Analysis of enterococci using portable testing equipment for developing countries – variance of Azide NutriDisk medium under variable time and temperature

2006 ◽  
Vol 54 (3) ◽  
pp. 127-134 ◽  
Author(s):  
S. Godfrey ◽  
J. Watkins ◽  
K. Toop ◽  
C. Francis
Keyword(s):  
Developing Countries ◽  
Drinking Water ◽  
Standard Method ◽  
Incubation Time ◽  
Membrane Filtration ◽  
Culture Medium ◽  
Incubation Temperature ◽  
Field Testing ◽  
Test Analysis ◽  
Survival Threshold

This report compares the enterococci count on samples obtained with Azide NutriDisk (AND) (sterile, dehydrated culture medium) and Slanetz & Bartley (SB) medium when exposed to a variable in incubation time and temperature. Three experiments were performed to examine the recovery of enterococci on AND and SB media using membrane filtration with respect to: (a) incubation time; (b) incubation temperature; and (c) a combination of the two. Presumptive counts were observed at 37, 41, 46 and 47 °C and at 20, 24, 28 and 48 h. These were compared to AWWA standard method 9230 C (44 °C, 44 h). Samples were confirmed using Kanamycin Aesculin Azide (KAA) agar. Friedman's ANOVA and Students t-test analysis indicated higher enumeration of enterococci when grown on AND (p=0.45) than SB (p=<0.001) at all temperatures with a survival threshold at 47 °C. Significant results for AND medium were noted at 20 h (p=0.021), 24 h (p=0.278) and 28 h (p=0.543). The study concluded that the accuracy of the AND medium at a greater time and temperature range provided flexibility in incubator technology making it an appropriate alternative to SB medium for monitoring drinking water using field testing kits in developing countries.

scholarly journals Presence of Helicobacter pylori in drinking water of Karachi, Pakistan

2011 ◽  
Vol 6 (03) ◽  
pp. 251-255 ◽  
Author(s):  
Adnan Khan ◽  
Amber Farooqui ◽  
Shahana Urooj Kazmi
Keyword(s):  
Developing Countries ◽  
Helicobacter Pylori ◽  
Drinking Water ◽  
Environmental Factors ◽  
Metropolitan Area ◽  
Membrane Filtration ◽  
Filtration Method ◽  
Contaminated Drinking Water ◽  
H Pylori ◽  
Drinking Water Samples

Background: Prevalence of Helicobacter pylori (H. pylori) infection is an increasing problem in developing countries. Several environmental factors such as overcrowding, poverty, contaminated drinking water and food are considered to contribute toward transmission of infection; however, little is known about their definitive roles. The aim of this study is to investigate the presence of H. pylori in drinking water samples of Karachi, Pakistan. Methodology: Samples of drinking water were collected from 18 different towns located in the metropolitan area of Karachi. Samples were concentrated by membrane filtration method and subjected to PCR for the detection of H. pylori. Results: Two out of 50 (4%) samples collected from two different densely populated town areas were found to be positive for H. pylori. Conclusion: The study provides evidence for the presence of H. pylori in municipal drinking water of Karachi.

Appropriate technologies for environmental hygiene

1980 ◽  
Vol 209 (1174) ◽  
pp. 37-46 ◽  
Keyword(s):  
Developing Countries ◽  
Drinking Water ◽  
Rural Areas ◽  
Low Cost ◽  
Field Testing ◽  
Water And Sanitation ◽  
Environmental Hygiene ◽  
Major Constraint ◽  
Effective Delivery ◽  
The Face

Appropriate technologies for environmental hygiene usually centre on the delivery of adequate and accessible water supply, and proper treat­ment and disposal of excreta and refuse. In the face of the International Drinking Water and Sanitation Decade of 1981-90, several research efforts are under way in the developing countries to develop technologies and approaches for improving environmental hygiene in both rural areas and urban squatter settlements. These are discussed and include the technical development and field testing of infiltration galleries, low-cost slow and fast filtration processes for water treatment, handpumps, on-site excreta disposal using aqua-privy and compost toilets, and excreta treatment and refuse through composting with refuse, biogas generation, fish culture and use of excreta as crop fertilizer. The relevant technology ‘hardware’ is but one of several components necessary for effective delivery of services. The dearth of qualified manpower at all levels is described as being the major constraint to the Water and Sanitation Decad.

Sexuality-related conditions: A multistakeholder approach to explore feasibility of field-testing ICD-11 revisions in developing countries.

2016 ◽  
Vol 5 (3) ◽  
pp. 184-191 ◽  
Author(s):  
Megan M. Campbell ◽  
Rebeca Robles ◽  
Denise L. Vieira ◽  
Brigitte Khoury ◽  
Saria Daouk ◽  
...  
Keyword(s):  
Developing Countries ◽  
Field Testing

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

Monitoring and maintaining the integrity of immersed ultrafiltration membranes used for pathogen protection

2002 ◽  
Vol 2 (5-6) ◽  
pp. 307-311
Author(s):  
P. Côté ◽  
J. Cadera ◽  
N. Adams ◽  
G. Best
Keyword(s):  
Drinking Water ◽  
Membrane Filtration ◽  
Ultrafiltration Membranes ◽  
Vacuum Decay ◽  
Integrity Monitoring ◽  
Pressure Decay ◽  
Decay Test ◽  
Conventional Technology ◽  
Water Borne

Membrane filtration has become the preferred alternative to conventional technology to remove water-borne pathogens in the preparation of drinking water. This paper presents the integrity monitoring and maintenance options for the ZeeWeed® immersed membrane. Results from two versions of air-based tests, a pressure decay test and a vacuum decay test are presented and shown to be conservative when compared to challenge results from independent studies.

