The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Imca Sampers - One of the best experts on this subject based on the ideXlab platform.

  • Chlorine dioxide as water disinfectant during fresh-cut iceberg lettuce washing: Disinfectant demand, Disinfection Efficiency, and chlorite formation
    LWT, 2017
    Co-Authors: S. Van Haute, I. Tryland, C. Escudero, M. Vanneste, Imca Sampers
    Abstract:

    The use of chlorine dioxide (ClO2) as water disinfectant during fresh-cut iceberg lettuce washing was studied concerning three key issues: i) disinfectant demand, ii) Disinfection Efficiency, and iii) production of chlorite (ClO2−). Standardized process water (SPW), a watery suspension of iceberg lettuce, was used as model water system. In SPW (chemical oxygen demand (COD) 1130 mg O2/L, 4 °C, pH 7) the chlorine demand was more than 10 times higher than the ClO2 demand. Dosing 5 mg/L ClO2 (0.40 mg/L residual after 2 min contact time) inactivated the total psychrotrophic plate count (TPC), including molds, to undetectable levels (>3 log reduction) after 2 min, and reduced Escherichia coli (E. coli) to undetectable levels (>5 log reduction) within 3 min. A dose of 70 mg/L chlorine (free chlorine residual of 1.7 mg/L after 2 min) was unsuccessful to inactivate molds to undetectable levels. About 77% of the consumed ClO2 was reduced to ClO2− due to reaction with the SPW. Concerning disinfectant dose, ClO2 is more efficient than free chlorine for disinfecting fresh-cut lettuce wash water. However, data on the transfer of ClO2− and chlorate (ClO3−) to the lettuce is needed before ClO2 can be recommended as wash water disinfectant.

  • methodology for modeling the Disinfection Efficiency of fresh cut leafy vegetables wash water applied on peracetic acid combined with lactic acid
    International Journal of Food Microbiology, 2015
    Co-Authors: S Van Haute, Vicente M Gomezlopez, Ana Allende, Francisco Lopezgalvez, Markus Eriksson, Frank Devlieghere, Imca Sampers
    Abstract:

    Abstract A methodology to i) assess the feasibility of water Disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant Efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA + LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6 log CFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA + LA. The Disinfection Efficiency of PAA + LA increased with decreasing pH. Furthermore, PAA + LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA + LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine.

  • wash water Disinfection of a full scale leafy vegetables washing process with hydrogen peroxide and the use of a commercial metal ion mixture to improve Disinfection Efficiency
    Food Control, 2015
    Co-Authors: S. Van Haute, I. Tryland, A Veys, Imca Sampers
    Abstract:

    Abstract Hydrogen peroxide (H 2 O 2 ) was used to maintain the microbial wash water quality of a full-scale leafy vegetables (radicchio, sugar loaf, curled endive, lollo, lollo rosso) wash water process. Despite addition of 300 L/h of 1.8% H 2 O 2 to a 450 L washing bath (333 ± 50 kg/h fresh-cut produce introduction speed), the H 2 O 2 quickly decreased and a lower wash water contamination of aerobic psychrotrophic plate count (APC) and enterococci than without addition of H 2 O 2 could not be maintained. There was no significant difference between the APC on fresh-cut leafy vegetables washed with H 2 O 2 and those washed with water. In a second part, lab-scale experiments were performed to assess the impact of a commercial metal ion formulation (Bacsan ® , containing a. o. Cu 2+ , Zn 2+ , Ag + ) on the stability of H 2 O 2 in artificial wash water, made from iceberg lettuce and tap water. Bacsan improved the stability of H 2 O 2 in artificial lettuce wash water and fresh-cut leafy vegetables wash water from a processing company and synergistically increased the Disinfection Efficiency of APC and Escherichia coli ( E. coli ) compared to H 2 O 2 or Bacsan. Increasing chemical oxygen demand (COD) had detrimental effect on the H 2 O 2 stability and Disinfection Efficiency. Addition of Ag + to Bacsan further synergistically enhanced the H 2 O 2 stability. H 2 O 2 is not suited as an in situ wash water disinfectant to avoid cross-contamination in fresh-cut leafy vegetables washing processes due to the slow water Disinfection kinetics and the rapid H 2 O 2 consumption. However, H 2 O 2 /Bacsan shows potential for use in off-line processes.

