UV disinfection costs FOR INACTIVATING <i>Cryptosporidium</i>

Cotton, Christine; Owen, Douglas; Cline, Gary C.; Brodeur, Timothy P.

doi:10.1002/j.1551-8833.2001.tb09228.x

Cited by 37 publications

(28 citation statements)

References 12 publications

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“…1. A target fluence of 40 mJ/cm 2 was used because it has been proposed as a recommended fluence for water treatment systems (13,38). Considered individually, the silver, given 130 min of contact time, and UV radiation resulted in approximately 0.28-log (47.52%) and 1.87-log (98.65%) inactivation, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Power requirements for UV systems are primarily a function of the desired fluence (the product of irradiance and exposure time). In addition to an increase in operating costs, an increase in fluence can also result in a significant increase in capital costs (13). Microbial inactivation goals, which are a function of a target organism, set the UV design fluence.…”

mentioning

confidence: 99%

“…Microbial inactivation goals, which are a function of a target organism, set the UV design fluence. Design fluences for water treatment can vary between 40 and 140 mJ/cm 2 (13). Fluences as high as 170 mJ/cm 2 have been reported for 4-log (99.99%) inactivation of adenoviruses in tertiary-treated wastewater, which indicates that fluences sufficient for inactivation of coliforms (e.g., ca.…”

mentioning

confidence: 99%

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Use of Aqueous Silver To Enhance Inactivation of Coliphage MS-2 by UV Disinfection

Butkus

Labare

Starke

et al. 2004

Appl Environ Microbiol

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A synergistic effect between silver and UV radiation has been observed that can appreciably enhance the effectiveness of UV radiation for inactivation of viruses. At a fluence of ca. 40 mJ/cm 2 , the synergistic effect between silver and UV was observed at silver concentrations as low as 10 g/liter (P < 0.0615). At the same fluence, an MS-2 inactivation of ca. 3.5 logs (99.97%) was achieved at a silver concentration of 0.1 mg/liter, a significant improvement (P < 0.0001) over the ca. 1.8-log (98.42%) inactivation of MS-2 at ca. 40 mJ/cm 2 in the absence of silver. Modified Chick-Watson kinetics were used to model the synergistic effect of silver and UV radiation. For an MS-2 inactivation of 4 logs (99.99%), the coefficient of dilution (n) was determined to be 0.31, which suggests that changes in fluence have a greater influence on inactivation than does a proportionate change in silver concentration.The bactericidal effects of silver have been known since the mid-1800s (11, 31). Given contact times on the order of hours, silver has been shown to be somewhat effective as a disinfectant against coliforms (9, 11) and viruses (41). In water, at concentrations sufficient for bactericidal activity, silver does not impart taste, color, or odor and has no apparent detrimental effects on mammalian cells (41). The only known negative health effect is argyria, an irreversible darkening of the skin and mucous membranes, which has been caused by prolonged silver therapy (34). Accordingly, there is no United States Environmental Protection Agency (USEPA) primary drinking water standard for silver. Two of the principal drawbacks associated with the use of silver as a disinfectant are the need for long contact times (4, 11) and the existence of silver-resistant organisms (5,15,33). However, use of silver by some European nations (34) suggests that it is considered feasible and economically viable in some cases. Silver is commonly used to prevent microbial growth in point-of-use filters (4, 32, 39); as a codisinfectant for swimming pool water, which allows for lower chlorine levels in pools (3, 41); and as a codisinfectant in hospital hot water systems (22).Unlike silver, UV radiation is widely considered a viable process for disinfecting drinking water and wastewater in largescale treatment systems (40) because it is an effective means of inactivating protozoa such as Cryptosporidium parvum (8,12,28) and Giardia lamblia (14, 24) and it does not create significant disinfection by-products (40). As with any disinfection process, an important consideration associated with UV radiation is cost. Power requirements for UV systems are primarily a function of the desired fluence (the product of irradiance and exposure time). In addition to an increase in operating costs, an increase in fluence can also result in a significant increase in capital costs (13). Microbial inactivation goals, which are a function of a target organism, set the UV design fluence. Design fluences for water treatment can vary between 40 and 140 mJ/cm 2 (13). Flu...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Use of Aqueous Silver To Enhance Inactivation of Coliphage MS-2 by UV Disinfection

Butkus

Labare

Starke

et al. 2004

Appl Environ Microbiol

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“…For the last two decades, photochromic compounds have been intensively studied [2][3][4][5][6][7][8][9][10][11] for many applications such as optical switch [12], optical memory [13], ophthalmic lens and light filters [7]. This manuscript concentrates on the photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphth [2,1-b] [1,4]oxazine] and 1',3'-dihydro-1',3',3'-trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2'-(2H)-indole] also called spirooxazine and spiropyran respectively.…”

Section: Introductionmentioning

confidence: 99%

“…A simple method is to use UV-C germicidal wavelength (λ = 253.7 nm) [5,20] to treat water. This method leads to high annihilation rate of bacteria [21,22], high reliability [6], ease of use and can be done cheaply. These systems inactivate the pathogenic microorganisms that could be responsible of diseases through contamination of water.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Spirooxazine and Spiropyran Hosted in Poly(Methyl Methacrylate) for Germicidal UV Source Indicator Application

Bonefacino¹,

Tse²,

Pun³

et al. 2013

OPJ

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A characterization of photophysical properties of 1, 3-dihydro-1,3,3-compounds hosted in poly(methyl methacrylate) (PMMA) was carried out. The parameters which influenced the photochromic behavior of both compounds were investigated. After ultraviolet (UV) irradiation, it was demonstrated that the temperature was the dominant factor which influenced the deactivation of both materials. For spiropyran, it was demonstrated that the process could be photo-induced with a certain wavelength which we have specified in this manuscript. It was also found that X-Ray did not affect the photo physical properties of spirooxazine and spiropyran. Finally, both materials could be used as low-cost germicidal UV indicators.

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