Development and evaluation of a small scale water disinfection system

2016 ◽  
Vol 6 (3) ◽  
pp. 389-400 ◽  
Author(s):  
Dorcas Alfa ◽  
Sudesh Rathilal ◽  
V. L. Pillay ◽  
Kumnandi Pikwa ◽  
Martha N. Chollom
Keyword(s):  
Rural Areas ◽  
Water Disinfection ◽  
Woven Fabric ◽  
Small Scale ◽  
E Coli ◽  
Point Of Use ◽  
Quality Of Water ◽  
Two Factors ◽  
Gravity Driven ◽  
High Turbidity

Provision of microbiologically safe drinking water for people living in the rural areas of developing countries remains a major challenge to date. A simple gravity-driven membrane point of use system was developed based on woven fabric microfiltration (WFMF) membranes. The WFMF is a loose type of membrane (0.45 μm). However, complete disinfection is not achieved with the WFMF, hence it was incorporated with two disinfectants. This study aimed to combine the WFMF with two disinfectants (WaterGuard and bromochlor tablets) to bring the water to the accepted quality for drinking. Four different types of water were sourced, considering two factors: E. coli and turbidity content. The WFMF demonstrated excellent filtration performance by producing permeates with turbidity less than 1 NTU for feed turbidity ranging between 10 and 200 NTU. There was 95–99.8% E. coli removal for raw feeds with influent E. coli ranging between 500 and 44,500 CFU/100 mL. Total disinfection was achieved with both disinfectants; however, the effectiveness of the chemical disinfectants in E. coli removal was affected by the quality of water to be disinfected. The study showed that turbidity plays a major role in disinfection performances by increasing chlorine demand on water sources with high turbidity levels.

scholarly journals A Non-electric and Affordable Surface Engineered Particle (SEP) based Point-of-Use (POU) Water Disinfection System

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Deepa Dixit ◽  
Virupakshi Soppina ◽  
Chinmay Ghoroi
Keyword(s):  
Developing Countries ◽  
Drinking Water ◽  
Low Income ◽  
Alkali Treatment ◽  
Health Hazard ◽  
Surface Hydrophobicity ◽  
Water Disinfection ◽  
Binding Property ◽  
Point Of Use ◽  
Gravity Driven

AbstractAccess to safe drinking water is still a distant dream to millions of people around the world. Especially, people from the low-income group in the developing countries remain deprived of this fundamental right and causes millions of death. There is an urgent need to develop affordable and easy to handle water filter which can provide desired drinking water quality without any electricity. In the present work, a simple and low-cost surface engineered particle (SEP) based filter is developed via alkali treatment of soda-lime-silica particle. The SEP based filter can be used as a portable, non-electric, gravity-driven Point-of-Use (POU) water disinfection system. The developed SEP-based filter is capable to arrest the 99.48% (~2 to 2.5 log10 reduction) of gram-negative bacteria Escherichia coli (E. coli OP50) on its surface from the water containing 3 × 108 cells/ml. No bacterial regrowth is observed in the purified water for 12 h. The performance of SEP bed filter is implicated to the nano-scale surface roughness, its distribution along with the surface charge and surface hydrophobicity which are favorable to attract and adhere the bacteria in the flowing water. The observation is consistent over multiple filtration cycles indicating the suitability of SEP based bed filter for POU water disinfection. The SEP surface with 0.05 mM Ag+ loading (SEP+) completely inactivated (>99.99999%) bacteria and protects any bacteria recontamination in the purified water for its long term usage. The strong and effective silver binding property of SEP surface enables very minimal silver loading and eliminates any health hazard due to low silver leaching (~50 ppb) which is well below the drinking water equivalent level (DWEL ≤ 100 ppb). In rural and urban slum areas of developing countries where no water purification system exists prior to consumption, the easy-to-implement and affordable SEP-based gravity-driven non-electric point-of-use water purifier (materials cost ~ 0.25 USD) can be used to protect millions of lives from water borne diseases.

