In-process tests of river water conditioning for domestic and drinking water supply in the city of Kurgan

Рассматривается опыт применения озонирования речной воды в лабораторных и пилотных масштабах. Вода реки Тобол – жесткая минерализованная со средними значениями цветности 24 град, содержанием марганца в зимний период более 0,8 мг/дм3. После определения рабочих доз реагентов (коагулянт гидроксохлорид алюминия, флокулянт Praestol 650TR) проводилось пробное озонирование с последующей реагентной обработкой на лабораторном флокуляторе. Для достижения норматива по содержанию марганца в речной воде 0,1 мг/дм3 потребовались высокие дозы озона – от 35 мг/дм3. Подщелачивание исходной воды до рН 9 позволило снизить дозу озона до 23 мг/дм3. Снижение цветности до 15 град происходит при дозах озона 6–7 мг/дм3. Очистка речной воды на пилотной установке производительностью 50 л/ч проводилась по полной технологической схеме (озонирование, обработка коагулянтом и флокулянтом, отстаивание, фильтрование через песчаный фильтр, фильтрование через угольный фильтр, опреснение-умягчение обратным осмосом). Доза коагулянта составляла 5 мг/дм3, флокулянта – 0,3 мг/дм3. В стационарном режиме работы пилотной установки при дозе озона 25 мг/дм3 были достигнуты следующие показатели качества фильтрата песчаного фильтра: цветность 5–7 град; марганец 0,05–0,15 мг/дм3; железо общее 0,02–0,03 мг/дм3; алюминий 0,05–0,08 мг/дм3; перманганатная окисляемость 3–4 мг/дм3. Исходя из расчетных показателей состава воды р. Тобол, для концентрации марганца в воде 0,8 мг/дм3теоретическая доза озона составляет ≈ 8 мг/дм3, проектная доза озона может быть принята 10 мг/дм3 (г/м3). The experience of using ozonation of river water on a laboratory and pilot scale is considered. The water of the Tobol River is hard and mineralized with an average color value of 24 degrees, a manganese concentration in the winter period of more than 0.8 mg/dm3. After determining the operational doses of the chemicals (polyaluminum chloride coagulant, Praestol 650TR flocculant), test ozonation was carried out followed by the chemical treatment in a laboratory flocculator. To achieve the standard for manganese concentration in river water of 0.1 mg/dm3, high doses of ozone were required – from 35 mg/dm3. Alkalinization of the initial water to pH 9 provided for reducing the ozone dose to 23 mg/dm3. A decrease in color to 15 degrees occurred at ozone doses of 6–7 mg/dm3. River water purification at a pilot plant with a capacity of 50 l/h was carried out according to the complete process flow scheme (ozonation, treatment with coagulant and flocculant, sedimentation, filtration in a sand filter, filtration in a carbon filter, desalination-softening by reverse osmosis). The coagulant dose was 5 mg/dm3, and that of the flocculant – 0.3 mg/dm3. In the steady run of the pilot plant at an ozone dose of 25 mg/dm3, the following quality indicators of the sand filter filtrate were achieved: color 5–7 degrees; manganese 0.05–0.15 mg/dm3; total iron 0.02–0.03 mg/dm3; aluminum 0.05–0.08 mg/dm3; permanganate index 3–4 mg/dm3. Based on the estimate indicators of the Tobol River water composition related to the manganese concentration in water of 0.8 mg/dm3, the theoretic dose of ozone is ≈ 8 mg/dm3, the design dose of ozone can be assumed as 10 mg/dm3 (g/m3).

