scholarly journals Sodium hypochlorite dosage for household and emergency water treatment: updated recommendations

2017 ◽  
Vol 16 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Natalie Wilhelm ◽  
Anya Kaufmann ◽  
Elizabeth Blanton ◽  
Daniele Lantagne
Keyword(s):  
Water Treatment ◽  
Sodium Hypochlorite ◽  
Diarrheal Disease ◽  
Microbiological Quality ◽  
Water Source ◽  
Field Studies ◽  
Household Water Treatment ◽  
E Coli ◽  
Log Reduction ◽  
Household Water

Abstract Household water treatment with chlorine can improve the microbiological quality of household water and reduce diarrheal disease. We conducted laboratory and field studies to inform chlorine dosage recommendations. In the laboratory, reactors of varying turbidity (10–300 NTU) and total organic carbon (0–25 mg/L addition) were created, spiked with Escherichia coli, and dosed with 3.75 mg/L sodium hypochlorite. All reactors had >4 log reduction of E. coli 24 hours after chlorine addition. In the field, we tested 158 sources in 22 countries for chlorine demand. A 1.88 mg/L dosage for water from improved sources of <5 or <10 NTU turbidity met free chlorine residual criteria (≤2.0 mg/L at 1 hour, ≥0.2 mg/L at 24 hours) 91–94% and 82–87% of the time at 8 and 24 hours, respectively. In unimproved water source samples, a 3.75 mg/L dosage met relaxed criteria (≤4.0 mg/L at 1 hour, ≥0.2 mg/L after 24 hours) 83% and 65% of the time after 8 and 24 hours, respectively. We recommend water from improved/low turbidity sources be dosed at 1.88 mg/L and used within 24 hours, and from unimproved/higher turbidity sources be dosed at 3.75 mg/L and consumed within 8 hours. Further research on field effectiveness of chlorination is recommended.

Microbiological quality of chlorinated water after storage in ceramic pots

2012 ◽  
Vol 2 (4) ◽  
pp. 250-253 ◽  
Author(s):  
Clair Null ◽  
Daniele Lantagne
Keyword(s):  
Storage Time ◽  
Diarrheal Disease ◽  
Microbiological Quality ◽  
World Health ◽  
Household Water Treatment ◽  
E Coli ◽  
Guideline Values ◽  
Household Water ◽  
Rural Kenya ◽  
Health Organization

Household water treatment with sodium hypochlorite has been shown to reduce self-reported diarrheal disease in developing countries. Reported hypochlorite use, time since treatment, total chlorine residual (TCR), and E. coli concentration results from 589 household surveys in rural Kenya were analyzed to quantify the effect of exceeding recommended 24 hour post-treatment water storage time in ceramic pots. Exceeding storage time recommendations impacted treatment efficacy, as 87% of reported treaters with TCR ≥ 0.2 mg/L storing their water ≤ 24 hours met World Health Organization (WHO) E. coli guideline values, compared to 77% of reported treaters with TCR ≥ 0.2 mg/L storing water >24 hours (p = 0.024) and 7% of reported non-treaters. Implementing organizations face the trade-off between promoting treating water every 24 hours and accepting slightly compromised efficacy.

Current practices in manufacturing locally-made ceramic pot filters for water treatment in developing countries

2013 ◽  
Vol 3 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Justine Rayner ◽  
Brian Skinner ◽  
Daniele Lantagne
Keyword(s):  
Quality Control ◽  
Water Treatment ◽  
Best Practice ◽  
Diarrheal Disease ◽  
Microbiological Quality ◽  
Household Water Treatment ◽  
Production Methods ◽  
Household Water ◽  
Control Procedures

Locally produced ceramic pot filters have been shown to improve the microbiological quality of household drinking water and reduce the burden of diarrheal disease in users. They are considered one of the most promising household water treatment methods. However, overarching manufacturing and quality control guidelines do not exist for the 35 decentralized filter factories in 18 countries that currently produce filters. In this study, we conducted manufacturing process surveys with 25 filter factories worldwide to document production methods and identify areas where manufacturing and quality control guidelines are needed. Our results show that manufacturing processes vary widely both between and within factories, including the consistency of materials, manufacturing methods, and quality control practices. These variations pose concerns about the consistency and quality of locally produced filters in the absence of standardized quality control procedures. We propose areas where manufacturing guidelines are needed to assist factories in producing consistently high quality filters, and identify topics where further research is needed to refine manufacturing recommendations. These results guided the development of a best practice manual that described consensus-based recommendations to advance consistent, quality-controlled filter production world-wide.

