Ag and Cu loaded on TiO2/graphite as a catalyst for Escherichia coli-contaminated water disinfection

2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Fitria Rahmawati ◽  
Triana Kusumaningsih ◽  
Anita Hapsari ◽  
Aris Hastuti
Keyword(s):  
Escherichia Coli ◽  
Tio2 Film ◽  
Water Disinfection ◽  
Graphite Substrate ◽  
Ammonium Bromide ◽  
Contaminated Water ◽  
Titanium Hydroxide ◽  
E Coli ◽  
Cetyl Trimethyl Ammonium ◽  
Cbd Method

AbstractTiO2 film was synthesized by means of the chemical bath deposition (CBD) method from TiCl4 as a precursor and surfactant cetyl trimethyl ammonium bromide (CTAB) as a linking and assembling agent of the titanium hydroxide network on a graphite substrate. Ag and Cu were loaded on the TiO2 film by means of electrodeposition at various applied currents. Photoelectrochemical testing on the composite of Ag-TiO2/G and Cu-TiO2/G was used to define the composite for Escherichia coli-contaminated water disinfection. Disinfection efficiency and the rate of disinfection of E. coli-contaminated water with Ag-TiO2/G as a catalyst was higher than that observed for Cu-TiO2/G in all disinfection methods including photocatalysis (PC), electrocatalysis (EC), and photoelectrocatalysis (PEC). The highest rate constant was achieved by the PEC method using Ag-TiO2/G, k was 6.49 × 10−2 CFU mL−1 min−1. Effective disinfection times of 24 h (EDT24) and 48 h (EDT48) were achieved in all methods except the EC method using Cu-TiO2/G.

A Comparison of the Survival in Feces and Water of Escherichia coli O157:H7 Grown under Laboratory Conditions or Obtained from Cattle Feces

2006 ◽  
Vol 69 (1) ◽  
pp. 6-11 ◽  
Author(s):  
L. SCOTT ◽  
P. McGEE ◽  
J. J. SHERIDAN ◽  
B. EARLEY ◽  
N. LEONARD
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogen ◽  
Hemorrhagic Colitis ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Cattle Feces ◽  
Oral Inoculation ◽  
Before And After ◽  
Uremic Syndrome

Escherichia coli O157:H7 is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic uremic syndrome. Cattle feces and fecally contaminated water are important in the transmission of this organism on the farm. In this study, the survival of E. coli O157:H7 in feces and water was compared following passage through the animal digestive tract or preparation in the laboratory. Feces were collected from steers before and after oral inoculation with a marked strain of E. coli O157:H7. Fecal samples collected before cattle inoculation were subsequently inoculated with the marked strain of E. coli O157:H7 prepared in the laboratory. Subsamples were taken from both animal and laboratory-inoculated feces to inoculate 5-liter volumes of water. E. coli O157:H7 in feces survived up to 97 days, and survival was not affected by the method used to prepare the inoculating strain. E. coli O157:H7 survived up to 109 days in water, and the bacteria collected from inoculated cattle were detected up to 10 weeks longer than the laboratory-prepared culture. This study suggests that pathogen survival in low-nutrient conditions may be enhanced by passage through the gastrointestinal tract.

Transfer of Escherichia coli O157:H7 to Romaine Lettuce due to Contact Water from Melting Ice

2008 ◽  
Vol 71 (2) ◽  
pp. 252-256 ◽  
Author(s):  
JIN KYUNG KIM ◽  
MARK A. HARRISON
Keyword(s):  
Escherichia Coli ◽  
Tap Water ◽  
Sampling Site ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
Romaine Lettuce ◽  
E Coli ◽  
Ice Melt ◽  
Leaf Surfaces ◽  
Shipping Containers

