Hiroaki I. Ogawa

Harbin Institute of Technology, Harbin, Heilongjiang Sheng, China

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Publications (2)1.44 Total impact

  • Weimin Xie, Qunhui Wang, Hongzhi Ma, Hiroaki Ogawa
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    ABSTRACT: The development and manufacture of an adsorbent to remove phosphate for the prevention of eutrophication in lakes is very important. The use of aluminium oxide (alumina) as an organic adsorbent to remove phosphate from wastewater has been investigated. The characteristics of this absorption process were investigated to determine the important parameters, such as the pH and the aluminium ion concentration. Moreover, chemical treatment methods to enhance the adsorption capacity of alumina were tested. Dynamic studies and equilibrium adsorption isotherm studies were conducted to determine the adsorption capacity and efficiency. The experimental results indicate that it is necessary to increase the temperature above 500°C in order to obtain a high-capacity adsorbent, and alumina treated with acid or calcium or magnesium has a larger adsorption capacity for phosphate than untreated adsorbent. Moreover, the adsorption of phosphate was enhanced at a lower pH and a higher aluminium ion concentration, and a simple Freundlich isotherm could express the equilibrium adsorption isotherm, and the intragranular diffusion controlling model was used to test the dynamic studies. These findings have important implications for the application and development of aluminium oxide as a prospective adsorbent.
    International Journal of Environment and Pollution 01/2005; 23(4). · 0.30 Impact Factor
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    ABSTRACT: An experiment of anaerobic filtration using a floating media was carried out in this study. In the present system, a bench-scale column of 50 mm in diameter and of 1500 mm in height and a floating media consisting of S-shaped polystyrene pieces were employed. The purpose of this study was to collect the basic data of anaerobic biological filtration using a floating media. Under the laboratory conditions, it was found that the start-up of an anaerobic biological filter took about half month at 20 degrees C and a lower BOD loading was favorable for this start-up. The BOD removal efficiency over 60% could be achieved at a BOD volumetric loading of the filter bed under 6 kg/m3/d. An effluent BOD concentration became high when the flow rate was high, especially with circulation of treated water, which afforded a large effect on an effluent BOD concentration. As for the mechanism of BOD removal by anaerobic filtration, it was evident that long retention time worked in favor for organic acid generation, and the circulation of treated water promoted decomposition of organic acids.
    Journal of Environmental Science and Health Part A 02/2004; 39(1):77-87. · 1.14 Impact Factor