In this study the effect of the ozonation procedure on the microbiological and antioxidant status of raspberries stored at room temperature was investigated. During the study, it was found that ozonation with a dose of 8–10 ppm for 30 min, every 12 hours, for 3 days effectively reduced the growth of aerobic mesophilic bacteria and fungi. On the last day of storage, infestation with Botrytis cinerea for control fruit amounted 100%, while for ozonated fruits it was only 12%. In addition, the ozonation process has preserved the high antioxidant potential of the fruits and reduced the loss of polyphenol compounds, including anthocyanin. The applied procedure was proven to be effective, showing the potential of ozone as a factor extending the high commercial and consumer value of fruit stored at room temperature.

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Due to a variety of physicochemical properties of the sewage sludge the selection of proper methods for its stabilization is difficult. In this work, the effect of ozone treatment on physico-chemical and microbiological parameters of sludge was investigated. Ozonation was carried out using a counter-current bed reactor, which ensures optimal mass transfer and the contact time of ozone with excessive sediment. The ozonation process was carried out for 15, 30, 45 and 60 min at an ozone concentration of 90–110 ppm. As a result of the ozone treatment it was possible to reduce the number of colony forming units. Also the potential for dewatering of the sludge improved while the total solids of the sludge did not change. The values of COD and BOD5 increased with time of the process.

Sewage sludge generated in the wastewater treatment process is a waste material and a serious environmental nuisance. Due to its specific properties, the management and final disposal of sewage sludge is a considerable problem also in Poland. Ozonation of sewage sludge is the most commonly used process based on the use of oxidizing agents for stabilization of the waste. This process results in substantial reduction of the sludge volume and simultaneous production of small amounts of toxic by-products. Despite the effectiveness of ozone in sanitation and reduction of sludge amounts and in improvement of many parameters, still little is known about the use of ozonated sewage sludge for agricultural purposes, e.g., fertilization of arable crops. Therefore, the present study was an attempt to evaluate the effect of ozone-stabilized sewage sludge on maize development in initial stages of growth in pot experiment conditions. We analyzed the effect of ozone-stabilized sewage sludge in soil on dry matter yields of aboveground parts of maize. We also conducted physiological measurements of chlorophyll content, fluorescence, and exchange. Additionally, the content of macro- and microelements and toxic heavy metals in aboveground maize biomass was determined. The ozone-stabilized sewage sludge exerted a positive impact on all maize parameters in the initial stage of growth. Compared to the control, plants fertilized with this type of sludge were characterized by a 50% higher yield of aboveground biomass and over 80% higher content of chlorophyll. Furthermore, the content of most macro- and microelements in the aboveground biomass was generally higher in plants fertilized with the ozonated sludge than in plants from the other experimental variants. The chlorophyll fluorescence and gas exchange parameters in plants fertilized with ozonated sludge were improved. No excessive accumulation of Pb and Cd was detected. The present results have confirmed that ozone-stabilized sewage sludge can be used for cultivation of agricultural plants, as it improves utilization of deposited nutrients. The improved bioavailability of nutrients was associated with ozonation-induced initial degradation of organic matter and release of deposited plant nutrients.