Tag Archives: point-of-use (POU)

Arsenic Removal by Table Top Water Pitcher Filters

Barnaby R, Liefeld A, Jackson BP, Hampton TH, Stanton, BA. Effectiveness of table top water pitcher filters to remove arsenic from drinking water. Environmental research. 2017 Jul 15;158:610-615. doi: 10.1016/j.envres.2017.07.018.

Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As3+ and As5+, from 1000μg/L to < 3μg/L, well below the MCL. Moreover, the amount of total dissolved solids or competing ions did not affect the ability of the ZeroWater® filter to remove arsenic below the MCL. Thus, the ZeroWater® pitcher filter is a cost effective and short-term solution to remove arsenic from drinking water and its use reduces plastic waste associated with bottled water.

Point of Use Filters for Waterborne Pathogen Removal

Totaro M, Valentini P, Casini B, Miccoli M, Costa AL, Baggiani A. Experimental comparison of point-of-use filters for drinking water ultrafiltration. J Hosp Infect. 2016 Dec 1. pii: S0195-6701(16)30543-6. doi: 10.1016/j.jhin.2016.11.017.

BACKGROUND: Waterborne pathogens such as Pseudomonas spp. and Legionella spp. may persist in hospital water networks despite chemical disinfection. Point-of-use filtration represents a physical control measure that can be applied in high-risk areas to contain the exposure to such pathogens. New technologies have enabled an extension of filters’ lifetimes and have made available faucet hollow-fibre filters for water ultrafiltration.

AIM: To compare point-of-use filters applied to cold water within their period of validity.

METHODS: Faucet hollow-fibre filters (filter A), shower hollow-fibre filters (filter B) and faucet membrane filters (filter C) were contaminated in two different sets of tests with standard bacterial strains (Pseudomonas aeruginosa DSM 939 and Brevundimonas diminuta ATCC 19146) and installed at points-of-use. Every day, from each faucet, 100 L of water was flushed. Before and after flushing, 250 mL of water was collected and analysed for microbiology.

FINDINGS: There was a high capacity of microbial retention from filter C; filter B released only low Brevundimonas spp. counts; filter A showed poor retention of both micro-organisms.

CONCLUSION: Hollow-fibre filters did not show good micro-organism retention. All point-of-use filters require an appropriate maintenance of structural parameters to ensure their efficiency.

Did Point-of-Use Chlorination Increase During a Cholera Epidemic?

McLennan, J.D. Original Research: Did point-of-use drinking water strategies for children change in the Dominican Republic during a cholera epidemic?  Public Health Nov 2015

Objective: Point-of-use (POU) strategies to improve drinking water, particularly chlorination, are promoted within cholera epidemics when centrally delivered safe drinking water is lacking. Most studies examining POU practices during cholera epidemics have relied on single cross-sectional studies which are limited for assessing behavioural changes. This study examined POU practices in a community over time during a cholera outbreak. 

Study design: Secondary data analysis of existing dataset. 

Methods: During attendance at well-baby clinics serving a low-income peri-urban community in the Dominican Republic, mothers had been routinely asked, using a structured questionnaire, about POU strategies used for drinking water for their children. Frequency distribution of reported practices was determined over a 21 month period during the cholera outbreak on the island of Hispaniola.

Results: An estimated 27.8% of children were reported to have had some exposure to untreated tap water. Unsustained reductions in exposure to untreated tap water were noted early in the epidemic. POU chlorination was infrequent and showed no significant or sustained increases over the study time period.

Conclusion: High reliance on bottled water, consistent with national household patterns prior to the cholera outbreak, may have reduced the perceived need for POU chlorination. Examination of the safety of relying on bottled water during cholera outbreaks is needed. Additionally, further inquiries are needed to understand variation in POU practices both during and beyond cholera outbreaks.

Chlorine addition to household drinking water was infrequent in the study community. No sustained water improvement practices were detected during a cholera outbreak. Extensive pre-existing bottled water use may have contributed to the lack of change.

Comparison of 4-Point of Use Water Filters

Pérez-Vidal A, Diaz-Gómez J, Castellanos-Rozo J, Usaquen-Perilla OL. Long-term evaluation of the performance of four point-of-use water filters. Water Research. 2016 Apr 12;98:176-182. doi: 10.1016/j.watres.2016.04.016.

