Ozone/oxygen mixed gas with different bubble diameters is supplied to ion-exchanged water or fulvic acid aqueous solution, and the effects of bubble diameter on initial ozone dissolution and reaction rates are quantified. As a result, it was clarified that both rates of the initial dissolution and reaction of ozone represent －0.5 order relative to the bubble diameter.
A flotation test was conducted for a culture fluid of marine diatoms, Chaetoceros gracilis, using a Venturi tube. Triacylglycerol in the foam increased as a result of flotation of cells using microbubbles without any coagulant and pH adjustment. It was found that an increase in air flow rate promoted the flotation of cells.
The objective of this study was to investigate the influence of calcium ions（Ca2＋）on the fouling propensity of a thin-film composite reverse osmosis（RO）membrane by alginate. Under the experimental conditions investigated in this study, an increase in Ca2＋ of up to 0.2 mmol/L accelerated the fouling of the RO membrane. However, the fouling propensity was not influenced by concentrations of Ca2＋ above 0.2 mmol/L. This result could be explained by the content of Ca2＋ in the fouling layer, which increased when the concentration of Ca2＋ in the feed water was 0.25 mmol/L or less and reached a plateau above 0.25 mmol/L.