • Balancing Funding Between WASH and Other Water Areas
  • Balancing Regional Investments
  • Ensuring Accuracy of Data
  • Sustainability/Prioritizing Operations and Management
  • Summary of Key Issues

Ryan Rowe – Malawi works to ensure safe water at home

September 13, 2012 · 0 comments

Malawi works to ensure safe water at home | Source: Ryan Rowe Blog, Aug 31, 2012

The Ministry of Health of Malawi hosted a meeting yesterday morning to seek input on a “zero draft” of its national action plan on home-based water treatment and safe storage. In Malawi about 20% of the population obtains their drinking water from unsafe sources: lakes, rivers, or unprotected wells or natural springs. The microscopic creatures living in the water can lead to diarrhoeal diseases such as cholera, dysentery and typhoid which kill more than 1.5 million people worldwide every year, most of these children, and Malawi is no exception to this global trend. Treating the water at home through filtration, chlorine or other means and storing it safely in a proper container afterwards can improve the quality of the water and reduce the chances of getting sick with diarrhoea by up to 47%.

The Malawi Ministry of Health seeking input on its draft national action plan on household water treatment

In addition to household treatment of drinking water, there are two other key practices that can reduce the burden of diarrhoeal disease: hand-washing with soap and the safe disposal of human faeces. The Government of Malawi has developed national approaches on both: the National Handwashing Campaign and the Open Defecation Free Strategy, leaving household water treatment as a key gap to be addressed and providing the impetus for the current initiative.

Efforts to develop a national action plan began earlier this year at a workshop hosted by the World Health Organization and UNICEF in Mozambique. Following the workshop I was invited to Malawi by the government to provide technical assistance to their work in this area. At the moment, the technical assistance consists chiefly of a review of the status of household water treatment in Malawi, specifically the policy environment, key stakeholders, current practices and products available in the market. The next step is to provide some input into the drafting of the action plan and help the Ministry implement it in months to come. This work has been generously funded by Aqua for All, a Dutch NGO, with input and support from 300in6, a safe water advocacy group.

 

Promoting Household Water Treatment through Women’s Self Help Groups in Rural India

September 13, 2012 · 0 comments

Promoting Household Water Treatment through Women’s Self Help Groups in Rural India: Assessing Impact on Drinking Water Quality and Equity. PLOS ONE, September 2012.

Matthew C. Freeman1,2*, Victoria Trinies3, Sophie Boisson2, Gregory Mak3, Thomas Clasen2

1 Department of Environmental Health, Center for Global Safe Water, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America,
2 Faculty of Infectious Disease, Environmental Health Group, London School of Hygiene and Tropical Medicine, London, United Kingdom, 3 Department of Environmental Health, Mailman School of Public Health, Columbia University, New York, New York, United States of America

Household water treatment, including boiling, chlorination and filtration, has been shown effective in improving drinking water quality and preventing diarrheal disease among vulnerable populations. We used a case-control study design to evaluate the extent to which the commercial promotion of household water filters through microfinance institutions to women’s self-help group (SHG) members improved access to safe drinking water. This pilot program achieved a 9.8% adoption rate among women targeted for adoption. Data from surveys and assays of fecal contamination (thermo tolerant coliforms, TTC) of drinking water samples (source and household) were analyzed from 281 filter adopters and 247 nonadopters exposed to the program; 251 non-SHG members were also surveyed.

While adopters were more likely than non-adopters to have children under 5 years, they were also more educated, less poor, more likely to have access to improved water supplies, and more likely to have previously used a water filter. Adopters had lower levels of fecal contamination of household drinking water than non-adopters, even among those non-adopters who treated their water by boiling or using traditional ceramic filters. Nevertheless, one-third of water samples from adopter households exceeded 100 TTC/100ml (high risk), and more than a quarter of the filters had no stored treated water available when visited by an investigator, raising concerns about correct, consistent use.

In addition, the poorest adopters were less likely to see improvements in their water quality. Comparisons of SHG and non-SHG members suggest similar demographic characteristics, indicating SHG members are an appropriate target group for this promotion campaign. However, in order to increase the potential for health gains, future programs will need to increase uptake, particularly among the poorest households who are most susceptible to disease morbidity and mortality, and focus on strategies to improve the correct, consistent and sustained use of these water treatment products.

Assessing hygiene cost-effectiveness: a methodology

September 11, 2012 · 0 comments

Assessing hygiene cost-effectiveness: a methodology, 2012.

Amélie Dubé, Peter Burr, Alana Potter and Maarten van de Reep. IRC International Water and Sanitation Centre

This Working Paper describes a methodological framework that is being proposed to assess the cost-effectiveness of a number of hygiene interventions. Currently being tested in Ghana, Burkina Faso, Mozambique and Andhra Pradesh, India – the methodology is designed to:

  • Capture the financial costs of labour and materials associated with the intervention, using a three-step approach. First, costs are categorised (e.g., investment costs, maintenance costs, etc.); second, data is gathered and basic statistic treatments are applied; finally, other economic costs (e.g., cost of health) are valued as financial costs.
  • Examine three key household hygiene behaviours: faecal containment and latrine use, handwashing with soap, and drinking-water management; and assess their levels of effectiveness. The levels – defined in a hygiene effectiveness ladder – allow for the systematic categorisation of hygiene behaviour data; from ‘not effective’ to ‘improved’. Several flowcharts are also introduced as tools to simplify data capture and the identification of failure points (if any), within the chain of events of certain hygienic practices and behaviours.