Lead removal from drinking water - development and validation of point-of-use treatment devices

2002 ◽  
Vol 2 (5-6) ◽  
pp. 209-216
Author(s):  
R. Sublet ◽  
A. Boireau ◽  
V.X. Yang ◽  
M.-O. Simonnot ◽  
C. Autugelle
Keyword(s):  
Drinking Water ◽  
Fixed Bed ◽  
Field Testing ◽  
Lead Removal ◽  
Ministry Of Health ◽  
Point Of Use ◽  
Taste And Odor ◽  
Wide Range ◽  
Lead Levels ◽  
Safety Considerations

Two lead removal water filters were developed to lower lead levels in drinking water below 10 μg.L-1 in order to meet the new regulation given by the European Directive 98-83, applicable in December 2013. An appropriate adsorbent was selected through a stringent research program among a wide range of media, and is composed of a synthetic zeolite and an activated carbon. Two prototypes were developed: the first is a faucet-mounted filter which contains a fixed bed of the adsorbent and a hollow fiber bundle, while the second is an under-sink cartridge made of a porous extruded block of carbon and adsorbent. Both are able to treat at least 1,000 litres of any water containing on average 100 to 150 μg Pb.L-1, by lowering the lead concentration below 10 μg.L-1. Once their safety considerations were addressed by an independent laboratory according to the French Ministry of Health recommendations, 20 prototypes were installed at consumers' taps in northeastern France. Their performance in terms of lead removal, HPC control and bad taste and odor reduction was followed for 6 months. This field testing program resulted in the validation of both prototypes which meet the new French Ministry of Health recommendations and assures that the filtered water is fully ED 98-83 compliant. Their commercialization will be launched first in France in middle 2002.

Water Quality and Health

1991 ◽  
Vol 23 (1-3) ◽  
pp. 201-209 ◽  
Author(s):  
W. Kreisel
Keyword(s):  
Water Quality ◽  
Developing Countries ◽  
Drinking Water ◽  
Water Supply ◽  
Human Health ◽  
Pollution Control ◽  
Wastewater Reuse ◽  
Water Supplies ◽  
Minimum Quality Standards ◽  
Quality Guidelines

Water quality can affect human health in various ways: through breeding of vectors, presence of pathogenic protozoa, helminths, bacteria and viruses, or through inorganic and organic chemicals. While traditional concern has been with pathogens and gastro-intestinal diseases, chemical pollutants in drinking-water supplies have in many instances reached proportions which affect human health, especially in cases of chronic exposure. Treatment of drinking-water, often grossly inadequate in developing countries, is the last barrier of health protection, but control at source is more effective for pollution control. Several WHO programmes of the International Drinking-Water Supply and Sanitation Decade have stimulated awareness of the importance of water quality in public water supplies. Three main streams have been followed during the eighties: guidelines for drinking-water quality, guidelines for wastewater reuse and the monitoring of freshwater quality. Following massive investments in the community water supply sector to provide people with adequate quantities of drinking-water, it becomes more and more important to also guarantee minimum quality standards. This has been recognized by many water and health authorities in developing countries and, as a result, WHO cooperates with many of them in establishing water quality laboratories and pollution control programmes.

Viruses and Water: Problems, Detection, and Control

1993 ◽  
Vol 27 (7-8) ◽  
pp. 127-133 ◽  
Author(s):  
H. Dizer ◽  
J. Dürkop ◽  
A. Grohmann ◽  
H. Kopecka ◽  
J. M. López-Pila
Keyword(s):  
Drinking Water ◽  
Surface Waters ◽  
Membrane Filtration ◽  
Wastewater Treatment Plants ◽  
Health Hazard ◽  
Primary Source ◽  
Detection Methods ◽  
Secondary Effluent ◽  
Naturally Occurring ◽  
Water Problems

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer. We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages. Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.

H2S papers as presumptive tests for Salmonella contamination in tropical drinking water

1996 ◽  
Vol 34 (7-8) ◽  
pp. 187-194 ◽  
Author(s):  
Tanya Gawthorne ◽  
Robyn A. Gibbs ◽  
Kuruvilla Mathew ◽  
Goen E. Ho
Keyword(s):  
Drinking Water ◽  
Hydrogen Sulphide ◽  
Incubation Temperature ◽  
Indicator Bacteria ◽  
Coliform Bacteria ◽  
Salmonella Spp ◽  
Faecal Contamination ◽  
Tropical Waters ◽  
Remote Areas ◽  
Traditional Indicator

Coliform bacteria may not be adequate as sole indicators of recent faecal contamination in tropical waters. Salmonella spp. in particular have been found in tropical waters in the absence of traditional indicator bacteria. Remote areas without access to a laboratory have no opportunity for salmonellae analysis as portable tests are currently not available. H2S papers indicate the presence of hydrogen sulphide producing bacteria, a characteristic shared by the majority of Salmonella spp.. The potential of H2S papers to act as a presumptive test for salmonellae in the absence of coliform bacteria was assessed. Salmonella spp. grew in the H2S medium, with an optimum incubation temperature of 37°C and a recommended length of incubation for a negative result of 48 hours. The presence of high numbers of the type of noncoliform bacteria commonly found in drinking water did not affect the performance of the H2S strips. H2S papers are recommended for use in conjunction with a coliform test as a presumptive test for the presence of Salmonella spp. in drinking water.

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