Abstract:-Systematic ozonation tests were conducted by means of a mobile pilot plant. Water source 1 was a low turbidity stream with very low solids content and very low turbidity, apparent color and alkalinity. Water source 2 was reservoir water with higher turbidity, solids content and alkalinity than source 1. The ozone plant was a counter-current contactor composed of four columns in series. Variations in contact time, in the feed gas concentration (in terms of percent by weight of ozone) and in splitting of the to… Show more
“…A Spectroquant ® Ozone Test kit 100607 (Merck, Darmstadt, Germany) was used to confirm the concentrations determined by the standardized method. Considering the previous data on the stability of O 3 in ultrapure water, which was previously considered the best type of water for increased O 3 stability [26,32], changes were applied in its physicochemical parameters. Samples of ultrapure water with these different physicochemical characteristics are displayed in Table S1, and the changes are related to the temperature and pH.…”
Section: Standardization and Quantification Of O 3 In Water Using The Spectrophotometric Methodsmentioning
confidence: 99%
“…The air is bubbled directly into the water through an air outlet. After this ozonation process, it is necessary to perform the quantification and determination of the dissolved O 3 concentration [25][26][27].…”
Section: Introductionmentioning
confidence: 99%
“…O 3 dissolved in water (or ozonized water) can be defined as water obtained after an O 3 infusion by the ozonation process. During this process, the only chemical reactions that can occur are those between O 3 and inorganic matter, organic matter, or biological materials that are available, emphasizing that there is no reaction with the pure water itself [25,26]. Some parameters of evaluation and maintenance of the stability of ozonized water are important for this process of production and use, such as the pH and temperature, these being among other important factors for the half-life of the gas dissolved in water [26,28].…”
O3 dissolved in water (or ozonized water) has been considered a potent antimicrobial agent, and this study aimed to test this through microbiological and in vitro assays. The stability of O3 was accessed following modifications of the physicochemical parameters of water, such as the temperature and pH, with or without buffering. Three concentrations of O3 (0.4, 0.6, and 0.8 ppm) dissolved in water were tested against different microorganisms, and an analysis of the cytotoxic effects was also conducted using the human ear fibroblast cell line (Hfib). Under the physicochemical conditions of 4 °C and pH 5, O3 remained the most stable and concentrated compared to pH 7 and water at 25 °C. Exposure to ozonized water resulted in high mortality rates for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans. Scanning electron micrograph images indicate that the effects on osmotic stability due to cell wall lysis might be one of the killing mechanisms of ozonized water. The biocidal agent was biocompatible and presented no cytotoxic effect against Hfib cells. Therefore, due to its cytocompatibility and biocidal action, ozonized water can be considered a viable alternative for microbial control, being possible, for example, its use in disinfection processes.
“…A Spectroquant ® Ozone Test kit 100607 (Merck, Darmstadt, Germany) was used to confirm the concentrations determined by the standardized method. Considering the previous data on the stability of O 3 in ultrapure water, which was previously considered the best type of water for increased O 3 stability [26,32], changes were applied in its physicochemical parameters. Samples of ultrapure water with these different physicochemical characteristics are displayed in Table S1, and the changes are related to the temperature and pH.…”
Section: Standardization and Quantification Of O 3 In Water Using The Spectrophotometric Methodsmentioning
confidence: 99%
“…The air is bubbled directly into the water through an air outlet. After this ozonation process, it is necessary to perform the quantification and determination of the dissolved O 3 concentration [25][26][27].…”
Section: Introductionmentioning
confidence: 99%
“…O 3 dissolved in water (or ozonized water) can be defined as water obtained after an O 3 infusion by the ozonation process. During this process, the only chemical reactions that can occur are those between O 3 and inorganic matter, organic matter, or biological materials that are available, emphasizing that there is no reaction with the pure water itself [25,26]. Some parameters of evaluation and maintenance of the stability of ozonized water are important for this process of production and use, such as the pH and temperature, these being among other important factors for the half-life of the gas dissolved in water [26,28].…”
O3 dissolved in water (or ozonized water) has been considered a potent antimicrobial agent, and this study aimed to test this through microbiological and in vitro assays. The stability of O3 was accessed following modifications of the physicochemical parameters of water, such as the temperature and pH, with or without buffering. Three concentrations of O3 (0.4, 0.6, and 0.8 ppm) dissolved in water were tested against different microorganisms, and an analysis of the cytotoxic effects was also conducted using the human ear fibroblast cell line (Hfib). Under the physicochemical conditions of 4 °C and pH 5, O3 remained the most stable and concentrated compared to pH 7 and water at 25 °C. Exposure to ozonized water resulted in high mortality rates for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans. Scanning electron micrograph images indicate that the effects on osmotic stability due to cell wall lysis might be one of the killing mechanisms of ozonized water. The biocidal agent was biocompatible and presented no cytotoxic effect against Hfib cells. Therefore, due to its cytocompatibility and biocidal action, ozonized water can be considered a viable alternative for microbial control, being possible, for example, its use in disinfection processes.