Byeongkyu Lee - One of the best experts on this subject based on the ideXlab platform.

  • cu doped tio2 gf for photocatalytic Disinfection of escherichia coli in bioaerosols under visible light irradiation application and mechanism
    Applied Surface Science, 2014
    Co-Authors: Thanhdong Pham, Byeongkyu Lee
    Abstract:

    Abstract This study investigated the role of Cu as a doping agent to enhance photocatalytic activity of TiO2 in Cu-doped TiO2/glass fibers (Cu-TiO2/GF) used for Disinfection of Escherichia coli (E. coli) in aerosols under visible light irradiation. Glass fiber was used as a substrate to immobilize TiO2 for Disinfection of E. coli in bioaerosols. Cu in the prepared photocatalyst acted as an intermediate agent for the transfer of photo-generated electrons from the valence band to the conduction band of TiO2. Cu dopants increased the electron-hole pair separation Efficiency, inhibited their recombination leading to a lifetime increase of the generated electrons, and thus improved photocatalytic activity even under visible light irradiation. Cu also defected the TiO2 lattice by producing Ti3+ ions, which can increase the electron-hole separation capacity of the photocatalyst, thereby increasing photocatalytic capacity. The optimal Cu content in Cu/TiO2 to enhance the photocatalytic activity of TiO2 was 5 wt.%. Among three humidity conditions (dry (40 ± 5%), moderate (60 ± 5%) and humid (80 ± 5%)), the moderate condition showed the highest Disinfection Efficiency of E. coli. When the 5% Cu-TiO2/GF was used under a moderate level of humidity, the highest Disinfection Efficiency and Disinfection capacity of E. coli were identified as 87.8% and 23 CFU/s cm2, respectively.

Eckhard Worch - One of the best experts on this subject based on the ideXlab platform.

  • vacuum uv radiation at 185 nm in water treatment a review
    Water Research, 2014
    Co-Authors: Kristin Zoschke, Hilmar Bornick, Eckhard Worch
    Abstract:

    The vacuum-UV radiation of water results in the in situ generation of hydroxyl radicals. Low-pressure mercury vapor lamps which emit at 185 nm are potential sources of VUV radiation. The scope of this article is to give an overview of the application of VUV radiation at 185 nm for water treatment including the transformation of inorganic and organic water constituents, and the Disinfection Efficiency. Another focus is on the generation of ozone by VUV radiation from oxygen or air and the application of the produced ozone in combination with VUV irradiation of water in the VUV/O3 process. The advantages and limitation of the VUV process at 185 nm as well as possible applications in water treatment are outlined.

Sven Liers - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of ultrasound technology for the Disinfection of process water and the prevention of biofilm formation in a pilot plant
    Water Science and Technology, 2010
    Co-Authors: N. Lambert, Ann Hulsmans, Y. De Laedt, Hans Rediers, Koen Joris, Priscilla Declerck, Sven Liers
    Abstract:

    In this study, we investigated the use of ultrasound for the Disinfection of process water as an alternative for more traditional techniques, like chlorination and UV-irradiation. A pilot plant was constructed to mimic circulating process water in industrial environments. The Disinfection Efficiency of ultrasound was assessed and compared to UV-treatment and chlorination. In addition, the operational costs for the different technologies were evaluated. Based on Disinfection Efficiency and operational costs, the pilot plant experiments indicate that chlorination is the method of preference to treat bacteria in suspension. In the prevention of biofilm formation, the results of UV irradiation and ultrasound are comparable, with a slightly higher energy consumption for the ultrasonic treatment. Finally, the use of ultrasound to prevent biofilms was also evaluated in an industrial environment (case study). The results obtained from the case study are in agreement with the results obtained from the pilot plant study. To our knowledge, this is the first study that evaluates the use of ultrasound technology for prevention of biofilm formation in realistic circumstances as encountered in an industrial environment.