Contamination of drinking water between source and point-of-use in rural households of South Africa and Zimbabwe: implications for monitoring the Millennium Development Goal for water

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
Stephen W. Gundry ◽  
James A. Wright ◽  
Ronan Conroy ◽  
Martella Du Preez ◽  
Bettina Genthe ◽  
...  
Keyword(s):  
South Africa ◽  
Drinking Water ◽  
Millennium Development Goal ◽  
Significant Deterioration ◽  
Development Goal ◽  
E Coli ◽  
Safe Water ◽  
Point Of Use ◽  
Quality Of Water

Aims: To assess contamination of drinking water in rural Zimbabwe and South Africa Methods: We conducted a cohort study of 254 children aged 12-24 months in rural South Africa and Zimbabwe. In dry and wet seasons, we measured water quality, using the indicator organism E. coli, at improved and unimproved sources, in household storage and drinking cups. We also recorded hygiene and socio-economic factors for each household. Results: For improved sources, samples with E. coli counts less than 10 cfu/100ml were as follows: at source: 165 (88%); in household storage 137 (59%); in drinking cups 91 (49%). The corresponding values for unimproved sources were: source 47 (29%); household storage 32 (19%); drinking cups 21 (18%). This significant deterioration in microbial quality of water from improved sources was seen in both countries and both survey rounds. Conclusion: Although improved sources generally delivered ‘safe’ water at the point-of-supply, 12% of source samples were contaminated and as such were ‘unsafe’. Furthermore, in household storage, more than 40% of samples were ‘unsafe’. For monitoring the Millennium Development Goal for water, UNICEF-WHO are assuming an equivalence between ‘improved’ sources and ‘safe’ water. Our findings suggest that this equivalence may be unsound.

scholarly journals Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy

1999 ◽  
Vol 122 (1) ◽  
pp. 83-90 ◽  
Author(s):  
R. E. QUICK ◽  
L. V. VENCZEL ◽  
E. D. MINTZ ◽  
L. SOLETO ◽  
J. APARICIO ◽  
...  
Keyword(s):  
Water Quality ◽  
Community Education ◽  
Water Disinfection ◽  
E Coli ◽  
Safe Storage ◽  
Point Of Use ◽  
Quality Testing ◽  
New Strategy ◽  
Diarrhoea Prevention ◽  
And Control

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P=0·002). Infants <1 year old (P=0·05) and children 5–14 years old (P=0·01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P=0·02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P<0·0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

scholarly journals Molecular and phenotypic characterization of diarrheagenic Escherichia coli isolated from groundwater in rural areas in southern Brazil

2019 ◽  
Vol 17 (4) ◽  
pp. 597-608
Author(s):  
Caroline Rodrigues da Silva ◽  
Matheus Silva Sanches ◽  
Kawana Hiromori Macedo ◽  
Angélica Marim Lopes Dambrozio ◽  
Sergio Paulo Dejato da Rocha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rural Areas ◽  
Microbiological Quality ◽  
Vero Cells ◽  
Phenotypic Characterization ◽  
Human Consumption ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Quality Of Water

Abstract Water-borne diseases like diarrheagenic Escherichia coli (DEC)-induced gastroenteritis are major public health problems in developing countries. In this study, the microbiological quality of water from mines and shallow wells was analyzed for human consumption. Genotypic and phenotypic characterization of DEC strains was performed. A total of 210 water samples was analyzed, of which 153 (72.9%) contained total coliforms and 96 (45.7%) E. coli. Of the E. coli isolates, 27 (28.1%) contained DEC genes. The DEC isolates included 48.1% Shiga toxin-producing E. coli (STEC), 29.6% enteroaggregative E. coli (EAEC), 14.9% enteropathogenic E. coli (EPEC), 3.7% enterotoxigenic E. coli (ETEC), and 3.7% enteroinvasive E. coli (EIEC). All the STECs had cytotoxic effects on Vero cells and 14.8% of the DEC isolates were resistant to at least one of the antibiotics tested. All DEC formed biofilms and 92.6% adhered to HEp-2 cells with a prevalence of aggregative adhesion (74%). We identified 25 different serotypes. One EPEC isolate was serotype O44037:H7, reported for the first time in Brazil. Phylogenetically, 63% of the strains belonged to group B1. The analyzed waters were potential reservoirs for DEC and could act as a source for infection of humans. Preventive measures are needed to avoid such contamination.

scholarly journals Evaluation of a small scale water disinfection system using WFMF

2015 ◽  
Author(s):  
◽  
Dorcas Enaji Alfa
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
River Water ◽  
Water Sources ◽  
Woven Fabric ◽  
Residual Chlorine ◽  
E Coli ◽  
Quality Of Water ◽  
Rural Water

