Photoreactivation of enterohemorrhagic Escherichia coli following UV disinfection

Tosa, Koji; Hirata, Tsuyoshi

doi:10.1016/s0043-1354(98)00226-7

Cited by 71 publications

(58 citation statements)

References 6 publications

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“…These results agreed with previous reports where 90% -99% of E. coli inactivation was reached using 5.4 and 8.1 mJ/cm 2 , respectively to avoid photoreactivation [16]. Other authors have reported UV doses as high as 35 mJ/cm 2 , for complete fecal coliforms inactivation, in the presence of high TSS concentrations (up to 40 mg/L) in wastewater [17].…”

Section: Uv Disinfection Assessmentssupporting

confidence: 92%

“…On the other hand, it has been reported that permeability of the outer membrane, which is the main shelter of the cell against oxidant species, increases at alkaline pH values [16]. It could be expected that at pH 9.0 the cells turned more sensitive than at pH 7.0.…”

Section: Ozone Disinfection and Organic Matter Oxidationmentioning

confidence: 96%

“…Completely different results were found at acid or alkaline values. Under acidic conditions, due to changes in H + ions permeability at lower pH (pH = 5), bacterial cells should adjust the influx or efflux of H + with the change of pH value from 7 to 5 to maintain the homeostasis of the cell [16]. It is known that, when a sudden change of pH from neutral to acidic environment occurs, E. coli induces the synthesis of cyclopropane fatty acids (CFAs).…”

Section: Uv Disinfection Assessmentsmentioning

confidence: 99%

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Disinfection of Primary Municipal Wastewater Effluents Using Continuous UV and Ozone Treatment

Bustos¹,

Vaca²,

López³

et al. 2014

JWARP

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UV radiation and ozonation were investigated as disinfection alternatives for the wastewater treatment plant. The inactivation of total and fecal coliforms using ozone and ultraviolet radiation as separate treatments was evaluated. Different ozone concentrations (3 to 40 mg O 3 /L) were applied and UV fluencies ranging from 8.5 to 12 mJ/cm 2 at different pH values (from 5 to 9) were tested. Best results were obtained for ozone doses near 20 mg/min with removals of 72% and 78% of fecal and total coliforms, respectively. The ozone also was capable of oxidizing organic matter in the effluent measured as COD (the highest removal obtained was 36% for 20 mg O 3 /min). Maximum bacterial resistance was observed at pH 7 in both cases. The UV light offered a high bacterial inactivation (over 80%) and the lowest bacterial inactivation was observed at pH 7. Finally, we obtained the electric energy per order (E EO , kWh/m 3 /order), defined as the electric energy (kW-h) required to degrade a contaminant by one order of magnitude in a unit volume of contaminated water, being noteworthy that E EO values for the UV process resulted were lower than those determined for the process with ozone in all the water flow tested.

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Section: Uv Disinfection Assessmentssupporting

confidence: 92%

Section: Ozone Disinfection and Organic Matter Oxidationmentioning

confidence: 96%

Section: Uv Disinfection Assessmentsmentioning

confidence: 99%

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Disinfection of Primary Municipal Wastewater Effluents Using Continuous UV and Ozone Treatment

Bustos¹,

Vaca²,

López³

et al. 2014

JWARP

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“…UV (ultraviolet) irradiation has become one of the most important alternatives to chlorination for disinfection throughout the world. 3 The ability of UV radiation to disinfect water has been known since the beginning of the twentieth century however, due to problems related to the technology and unreliability of the equipment, this process was abandoned for some time. Once these problems were solved, the treatment of water with UV radiation gained popularity, mainly in European countries.…”

Section: Introductionmentioning

confidence: 99%

Inactivation of Escherichia coli in water by TiO2-assisted disinfection using solar light