Assessment of the quality, effectiveness, and acceptability of ceramic water filters in Tanzania

2016 ◽  
Vol 6 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Ansley Lemons ◽  
Ariel Branz ◽  
Mesiaki Kimirei ◽  
Tracy Hawkins ◽  
Daniele Lantagne
Keyword(s):  
Flow Rate ◽  
Mixed Methods Research ◽  
Diarrheal Disease ◽  
Group Discussions ◽  
Household Water Treatment ◽  
Ceramic Filters ◽  
E Coli ◽  
Ceramic Water Filters ◽  
Household Water

Globally, approximately two billion people drink contaminated water. Use of household water treatment (HWT) methods, such as locally manufactured ceramic filters, reduces the diarrheal disease burden associated with unclean water. We evaluated the quality, effectiveness, and acceptability of ceramic filters in two communities in Arusha, Tanzania, by conducting: 1) baseline household surveys with 50 families; 2) filter flow rate testing; 3) filter distribution with training sessions; 4) follow-up surveys at 2, 4, and 6 weeks after distribution; and 5) project end focus group discussions. We tested Escherichia coli (E. coli) and turbidity at baseline and the first two follow-ups. We found: 1) filter quality was low, as only 46% of filters met recommended flow rate guidelines and 18% of filters broke during the 6-week study; 2) filter effectiveness was moderate, with 8% and 35% of filters effectively reducing E. coli to <1 CFU/100 mL and <10 CFU/100 mL, respectively, at follow-ups; and, 3) filter acceptability was high, with 94% overall satisfaction and 96–100% reported use in the previous day. These results highlight the importance of mixed methods research as HWT product quality, effectiveness, and acceptability all impact product efficacy, and the need for quality assurance/quality control and certification schemes for locally manufactured HWT products.

scholarly journals A rapid assessment of drinking water quality in informal settlements after a cholera outbreak in Nairobi, Kenya

2014 ◽  
Vol 13 (3) ◽  
pp. 714-725 ◽  
Author(s):  
Elizabeth Blanton ◽  
Natalie Wilhelm ◽  
Ciara O'Reilly ◽  
Everline Muhonja ◽  
Solomon Karoki ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Treatment ◽  
Disease Transmission ◽  
Rapid Assessment ◽  
Informal Settlements ◽  
Epidemic Disease ◽  
Household Water Treatment ◽  
E Coli ◽  
Household Water ◽  
Water And Sanitation Infrastructure

Populations living in informal settlements with inadequate water and sanitation infrastructure are at risk of epidemic disease. In 2010, we conducted 398 household surveys in two informal settlements in Nairobi, Kenya with isolated cholera cases. We tested source and household water for free chlorine residual (FCR) and Escherichia coli in approximately 200 households. International guidelines are ≥0.5 mg/L FCR at source, ≥0.2 mg/L at household, and <1 E. coli/100 mL. In these two settlements, 82% and 38% of water sources met FCR guidelines; and 7% and 8% were contaminated with E. coli, respectively. In household stored water, 82% and 35% met FCR guidelines and 11% and 32% were contaminated with E. coli, respectively. Source water FCR ≥0.5 mg/L (p = 0.003) and reported purchase of a household water treatment product (p = 0.002) were associated with increases in likelihood that household stored water had ≥0.2 mg/L FCR, which was associated with a lower likelihood of E. coli contamination (p < 0.001). These results challenge the assumption that water quality in informal settlements is universally poor and the route of disease transmission, and highlight that providing centralized water with ≥0.5 mg/L FCR or (if not feasible) household water treatment technologies reduces the risk of waterborne cholera transmission in informal settlements.

scholarly journals Chitosan Coagulation Pretreatment to Enhance Ceramic Water Filtration for Household Water Treatment

2021 ◽  
Vol 22 (18) ◽  
pp. 9736
Author(s):  
Collin Knox Coleman ◽  
Eric Mai ◽  
Megan Miller ◽  
Shalini Sharma ◽  
Clark Williamson ◽  
...  
Keyword(s):  
Water Treatment ◽  
Diarrheal Disease ◽  
Continuous Treatment ◽  
Water Filtration ◽  
Culture Methods ◽  
Household Water Treatment ◽  
Virus Removal ◽  
Treated Effluent ◽  
Life Years ◽  
Household Water