Ice can be used to chill romaine lettuce and maintain relative humidity during transportation. Escherichia coli O157:H7 may contaminate water used for ice. The objective of this study was to determine the potential for E. coli O157:H7 contamination of romaine lettuce from either ice contaminated with the pathogen or by transfer from lettuce surfaces via melting ice. In experiment 1, lettuce was spot inoculated with E. coli O157:H7 and chilled with ice prepared from uncontaminated tap water. In experiment 2, water inoculated with this pathogen was frozen and used to ice lettuce. Three heads of lettuce were stacked in each container and stored at 4 or 20°C. After the ice melted, E. coli O157:H7 attachment to and recovery from the lettuce leaves were determined. For experiment 1, the population of E. coli O157:H7 attached to inoculated sites averaged 3.8 and 5.5 CFU/cm2 at 4 and 20°C, respectively. Most of the uninoculated sites became contaminated with the pathogen due to ice melt. For experiment 2, 3.5 to 3.8 log CFU E. coli O157:H7 per cm2 was attached to the top leaf on the first head. After rinsing with chlorinated water (200 μg/ml), E. coli O157:H7 remained on the surface of the top head (1.8 to 2.0 log CFU/cm2). There was no difference in numbers of E. coli O157:H7 recovered from each sampling site at 4 and 20°C. Results show that E. coli O157:H7 can be transferred onto other produce layers in shipping containers from melted ice made of contaminated water and from contaminated to uncontaminated leaf surfaces.

Influence of pyrolytic seeds on ZnO nanorod growth onto rigid substrates for photocatalytic abatement of Escherichia coli in water

2014 ◽  
Vol 14 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Luis Sanchez ◽  
Lucas Guz ◽  
Pilar García ◽  
Silvia Ponce ◽  
Silvia Goyanes ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Zno Nanorods ◽  
Water Disinfection ◽  
Acetate Solution ◽  
Ethanol Mixture ◽  
E Coli ◽  
The Relationship ◽  
Nanorod Growth

ZnO nanorods (ZnO NRs) were grown on ZnO seeded fluorine doped tin oxide (FTO) substrates at low temperatures (90 °C) from Zn2+ precursors in alkaline aqueous solution. The ZnO seeds were deposited on the FTO substrate heated at 350 °C by spray pyrolysis of a zinc acetate solution in a water ethanol mixture. The structure of seeds was tuned by the ethanol water ratio, Γ, which controls the solvent evaporation rate of drops impinging the substrate. The relationship between the microstructure and optical properties of the ZnO NR films and the photocatalytic antibacterial activity for Escherichia coli abatement, was determined through a detailed characterization of the material. The higher photocatalytic antibacterial activity was performed by ZnO NR films grown on seeds deposited from solutions with Γ in the 0.0–0.03 range. With these films, the population of viable E. coli dropped more than six orders, from 8 × 108 to 4 × 102 CFU. These results show the potential of these materials in water disinfection.

scholarly journals Nanotextile membranes for bacteria Escherichia coli capturing

2010 ◽  
Vol 58 (5) ◽  
pp. 239-246
Author(s):  
Jaroslav Lev ◽  
Libor Kalhotka ◽  
Michal Černý
Keyword(s):  
Escherichia Coli ◽  
Experimental Study ◽  
Microbial Contamination ◽  
Model Simulation ◽  
Water Filtration ◽  
Contaminated Water ◽  
Air Filtration ◽  
E Coli ◽  
Before And After ◽  
Input Side

The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP). As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

scholarly journals Photocatalytic Inactivation of Enterobacter cloacae and Escherichia coli Using Titanium Dioxide Supported on Two Substrates

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 137
Author(s):  
Yelitza Aguas ◽  
Margarita Hincapié ◽  
Camilo Sánchez ◽  
Liliana Botero ◽  
Pilar Fernández-Ibañez
Keyword(s):  
Escherichia Coli ◽  
Borosilicate Glass ◽  
Enterobacter Cloacae ◽  
Water Disinfection ◽  
Inactivation Rate ◽  
E Coli ◽  
Bacteria Inactivation ◽  
Glass Tubes ◽  
Bacterial Concentrations ◽  
Total Bacteria

