Nutrient Solution Prepared with Ozonated Water does not Damage Early Growth of Hydroponically Grown Tomatoes

Ozonated water as a water source for nutrient solution was investigated in hydroponically grown tomatoes. Nutrient solution was prepared by diluting concentrated nutrient solutions with ozonated water with dissolved ozone (DO₃) concentrations of 0 to 10 mg L^?1. Manganese concentration in the nutrient solution decreased with increasing DO₃ concentrations. Initial growth of tomato plants supplied with nutrient solution prepared with ozonated water with a DO₃ concentration of 1.5 mg L^?1 was greater than that with a DO₃ concentration of 0 mg L^?1. These results indicate that ozonated water can be used as a disinfectant for source water in hydroponics during the early growth stage of tomatoes.     

Effect of Different Concentrations of Ozone on in Vitro Plant Pathogens Development,Tomato Yield and Quality,Photosynthetic Activity and Enzymatic Activities

ABSTRACT

As an effective alternative to traditional pesticides, ozonated water has been used for direct immersion and spraying applications, respectively, against the pathogenic bacterium Ralstonia solanacearum (R. solanacearum) and fungus Alternaria solani (A. solani) that are pathogens of tomato. Immersing R. solanacearum in 0.8 mg/L ozonated water resulted in complete inactivation, while the growth-inhibition rates of the A. solani radial mycelia gradually increased with a 67.0% decrease compared to those of the control at an ozonated water concentration of 7.5 mg/L. This indicated that ozonated water was effective at restraining pathogens in the tomato plant. In addition, spraying wild tomato species (Solanum lycopersicum) plants with ozonated water at concentrations below 10 mg/L for 25 d had no negative effects after treatment compared to those of the control. Photosynthetic activities and the antioxidant system response in the untreated and ozonated water-treated plant leaves had no observable changes. To determine the optimal ozonated water concentration for the pathogen and its host plant, we examined a variety of modes of action, and then, below 10 mg/L of ozonated water. Thus, ozonated water not only inhibits the proliferation of plant pathogens, but is an effective alternative to the pesticides traditionally used to prevent disease in agricultural production.     

Ozone Application for Postharvest Disinfection of Tomatoes

Ozone is an effective alternative for the postharvest treatment of fruits and vegetables. The purpose of this study was to evaluate the ozone application in gaseous or aqueous phases for postharvest disinfection of tomatoes (Lycopersicon esculentum Mill) cultivar FA-180. Fruits harvested at the breaker stage were exposed to ozone concentrations of 25 and 45 mg m^?3 for 2 h per day during 16 days, at non-controlled temperature and relative humidity. Exposure to ozone during storage extends the shelf-life of tomatoes, besides preserving its sensory attributes. Mature tomatoes, inoculated with Escherichia coli ATCC 25922, were washed with ozonated water containing 0.5 to 1.0 mg L^?1 during 15 to 30 min. To achieve an adequate disinfection, 1 mg L^?1 and 15 min are recommended. The disinfection with ozonated water was effective.     

Potential of Ozonated Water at Different Temperatures to Improve Safety and Shelf-Life of Fresh Cut Lettuce

The present study was carried out to determine the effect of ozonated water (2 mg L^?1) at different temperatures (4 °C and 15 °C) on the microbiological, color and sensory properties of lettuce. Cold ozone treatment (4 °C) significantly reduced the natural background microflora of lettuce. Salmonella Typhimurium and Escherichia coli inoculated on lettuce samples were insignificantly influenced by the temperature of water. During storage period at +4 °C for 14 days, the highest quality was observed from the samples treated with cold ozonated water. Ozone treatments did not affect the color properties and sensory quality of lettuce samples.     

Effects of Semicontinuous and Batch System Ozonation on Wheat and Corn Starches

Wheat starch-water and corn starch-water suspensions (10%; w/w) were exposed to ozone gas by using two different contact systems; semicontinuous and batch systems. In semicontinuous contact mode, fresh ozone was applied to starch suspensions at a concentration of 4.2 mg dissolved ozone L^?1 water for 30 min, while in closed batch contact mode, starch suspensions were stirred with ozone gas at a rate of 60 g/h for 30 min. Gelatinization temperatures and enthalpies of wheat and corn starch were increased in a semicontinuous system. However, no change was observed for the gelatinization characteristics of starch samples ozonated- in batch system. Structures and birefringences of wheat and corn starch ozonated in both semicontinuous and batch operations were not differentiated clearly. Higher lightness and whiteness values were observed for both wheat and corn starch ozonated in semicontinuous system than the controls and ozonated samples in batch system. Corn starch ozonated in semicontinuous system has lower chroma and yellowness values than the others. Total color difference for the samples ozonated in semicontinuous system is significantly different from the samples ozonated in batch system. Semicontinuous ozonation system is more effective on the thermal and color properties of wheat and corn starches than the batch ozonation system.     

