Testing of Home Use Carbon Filters

Taylor, Raymond H.; Allen, Martin; Geldreich, Edwin E.

doi:10.1002/j.1551-8833.1979.tb04423.x

Cited by 23 publications

(13 citation statements)

References 5 publications

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“…In this regard, 1t 1s noteworthy that the small carbon filters for home use may cause trouble by Increasing the chloroform content 1n the purified water, for the carbon filters are capable of eliminating or substantially reducing levels of free chlorine residuals, thus causing microorganisms to grow vigorously 1n the carbon beds, which In turn make the chloroform content 1n the effluent Increase markedly over that of the influent, I.e., the tapwater, through biodégradation of chlorinated organic substances adsorbed on the carbon surface. This fact also was verified 1n another study (15).…”

Section: Ho'clsupporting

confidence: 58%

A Preliminary Study of the Efficiency And Mechanism of the Removal in the Ozonation and Bac Process

Wang¹,

Yin²,

Jinzhi³

et al. 1984

Ozone: Science & Engineering

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A preliminary study on removing THMs from chlorinated water by ozonation ( " O 3 " process) and granular activated carbon bed filtration and adsorption ("AC" process) was carried out. It was found that the chloroform content In chlorinated water was reduced to some extent by ozonation at low dosages, but then It Increased steeply with time, and finally reached much higher than the original values.The GAC beds In both the "AC" and " O 3 + AC" processes were found to be effective in removing chloroform by adsorption during their early operating period, corresponding to 4,000 -5,000 bed volumes throughput, or one month duration for carbon X-ll and carbon ZJ-15 beds 1n the "AC" process. With preozonation. I.e., the " O 3 + AC" process, the operating period with positive chloroform removal effi ciencies was tripled. Nevertheless, the chloroform content 1n effluents from the GAC bed 1n both processes Increased with operating time and throughput, and finally became much higher than the level In the Influents. The phenomenon presumably was due to three mechanisms occurring 1n the carbon beds: 1) the biodégradation of complex chlori nated compounds Into THMs; 2) the anaerobic digestion products can react with free chlorine 1n water to form THMs; 3) the desorptlon of THMs adsorbed on the carbon surfaces.In order to prevent the treated water from producing high concentrations of THMs, chlorlnatlon should be avoided before either the "AC" or the "Og + AC" process. Home use carbon filters also are recommended to be used carefully and reasonably, for they can Increase THM concen trations 1n effluents to levels much higher than those In the Influents after a certain time of operation.

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Section: Ho'clsupporting

confidence: 58%

A Preliminary Study of the Efficiency And Mechanism of the Removal in the Ozonation and Bac Process

Wang¹,

Yin²,

Jinzhi³

et al. 1984

Ozone: Science & Engineering

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“…The proliferation of bacteria depends upon the concentration of disinfectant in the distribution system, temperature, season, and the amount of organic matter. Bacterial densities in water after passage through activated carbon containing POU-devices can be expected to increase by one or two logs over the number detected in water supplies (Taylor et al 1979). Wallis et al (1974) observed that bacterial densities increased in devices containing activated carbon after an overnight period of non-use.…”

Section: Introductionmentioning

confidence: 98%

Comparison of the microbiologic quality of point-of-use (POU)-treated water and tap water

Cháidez

Gerba

2004

International Journal of Environmental Health Research

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Activated carbon filtration devices placed on household faucets are used to improve the taste and odour of tap water. However, there has been a concern that the growth of bacteria capable of causing opportunistic infections in these devices might present a public health risk. The water quality from point-of-use (POU) water activated carbon treatment devices and that of tap water with POU-connections and tap water without POU devices were compared. Heterotrophic plate count (HPC) bacteria, total and faecal coliforms, and acid-fast organisms (Mycobacteria spp.), as well as, the opportunistic bacterial pathogens Aeromonas hydrophila, Plesiomonas shigelloides, and Pseudomonas aeruginosa were enumerated. The highest concentration of bacteria was found in POU-treated water. P. aeruginosa, acid-fast organisms, and total coliforms were present in 38.5, 43.8, and 82.4% of the samples, respectively. HPC bacteria were present in all of the POU-treated water samples, with concentrations ranging from 10(2) to 10(7) colony forming units/mL. Neither faecal coliforms nor P. shigelloides were recovered from any samples. Tap water with a POU-connection also had higher numbers of bacteria than tap water samples. It was concluded that tap water without POU devices had lower numbers of A. hydrophila, acid-fast organisms, HPC bacteria, P. aeruginosa and coliforms than POU-treated water, and tap water with a POU-connection. The use of POU-devices may amplify the numbers of bacteria present in the tapwater by promoting biofilm formation. Based on a daily ingestion of two liters of POU treated water, A. hydrophila and P. aeruginosa had a probability of less than 10(-6) of colonizing the gut; however, annual risks could be as much as 100-fold greater.

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“…Granular activated carbon has an exceptionally high surface area and hence it is frequently used for silver deposition. However, a literature survey indicates that activated carbon filters are susceptible to colonisation (10)(11)(12)(13)(14) and after a certain period of time, shed bacteria into the water. It has also been observed that silver containing activated carbon filters suppress total coliform but not total bacterial growth (15).…”

Section: Introductionmentioning

confidence: 99%

Microbial evaluation of silver coated/impregnated sand for purification of contaminated water

Mahmood

Naeem

Basit

et al. 1993

Environmental Technology

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Silver coated sand has been used for the disinfection of contaminated water. Highly contaminated water has been passed through 1:1, 1:2 and 1:3 mixtures of silver treated and untreated sands of 10, 35 and 60 mesh sizes and bactericidal efllciency of each mixture has been evaluated. Data in this study suggest that the sand mixtures of 35 mesh remove coliform and faecal coliform more effectively and may be used as a water disinfectant and the silver coated sand may also substitute silver impregnated activated carbon in water treatment equipment.

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Testing of Home Use Carbon Filters

Cited by 23 publications

References 5 publications

A Preliminary Study of the Efficiency And Mechanism of the Removal in the Ozonation and Bac Process

A Preliminary Study of the Efficiency And Mechanism of the Removal in the Ozonation and Bac Process

Comparison of the microbiologic quality of point-of-use (POU)-treated water and tap water

Microbial evaluation of silver coated/impregnated sand for purification of contaminated water

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