The cost-effectiveness measure of each intervention is intended to result in a comparison of household costs with measured efficacy, in terms of behaviour change: moving from one set of behaviours (prior to intervention) to the current set of behaviours (post intervention). The proposed methodology aims to provide further evidence for policy decision-making and investment in the WASH and public health sectors. As it in its testing phase, this working paper also articulates its main limitations.

Use of household water treatment and safe storage methods in acute emergency response

September 11, 2012 · 0 comments

Use of household water treatment and safe storage methods in acute emergency response: case study results from Nepal, Indonesia, Kenya, and Haiti. Environ. Sci. Technol., September 10, 2012.

Daniele S. Lantagne and Thomas F. Clasen

Household water treatment (HWTS) methods, such as boiling or chlorination, have long been recommended in emergencies. While there is increasing evidence of HWTS efficacy in the development context, effectiveness in the acute emergency context has not been rigorously assessed. We investigated HWTS effectiveness in response to four acute emergencies by surveying 1,521 targeted households and testing stored water for free chlorine residual and fecal indicators. We defined “effective use” as the percentage of the targeted population with contaminated household water who used the HWTS method to improve stored drinking water microbiological quality to internationally-accepted levels.

Chlorine-based methods were distributed in all four emergencies, and filters in one emergency. Effective use ranged widely, from 0%-67.5%, with only one pre-existing chlorine program in Haiti and unpromoted boiling use in Indonesia reaching >20%. More successful programs provided an effective HWTS method, with the necessary supplies and training provided, to households with contaminated water who were familiar with the method before the emergency. HWTS can be effective at reducing the risk of unsafe drinking water in the acute emergency context. Additionally, by focusing on whether interventions actually improve drinking water quality in vulnerable households, “effective use” provides an important program evaluation metric.

Speeding up the solar water disinfection process (SODIS) against Cryptosporidium parvum

September 6, 2012 · 0 comments

Acta Trop. 2012 Aug 31.

Speeding up the solar water disinfection process (SODIS) against Cryptosporidium parvum by using 2.5 l static solar reactors fitted with compound parabolic concentrators (CPCs).

Gómez-Couso H, Fontán-Sainz M, Fernández-Ibáñez P, Ares-Mazás E.

Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, A Coruña, Spain.

Water samples of 0, 5, and 100 nephelometric turbidity units (NTU) spiked with Cryptosporidium parvum oocysts were exposed to natural sunlight in 2.5 l static borosilicate solar reactors fitted with two different compound parabolic concentrators (CPCs), CPC1 and CPC1.89, with concentration factors of the solar radiation of 1 and 1.89, respectively. The global oocyst viability was calculated by the evaluation of the inclusion/exclusion of the fluorogenic vital dye propidium iodide and the spontaneous excystation. Thus, the initial global oocyst viability of the C. parvum isolate used was 95.3±1.6%.

Using the solar reactors fitted with CPC1, the global viability of oocysts after 12h of exposure was zero in the most turbid water samples (100 NTU) and almost zero in the other water samples (0.3±0.0% for 0 NTU and 0.5±0.2% for 5 NTU). Employing the solar reactors fitted with CPC1.89, after 10h exposure, the global oocyst viability was zero in the non-turbid water samples (0 NTU), and it was almost zero in the 5 NTU water samples after 8h of exposure (0.5±0.5%). In the most turbid water samples (100 NTU), the global viability was 1.9±0.6% after 10 and 12h of exposure.

In conclusion, the use of these 2.5 l static solar reactors fitted with CPCs significantly improved the efficacy of the SODIS technique as these systems shorten the exposure times to solar radiation, and also minimize the negative effects of turbidity. This technology therefore represents a good alternative method for improving the microbiological quality of household drinking water in developing countries.

Impact of a School-Based Hygiene Promotion and Sanitation Intervention on Pupil Hand Contamination

September 6, 2012 · 1 comment

Am J Trop Med Hyg, Sept 2012 87:385-393; doi:10.4269/ajtmh.2012.11-0633

Impact of a School-Based Hygiene Promotion and Sanitation Intervention on Pupil Hand Contamination in Western Kenya: A Cluster Randomized Trial

Leslie E. Greene, Matthew C. Freeman, Daniel Akoko, Shadi Saboori, Christine Moe, and Richard Rheingans

Handwashing with soap effectively reduces exposure to diarrhea-causing pathogens. Interventions to improve hygiene and sanitation conditions in schools within low-income countries have gained increased attention; however, their impact on schoolchildren’s exposure to fecal pathogens has not been established. Our trial examined whether a school-based water, sanitation, and hygiene intervention reduced Escherichia coli contamination on pupils’ hands in western Kenya.

A hygiene promotion and water treatment intervention did not reduce risk of E. coli presence (relative risk [RR] = 0.92, 95% confidence interval [CI] = 0.54–1.56); the addition of new latrines to intervention schools significantly increased risk among girls (RR = 2.63, 95% CI = 1.29–5.34), with a non-significant increase among boys (RR = 1.36, 95% CI = 0.74–2.49). Efforts to increase usage of school latrines by constructing new facilities may pose a risk to children in the absence of sufficient hygiene behavior change, daily provision of soap and water, and anal cleansing materials.

 

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