Disinfection of bacteria in water systems by using electrolytically generated copper:silver and reduced levels of free chlorine

1990 ◽  
Vol 36 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Moyasar T. Yahya ◽  
Lee K. Landeen ◽  
Maria C. Messina ◽  
Susan M. Kutz ◽  
Richard Schulze ◽  
...  
Keyword(s):  
Drinking Water ◽  
Key Words ◽  
Tap Water ◽  
Total Coliform ◽  
Water Systems ◽  
Free Chlorine ◽  
Drinking Water Standards ◽  
Indoor And Outdoor

As an alternative disinfectant to chlorination, electrolytically generated copper:silver (400 and 40 μg/L copper and silver, respectively) with and without free chlorine (0.3 mg/L) was evaluated over a period of 4 weeks in indoor and outdoor water systems (100 L tap water with natural body flora and urine). Numbers of total coliform, pseudomonas, and staphylococci were all less than drinking water standards in systems treated with copper:silver and free chlorine and systems treated with free chlorine alone (1.0 mg/L). No significant differences (p ≤ 0.05) in bacterial numbers were observed between systems with copper:silver and free chlorine and those with free chlorine alone. Overall, free-chlorine treatments (0.3 or 1.0 mg/L) showed significantly lower heterotrophic plate numbers than those without free chlorine. When challenged with a natural Staphylococcus sp. isolate, water with copper:silver and free chlorine had a 2.4 log10 reduction in bacterial numbers within 2 min, while free chlorine alone or copper:silver alone showed 1.5 and 0.03 log10 reductions, respectively. Addition of copper:silver to water systems may allow the concentration of free chlorine to be reduced while still providing comparable sanitary quality of the water. Key words: disinfection, water, copper, silver, chlorine.

scholarly journals The health-related microbiological quality of bottled drinking water sold in Dar es Salaam, Tanzania

2006 ◽  
Vol 5 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Gabriel R. Kassenga
Keyword(s):  
Drinking Water ◽  
Heterotrophic Bacteria ◽  
Tap Water ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Dar Es Salaam ◽  
Bottled Water ◽  
Faecal Coliform ◽  
Coliform Bacteria

The consumption of bottled and plastic-bagged drinking water in Tanzania has increased largely because of the deteriorating quality of tap water. It is uncertain whether these water products are safe for drinking. In this study, the microbiological quality of bottled and plastic-bagged drinking water sold in Dar es Salaam, Tanzania, was investigated. One hundred and thirty samples representing 13 brands of bottled water collected from shops, supermarkets and street vendors were analysed for total coliform and faecal coliform organisms as well as heterotrophic bacteria. These were compared with 61 samples of tap water. Heterotrophic bacteria were detected in 92% of the bottled water samples analysed. Total and faecal coliform bacteria were present in 4.6% and 3.6%, respectively, of samples analysed with a tendency for higher contamination rates in plastic-bagged drinking water. Microbiological quality of tap water was found to be worse compared with bottled water, with 49.2% and 26.2% of sampling points showing the presence of total coliform and faecal coliform organisms, respectively. The results suggest caution and vigilance to avert outbreaks of waterborne diseases from these types of drinking water.

scholarly journals Drinking Water Quality of Kathmandu Valley

2015 ◽  
Vol 15 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Neel Kamal Koju ◽  
Tista Prasai ◽  
Sujen Man Shrestha ◽  
Prakash Raut
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Samples ◽  
Tap Water ◽  
Total Coliform ◽  
Coliform Bacteria ◽  
Kathmandu Valley ◽  
Treated Water ◽  
Who Standards