The antibacterial photocatalytic activity of TiO2 supported over two types of substrates, borosilicate glass tubes (TiO2/SiO2-borosilicate glass tubes (BGT)) and low-density polyethylene pellets (TiO2-LDPE pellets), which were placed in a compound parabolic collectors (CPC) reactor, was evaluated against Enterobacter cloacae and Escherichia coli under sunlight. Three solar photocatalytic systems were assessed, suspended TiO2, TiO2/SiO2-BGT and TiO2-LDPE pellets, at three initial bacterial concentrations, 1 × 105; 1 × 103; 1 × 101 CFU/mL of E. coli and total bacteria (E. cloacae and E. coli). The solar photo-inactivation of E. coli was achieved after two hours with 7.2 kJ/L of UV-A, while total bacteria required four hours and 16.5 kJ/L of UV-A. Inactivation order of E. coli was determined, as follows, suspended TiO2/sunlight (50 mg/L) > TiO2-LDPE pellets/sunlight (52 mg/L) > TiO2/SiO2-BGT/sunlight (59 mg/L), the best E. coli. inactivation rate was obtained with TiO2-LDPE pellets/sunlight, within 4.5 kJ/L and 90 min. The highest total bacteria inactivation rate was found for TiO2/sunlight (50 mg/L) and TiO2-LDPE pellets/sunlight (52 mg/L), within 11.2 kJ/L and 180 min. TiO2 deposited over LDPE pellets was the most effective material, which can be successfully used for water disinfection applications. Bacterial regrowth was assessed 24 h after all photocatalytic treatments, none of those microorganisms showed any recovery above the detection limit (2 CFU/mL).

Prevalence of Escherichia coli Associated with a Cabbage Crop Inadvertently Irrigated with Partially Treated Sewage Wastewater

2002 ◽  
Vol 65 (3) ◽  
pp. 471-475 ◽  
Author(s):  
MARIAN R. WACHTEL ◽  
LINDA C. WHITEHAND ◽  
ROBERT E. MANDRELL
Keyword(s):  
Escherichia Coli ◽  
Contaminated Water ◽  
Lettuce Seedling ◽  
E Coli ◽  
Field Crops ◽  
Treated Effluent ◽  
Treated Sewage ◽  
Lower Root ◽  
Seedling Roots ◽  
Many Sources

Preharvest contamination of field crops may have many sources, including feces, soil, and irrigation water. In March 2000, a sewage spill released unchlorinated tertiary-treated effluent into a creek used to irrigate commercial produce. A field of young cabbage transplants was irrigated with creek water as the contaminated water flowed past this land. Cabbage samples were taken from plots within this field, and Escherichia coli was isolated from the roots of these plants but not from the edible portion of the cabbage. No E. coli was isolated from water samples or from control samples taken from a nearby cabbage field watered with chlorinated municipal water. The cabbage field under study had not been fertilized with manure for at least 2 years prior to the contamination incident. Six different E. coli serotypes were identified, although none of them proved to be pathogenic. These serotypes were separated into five groups by a RiboPrinter; the resulting groups correlated well with the serotypes and the locations in the field from which these strains were isolated. We previously found that certain nonpathogenic E. coli strains displayed lower levels of adherence to lettuce seedling roots in a hydroponic adherence assay. The E. coli field strains displayed variable patterns of adherence to lettuce seedlings: strain MW421 showed significantly lower root and shoot adherence levels than did the other field strains, while strains MW423 and MW425 showed significantly higher root and shoot adherence levels. These data suggest that water quality is of paramount importance for the food safety of growing crops.

scholarly journals Preparation of multilayer polyelectrolyte ceramic membrane for water disinfection

2020 ◽  
Vol 20 (8) ◽  
pp. 3207-3215
Author(s):  
Mohamed Boussemghoune ◽  
Chikhi Mustapha ◽  
Yasin Ozay ◽  
Nadir Dizge
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ceramic Membrane ◽  
Ceramic Membranes ◽  
Water Disinfection ◽  
Clay Material ◽  
Test Results ◽  
E Coli ◽  
The Impact ◽  
Scanning Electron

Abstract A multilayer polyelectrolyte ceramic membrane using LbL was assembled to test the performance of water disinfection capability. The natural raw clay material (kaolin) was used as the main ceramic membrane (CM) support. The impact of the number of polyelectrolyte bilayers (2, 4, 6) on the retention of Escherichia coli was systematically investigated. Test results showed the water permeability coefficients (Lp) were 85.3 L/m2.h.bar and 69.5, 28.3, 50.1 L/m2.h.bar for pristine (CM0) and ceramic membranes with two bilayers (CM2), four bilayers (CM4), and six bilayers (CM6), respectively. Complete retention of E. coli was achieved by the multilayer polyelectrolyte ceramic membrane with four bilayers. The surface morphology of the multilayer polyelectrolyte ceramic membrane was identified by scanning electron microscopy (SEM). The results showed that the multilayer polyelectrolyte ceramic membrane can be safely applied in providing water disinfection.