“…Summerfelt & Hochheimer ; Summerfelt et al . ; Lage Filho ). Briefly, the highly reactive nature of ozone means that it decomposes to free radicals and other ozone‐derived chemical species, leaving ‘residual’ dissolved ozone.…”
Section: Factors That Influence Direct Ozonation In Aquaculturementioning
confidence: 97%
“…The rate of ozone decay increases with time after deployment, whilst higher flow rates (differing hydraulic retention time) or low initial dosages and high water pH may reduce ozone concentration (previously reviewed by Lage Filho ; Gonçalves & Gagnon ; Rahmadi & Kim ). Sharrer and Summerfelt () also suggested that bacteria embedded within particulate matter, or that formed bacterial aggregates, provided shielding from oxidation.…”
Section: Factors That Influence Direct Ozonation In Aquaculturementioning
Ozone (O3) is a powerful oxidant that has been used in both the aquaculture and water treatment industries to improve water quality and reduce pathogens during pretreatment, treatment of effluent, as a continual treatment during RAS operations, and for bivalve depuration. As ozone can be toxic to aquatic organisms, the technology has also been investigated to destroy invasive or nuisance species, and other research has also highlighted negative effects of residual ozone on water courses. Ozone and ozone‐produced oxidants used in aquaculture operations have therefore typically been removed from water prior to entry into tanks holding stock animals. However, a growing body of research has identified direct application of ozone, here defined as exposure of residual ozone and ozone‐produced oxidants to cultured species of finfish, shellfish and live feeds across various life stages. This approach appears to be increasingly employed as a beneficial technology due to proven enhancement of hygiene and water quality, provided dosages or concentrations are appropriate to maintain animal health and welfare. This review paper concentrates on the observed benefits and drawbacks of direct ozonation, influencing factors and future considerations for standardisation and uptake of the technology.
Landfill leachate is well known as a hazardous byproduct from dumpling sites that has a negative impact on the environment and human life. Therefore, an effective treatment is imperative to overcome this issue. This research study investigates the effectiveness of zirconium tetrachloride (ZrCl4) and tin tetrachloride (SnCl4) as a coagulant in leachate treatment. Two parameters selected as a performance indicator in this study are color and chemical oxygen demand (COD). The data obtained showed that SnCl4 performed well as a coagulant with removal percentages of color and COD, which are 97% and 77%, respectively. Furthermore, the potential of integrated treatment using ozonation (O3) and the coagulation‐flocculation process was also investigated. Four sequences of integrated treatment setup for this study were ozonation followed by jar test (ZrCl4 as a coagulant), ozonation followed by jar test (SnCl4 as a coagulant), jar test (ZrCl4 as a coagulant) followed by the ozonation process, and jar test (SnCl4 as a coagulant) followed by the ozonation process. The experimental data showed that the combination treatment of SnCl4 as a coagulant (jar test) followed by the ozonation process had recorded the highest removal of color (97.1%) and COD (88%) compared to other sequences. Moreover, the biodegradability ratio of this sequence also improved from 0.03 to 0.28, compared with other methods. Comparatively, integrated treatment is more effective in treating stabilized landfill leachate compared to the coagulation flocculation process alone.
Practitioner Points
Stabilized landfill leachate is difficult to be treated by natural coagulants or biological process.
SnCl4 performed well as a coagulant in removing COD and colour from landfill leachate compared to ZrCl4.
However, too much usage of SnCl4 potentially generate secondary pollutant. Therefore, combination with O3 as pre‐treatment is investigated.
Combination treatment of SnCl4 ( as coagulant) with O3 had recorded the highest removal of colour (97.1%) and COD (88%).
The biodegradability ratio of this sequence also improved from 0.03 to 0.28.
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