Treatment performance of metal membrane microfiltration and electrodialysis integrated system for wastewater reclamation

The integrated system with microfiltration/electrodialysis was proposed for wastewater reclamation. The filterability of metal membrane, membrane fouling reduction by ozonated water and the effect of operational parameters were experimentally investigated. Backwashing by ozonated water showed stable and effective membrane fouling reduction. The removal ratio of nutrients such as NH₄⁺-N and PO₄³⁻-P concentration was about 96 and 94%, respectively, within 30 min of operation in the system. Proposed system showed good rejections on bacteria, suspended solids as well as ionic nutrients. Suggested wastewater reclamation system showed stable water quality during operational period over 6 months. Therefore, it is expected to be an effective and useful system for the reclamation of wastewater.     

Efficacy of Ozonated Water Against Erwinia carotovora subsp. carotovora in Brassica campestris ssp. chinensis

Erwinia carotovora subsp. carotovora (Ecc) is a bacterial pathogen that causes decay of vegetables and is found in a wide range of Brassica crops in the Shanghai area, particularly in non-heading Chinese cabbage (NHCC). In this study, aqueous ozone was used as an antimicrobial agent to prevent the growth of Ecc bacterial colonies. Ecc that were treated with aqueous ozone were completely inactivated after the bacteria had been exposed to 0.5 mg/L ozone at 28 °C. Furthermore, a susceptible NHCC cultivar was directly sprayed with different concentrations of dissolved ozonated water as a pesticide substitute. The effects of the treatments on morphology were analyzed, and some treatments were characterized by induction of visible symptoms of senescence. No negative effects were observed after treatment by spraying ozonated water compared with the control at concentrations below 8 mg/L. However, visible damage to leaves was observed after the plants were exposed to 10 mg/L ozonated water via spraying for 15 days during the plant reproductive stage. Additionally, enzyme activities and antioxidant responses gradually increased to a certain degree and then decreased in the untreated and ozonated water-treated plants. These results showed that ozonated water was effective in restraining pathogens and potentially defending against disease in growing NHCC plants within a certain concentration range. These results provide a theoretical basis for preventing disease by applying ozonated water to vegetables as an alternative to pesticides.     

Ozone Cleaning of Fouled Poly(Vinylidene) Fluoride/Carbon Nanotube Membranes

This research demonstrates for the first time that ozone is an effective cleaning agent for polyvinylidene fluoride (PVDF) membranes fouled by natural organic matter (NOM). Bare PVDF membranes as well as PVDF impregnated with CNTs (pristine (CNTs–P) and oxidized (CNTs–O)) at 0.3% mass membranes were used. Three different methods were investigated for cleaning the fouled membranes including; A: 10-min cleaning by pure water, B: 5-min water followed by 5-min ozonated water, and C: 10-min fully ozonated water. It was found that the application of fully ozonated water for 10 min was very effective to reinstate the flux to almost its original value of unfouled membrane. The CNTs–P/PVDF membrane exhibited the highest fouling with a total fouling ratio of 81%, while for the bare PVDF and the CNTs–O/PVDF membranes, the fouling ratios were 76% and 74%, respectively. The full ozonated water cleaning method gave the highest removal of fouling leaving the lowest irreversible fouling on the membrane as compared to the other cleaning methods. On the other hand, the highest removal of NOM fouling was obtained for CNTs–O/PVDF membranes indicating that fouling on CNTs–O/PVDF membrane was less bound than the other membranes. Contact angle measurements of the fouled membranes showed that all membranes exhibited increased contact angles due to the NOM deposition but after cleaning, particularly with ozonated water, the membrane contact angles returned to almost their original values. FTIR analysis of the membranes corroborated the results obtained.     

Effects of Ozonated Water Application on the Population Density of Fusarium oxysporum f. sp. lycopersici in Soil Columns

The potential of ozonated water was investigated as an alternative to soil disinfectants in reducing the population densities of Fusarium oxysporum f. sp. lycopersici in artificially infested quartz sand and Kuroboku soil columns. Significant reductions in the population density were observed with dissolved ozone concentrations (DOCs) of 6 and 12 mg L^?1 in infested quartz sand but not in infested Kuroboku soil. The results indicate that repetitive application of ozonated water with higher DOCs should be required for reducing the population density of F. oxysporum in soils with high content of organic substances and large surface area.     