Despite technological advances water supply quality and poor access to safe water remain a major problem in developing countries, especially in rural areas. Point-of-use (POU) water treatment has been shown to be a viable option to produce safe drinking water quality. The aim of this study was to evaluate, under laboratory conditions over 14 months, the performance of four household filtration systems: membrane filter (MF), one-candle ceramic filter (1CCF), two-candle ceramic filter (2CCF) and pot ceramic filter (PCF). The evaluation was made using spiked water having the required concentrations of turbidity, Escherichiacoli and Total Dissolved Solids (TDS). The results show that all systems have high removal efficiencies for turbidity (98-99%), and E. coli 4-5 Log Reduction Value (LRV). The poorest efficiency was for TDS (9-18%). The MF and the CCF displayed no significant difference in efficiencies for these parameters. The PCF had less significant differences for turbidity removal than the other systems. The average filtration rate for all systems decreased during the operation time. The CPF showed the major potential to be used in rural communities mainly for its low operational level and maintenance requirements as well as its local craftsmanship. It was observed that the efficiency of the systems is highly sensitive to cleaning and maintenance activities and therefore, the system sustainability will depend considerably on the training and education of the potential users.

POU Reverse Osmosis Units Require Careful, On-Going Maintenance

Sacchetti R, De Luca G, Guberti E, Zanetti F. Quality of Drinking Water Treated at Point of Use in Residential Healthcare Facilities for the Elderly. International Journal of Environmental Research and Public Health. 2015 Sep 9;12(9):11163-77. doi: 10.3390/ijerph120911163.

Municipal tap water is increasingly treated at the point of use (POU) to improve the acceptability and palatability of its taste. The aim of this study was to assess the bacteriologic and nutritional characteristics of tap water treated at the point of use in residential healthcare facilities for the elderly. Two types of POU devices were used: microfiltered water dispensers (MWDs) and reverse-osmosis water dispensers (ROWDs). All samples of water entering the devices and leaving them were tested for the bacteriological parameters set by Italian regulations for drinking water and for opportunistic pathogens associated with various infections in healthcare settings; in addition, the degree of mineralization of the water was assessed. The results revealed widespread bacterial contamination in the POU treatment devices, particularly from potentially pathogenic species. As expected, the use of ROWDs led to a decrease in the saline content of the water. In conclusion, the use of POU treatment in healthcare facilities for the elderly can be considered advisable only if the devices are constantly and carefully maintained.

Coliphage as Human-Virus Surrogates

Gerba CP, Abd-Elmaksoud S, Newick H, El-Esnawy NA, Barakat A, Ghanem H. Assessment of Coliphage Surrogates for Testing Drinking Water Treatment Devices. Food and Environmental Virology. 2014 Nov 16.

Test protocols have been developed by the United States Environmental Protection Agency (USEPA) and the World Health Organization (WHO) to test water treatment devices/systems that are used at the individual and home levels to ensure the removal of waterborne viruses. The goal of this study was to assess if coliphage surrogates could be used in this testing in place of the currently required use of animal or human enteric viruses. Five different coliphages (MS-2, PRD1, ΦX-174, Qβ, and fr) were compared to the removal of poliovirus type 1 (LSc-2ab) by eight different water treatment devices/systems using a general case and a challenge case (high organic load, dissolved solids, and turbidity) test water as defined by the USEPA. The performance of the units was rated as a pass/fail based on a 4 log removal/inactivation of the viruses. In all cases, a failure or a pass of the units/system for poliovirus also corresponded to a pass/fail by all of the coliphages. In summary, in using pass/fail criteria as recommended under USEPA guidelines for testing water treatment device/systems, the use of coliphages should be considered as an alternative to reduce cost and time of testing such devices/systems.

Click here for paper (fee).

Water treatment scam in United Arab Emirates (UAE)

In Dubai, a scam was uncovered where dodgy firms go door to door using scare tactics and fraudulent methods to sell overpriced water filters and purification systems……using electrolysis to foul the water…..click here.