Viruses are major contributors to the annual 1.3 million deaths associated with the global burden of diarrheal disease morbidity and mortality. While household-level water treatment technologies reduce diarrheal illness, the majority of filtration technologies are ineffective in removing viruses due to their small size relative to filter pore size. In order to meet the WHO health-based tolerable risk target of 10−6 Disability Adjusted Life Years per person per year, a drinking water filter must achieve a 5 Log10 virus reduction. Ceramic pot water filters manufactured in developing countries typically achieve less than 1 Log10 virus reductions. In order to overcome the shortfall in virus removal efficiency in household water treatment filtration, we (1) evaluated the capacity of chitosan acetate and chitosan lactate, as a cationic coagulant pretreatment combined with ceramic water filtration to remove lab cultured and sewage derived viruses and bacteria in drinking waters, (2) optimized treatment conditions in waters of varying quality and (3) evaluated long-term continuous treatment over a 10-week experiment in surface waters. For each test condition, bacteria and virus concentrations were enumerated by culture methods for influent, controls, and treated effluent after chitosan pretreatment and ceramic water filtration. A > 5 Log10 reduction was achieved in treated effluent for E.coli, C. perfringens, sewage derived E. coli and total coliforms, MS2 coliphage, Qβ coliphage, ΦX174 coliphage, and sewage derived F+ and somatic coliphages.

scholarly journals Antibacterial and antiviral effectiveness of two household water treatment devices that use monobrominated hydantoinylated polystyrene

2016 ◽  
Vol 14 (6) ◽  
pp. 950-960
Author(s):  
Kyle S. Enger ◽  
Emaly S. Leak ◽  
Tiong Gim Aw ◽  
Angela D. Coulliette ◽  
Joan B. Rose
Keyword(s):  
Developing Countries ◽  
Water Treatment ◽  
Diarrheal Disease ◽  
Human Adenovirus ◽  
Murine Norovirus ◽  
Household Water Treatment ◽  
Bacteriophage Ms2 ◽  
Household Water ◽  
Before And After ◽  
Antimicrobial Effectiveness

Many different household water treatment (HWT) methods have been researched and promoted to mitigate the serious burden of diarrheal disease in developing countries. However, HWT methods using bromine have not been extensively evaluated. Two gravity-fed HWT devices (AquaSure™ and Waterbird™) were used to test the antimicrobial effectiveness of HaloPure® Br beads (monobrominated hydantoinylated polystyrene) that deliver bromine. As water flows over the beads, reactive bromine species are eluted, which inactivate microorganisms. To assess log10 reduction values (LRVs) for Vibrio cholerae, Salmonella enterica Typhimurium, bacteriophage MS2, human adenovirus 2 (HAdV2), and murine norovirus (MN), these organisms were added to potable water and sewage-contaminated water. These organisms were quantified before and after water treatment by the HWT devices. On average, 6 LRVs against Vibrio were attained, as well as 5 LRVs against Salmonella, 4 LRVs against MS2, 5 LRVs against HAdV2, and 3 LRVs against MN. Disinfection was similar regardless of whether sewage was present. Polymer beads delivering bromine to drinking water are a potentially effective and useful component of HWT methods in developing countries.

scholarly journals Residual Maintenance Using Sodium Hypochlorite, Sodium Dichloroisocyanurate, and Chlorine Dioxide in Laboratory Waters of Varying Turbidity

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1309 ◽  
Author(s):  
Karin Gallandat ◽  
David Stack ◽  
Gabrielle String ◽  
Daniele Lantagne
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Storage Time ◽  
Water Storage ◽  
Decay Rates ◽  
Kaolin Clay ◽  
Household Water Treatment ◽  
E Coli ◽  
Household Water ◽  
Sodium Dichloroisocyanurate

Sodium hypochlorite (NaOCl) and sodium dichloroisocyanurate (NaDCC) are commonly used for household water treatment (HWT); chlorine dioxide (ClO2) is a potential new HWT option. We compared the residual maintenance of NaOCl, NaDCC, and ClO2 over 24 hours using recommended dosages (2 and 4 mg/L) in waters of varying turbidity (0–300 NTU, from kaolin clay or creek-bottom sediments) and total organic carbon (TOC) concentrations (0–100 mg/L), for a total of 324 reactors. NaOCl and NaDCC had similar free chlorine decay rates, and ClO2 decayed more rapidly across all of the tested conditions. Little variability was observed across clay-based turbidity levels and TOC concentrations. With a dosage of 2 mg/L, a residual ≥0.2 mg/L was maintained at 30 NTU for NaOCl and 100 NTU for NaDCC; for ClO2, 4 mg/L were required to maintain ≥0.2 mg/L under all conditions except at zero turbidity. Comparisons with data from the literature suggest that the three compounds would inactivate E. coli, rotavirus, and Giardia cysts within 1 hour under all conditions, except 300 NTU for NaOCl and NaDCC. All three disinfectants are similarly efficacious for this usage; however, differences are seen in decay rates that may influence disinfectant selection depending on water storage time.