Role of O3 and OH· Radicals in Ozonated Aqueous Solution for the Photoresist Removal of Semiconductor Fabrication

The role of direct oxidation by aqueous O₃ and advanced oxidation by OH^· in the removal of photoresist was studied by chemical kinetic simulation and experiments of O₃ reactivity and decomposition in homogeneous aqueous solutions. O₃ is the main species responsible for the removal of conventional photoresist in the ozonated water cleaning process, and the timing of initiator addition to ozonated water is important to maintain high O₃ concentration. Simulation using t-butanol implies that maintenance of a high OH^· concentration is required to remove highly implanted photoresists that O₃ itself cannot easily remove.     

The Safety and Anti-Tumor Effects of Ozonated Water in Vivo

Ozonated water is easier to handle than ozone gas. However, there have been no previous reports on the biological effects of ozonated water. We conducted a study on the safety of ozonated water and its anti-tumor effects using a tumor-bearing mouse model and normal controls. Local administration of ozonated water (208 mM) was not associated with any detrimental effects in normal tissues. On the other hand, local administration of ozonated water (20.8, 41.6, 104, or 208 mM) directly into the tumor tissue induced necrosis and inhibited proliferation of tumor cells. There was no significant difference in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL)-positive cells following administration of ozonated water. The size of the necrotic areas was dependent on the concentration of ozonated water. These results indicate that ozonated water does not affect normal tissue and damages only the tumor tissue by selectively inducing necrosis. There is a possibility that it exerts through the production of reaction oxygen species (ROS). In addition, the induction of necrosis rather than apoptosis is very useful in tumor immunity. Based on these results, we believe that administration of ozonated water is a safe and potentially simple adjunct or alternative to existing antineoplastic treatments.     

The Use of Ozone in a CIP System in the Wine Industry

This study tested the efficacy of ozone in a CIP system of a wine industry, for that, a hose that transported wine was submitted to the following treatments: ozonated water at 28 ± 1 °C (in concentrations of 0.38 and 1.03 ppm for one, five and nine minutes); hot water (85 ± 1 °C for 15 minutes); peracetic acid (0.3% for 15 minutes); and a caustic soda solution (2%) with peracetic acid (0.3% for 15 minutes). The results indicate that the use of ozonated water is more effective than the isolated use of peracetic acid and the combined use of soda and peracetic acid.     

Effect of Ozonated Water Treatment on Fatty Acid Composition and Some Quality Parameters of Olive Oil

The organic olives from Çine-Ayd?n (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO₂/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K₂₃₂ and K₂₇₀ values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K₂₃₂ value. Ozonated water washes had almost no effect on fatty acid composition.     

Eightfold increased membrane flux of NF 270 by O3 oxidation of natural humic acids without deteriorated permeate quality

BACKGROUND: Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O₃ oxidation. RESULTS: At a specific O₃ dose of 2.11 g O₃ per g COD (17.0 g m^?3 O₃ (g) for 20 min), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 × 10^?9 L s^?1 m^?2 Pa^?1) than the permeability if the untreated solution is filtered (2.4 × 10^?9 L s^?1 m^?2 Pa^?1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H₂O₂ allows a better mineralization degree, i.e. UVA removal increased from 53% to 66% if H₂O₂ was added as from 10 min oxidation at the same molar flow rate as O₃. CONCLUSION: O₃ oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H₂O₂ can slightly improve its decomposition. Copyright © 2010 Society of Chemical Industry     

Promotion of Adventitious Roots in Chrysanthemum Cuttings by Soaking in Ozonated Water

To examine the effect of soaking in ozonated water (OW) on development of adventitious roots, basal ends of chrysanthemum cuttings (Chrysanthemum morifolium Ramat.) were soaked in 1, 3 or 5 mg L^?1 OW, in an indol-3-butyric acid (IBA) solution prepared from a commercial root promoting agent or in distilled water (DW). At 20 day after transplanting (DAT), a significant increase in adventitious root number (ARN) was observed in the IBA-treated cuttings but early root elongation was delayed. When soaked in the 5 mg L^?1 OW, ARN and total root length (TRL) grown over 40 mm were increased with a decrease in soaking duration (from 50 to 5 min). Lateral root number (LRN) of the cuttings soaked in the 3 mg L^?1 OW for 1 h showed four times higher than that of the DW treatment at 19 DAT. Optimal combination of dissolved ozone concentration and soaking duration can promote early root elongation and LRN of chrysanthemum cuttings. From a comprehensive standpoint, a high DOC of OW with a short soaking duration (3 mg L^?1 × 1 h and 5 mg L^?1 × 5 min) worked as well as IBA for adventitious rooting of chrysanthemum cuttings. These findings indicate that ozonated water can be an alternative to root promotion agents for adventitious rooting of chrysanthemum cuttings.     