This research was conducted to analyze drinking water quality of Kathmandu valley. Total 969 water samples (392 from dug wells, 287 from deep boring, 218 from treated water, 46 from tap and 26 from other water sources) received from different places of Kathmandu, Lalitpur and Bhaktapur districts during March 2012 to March 2013. These samples were analyzed for the determination of physical (pH, temperature, conductivity, turbidity), chemical (hardness, chloride, iron, arsenic, ammonia, nitrate) and microbiological (total Coliform) parameters. It was found that the temperature and nitrate were within the WHO standards while pH, conductivity, turbidity, chloride, iron, arsenic, ammonia, and Coliform bacteria exceeded the WHO standard guideline. In ground water ( well and Boring), pH, conductivity, hardness, turbidity, iron, arsenic, chloride, ammonia and total Coliform count crossed WHO standards as 5%, 2%, 0.8%, 36%, 51%, 0.1%, 2%, 11% and 86 % respectively. Hardness was within the standard in both  reated and tap water samples. Compared to treated water, pH, arsenic and chloride were within the standard in tap water. The common problematic parameters of different sources of drinking were turbidity, iron, ammonia and conductivity. Coliform bacteria were found in 36% samples of treated water whereas 80% tap water samples were contaminated from Coliform bacteria.DOI: http://dx.doi.org/10.3126/njst.v15i1.12027Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 115-120

scholarly journals The effectiveness of disinfection and flushing procedures to prevent coliform persistence in aircraft water systems

2018 ◽  
Vol 19 (5) ◽  
pp. 1339-1346
Author(s):  
Jeffrey Szabo ◽  
Mark Rodgers ◽  
Jatin Mistry ◽  
Joshua Steenbock ◽  
John Hall
Keyword(s):  
Drinking Water ◽  
Chlorine Dioxide ◽  
Glycolic Acid ◽  
Tap Water ◽  
Water System ◽  
Water Systems ◽  
Full Scale ◽  
Free Chlorine ◽  
Drinking Water System ◽  
The One

Abstract A full-scale reproduction of an aircraft drinking water system was conditioned using municipal tap water with a mixture of free chlorine and chloramines, and subsequently contaminated with coliforms. Disinfection was undertaken using chlorine dioxide, ozone and a mixed oxidant solution followed by flushing until no disinfectant residual remained. Results showed that coliforms were not persistent on the aircraft plumbing surfaces, and coliforms were not detected after disinfection and flushing with any disinfectant. The one exception was the aerator installed in the lavatory faucet, which was coliform positive after disinfection with ozone and mixed oxidants. These data suggest that the faucet aerators could be a source of coliform contamination that may result in coliform positive samples. Further experiments conducted on disinfection of aerators with glycolic acid and quaternary ammonia (both commonly used by the airlines) showed no detectable coliforms on coliform contaminated aerators after 30 minutes of soaking in the disinfectants.

scholarly journals The Water Safety Plan Approach: Application to Small Drinking-Water Systems—Case Studies in Salento (South Italy)

2021 ◽  
Vol 18 (8) ◽  
pp. 4360
Author(s):  
Francesca Serio ◽  
Lucia Martella ◽  
Giovanni Imbriani ◽  
Adele Idolo ◽  
Francesco Bagordo ◽  
...  
Keyword(s):  
Drinking Water ◽  
Case Studies ◽  
Distribution Systems ◽  
Water Systems ◽  
Water Safety ◽  
Quality Of Water ◽  
Safety Plan ◽  
Water Safety Plan ◽  
Drinking Water Systems

Background: The quality of water for human consumption is an objective of fundamental importance for the defense of public health. Since the management of networks involves many problems of control and efficiency of distribution, the Water Safety Plan (WSP) was introduced to address these growing problems. Methods: WSP was applied to three companies in which the water resource assumes central importance: five water kiosks, a third-range vegetable processing company, and a residence and care institution. In drafting the plan, the terms and procedures designed and tested for the management of urban distribution systems were applied to safeguard the resource over time. Results: The case studies demonstrated the reliability of the application of the model even to small drinking-water systems, even though it involved a greater effort in analyzing the incoming water, the local intended use, and the possibilities for managing the containment of the dangers to which it is exposed. This approach demonstrates concrete effectiveness in identifying and mitigating the dangers of altering the quality of water. Conclusions: Thanks to the WSP applied to small drinking-water systems, we can move from management that is focused mainly on verifying the conformity of the finished product to the creation of a global risk assessment and management system that covers the entire water supply chain.