Comparative Studies of Carbon Materials Synthesized From Waste as Catalysts for Ozonation of Real Textile Wastewater

In the present work, evaluation of two catalysts, Activated carbon (AC) synthesized from agricultural waste and Multiwalled carbon nanotubes (MWCNT) synthesized from plastic waste, were done for the ozonation of real textile wastewater using para- chloro benzoic acid (p-CBA) as a probe compound. The effect of pH and catalyst dose were studied in terms of •OH exposure, Rct, rate of p-CBA degradation and ozone degradation. The rate constant for the reaction of organic matter with hydroxyl radicals was determined using competition kinetics. The threshold ozone dose for real textile wastewater was found to be 0.51 gm/gm of TOC. With an increase in specific ozone dose, the rate of p-CBA degradation was found to be increasing and has shown a positive effect on •OH exposure and Rct. The increasing pH had shown a positive effect on the rate of degradation and decomposition of p-CBA and ozone respectively in the case of AC catalyzed ozonation. A similar trend was observed in the case of MWCNTs catalyzed ozonation. A positive effect of pH was observed on •OH exposure and Rct, in AC as well as MWCNTs catalyzed ozonation. The effect of catalyst loading has shown significant enhancement in p-CBA degradation, ozone decomposition, •OH exposure and Rct in both AC as well as MWCNTs catalyzed ozonation. However, MWCNTs have proved better than AC as a catalyst for ozonation in studied experimental parameters.

Effect of Applied Ozone Dose, Time of Ozonization, and Storage Time on Selected Physicochemical Characteristics of Mushrooms (Agaricus bisporus)

The impact of ozone dose and time of ozonization on the selected physicochemical properties of Agaricus bisporus stored for 14 days in 2 °C was investigated. Mushrooms were subjected to gaseous ozone with increasing concentrations of 0.5, 1.0, and 2.0 mg L−1 and applied two times to ozonization: 30 and 60 min. The following parameters were evaluated: weight loss, internal and external color L*a*b* parameters, overall color change (ΔE), browning index (BI), firmness, total phenolic content (TPC), and total antioxidant activity (TAA). After storage, mushrooms had a higher level of firmness, especially for group ozonized with 2 mg L−1 for 30 or 60 min. Mushrooms from group (1 mg L−1) subjected to ozonization within 30 and 60 min had a high ability to neutralize DPPH-free radical (42.45 ± 0.43 and 41.34 ± 0.29, respectively). Exposure of mushrooms to ozone atmosphere does not cause large changes in quality and physical parameters of Agaricus bisporus.

Ozone inactivation of fungi associated with barley grain

The use of ozone as a fungicide for barley storage was studied. The effects of ozone on the inactivation of natural and inoculated fungi on barley were evaluated at different water activities and temperatures. Results indicated that higher ozone doses were better at inactivating the natural fungi on barley than lower ozone doses. An ozone dose of 0.98mg/g • min was able to reduce the natural fungi counts on the barley at 0.98aw by over 97% after 45 minutes of ozone contact time. The inactivation of the natural fungi and Aspergillus flavus on the barley was favoured by higher temperatures. Ozone consumption of the barley was higher at higher temperatures. Tests on A. flavus spores inoculated on barley indicated that they were resistant to ozone doses up to 4.90mg/g while Penicillium, verrucosum spores showed no resistance to any ozone doses that were tested. Inactivation of A. flavus (vegetative state) and P. verrucosum spores were favoured by higher water activities. The effect of ozone on barley germination was also examined. By 15 minutes of treatment at an ozone dose of 0.98mg/g • min, all the fungi tested were inactivated by over 90%, while germination was only reduced by 6%. Different water activities had no effect on the germination of barley. The findings show that ozone may be applied as a fumigant against fungi attacking high moisture content barley and provide the possibility of using it as an alternative to current chemicals for preserving stored barley.

Ozone inactivation of fungi associated with barley grain

The use of ozone as a fungicide for barley storage was studied. The effects of ozone on the inactivation of natural and inoculated fungi on barley were evaluated at different water activities and temperatures. Results indicated that higher ozone doses were better at inactivating the natural fungi on barley than lower ozone doses. An ozone dose of 0.98mg/g • min was able to reduce the natural fungi counts on the barley at 0.98aw by over 97% after 45 minutes of ozone contact time. The inactivation of the natural fungi and Aspergillus flavus on the barley was favoured by higher temperatures. Ozone consumption of the barley was higher at higher temperatures. Tests on A. flavus spores inoculated on barley indicated that they were resistant to ozone doses up to 4.90mg/g while Penicillium, verrucosum spores showed no resistance to any ozone doses that were tested. Inactivation of A. flavus (vegetative state) and P. verrucosum spores were favoured by higher water activities. The effect of ozone on barley germination was also examined. By 15 minutes of treatment at an ozone dose of 0.98mg/g • min, all the fungi tested were inactivated by over 90%, while germination was only reduced by 6%. Different water activities had no effect on the germination of barley. The findings show that ozone may be applied as a fumigant against fungi attacking high moisture content barley and provide the possibility of using it as an alternative to current chemicals for preserving stored barley.