An On-Site Cooling Tower Treated by Stand-Alone Low-Concentration Dissolved Ozone

We report on an on-site 500 RT cooling tower ozone treatment process, in which chemicals other than ozone itself were completely eliminated. Ozone in an amount leading to less than 0.1 ppm of dissolved ozone was continuously introduced via side-stream injection into the circulating water returning from the chiller. The ozonated water was initially made to flow from the distributor to the filler in order to eliminate the growth of algae, and then to the chiller to reduce the corrosion and the fouling in the water. Positive ions such as Ca⁺² and Mg⁺² in the circulating water were precipitated by chelating them with carboxylic acids formed by the oxidation of organic compounds. We observed that using an ozone dosage of 0.1 ppm resulted in a colony-forming unit (CFU) less than 2 × 10³ /mL. With that well-controlled CFU, corrosion controlling and scale reducing were achieved as well.     

Wastewater Disinfection : Elimination of Fecal Bacteria and Eneric Viruses By Ozone

Wastewater containing indigenous bacteria and enteric viruses was ozonated in a contact column with counter-current circulation of ozonated air and water. The mean slope of the inactivation curve for indigenous viruses is about half that observed for E. coli and fecal streptococci. For 3 rag osub3;/l, in the presence of residual ozone and a contact time of 19 min, inactivation of 1 log for the viral population and 2 logs for the fecal bacteria are observed. A negative correlation exists between inactivation and organic content.     

The Efficacy of Ozone/BAC Treatment on Non-Steroidal Anti-Inflammatory Drug Removal from Drinking Water and Surface Water

Three non-steroidal anti-inflammatory drugs (NSAIDs)—ketoprofen, naproxen and piroxicam—in both deionized (DI) water and surface lake water (SW) (Tallahassee, FL), were exposed to varying ozone treatment regimes or H₂O₂/O₃ advanced oxidation on the laboratory bench. Recently used biofilm-supporting granular activated carbon (BAC) was sampled from a municipal drinking water treatment facility (Tampa, FL, USA), and employed to determine the bio-availability of chemical intermediates formed in ozonated water. Advanced chemical analysis was used to identify oxidation by-products formed and combined with a bioanalytical tool to assess non-specific toxicity (Microtox assay). All 3 target pharmaceuticals were efficiently removed by different processes, with a lower NSAIDs removal yield observed in lake water compared to DI water experiments. The removal yields of ketoprofen, naproxen, and piroxicam improved with increasing ozone dose, H₂O₂/O₃ ratio and empty bed contact time (EBCT) with BAC. Ozonation with BAC filtration had a positive impact by reducing the initial ozone dose required to achieve > 90% removal of all 3 pharmaceuticals (when an initial ozone dose < 1 mg L^-1 was combined with EBCT < 15 min). The toxicity evolution of the treated samples was monitored by Microtox bioassay. Ozone doses higher than 2 mg L^-1 for 2 min contact time were optimal to reach the lower water samples toxicity with NSAIDs removal yields ranging from 95.5 to 99.0% in DI water and from 77 to 90% in SW. Also, higher ozone doses were not shown to remove the residual toxicity. In contrast, the BAC filtration hardly decreases the sample toxicity when an EBCT of 15 min was chosen despite a NSAIDs removal yield equal or higher than 90% in SW.     

Effects of Spraying Ozonated Water on the Severity of Powdery Mildew Infection on Cucumber Leaves

Effects of spraying ozonated water on the severity of powdery mildew infection, visible disorder/injury occurrence, and net photosynthesis in cucumbers were investigated. The severity in the ozonated water treatment was contained to almost the same level throughout the 14-day period of the experiment, while the severity steadily increased in the non-treated control and distilled water treatment. Neither visible disorder/injury on the leaves nor a large difference in net photosynthesis between before and after spraying the ozonated water was observed. The results indicate that ozonated water can be at least a partial alternative to agricultural chemical fungicides for powdery mildew on cucumber leaves.     

Electron-induced cutting of single-walled carbon nanotubes

Electron beam irradiation with moderate fluences of approximately 10¹⁶-10¹⁷ electrons per cm² is used for controllable, bulk-scale cutting of single-walled carbon nanotubes (SWCNTs). The effectiveness of high energy electron irradiation in cutting SWCNTs is dependent on the nature of the sidewall. While pristine nanotubes are very stable under irradiation conditions, ozonated SWCNTs combined with a moderate fluence of electrons resulted in bulk-scale cutting of nanotubes. The length distribution of the cut SWCNTs could be controlled by adjusting the irradiation fluence. The average length of the cut nanotubes was 65 nm with 85% of the nanotubes shorter than 100 nm.