Persistence of Escherichia coli on Injured Iceberg Lettuce in the Field, Overhead Irrigated with Contaminated Water

2009 ◽  
Vol 72 (3) ◽  
pp. 458-464 ◽  
Author(s):  
FIONA BARKER-REID ◽  
DEAN HARAPAS ◽  
SIEGFRIED ENGLEITNER ◽  
SIMONE KREIDL ◽  
ROBERT HOLMES ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Management Practices ◽  
Microbiological Quality ◽  
Contaminated Water ◽  
E Coli ◽  
Log Reduction ◽  
Iceberg Lettuce ◽  
Quality Of Water ◽  
Plant Injury ◽  
The Impact

Fresh produce is increasingly implicated in food-related illnesses. Escherichia coli can survive in soil and water and can be transferred onto plant surfaces through farm management practices such as irrigation. A trial was conducted to evaluate the impact of field conditions on E. coli persistence on iceberg lettuce irrigated with contaminated water, and the impact of plant injury on the persistence of E. coli. Lettuce heads were injured at 14, 7, 3, 2, 1, and 0 days before inoculation, with uninjured heads used as a control. All lettuce heads (including controls) were overhead irrigated with a mixture of nonpathogenic E. coli strains (107 CFU/ml). E. coli counts were measured on the day of inoculation and 5 days after, and E. coli was detected on all lettuce head samples. Injury immediately prior to inoculation and harvest significantly (P = 0.00067) increased persistence of E. coli on lettuce plants. Harsh environmental conditions (warm temperatures, limited rainfall) over 5 days resulted in a 2.2-log reduction in E. coli counts on uninjured lettuce plants, and lettuce plants injured more than 2 days prior to inoculation had similar results. Plants with more recent injuries (up to 2 days prior to inoculation) had significantly (P = 7.6 × 10−6) greater E. coli persistence. Therefore, growers should postpone contaminated water irrigation of lettuce crops with suspected injuries for a minimum of 2 days, or if unavoidable, use the highest microbiological quality of water available, to minimize food safety risks.

Solar photocatalysis: A green technology for E. coli contaminated water disinfection. Effect of concentration and different types of suspended catalyst

2014 ◽  
Vol 276 ◽  
pp. 31-40 ◽  
Author(s):  
Sihem Helali ◽  
Maria Inmaculada Polo-López ◽  
Pilar Fernández-Ibáñez ◽  
Bunsho Ohtani ◽  
Fumiaki Amano ◽  
...  
Keyword(s):  
Green Technology ◽  
Water Disinfection ◽  
Contaminated Water ◽  
Solar Photocatalysis ◽  
E Coli ◽  
Different Types

Decolorization of Azo Dyes by a New Strain CD-2 Isolated from the Textile Dye Contaminated Water

2011 ◽  
Vol 183-185 ◽  
pp. 381-386 ◽  
Author(s):  
Dai Zong Cui ◽  
Min Zhao ◽  
Guo Fang Li ◽  
Xiao Xu Gu ◽  
Guang Ying Hui Du ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Azo Dyes ◽  
Azo Dye ◽  
Dye Removal ◽  
Contaminated Water ◽  
Textile Dye ◽  
Methyl Red ◽  
E Coli ◽  
Eriochrome Black T ◽  
Ph Range

In this study, a new strain was isolated by us based on its efficiency to decolorize azo dyes. Identification of this isolate by 16S rDNA technique revealed that the strain belonged to Escherichia, and clustered within Escherichia coli. According to this, we renamed our strain as E. coli CD-2. The strain CD-2 could decolorize azo dyes effectively under aerobic conditions. CD-2 exhibited good decolorization ability in the pH range from 3 to 11, temperature from 30°C to 42°C and salinity from 1% to 4%. CD-2 could decolorized different azo dyes (methyl red, Congo red, eriochrome black T and eriochrome red B) within 16h, and the decolorizing rate were 97.15%, 86.03%, 56.92% and 81.14%, respectively. This degradation potential increased the applicability of this strain for the azo dye removal.

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