  • Evaluation of process parameters of ultrasonic treatment of bacterial suspensions in a pilot scale water Disinfection system
    Ultrasonics - Sonochemistry, 2009
    Co-Authors: Ann Hulsmans, Yasmine Delaedt, Frans Ollevier, Hans Rediers, Nico Lambert, Koen Joris, Priscilla Declerck, Sven Liers
    Abstract:

    a b s t r a c t In this study, several process parameters that may contribute to the Efficiency of ultrasound Disinfection are examined on a pilot scale water Disinfection system that mimics realistic circumstances as encoun-tered in an industrial environment. The main parameters of sonication are: (i) power; (ii) duration of treatment; (iii) volume of the treated sample. The specific energy (E s) is an indicator of the intensity of the ultrasound treatment because it incorporates the transferred power, the duration of sonication and the treated volume. In this study, the importance of this parameter for the Disinfection Efficiency was assessed through changes in volume of treated water, water flow rate and electrical power of the ultra-sonic reactor. In addition, the influences of the initial bacterial concentration on the Disinfection effi-ciency were examined. The Disinfection Efficiency of the ultrasonic technique was scored on a homogenous and on a mixed bacterial culture suspended in water with two different types of ultrasonic reactors (Telsonic and Bandelin). This study demonstrates that specific energy, treatment time of water with ultrasound and number of passages through the ultrasonic reactor are crucial influential parameters of ultrasonic Disinfection of contaminated water in a pilot scale water Disinfection system. The promising results obtained in this study on a pilot scale water Disinfection system indicate the possible application of ultrasound technology to reduce bacterial contamination in recirculating process water to an accept-able low level. However, the energy demand of the ultrasound equipment is rather high and therefore it may be advantageous to apply ultrasound in combination with another treatment.

Sihui Zhan - One of the best experts on this subject based on the ideXlab platform.

  • efficient water Disinfection with ag2wo4 doped mesoporous g c3n4 under visible light
    Journal of Hazardous Materials, 2017
    Co-Authors: Pengfei Wang, Qianlei Hou, Jingjing Han, Sihui Zhan
    Abstract:

    Ag2WO4/g-C3N4 composite photocatalyst was synthesized by polymerization of thiourea and ammonia chloride combined with the deposition-precipitation method, which was applied as an efficient visible-light driven photocatalyst for inactivating Escherichia coli (E. coli). The physicochemical properties of these photocatalysts were systematically characterized by various techniques such as SEM, TEM, XRD, FT-IR, BET, UV-vis DRS and PL. The synthesized photocatalysts exhibited outstandingly enhanced photocatalytic Disinfection Efficiency compared with that of pure g-C3N4 and Ag2WO4 under visible light. Furthermore, the optimal mass ratio of the Ag2WO4 to g-C3N4 was 5wt%, and a number of live bacteria could be completely inactivated with Ag2WO4(5%)/g-C3N4 (100μg/mL) after 90min under visible light irradiation. The high Disinfection Efficiency is due to the synergetic effect between g-C3N4 and Ag2WO4, including a good distribution of Ag2WO4 particles on the surface of g-C3N4 and an improved separation rate of photogenerated electron-hole pairs. The enhanced Disinfection mechanism was also investigated using photogenerated current densities and electrochemical impedance spectroscopy (EIS). Considering the bulk availability and excellent Disinfection activity of Ag2WO4/g-C3N4 composite, it is a promising solar-driven photocatalyst for cleaning the microbial contaminated water.