International standards for services activities relating to drinking water supply systems and wastewater systems: Implications for developing countries

2006 ◽  
Vol 53 (6) ◽  
pp. 75-82
Author(s):  
S. Lee ◽  
D. Cha ◽  
H. Park
Keyword(s):  
Developing Countries ◽  
Drinking Water ◽  
Water Systems ◽  
International Standards ◽  
Water Supply Systems ◽  
System Quality ◽  
Wastewater Systems ◽  
Service Standards ◽  
Supply Systems

In developing countries, the PPP (Public–Private–Partnerships) programs have been unsatisfied during the last decade. This study analyzed one of the main causes is low quality of the system. That is, no matter what supports developing countries may get through PPP, reforming water systems can be hardly successful without appropriate system quality. With this background, this study introduces service standards of ISO/TC 224 as an option to improve system quality of developing countries. To analyze its effects, system dynamic modeling was conducted. The results indicated that service standards, working with the PPP programs, can benefit all the stakeholders involved in the water systems in developing countries. Also this indicates further that this approach with service standards deserves more detailed study for improving the ailing water systems in developing countries.

scholarly journals KUALITAS BAKTERIOLOGI AIR MINUM ISI ULANG DITINJAU DARI METODE DISINFEKSI YANG DIGUNAKAN DI KABUPATEN NGAWI

2017 ◽  
Vol 13 (3) ◽  
Author(s):  
Suhadi Prayitno
Keyword(s):  
Drinking Water ◽  
Reverse Osmosis ◽  
Total Coliform ◽  
Water Disinfection ◽  
Cluster Sampling ◽  
Bacteriological Quality ◽  
Consumer Protection Act ◽  
Key Word ◽  
Reduction Percentage

Cases, concerns and complaints in public about refill drinking water,  low businessmen DAMIU are checked routinely product processed as well as the mandate of the Consumer Protection Act, Kepmerindag RI and Permenkes RI on monitoring refill drinking water background for the author to conduct research. Purpose to describe the bacteriological quality of refill drinking water in terms of disinfection method used in District Ngawi. This method is descriptive study and cluster sampling to 49 samples DAMIU in District Ngawi with the results of the method used, namely ultraviolet disinfection, ozonation and reverse  osmosis. The results bacteriological quality (total coliforms) of any disinfection method shows a different picture, which shows the method of disinfection reverse osmosis bacteriological quality with the percentage of 50.00%, followed by ozonation method of 46.15% and the latter by the ultraviolet method percentage value 44.12 %. The ability of any reduction in total coliform disinfection method shows a different picture, in which the reverse osmosis method of disinfection showed total coliform reduction percentage of 94.08%, followed by ozonation method of 91.46% and the latter by the ultraviolet method percentage value 86.09%. The conclusion willingness, support and cooperation of all stakeholders is needed to improve the supervision, guidance and inspection of the quality of refill drinking water in Ngawi. Key word : water, disinfection, coliform

scholarly journals An investigation of tap water quality in Kuantan, Pahang, Malaysia

2020 ◽  
Vol 49 (1) ◽  
pp. 191-196
Author(s):  
HO Salah ◽  
IM Sujaul ◽  
Md Abdul Karim ◽  
MH Mohd Nasir ◽  
A Abdalmnam ◽  
...  
Keyword(s):  
Water Quality ◽  
Tap Water ◽  
Quality Standard ◽  
Total Coliform ◽  
Total Hardness ◽  
Aspergillus Aculeatus ◽  
Purpureocillium Lilacinum ◽  
Aspergillus Sp ◽  
Tap Water Quality