Provision of microbiologically safe drinking water for people living in the rural areas of developing countries remains a major challenge to date. One of the reasons is due to the inability to access potable water mainly because of poor existing water purification systems. Current measures have been put in place to address the challenges of rural water supply. Development of appropriate technologies such as decentralized water treatment supply in the form of point of use (POU) systems are been considered. In lieu of the above, an appropriate POU system known as the Remote Rural Water Treatment System (RRWTS) was developed at Durban University of Technology (DUT). The RRWTS is polyester based locally sourced Woven Fabric Microfiltration (WFMF) membrane system. The unit is made up of flat sheet modules that are assembled into a pack. It is a robust gravity driven system with the ability to remove suspended solids and colloids in the form of turbidity. The system has high flux of 35 ± 7 LMH and turbidity below 1 NTU, it has the ability to remove pathogens well above 95%. However, this does not comply with WHO and SANS drinking water standards of zero E. coli count/100 ml of treated water. In order to bring the water treated by RRWTS to a satisfactory level for drinking, it is then necessary to add a separate disinfection step like chlorination step to further remove the remaining microbial contaminants. Thus the main objective of the study was to evaluate the disinfection efficacy of two disinfectants namely waterguard and bromochlor tablet disinfectants and investigate their integration with the WFMF membrane. The study was categorised into three parts. The first part is the addition of disinfectants to unfiltered river water sources for the determination of residual chlorine and the most optimum dose that will yield effective disinfection and also evaluate the extent of E. coli removal by the disinfectants. The second stage was the filtration of four river water sources using the woven fibre membrane (WFM) to determine the efficiency of WFMF. Finally the effect of disinfection kinetics on disinfection was achieved by agitating the water after disinfection and allowing it to stand at different contact times. Performance of the RRWTS was determined by the amount of E. coli and turbidity removed during filtration using WFMF and by chemical disinfectants after filtration. The results on residual chlorine for different water sources showed that feed quality and disinfectant dose determines the quantity of residual chlorine on all the water sources. The effectiveness of chemical disinfectants in E. coli removal is affected by the quality of water to be disinfected. The study showed that turbidity plays a major role on disinfection by increasing chlorine demand on water sources with high turbidity levels. The WFMF demonstrated excellent filtration performance by producing permeates with turbidity less than 1 NTU for feed turbidities ranging from 10 to 200 NTU. The E. coli removal efficiency by WFMF was very high on all the water sources treated. There was 95-99.8% E. coli removal on raw feeds with influent E. coli ranging between 500 and 44500 CFU/100 ml. It was seen that major benefits are derived from integrating the WFMF (RRWTS) with chemical disinfection. The benefits includes; better disinfection that meets drinking water set guidelines of zero E. coli and improved quality of water. The need for disinfection kinetics in order to obtain superior disinfection was eliminated. The possibility of disinfection-by-product formation was reduced as smaller quantities of chemical disinfectants were required for complete disinfection on the filtered water.

scholarly journals Effect of single and combined exposures to UV-C and UV-A LEDs on the inactivation of Klebsiella pneumoniae and Escherichia coli in water disinfection

2021 ◽  
Author(s):  
María-Angélica Galezzo ◽  
Manuel Rodríguez Susa
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Water Disinfection ◽  
Dark Repair ◽  
Light Emitting ◽  
E Coli ◽  
Point Of Use ◽  
Combined Exposures ◽  
Uv Leds ◽  
Uv C

Abstract A system consisting of one UV-A (365 nm) and two UV-C (265 nm) light-emitting diodes (LEDs) was built to evaluate the effect of single and combined exposures to UV-A and UV-C LEDs on Klebsiella pneumoniae and Escherichia coli inactivation and subsequent reactivation. The dose was measured by actinometry using potassium ferrioxalate. Of laboratory prepared samples, 10 mL were irradiated for 20, 30, 45, 60 and 90 s. Logarithmic inactivation and percentages of photoreactivation and dark repair were calculated. E. coli and K. pneumoniae were reduced by more than 7 and 4 logs, respectively, at a dose of 21.5 mJ cm−2 using UV-C. No positive synergistic effect on the inactivation of the two bacteria was observed when using a simultaneous combination of UV-C and UV-A, probably due to a reactivation of the bacteria in the presence of UV-A light, which was not observed in irradiated samples under an individual exposure of 265 nm. For E. coli under 265 nm, the percentage of photoreactivation amounted to 10%, 3 h after irradiation. The results of this study demonstrated the capacity to inactivate E. coli and K. pneumoniae up to a considerable level and provide information for the application of UV LEDs in point-of-use systems.

scholarly journals Field trial of an automated batch chlorinator system at shared water points in an urban community of Dhaka, Bangladesh

2016 ◽  
Vol 6 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Nuhu Amin ◽  
Yoshika S. Crider ◽  
Leanne Unicomb ◽  
Kishor K. Das ◽  
Partha Sarathi Gope ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Low Income ◽  
Technology Development ◽  
User Preferences ◽  
Intermittent Flow ◽  
Small Scale ◽  
E Coli ◽  
Point Of Use ◽  
Colony Forming Units