Combined Iron-Loaded Zeolites and Ozone-Based Process for the Purification of Drinking Water in a Novel Hybrid Reactor: Removal of Faecal Coliforms and Arsenic

This study was carried out to provide a novel solution to treat drinking water at household levels, specifically removing arsenic (As) and faecal coliforms (microbes). In the current investigation, a synergistic iron-loaded zeolites and ozonation process (O3/Fe-ZA) was used for the first time in a modified batch reactor to remove coliform bacteria and arsenic in tap water. Moreover, the study utilizes the human health risk assessment model to confirm the health risk due to As intake in drinking water. The risk assessment study revealed a health risk threat among the residents suffering from the adverse effects of As through its intake in drinking water. Furthermore, the results also suggested that the O3/Fe-ZA process significantly removes faecal coliforms and As, when compared with single ozonation processes. Additionally, the ozone dose 0.2 mg/min and Fe-ZA dose of 10 g (in the O3/Fe-ZA process) gives the maximum removal efficiency of 100% within 15 min for faecal coliform removal. In 30 min, the removal efficiency of 88.4% was achieved at the ozone dose of 0.5 mg/min and 93% removal efficiency was achieved using 10 g Fe-ZA for the removal of As in the O3/Fe-ZA process. Hence, it was concluded that the O3/Fe-ZA process may be regarded as an effective method for removing faecal coliforms and As from drinking water compared to the single ozonation processes.

Microcirculatory effects of systemic metabolic correction with reactive oxygen species: An experimental study

Introduction: The purpose of this study is to estimate microcirculation changes under systemic (intraperitoneal) administration of ozonized saline. Methods: For this study, we formed four equal groups of Wistar male rats (n = 10 per group). Rats of first (control) group was intraperitoneally injected with non-ozonized sterile saline solution (daily administration volume — 1 ml.) during 30 days. Animals of other groups (n = 10 for second, third and fourth groups) received 30 intraperitoneal infusions (1 ml/day) daily with ozonized saline solution (saturating ozone concentration for indicated groups — 3000, 10000 and 40000 mcg/l, ozone dose per procedure — 0.75, 2.5 and 10 mcg, respectively). Technology of the Laser Doppler Flowmetry (LDF) along with ``LAKK-02'' device (Moscow, Russia) was used for complex estimation of skin microcirculation state. This technology allows us to study blood flow intensity in skin microvessels at the first and thirty-first days of the experiment. We also can estimate regulatory mechanisms of microcirculation support and the presence of shunt paths of the microcirculation. Results: We studied the dose-dependent response of microcirculation on ozone infusions in chronic experiments. We found that long-lasting course (30 procedures) of intraperitoneal administration of ozonized sodium chloride solution provides an increase in the level of microcirculation index compared to that of the control (injections of nonozonized saline solution), regardless of the applied dose of ozone. At the same time, the level of the microcirculation response was directly determined by the introduced amount of ozone, and we fixed non-linear dependence on it. Our study allowed us to show that only low doses of ozone (0.75 mcg/day) have proadaptive effects on the microcirculatory bed. This was shown both in the dynamics of the microcirculation index and the state of regulatory mechanisms. Middle ozone dose (2.5 mcg/day) also caused the stimulation of blood flow in small vessels, though this was predominantly through other mechanisms (neurogenic components). The most negative reaction of microcirculation was observed for high ozone dose (8 mcg). Conclusion: Despite the activation of microcirculation observed in this case, we have identified that the mechanism was primarily through the respiratory component regulation and via formation of "steal syndrome" in the tissue.