scholarly journals Laboratory efficacy and field effectiveness of hollow fiber membrane microfilters used for household water treatment in Honduras

2017 ◽  
Vol 7 (1) ◽  
pp. 74-84 ◽  
Author(s):  
Anna L. Murray ◽  
Barbara Stewart ◽  
Catherine Hopper ◽  
Ellen Tobin ◽  
Jimmy Rivera ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Waters ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Geometric Mean ◽  
International Standards ◽  
Fiber Membrane ◽  
Household Water Treatment ◽  
E Coli ◽  
Household Water

The Sawyer PointONE™ hollow fiber membrane filter is increasingly promoted for long-term household water treatment in developing countries. Limited data demonstrate PointONE™ microbiological laboratory efficacy and short-term diarrheal disease reduction among users, but household microbiological data is lacking. To compare laboratory and household PointONE™ filter microbiological performance, we enumerated Escherichia coli (E. coli) and total coliforms in source and filtrate water from: (1) one new filter with E. coli-spiked water (107–109 CFU/100 mL) in the laboratory, (2) one new filter with natural Maine and Honduran surface waters, and (3) 50 filters used in Honduran homes for 1–3 years. In laboratory tests, all filtrate samples had <1 CFU/100 mL E. coli (>99.99999% reduction). In natural surface waters, all filtrate samples had ≤1 MPN/100 mL E. coli (≥99.5% reduction). In households, filtrate samples had geometric mean 5.1 MPN/100 mL E. coli (90% reduction), with only 30% of filtrate samples complying with international standards of undetectable E. coli. Total coliform presence in natural water filtrate varied for both new and household filters. The discrepancy between laboratory and household results and premature filter failure are not well understood. Further research is recommended to understand this performance disparity and determine filter failure mechanisms in households.

scholarly journals A comparative study on the effect of household water treatment on diarrhoea morbidity among under-fives in Plateau State, Nigeria using two treatment modalities

2020 ◽  
Vol 8 (05) ◽  
pp. 1789-1799
Author(s):  
Elizabeth Onyi Okoh ◽  
Esther Awazzi Envuladu ◽  
Chundung Asabe Miner ◽  
Amina Mohammed ◽  
Gloria Nengi Ode ◽  
...  
Keyword(s):  
Water Treatment ◽  
Rural Communities ◽  
Sodium Hypochlorite ◽  
Intervention Group ◽  
Control Group ◽  
Sodium Hypochlorite Solution ◽  
Household Water Treatment ◽  
Significant Difference ◽  
Household Water ◽  
Plateau State

Background: Consumption of unsafe water contributes to diarrhoeal burden in sub-Sahara Africa. This burden can be reduced by simple and affordable methods of household water treatment. The study aims at comparing the effect of two of such methods on diarrheal burden among under-fives in rural communities of Plateau State. Methodology: A community-based quasi experimental study was conducted among 202 underfive-caregiver pairs in two selected rural communities of Plateau State, involving household water treatment with flocculant-disinfectant powder in intervention group and sodium hypochlorite solution in control group respectively. History of diarrhoea before intervention, at 2 weekly intervals during the intervention and after intervention was assessed. Data obtained was analyzed using SPSS version 23. Prevalence and incidence of diarrhoea were calculated and compared among the two groups. Result: Diarrhoea prevalence at pre-intervention was 19.6% in flocculant-disinfectant group and 17.0% in sodium hypochlorite group. At post intervention, the prevalence reduced significantly by 94.7% (19.6% to 1%) in intervention group and by 76.5% (17% to 4.2%) in control group. There was no statistical significant difference in the prevalence of diarrhoea between the two groups, however, diarrhoea incidence in the sodium hypochlorite group (1.12 episode per child per year) was significantly higher than the incidence in the flocculant-disinfectant group (0.59 episodes per child per year) with a  risk-ratio of 1.93 (95% CI: 1.037 - 3.703). Conclusion: Household water treatment with flocculant-disinfectant reduced diarrhoea burden better than sodium hypochlorite. This technology should be made more available and assessible to rural communities where diarrhea burden is high.

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