Assessment of the quality of tap water at Kuantan area of Pahang, Malaysia was investigated. The parameters analyzed were total coliform, Escherichia coli, pH, total hardness, sulfate, and selected heavy metal based on drinking water quality standard Malaysia and WHO. The results showed that the fungi in the tap water in Kuantan area in different concentrations were Aspergillus sp., Rhodotorula mucilaginosa, Penicillium citrinum, Cladosporium cladosporioides, Cerrena sp., Aspergillus aculeatus, A. flavus, Cryptococcus sp., Cladosporium perangustum, Purpureocillium lilacinum and Candida catenulata. The residual free chlorine varied from 0.05 to 1.97 mg/l.

scholarly journals Low-Pressure Membrane for Water Treatment Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Huda AlFannakh ◽  
Heba Abdallah ◽  
S. S. Ibrahim ◽  
Basma Souayeh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Drinking Water ◽  
Humic Acid ◽  
Tap Water ◽  
Permeate Flux ◽  
Membrane Performance ◽  
Polyethersulfone Membrane ◽  
Contaminated Drinking Water

Three ultrafiltration membranes were prepared using phase separation techniques. The membranes were characterized by scan electron microscope, porosity, pore size distribution measurement, and mechanical properties. The membrane performance was carried out using synthetic solutions from humic acid and tap water to express the contaminated drinking water. The polyvinylidene difluoride (M2) has the highest tensile strength 33.2 MPa with elongation of 52.3%, while polyacrylonitrile (M3) has the lowest mechanical properties, tensile strength 16.4 MPa with elongation of 42.7%. Polyethersulfone membrane (M1) provides the highest removal of humic acid, which was 99.5, 98.8, and 98.2% using feed concentrations 0.1, 0.3, and 0.5 g/l, respectively, while M3 provides the highest permeate flux which was 250, 234.4, and 201.4 l/m2 h using feed concentrations 0.1, 0.3, and 0.5 g/l, respectively. Analysis of water samples indicates that the prepared membranes can be used to treat the contaminated drinking water which produced the high quality of drinking water after treatment.

Bacterial quality of drinking water sources and antimicrobial resistance profile of Enterobacteriaceae in Bahir Dar city, Ethiopia

2014 ◽  
Vol 4 (3) ◽  
pp. 384-390 ◽  
Author(s):  
Bayeh Abera ◽  
Mulugeta Kibret ◽  
Goraw Goshu ◽  
Mulat Yimer
Keyword(s):  
Drinking Water ◽  
Antimicrobial Resistance ◽  
Water Samples ◽  
Multiple Drug Resistance ◽  
Tap Water ◽  
World Health ◽  
Most Probable Number ◽  
Bahir Dar ◽  
Probable Number

A cross-sectional study was conducted to determine the bacterial quality and antimicrobial susceptibility profiles of Enterobacteriaceae from drinking water in Bahir Dar city. A total of 140 water samples were collected in the wet and dry periods from springs (n = 4), reservoirs (n = 10) and private tap water at households (n = 126). Bacteriological analysis of water was conducted using multiple tube method. Overall, 21.4%, 18.6% and 17.8% of drinking water samples had total coliforms (TC), faecal coliforms (FC) and Escherichia coli, respectively. All spring water samples and 29.2% of private tap water had the highest TC load (18 most probable number/100 mL, 95% CI: 100). For FC, 81.4% of the drinking water supplies tested complied with both World Health Organization and Ethiopian Standards. High levels of resistance (98–100%) were observed for ampicillin by Enterobacteriaceae and Pseudomonas aeruginosa. All P. aeruginosa isolates and 20 (66.7%) of E. coli revealed multiple drug resistance. Enterobacteriaceae and P. aeruginosa isolates exhibited high levels of antimicrobial resistance. The bacterial quality of drinking water in Bahir Dar city was poor. Microbial surveillance and monitoring with periodic assessment on physical integrity of the water pipelines need to be undertaken.

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