Rodrigues¹,

Ziolli²,

Guimarães³

2007

J. Braz. Chem. Soc.

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Estudou-se a desinfecção de águas de abastecimento por fotocatálise heterogênea usando um reator de fluxo em um sistema composto por uma placa de vidro com TiO 2 P 25 (Degussa) imobilizado e luz solar como fonte de radiação. Foram utilizados dois modos de operação do reator: passagem única e recirculação. Os experimentos foram conduzidos utilizando inicialmente uma água preparada em laboratório e posteriormente água coletada em poços e lagos de uma região próxima à Campinas, SP. Estudou-se a influência de fatores, tais como, o modo de operação do reator, a cor e turbidez da água, os quais influenciam significativamente na eficiência fotocatalítica de descontaminação e, portanto, na viabilidade da aplicação do processo. Em dias ensolarados, alcançou-se uma redução na carga bacteriológica de cerca de 100% do valor inicial de Escherichia coli (2 × 10 3 NMP per 100 mL) para soluções de água sintética, e, 80% do valor inicial de Escherichia coli (16.6 to 22.2 × 10 3 MPN per 100 mL) para água in natura, através da fotocatálise heterogênea usando TiO 2 .TiO 2 -assisted heterogeneous photocatalysis and photolysis were evaluated for the disinfection of water samples using a glass reactor with immobilized TiO 2 (catalyst), solar light and E. coli as an indicator microorganism of the efficiency of disinfection. Parameters such as color and turbidity of the water, level of coliform bacteria (by the Colilert ® method), inclination angle of the solar reactor, solar light intensity, flow rate and retention time were controlled during the experiments. Two different operational modes were used for the solar reactor: single pass mode and recirculation mode. First, synthetic water was used in the disinfection tests as a model system; second, tests were conducted using natural samples specifically groundwater collected from a lake and a well. In bacterial suspensions in synthetic water in the absence of color and turbidity, heterogeneous photocatalysis was responsible for the reduction of approximately 100% of the initial concentration of E. coli. Only a 56.5% reduction was obtained by photolysis during the same solution recirculation time, which indicated a better efficiency using the catalyst. From the natural samples, total inactivation was not achieved in the studied cases. However, photocatalysis using TiO 2 /solar light was shown to be quantitatively efficient in the destruction of the total coliforms in water, reaching values up to around 80% inactivation in natural waters with initial levels of total coliforms ranging from 16.6 to 22.2×10 3 MPN per 100 mL.

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“…To date, no studies have investigated DNA repair in E. coli O157:H7 following MP UV and only limited conflicting studies have evaluated repair following LP UV exposure in water (Tosa & Hirata 1999;Sommer et al 2000;Mofidi et al 2002). Recent studies performed using non-pathogenic E. coli have indicated differences in the repair following low doses of MP and LP UV irradiation (Oguma et al 2002;Zimmer & Slawson 2002).…”

Section: Introductionmentioning

confidence: 99%

A comparison of DNA repair and survival of Escherichia coli O157:H7 following exposure to both low- and medium-pressure UV irradiation

Zimmer-Thomas

Slawson

Huck

2007

Journal of Water and Health

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DNA repair and survival of pathogenic E. coli O157:H7 was investigated following exposure to ultraviolet (UV) radiation from both low-pressure (LP) and medium-pressure (MP) lamps. This study included irradiation at UV doses used in drinking water treatment and lower doses indicative of potential treatment problems. Immediately following UV exposure, an average log inactivation of 4.5 or greater was observed following all tested doses of LP (5,

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Photoreactivation of enterohemorrhagic Escherichia coli following UV disinfection

Cited by 71 publications

References 6 publications

Disinfection of Primary Municipal Wastewater Effluents Using Continuous UV and Ozone Treatment

Disinfection of Primary Municipal Wastewater Effluents Using Continuous UV and Ozone Treatment

Inactivation of Escherichia coli in water by TiO2-assisted disinfection using solar light

A comparison of DNA repair and survival of Escherichia coli O157:H7 following exposure to both low- and medium-pressure UV irradiation

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