Point-of-use water treatment with chlorine is underutilized in low-income households. The Zimba, an automated batch chlorinator, requires no electricity or moving parts, and can be installed at shared water points with intermittent flow. We conducted a small-scale trial to assess the acceptability and quality of Zimba-treated municipal water. Fieldworkers collected stored drinking water over a 10-week period from control (n = 24 households) and treatment (n = 30 households) compounds to assess levels of free chlorine and E. coli contamination. Overall, 80% of stored drinking water samples had a safe chlorine residual among treatment households, compared to 29% among control households (P &lt; 0.001). Concentrations of E. coli were lower (mean difference = 0.4 log colony-forming units/100 mL, P = 0.004) in treatment compared to control households. Fifty-three percent of mothers (n = 17), thought the Zimba was easy to use and 76% were satisfied with the taste. The majority of mothers mentioned that collecting water from the Zimba took more time and created a long queue at the handpump. The Zimba successfully chlorinated household stored drinking water; however, further technology development is required to address user preferences. The Zimba may be a good option for point-of-collection water treatment in areas where queuing for water is uncommon.

scholarly journals Fast Disinfection ofEscherichia coliBacteria Using Carbon Nanotubes Interaction with Microwave Radiation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Samer M. Al-Hakami ◽  
Amjad B. Khalil ◽  
Tahar Laoui ◽  
Muataz Ali Atieh
Keyword(s):  
Carbon Nanotubes ◽  
Microwave Radiation ◽  
Pathogenic Bacteria ◽  
Removal Rate ◽  
Water Disinfection ◽  
E Coli ◽  
Point Of Use ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fischer Esterification

Water disinfection has attracted the attention of scientists worldwide due to water scarcity. The most significant challenges are determining how to achieve proper disinfection without producing harmful byproducts obtained usually using conventional chemical disinfectants and developing new point-of-use methods for the removal and inactivation of waterborne pathogens. The removal of contaminants and reuse of the treated water would provide significant reductions in cost, time, liabilities, and labour to the industry and result in improved environmental stewardship. The present study demonstrates a new approach for the removal ofEscherichia coli(E. coli) from water using as-produced and modified/functionalized carbon nanotubes (CNTs) with 1-octadecanol groups (C18) under the effect of microwave irradiation. Scanning/transmission electron microscopy, thermogravimetric analysis, and FTIR spectroscopy were used to characterise the morphological/structural and thermal properties of CNTs. The 1-octadecanol (C18) functional group was attached to the surface of CNTs via Fischer esterification. The produced CNTs were tested for their efficiency in destroying the pathogenic bacteria (E. coli) in water with and without the effect of microwave radiation. A low removal rate (3–5%) of (E. coli) bacteria was obtained when CNTs alone were used, indicating that CNTs did not cause bacterial cellular death. When combined with microwave radiation, the unmodified CNTs were able to remove up to 98% of bacteria from water, while a higher removal of bacteria (up to 100%) was achieved when CNTs-C18was used under the same conditions.

scholarly journals A novel point-of-use water treatment method by antimicrobial nanosilver textile material

2014 ◽  
Vol 12 (4) ◽  
pp. 670-677 ◽  
Author(s):  
Hongjun Liu ◽  
Xiaosheng Tang ◽  
Qishan Liu
Keyword(s):  
Water Treatment ◽  
Emergency Preparedness ◽  
Rural Areas ◽  
Pathogenic Bacteria ◽  
Cost Effective ◽  
Treatment Method ◽  
Water Disinfection ◽  
Textile Material ◽  
Plastic Tube ◽  
Point Of Use

Pathogenic bacteria are one of the main reasons for worldwide water-borne disease causing a big threat to public health, hence there is an urgent need to develop cost-effective water treatment technologies. Nano-materials in point-of-use systems have recently attracted considerable research and commercial interests as they can overcome the drawbacks of traditional water treatment techniques. We have developed a new point-of-use water disinfection kit with nanosilver textile material. The silver nanoparticles were in-situ generated and immobilized onto cotton textile, followed by fixing to a plastic tube to make a water disinfection kit. By soaking and stirring the kit in water, pathogenic bacteria have been killed within minutes. The silver leaching from the kit was insignificant, with values &lt;100 ppb – the current US EPA and WHO limit for silver level in drinking water. Herein, the nanosilver textile water disinfection kit could be a new, efficient and cost-effective point-of-use water treatment method for rural areas and emergency preparedness.

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